|Table of Contents|
Table of Contents
List of Tables
List of Figures
Chapter 1. Introduction
Chapter 2. The geographic context of adaptive viticulture
Chapter 3. Adaptive hybridization in Florida: Origins and diffusion
Chapter 4. Adaptive pruning in Venezuela: Evolution of a paradigm
Chapter 5. Toward adaptive synthesis: Puerto Rico
Chapter 6. Conclusion
ADAPTIVE VITICULTURE IN THE CARIBBEAN BASIN
A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY
UNIVERSITY OF FLORIDA
I would like to express my appreciation to those who contributed in
some way to make this dissertation a reality.
Foremost is Dr. Cesar Caviedes, whose enlightened understanding made
the project possible, whose enviable breadth of expertise contributed
decisively to it, and whose skilled guidance saw it through. I am
similarly obliged to Dr. Jerald Milanich, whose early recognition and
continuing confidence bolstered my determination through difficult times.
I am especially grateful to Lee Newsom for her solidarity, and
selfless contribution of grape seed measurements which will help lend
credibility to the "Sauer grape theory."
Chapter 2 would not have been possible without the generous
assistance of Dr. John McGrew, perhaps the most knowledgeable American
authority on viticultural history. Dr. McGrew provided access to little-
known documentary sources and contributed useful comments on the first
draft. Others who read early drafts of chapter 2, offering encouragement
and constructive comments, were Dr. Harm de Blij, Editor of National
Geographic Research, and Dr. Max Rives of the Consultative Group on
International Agricultural Research. Dr. Rives work was a major source
of inspiration and documentation.
Chapter 3 was reviewed by Dr. David Rogers, taxonomical authority
on native Florida grapes, and Dr. John Mortensen, viticultural geneticist
of the Leesburg, Florida, Agricultural Research and Education Center.
Their comments and suggestions are much appreciated.
Much of the information for Chapter 4 was obtained through the
cooperation of the "Instituto de la Uva" (Lara), and the "Centro de
Viticultura Tropical" (Zulia). Special thanks are due Pastor Petit,
Guillermo Vargas, Damaso Bautista, Eliezer Tortolero, Francisco Araujo and
Pedro Corzo, among others.
Chapter 5 was brought to a happy conclusion due in good measure to
the timely assistance of Dr. Amador Belardo and Dr. Angel Cruz-Baez of the
University of Puerto Rico.
My sincere appreciation is extended also to Ms. Desired Robinett,
who conscientiously processed the manuscript through the final finishing
At last, I would like to thank Dr. Thomas Matthews, who got me to
follow the course of Ponce de Leon, and to Dr. Gordon Lewis, both former
directors of the Institute of Caribbean Studies of the University of
Puerto Rico. Dr. Lewis was unfailing in his endorsement of this project.
Finally, without the support of my parents at critical junctures
this dissertation would not have come to fruition.
TABLE OF CONTENTS
ACKNOWLEDGEMENTS . . . . . . . . . . .
LIST OF TABLES . . . . . . . . . . .
LIST OF FIGURES ........ ......................
ABSTRACT . . . . . . . . . . . . .
1 INTRODUCTION . . . . . . . . .
Notes ........ .....................
2 THE GEOGRAPHIC CONTEXT OF ADAPTIVE VITICULTURE
State of Knowledge . . . . . . .
Adaptation in Grapes . . . . . .
Adaptation in Viticulture ... ............
Adaptive Insolation Optimization ....
Adaptive Pruning . . . . . .
Adaptive Hybridization .........
Notes ........ .....................
* . viii
* . ix
3 ADAPTIVE HYBRIDIZATION IN FLORIDA:
ORIGINS AND DIFFUSION ..........
The Florida Mission Grapes ...
An Archaeological Clue ......
A Search for "El Dorado" .....
Notes ..... ................
4 ADAPTIVE PRUNING IN VENEZUELA:
EVOLUTION OF A PARADIGM ........
The Beginning ... ............
The Pruning Calendar .......
The Creole Hybrids ........
Notes ..... ................
. . . 30
. . . . . 64
. . . . . 67
. . . . . 90
. . . . . 96
5 TOWARD ADAPTIVE SYNTHESIS: PUERTO RICO ....... ... 98
A History of Trials ..... ................. ....100
Adaptive Grape Breeding .... ............... ....128
A Viticultural Prospectus .... .............. ... 143
Notes ........ ........................ ...151
6 CONCLUSION .......... ..................... 156
Notes ........ ........................ ...161
REFERENCES ......... ........................... ....163
BIOGRAPHICAL SKETCH ....... ....................... ....184
LIST OF TABLES
Table I Hontoon Grape Seeds, Summary of Comparative
Measurements ...... .................... .... 43
Table 2 Simpson's Grape (Fla. 399) Seeds, Summary
of Comparative Measurements ...... ............ 44
Table 3 Fennell's Grape Seeds, Summary of Comparative
Measurements ...... .................... .... 45
Table 4 Vineyard Area in Venezuela, by State,
1969 and 1975 ...... .................... .... 61
Table 5 Evaluation of Fertility Differences in Grape
Cultivars, by Semester (Merida, Venezuela:
latitude 830'N) ...... .................. ... 80
Table 6 Critical Maxima, Monthly Rainfall: El Tocuyo
(Lara), Venezuela, 1978-1988 ...... ............ 89
Table 7 Puerto Rico: Mean Maximum and Minimum
Temperatures and Range, Selected Periods
and Stations ....... .................... .... 119
Table 8 Enological Characteristics of Valplatinta ... ...... 143
Table 9 Puerto Rico: Mean Monthly Rainfall,
Selected Stations ...... .................. ....145
LIST OF FIGURES
Figure I Transit of daylength at selected
northern latitudes . . . . . . .
Figure 2 Hontoon Grape seed (vitis x hontunensis)
Figure 3 Semiarid areas of western Venezuela, and
approximate extent of April-June and
September-November tolda (6/8ths cloud cover)
Figure 4 Mean monthly rainfall in El Tocuyo, Lara,
Venezuela ...... ..................
Figure 5 An impressionistic comparison of rainfall and
number of days with tolda (7/8ths cloud cover)
by month in Maracaibo, Zulia, Venezuela . .
Figure 6 Puerto Rico: proposed viticultural regions .
Figure 7 Aibonito: Mean monthly rainfall ......
Figure 8 Isabela: Mean monthly rainfall ..........
Juana Diaz (Fortuna): Mean monthly rainfall
Vieques Island: Mean monthly rainfall . .
Diurnal build up of tolda (cloud cover) in
western Puerto Rico, and approximate relation
to daylength . . . . . . . .
. . 63
. . 88
. . 91
. . 106
. . 146
. . 146
. . 147
. . 147
. . 149
Abstract of Dissertation Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy
ADAPTIVE VITICULTURE IN THE CARIBBEAN BASIN
Chairman: Cesdr Caviedes
Major Department: Geography
This dissertation consists of three inter-related case studies on
the origins and evolution of viticultural adaptation in the Caribbean
tropics and Florida. Although the Old World grapevine (Vitis vinifera L.)
is not a tropical plant, European immigrants have intuitively practiced
adaptive insolation optimization for viticulture in the tropics by seeking
out semiarid areas that are relatively free of cloud cover.
Another adaptive technique, hybridization with native American
forms, began in early Spanish Florida and has evolved into a modern
scientific approach which, nonetheless, has been slow to diffuse to the
tropics. One more important technique, adaptive pruning, seeks to
coordinate grapevine phenology with seasonal changes in weather. It has
become a quasi-paradigmatic approach in Venezuela, but attempts to
transfer the technology elsewhere have been disappointing.
In Puerto Rico both hybrids from Florida and Venezuelan pruning were
uncritically introduced with confusing results. Independently, a more
promising mode of adoption and synthesis of the alternative techniques is
beginning to emerge. Throughout the three case studies--Florida,
Venezuela, and Puerto Rico--it is argued and demonstrated that a
geographical variable, effective daylenth, underlies all of the
traditional empirical techniques of adaptive viticulture, a fact that has
escaped recognition by local and international viticultural research and
Even the best of our agricultural textbooks are right and
valid only for a given set of circumstances; that they fail to make
this explicit, and so convey an air of general validity, is a most
How does the soil-yield change with latitude, assuming that
soil is everywhere of the same quality, with the same humus content?
(J. H. von Thunen, 1826/1966: pp. 277-278)
In the Caribbean basin there is need for higher income agri-
industrial crops such as grapes, which do well under permanent minimal
tillage cultivation even on degraded hilly terrain (Olmo, 1979). Grape
growing could provide supplementary income for many families that subsist
in marginal rural situations and depend on irregular low-wage jobs in
urban-centered economies (Lewis and Thiele, 1979).
Traditional adaptational practices in viticulture have been
repeatedly introduced to European settlements of the Caribbean basin along
with Old World grapevines (Vitis vinifera L.). Geo-environmental
latitudinal differences, that will be explained in due course, have
favored the development of alternative approaches to viticultural
adaptation, namely, adaptive hybridization in Florida and adaptive pruning
in Venezuela. The search for locations that optimize exposure to sunlight
(insolation) has been, perhaps, the most universal practice in the search
for optimal locations. The empirical adaptive'techniques evolving in
different areas have not been previously analyzed as a coherent system
much less interpreted in terms of a unifying geographic concept that lends
simplicity to a wider understanding of viticultural adaptation in the
A better understanding of the geographical imperatives that underlie
traditional viticultural technology should go far toward enhancing its
effectiveness. Traditional practices and imported innovations must be
studied and applied collaterally, since as one cultural geographer has put
Traditional techniques have deep roots in the aboriginal and
colonial past. Some of the approaches . have been or could be
applied to modern systems. And in Latin America today many, if not
most, farmers make use of both modern and traditional techniques.
(Denevan, 1980: p. 177)
However, folk technology is much too often underestimated by local
agricultural research and extension agencies, which similarly tend to
disregard the perspectives that "outside" disciplines, such as geography,
can offer to the discussion of cultural adaptation.
Although American cultural geographers from Sauer (1969, 1971) to
de Blij (1981) have written extensively on regional viticultural
traditions, none have undertaken the complex task of evaluating imported
viticultural technology in its adaptation to New World geo-environmental
conditions. There are, nonetheless, relevant antecedents in Kollmorgen's
(1943) model of crop-technology complex diffusion from institutional,
corporate and political "culture islands," and Lewis' (1979) correlation
of introduced grape cultigens and immigrant provenance in 19th century
Kollmorgen addresses pertinently the problem of the
institutionalization in Florida (and other Gulf areas) of maladaptive
agricultural technology developed for northern American and European
geographic conditions. A similar concern has occasionally been expressed
with reference to the tropics (Barringer, 1965; Janzen, 1973; Blaut,
A research problem emerges because in viticulture, as in agriculture
generally, cultivational practices are circumscribed geographically by
their very nature. A cultural success, on the other hand, has a tendency
to spread far beyond its area of origin, the locus of its original
adaptation. This means that adaptive processes, bio-genetical and
cultural, must continuously begin anew as a crop is introduced to new
The issue that arises is twofold. Cultivated plants must undergo
phylogenetic adaptation, an evolutionary process that takes time, though
not necessarily a very long time. More difficult, perhaps, is the
institutional tendency to enshrine traditional practices and artifacts
(including plants) that buttress cultural continuity. Does scientific
training contribute to adaptive change? Not necessarily, this
researcher's experience concurs with that of other observers. Modern
agricultural science is often strongly paradigmatic, parochial, and
politicized (Janzen, 1973; Busch and Lacy, 1983; Smith, 1990). Its
assumptions, procedures, objectives, achievements and limitations reflect
the biases of structural vested interests and traditions as much as any
other activity or institution.
Agricultural experiment stations in the tropics are no exceptions.
As Janzen pointed out:
Nearly all research in tropical agriculture is highly reductionist,
parochial and discipline oriented.
the plea for technological advance gives the scientific
community a perfect excuse to continue their reductionist and
esoteric approaches. (Janzen, 1973: p. 1212)
Local grassroots development of appropriate techniques obtained through
empirical trial and error may counterbalance a "reductionist" scientism,
whether or not this is a veil for self-serving chauvinism (Blaut, 1977).
For as one anthropologist has geographically observed:
Humans are unlike other animals in that they alone project
culture, in the form of conventional understandings, onto the
physical surroundings and then act on and interact with the cognized
environment. (Marquardt, 1985).
Thus, it has been suggested that scientifically sound practices are
empirically selected in cultural evolution (1), despite initial rejection
or lack of recognition by institutional superstructures that resist
deviations from paradigmatic (i.e., "internationally accepted") standards
This dissertation is a broadly-based case study of viticultural
evolution in the Caribbean realm, considered from an "anthropogeographic"
perspective. It pursues a qualitative understanding of the complex
relationship between natural phylogenetic evolution in a crop plant, the
grapevine, and the development of its manipulation for human cultural
purposes under diverse tropical ecological conditions. The geographically
variable physical background in which the interaction takes place implies
that the dynamics of the relationship are adaptive (in specific geo-
environmental locations) and diffusionary (to different geographic
locations). Therefore, in the following chapters adaptation and diffusion
in viticultural geography will be explored in a manner which differs from
the descriptive "geography of viticulture" expounded by de Blij (1981) in
its quest for geographically specific adaptive transformation of
viticultural techniques, and of evolution in grapes as "living artifacts"
of culture (Sauer, 1969).
Actually, C. 0. Sauer insisted that the evolution of crop plants be
studied as the conjunction of both physical geographical environment and
of cultivational traditions. He was also, apparently, the first to
propose a likely continuity of specific grape cultigens from prehistory
to the present, and to suggest that the study of aboriginal grapes might
provide an exemplar of fruit crop evolution for southeastern North
Sauer's passing attention to grapes must be understood in the much
broader context of his interest in the New World's agricultural origins.
He seems to have discerned, before anyone else, that the cultural
evolution of perennial crops requiring long term fixed location would have
accompanied, if not preceded, the development of permanent settlements.
The persistence of orchards would have contributed to reinforce
territorial attachment to desirable sites (Sauer, 1971). His real concern
was to find ways of tracing cultural evolution within what he understood
as its proper geographic context--the continuity of human settlements in
Sauer's conceptualization of permanent settlement in no way
conflicts with sequent discontinuities that result from destruction and
abandonment, or seasonal occupancy. Sauer understood that the same
favored locations are settled, disputed and resettled for similar
geographic reasons. Long lived, fire resistant orchard plants are likely
to be inherited by the successive occupants of a given site. Over time,
such crops would be modified by natural and cultural processes affecting
evolutionary selection in humanized environments. The human cultural
sequence would, thus, be reflected in the evolutionary sequences in hard
seeded crops such as grapes that leave clues in the archaeological record,
and in behavioral contexts as well, as it is discussed in Chapter 3.
Sauer was prescient that the study of cultural evolution in native
grapes would reveal much about Southeastern agricultural origins. He
implicitly proposed that grapes be examined as artifacts of material
culture, both in historic and prehistoric times, and he summarized his
insight memorably in the following passage:
Cultivated plants are living artifacts of times past,
available where archaeology and written document are wanting, or
making these more explicit. (Sauer, 1969: p. vii)
The present investigation follows a Sauerian methodological strategy
in which an explanatory framework is woven from diverse sources of
knowledge within the guiding coordinates of a historical and cultural
geographical perspective. Within this approach the research problem can
be expressed as follows: Why has viticulture, a modern crop-technology
supported by a sophisticated international research establishment,
remained underdeveloped in the Caribbean tropics, despite a long history
of incipiency? A corollary question that arises is: What are the
geographical barriers, physical and cultural, that have hindered the
diffusion of modern viticulture in the Caribbean and/or curtailed its
In Chapter 2, the researcher expounds his hypothesis that a
geographical variable, daylength, underlies traditional techniques for
viticultural adaptation, from which the following two distinct regional
approaches have emerged. Chapter 3 proceeds to explore the tradition of
adaptive hybridization which is the dominant approach in Florida. Chapter
4 examines the emergence of adaptive pruning as a paradigmatic tradition
in Venezuela, while Chapter 5 evaluates critically the geographical
"barriers," physical and cultural, that have retarded viticultural
development in Puerto Rico, and articulates the prospects for a "state of
the art" synthesis of adaptive techniques. Finally, Chapter 6 offers
general conclusions that can be drawn from interweaving the preceding
cases into a conceptual tapestry that has wider implications for the
future of this activity.
The sources of information on which this dissertation is based vary
for each of the four main chapters because they constitute separate,
although conceptually interrelated, case studies. All rely to some extent
on the critical analysis of documentary sources. These comprise an
exhaustive and current cross-disciplinary bibliography, accumulated over
many years, and a personal collection of published and unpublished
documents: books, reports, letters and articles on viticulture and
related subjects pertinent to the research subject. The core of this
collection is the researcher's personal file of correspondence (1961-1990)
with leading figures of adaptive grape breeding in the Americas.
Additional sources of information resulted from course work in
anthropology and archaeology at the University of Florida between 1981 and
1984. This provided the philosophical rationale for understanding the
evolution of adaptive viticulture, and also an opportunity for the direct
study of archaeological and living grape seeds and grape vines as
artifacts of material culture. In addition, the researcher was able to
improve his skills in the use of interviewing techniques as research
sources and the recording of oral history.
Taped and untaped interviews with the pioneers of adaptive grape
breeding in Florida, with members of the Florida Grape Growers Association
and the North American Grape Breeders Conference, became important sources
of information on adaptive strategies. In addition, direct observation
of viticultural techniques were made in a number of Florida vineyards and
the native cultivars and wild grapes surveyed in much of the state,
including the extensive collection in the Leesburg Agricultural Research
and Education Center. Grape seeds were obtained from various herbaria
(see Chapter 3) as well as directly from the field.
Comprehensive field work that utilized various of the above
mentioned approaches of information gathering was conducted during two
visits to Venezuela, in April of 1988 (to the Tropical Viticulture
Development Center, near Maracaibo), and in November of 1989 (to the Grape
Institute, near Barquisimeto). Each visit was for a period of a week.
Similar field work has been realized in Puerto Rico, on a continuing
basis, from 1985 to the present.
Years earlier, before engaging in doctoral studies, periodic visits
were made to viticultural research centers in Brazil: in 1967 to the
Agronomic Institute in Campinas (Sao Paulo) and the School of Viticulture
and Enology in Bento Gon~alves (Rio Grande do Sul). Likewise, the
researcher participated in 1971 in the first congress of the Brazilian
Fruit Culture Society, held in Campinas, in which viticulture was an
important component. A charter member, the researcher attended subsequent
congresses in 1973 and 1976. In 1975 he visited the Leesburg and
Homestead ARECs, the Interamerican Institute of Agricultural Sciences in
Turrialba, Costa Rica, site of early tropical grape breeding, and attended
the 33rd Congress of the American Society for Horticultural Science,
Tropical Region, in which he was also active for several years. The
following year at the 34th Congress he delivered a paper which heralded
the present dissertation (Watlington-Linares, 1976b). To conclude, the
researcher's long years of "fruitful" experience as an adaptive grape
breeder and experimental viticulturist in the tropics has given him the
knowledge necessary to integrate his sources of information effectively,
and to elaborate and articulate this dissertation.
The cumulative body of research comprised in this work is "grounded"
in the life experience of its protagonist. Consequently, the "design of
research" is to be understood in terms of the qualitative paradigm (Cook
and Reichardt, 1979). This dissertation is the outcome of a personal
inquiry that began as an avocational involvement with tropical viticulture
in the early 1960s, in Puerto Rico. In pursuit of a dream of independence
on a few acres, this researcher was belatedly caught up in the social and
political turmoil of the times. Isolated from active participation by
personal circumstances, he sought an opportunity to make a meaningful
Breeding grapes for the tropics eventually became a major endeavor
within a "scientific" activism that gave expression to his multifarious
interests and commitment. By the early 1970s these had become inseparable
from his professional livelihood, under an umbrella of his creation, the
"Aquarius Experiment Station." His growing personal research and
experience as a "back to the land" consultant raised questions that
participation in international horticultural congresses and visits to
tropical and subtropical experiment stations throughout the Americas could
Discontent with the philosophical and practical mediocrity that
seemed to characterize mainstream horticultural research, forced this
researcher to seek enlightenment through advanced academic studies in
geography. In due course he realized that the lack of geographic
awareness that seemed to permeate applied agricultural science was
compounded by an equally blatant disregard for humanistic (i.e.,
anthropologic) considerations. Again, it was the author's minor field,
anthropology, that provided the qualitative rationale of scientific
research (Cook and Reichardt, 1979), that he opposes to the positivist
paradigm dominating horticulture.
The scope of this dissertation is necessarily circumscribed to a
consideration of the climatic parameters assumed to be critical in the
tropical adaptation of viticulture. Soil, for example, is considered here
only as a secondary factor, in accordance with recent authoritative
opinion (Santibafiez et al., 1986).(2) For analogous reasons, economics
are not extensively considered either. However, adaptation clearly has
a direct bearing on production costs and, therefore, on long term economic
1. Cultural evolution is here defined as the adaptive transformation
of a cultural form, in this case a specific crop-technology complex,
through geo-environmental and cultural factors. It is equivalent
to Sahlins' (1960) "specific evolution," amended to emphasize
natural selection (Stoddart, 1966; Dunnell, 1978) and cultural
selection (Campbell, 1965; De Wet and Harlan, 1975).
2. Winkler (1962) was one of the first to challenge the "proprietary"
European view that assigned decisive qualitative attributes to
particular soil compositions and textures. Winkler conceded that
in northern regions, such as in Germany, slate-stone and shale might
be beneficial by absorbing heat during the day. Similarly,
limestone would offset the high acidity of grapes grown in the
cooler winegrowing areas of France (Ibid.).
THE GEOGRAPHIC CONTEXT OF ADAPTIVE VITICULTURE
State of Knowledqe
In this chapter the working hypothesis of the present dissertation
is elaborated. The research method utilized has been the historical
analysis of adaptive techniques in viticulture recorded from the earliest
to the most recently available documents. On one hand, the survey focuses
on how these relate to environmental conditions, and on the other hand,
to grapevine phenology and physiology. Consequently, the research is both
cross-disciplinary and cross-cultural, as well as historical.
Adaptive viticultural techniques linked to geographic parameters
have been reported in European agricultural treatises of the Classic,
Medieval and Renaissance periods. Exemplary contributions are those of
the Andalusian Spanish agronomists Columella (42/1941), Ibn Al-Awwam
(1200/1802), and Herrera (1513/1970). It has been suggested that
traditional folk technology for grape cultivation was introduced to the
Spanish settlements of the New World in the 16th century, precisely from
Andalusia, along with the Old World grape cultigen Vitis vinifera L.
Adaptive viticulture evolved empirically in various regions of the
Ibero-American tropics and subtropics since the early colonial period.
However, its counterpart in modern middle latitude viticultural technology
has formal antecedents in 19th century European biogeography. In the
United States this is epitomized by the work of De Candolle (1859),
Lippencott (1862) and finally Koppen, who in 1900 summarized his
predecessors' efforts to correlate climatic variation and plant adaptation
(Thornthwaite, 1943), but unlike them had no special interest in grapes.
In the first half of the 20th century, research on viticultural
adaptation in the United States declined and became parochial as the
result of a conjunction of political interests opposed to the expansion
of wine growing (Adams, 1978). Consequently, 19th century "heat
summation" remained a popular adaptational criterion in American
viticulture.(1) The concept was refurbished by Winkler (1938) with
refinements added by others over the years (Branas et al., 1946;
Santibahez et al., 1986).
Poor adaptedness of high latitude grapes in the lower latitudes has
commonly been attributed to lack of winter chilling (Magoon and Dix, 1943;
Mortensen, 1981; Olmo, 1986). However, a chilling requirement is not
mentioned in specialized reviews of climatic factors and grape phenology
(Buttrose, 1974; Alleweldt and Hofacker, 1975; Srinivasan and Mullins,
1981). Nonetheless, the belief that grapevines need periods of cold
weather remains somewhat paradigmatic (sensu Kuhn, 1970) in Caribbean
agricultural extension service lore.
Modern experimental studies on geo-climatic influences in grape
phenology were initiated in the mid-1930s in Germany (Moschkov, 1935;
Hackbarth and Scherz, 1935; Husfeld, 1936) dealing mainly with acclimation
to freezing weather. After World War II the work was resumed in West
Germany (Burckhardt, 1958) and taken up in other countries, including
France (Huglin, 1958), Russia (Grecisnikov, 1958), Italy (Khalil, 1961),
Japan (Kobayashi et al., 1966), and Australia (Antcliff and May, 1961).
The cumulative findings of this accruing body of research point
unequivocally to a geographical variable, latitudinal daylength, as the
principal parameter of viticultural adaptation. Concurrently, ambient
temperature has been qualified as an important complementary factor
(Kobayashi et al., 1967; Kliewer, 1973; Hale and Buttrose, 1974).
The viticultural implications of the latitudinal variation of the
amplitude of seasonal daylength as an adaptive parameter in grapes has not
been widely recognized. Physiological studies have been concerned
primarily with the abstraction termed "photoperiodism" (i.e.,
physiological responses to experimental cycles of light and darkness, in
abeyance of actual geographical conditions), in the controlled, artificial
environment of "growth cabinets" (Buttrose, 1974). Their research design,
interpretation of findings, and extrapolation to the "field" reveals, by
and large, surprising indifference to the geographic context of
Alvim (1964) reviewed the phenological effects of seasonal daylength
variation on perennial crops in the tropics and indicated that slight
seasonal fluctuations in calendar daylength is sufficient for response to
photoperiodicity in latitudes as low as 10 degrees or less. Alvim also
garnered evidence that photo-phenology in tropical fruit and nut crops is
often synchronized with alternating periods of clear skies rather than
with calendar daylength.(2)
Because rainfall in the tropics is essentially convective (Flohn,
1973), rainy periods are normally accompanied by heavy overcast or tolda
of cumulonimbus cloud cover. It has been observed that tolda may
influence daylength responses in many plants, particularly if occurring
at the beginning of day, thereby extending the duration of night-time, the
effective "operand" of photoperiodism (Vince-Prue, 1975). Nonetheless,
over half a century since Garner and Allard first defined photoperiodism
(Ibid.) the lack of an applied integration with actual geographic
daylength is suggested by the questions raised in a current review of the
state of knowledge on photo-phenology.
Under natural conditions the transition to and from darkness is not
abrupt but occurs through a gradually changing intensity of
twilight. At what point does the plant begin to respond to
darkness? Or to light at dawn? Is the effective length of day
influenced by morning or evening clouds? . It has been suggested
that the presence of clouds during twilight and dawn can influence
the photo-periodic response. (Vince-Prue, 1975: 80-81).
Adaptation in Grapes
All grapes are perennial woody vines that respond to seasonal
changes in their native habitats with appropriate physiological
adjustments (Branas, 1974). They tend to stop growing and shed their
leaves in response to shortening daylengths that signal the arrival of a
season sensed as unfavorable: winter in the higher latitudes, estio or
dry season in the "wet-and-dry" tropics (Critchfield, 1974). However,
seasonal vegetative inhibition also promotes conditioning for the fruiting
cycle that ensues with the return of longer days and favorable weather
(Kliewer, 1981). Adaptation in grapes is thus conditioned by the need for
alternating periods of both "favorable" and "unfavorable" daylengths.
Because the onset of critical seasonal changes is generally preceded
by equinoctial daylength, most grapes require days longer than twelve
hours for normal growth and productivity (Buttrose, 1969a; Sugiura et al.,
1975). How much longer for grapes in their native habitat depends on the
particular daylengths that commonly precede critical weather at a specific
latitudinal location and on the time required for appropriate
Grapes native to climatic belts north of the 30th parallel respond
to equinoctial or lesser daylengths by preparing for freezing weather
(Moschkov, 1935). The more northerly forms must be progressively
unresponsive to daylengths not considerably longer than the equinoctial
threshold (Pierquet and Stushnoff, 1978). On the other hand, the
neotropical pan-species V. caribaea D.C. interprets shorter than
equinoctial daylengths as the harbinger of annual drought lasting around
four months (Schwerdtfeger, 1976). Though the range of variation in
daylength duration increases away from the equator, it appears to be
significant at least to latitude 100 or lower (Figure 1), where V.
caribaea is native.(3)
Daylength requirements and related responses for different stages
of the phenological cycle vary geographically between and within grape
species (Hackbarth and Scherz, 1935; Pierquet and Stushnoff, 1978). It
follows that natural selection in grapes favors ecotypical (essentially
latitudinal) adaptation in terms of synchronization of photo-phenology
with local seasonal climates (Rives, 1972). Consequently, adaptation to
a given daylength regime will largely determine 1) the comparative
adaptability of non-native cultivars; 2) the manipulation of phenological
cycles to coincide with tolerable daylengths and seasonal climatology;
Mar- -Apr-May- -Jun-Jul- -Aug- -Sep-Oct- -Nov- -Dec
Figure 1. Transit of daylength at selected northern latitudes.
Source: Drawn by the author from data in the United States Naval
Observatory Air Almanac, 1960.
and, 3) the selection of adapted (i.e. healthy and productive) cultivars
from hybrid progeny.
Adaptation in Viticulture
Viticultural adaptation in the lower latitudes has been achieved
traditionally through empirically developed techniques that implicitly
circumvent the native adaptive responses of immigrant high-latitude grapes
to daylength patterns of the lower latitudes. Three specific approaches
can be recognized: 1) Adaptive Insolation Optimization; 2) Adaptive
Pruning; and, 3) Adaptive Hybridization. They have emerged as regional
practices that are presumably successful under the geo-environmental
conditions where they developed. When a locally adaptive tradition is
introduced to a different latitudinal region, it may, of course, become
Adaptive Insolation Optimization
Adaptive insolation optimization concerns the interpretation of
solar intensity and daylength interactions with seasonal and diurnal cloud
cover patterns. The interplay of physiological and geographical factors
underlying insolation-adaptive viticulture has been understood by
viticulturists since ancient times. European immigrants in the New World
tropics and subtropics sought out locations for viticulture guided by the
perception of environmental analogy between colonial and Old World
Apparent similarities of vegetation and soils have served to
identify semi-arid areas that provide the high levels of insolation known
to be essential for adequate development of fruit buds, blooming, fruit
set and maturation in Old World grapes (Baldwin, 1964; Kliewer,1981).
Such areas, where clear skies prevail, are in fact the major commercial
vineyard locations in the American tropics (Pansiot and Libert, 1970;
Even such seemingly favorable areas tend to be perceived as somehow
environmentally inferior to the "old country." Under shorter daylength
regimes, most cultivars of European V. vinifera become relatively
unproductive, develop poorly and are prone to physiological maladies in
regions below the 30th parallel (Winkler, 1962; Branas, 1974).(4)
Controlled environment research suggests that the daily duration of photo-
inductive daylight is a regulator of adaptedness and productivity separate
from that of solar intensity, with which it interacts to some degree
On the other hand, low latitude regions with warm rainless periods
are partially analogs of the Mediterranean growing season, uninterrupted
in the tropics by extremely short days and rest-enforcing cold weather.
Although summer days in the tropics are shorter than those at higher
latitudes, tropical winter days are considerably longer than those at
latitude 30 N, the approximate southern viticultural border of the
Mediterranean subtropics. Therefore, reduction in native fertility of
adaptable immigrant cultivars is offset, often to a surprising degree by
more or less continuous cropping (Corzo, 1987).
The influence of latitudinal daylength on grape phenology is subject
to modification by the diurnal pattern of seasonal cloud cover and by
local topography and temperature regimes as well. Reduction of effective
daylength by morning or evening tolda can be enhanced by mountains that
intersect the angle of incidence of the sun (Mac Hattie and Schnelle,
1974). Thus, narrow interior and coastal valleys bordered by north-south
ranges can be influenced by tolda much more than the highlands that rise
above them. Herrera was emphatic in stating that: "Valleys, mainly if
they are deep, are the worst of all places for vineyards." (Herrera, 1513:
Immigrant high-latitude viticulture would be expected to adapt best
to locations least disadvantageous in terms of interactive daylength-
restricting topographic conditions. In addition, favored sites should
have locations that counteract high atmospheric humidity. For example,
viticulturists throughout the Caribbean would agree with the Sevillean
agronomist Ibn Al-Awwam (of 12th century Seville) in that:
Grapes prosper by the sea, and are benefitted by maritime breezes,
which is not the case in the vicinity of rivers where there are
marshes and lagoons. (Ibn Al-Awaam, 12th century: p. 214)
On the other hand, cool temperature regimes of tropical highland climates
seem to counteract the inhibitory effects of inadequate daylength on some
high latitude cultivars (Sugiura et al., 1975).
Pruning is the primary cultivational technique used to control and
optimize production of grapes in a particular geographical environment.
Its adaptational purpose is to coordinate fruiting phenology with
relatively favorable climatic conditions, including optimal effective
daylength. Thus, the calendar of pruning in varying photoclimatic regimes
at different latitudes is a major concern of adaptive viticulture.
Reproductive and vegetative development in grapes, as in other
perennials, is controlled mainly through leaves and buds that sense and
respond to seasonal changes in daylength stimuli (Vince-Prue, 1975).
Flower clusters emerge and develop with new growth from fertile buds
formed during the preceding growth season (Kobayashi, et al., 1966;
Buttrose, 1969a). At the same time, new buds are formed containing the
flower initials that would normally develop in the following growing
season. In the higher latitudes, where most cultivated grapes have
originated, new buds are formed in an environment of rapidly expanding
daylength and luminescence.
To be adaptable in the tropics, non-native cultivars from higher
latitudes must be tolerant of relatively short photo-inductive daylengths.
For those that do adapt, productivity depends on a sufficient daily
duration of high level insolation (Kliewer, 1981). Cumulatively, a season
with such days long enough for completion of the critical formative stage
(Buttrose, 1969b) is required. In the tropics, therefore, pruning must
be scheduled so that critical fruit-bud formation occurs during
predictable periods of relatively clear skies, and, preferably, with
daylengths of twelve or more hours.
Conversely, mature leaves respond to shortening days by directing
the physiological process towards vegetative rest or inhibition (Hackbarth
and Scherz, 1935; Moschkov, 1935). In the leafless vine rest is
maintained by the collective influence of daylength receptive dormant buds
(Alleweldt and Istar, 1969). After a period of vegetative inactivity,
when daylength again increases beyond the equinoctial threshold, the
reproductive cycle is reactivated with the oncoming season's growth.
Pruning may have developed as an adaptive technique when viticulture
diffused into areas subject to late killing frosts, as a means of
retarding spring budbreak. Because of apical dominance, when buds begin
to swell in spring, pruning delays budbreak temporarily (Rives, 1967;
Pool, 1984). However, since pruning uninhibits vine growth by eliminating
the distal buds that register and regulate daylength control of vegetative
activity, it can prove to be counter-adaptive if done too early (Ibid.).
The classical agronomists generalized that early pruning (November-
December) should be the rule in areas where cool winter weather arrived
early and remained constant until spring. Late pruning (February-March)
was considered advisable in areas with relatively warm winters, subject
to late freezes. This practice conveniently anticipates the equinoctial
change to longer days.
Dates for pruning grapevines differ substantially between
latitudinal subregions of the Caribbean. In the mid-region islands of
Puerto Rico and Hispaniola the custom of late pruning as practiced in
Arabic Andalusia--as described by Al-Awwam--still prevails. An annual
cycle of cropping which follows the rise and decline of latitudinal
daylength is thereby established. Both Florida, located roughly between
latitudes 250 and 30 N, and the Greater Antilles at nearly latitude 20N
have been restricted to a single yearly pruning, because of the
inevitability of freezing weather in the first case, and because of the
inhibiting effect of relatively short "off-season" daylengths in both
It is in the southern borderland of the Caribbean, at a
significantly lower latitude, that pruning attains its greatest potential
as an adaptive technique. In Venezuela (latitude 10N), where winter
daylengths are near the equinoctial threshold, pruning has been used
advantageously since early colonial times (Latorre, 1919) to promote
reproductive new growth during periods of high insolation throughout the
year. Even without pruning, the best adapted of the introduced cultivars
tend to grow in vegetative flushes the year around following changes in
available insolation levels and effective daylength (Purohit et al.,
The use of hybridization as an adaptive technique in New World
viticulture has evolved from the experience that hybrid forms often
combine desirable traits of widely differing "races." The recognition and
selection of hybrids between indigenous forms and introduced cultivars has
been traditionally understood as essentially adaptational, although
appraisal of environment conditions has usually focused on "disease
resistance" rather than on daylength. Though evidence of colonial grape
breeding is rare, the exploitation of hybridity requires only the
recognition of sexual reproduction in grapes. A practical understanding
of plant sexuality was part of the Arabic agricultural legacy of Andalusia
at the time of the Discovery. On describing the well documented ancient
technique of hand pollinating the date palm, Ibn Al-Awwam adds:
Some horticulturists say that all trees are susceptible to talkih
or fecundation, by which means they yield very good fruit, and these
drop off less, and so it is said that all trees being male or
female, the latter are fecundated by the former. (Ibn Al-Awwam, 12th
century: p. 291)
Talkih, he explains, is the dusting of flowers on a female date palm with
"seminal dust" (pollen) from a male date palm.(7)
When the New World was colonized, Spanish agriculturists were well
aware that many orchard crops need cross pollination, and that some are
dioecious (separately sexed) like the date palm (Herrera, 1513).(8) All
species of grapes are largely dioecious in the truly wild state (Levadoux,
1956). While selection has made functional hermaphroditism the prevalent
condition in cultivated grapes, exceptional female cultivars have been
handed down through the centuries. Such is the Ohanez of Almeria, a
traditional Andalusian export grape which is artificially pollinated in
the same manner as date palms (Rueda-Ferrer, 1953).
Herrera advocated interplanting a few males in orchards of female
cultivars. Attributing fecundity to male "odor" (pollen?) and "heat"
(Herrera, 1513: p. 113), he alternatively proposed grafting female scions
on male rootstocks. Both practices enhance the possibility of
interspecific hybridization. Spanish horticulturists were presumably
aware of this. It is implicit in Herrera's praise of grafting:
With [grafting] more than any other craft wild trees become
domesticated, the sterile become fertile, the good much better.
[Grafting] is the cause for there to be each day new kinds of fruits
which did not exist anciently, nor were created at the beginning of
the world. So much so, that there are scarcely less trees invented
than natural, as from two species of animals a third is engendered
that is very different. (Herrera, 1513: p. 120).(9)
Grafting has long been appreciated as a means for quickly
establishing productive vineyards in newly colonized lands. The basic
idea is that well-developed native vines be used as adapted rootstocks,
following the general rule that "where there are similar wild species
doing well, domesticates of their own kind can be planted." (Herrera,
1513: p. 101). There is little doubt that Spanish grapes in the New World
colonies were routinely propagated and grown on stocks of native American
grape species. Expressions of wonder at the abundance and fertility of
the native grapevines are found throughout accounts of the Contact period.
In the circum-Caribbean mainland and major islands, V. caribaea was
common (Levadoux et al., 1962; Olmo, 1968). In Florida a surprising array
of grape species, possibly including indigenous cultivars, awaited the
Spanish settlers (Sauer, 1969, 1971; Rogers and Mortensen, 1979). A
bewildering diversity of forms was available in Mexico (Olmo, 1976).
Cortes, the Conquistador of Mexico, made sure the indigenous vines were
put to good use, and in his "Ordenanzas" of 1524 decreed that every
settler who received an allotment of land and Indians was obliged to plant
a proportionate number of native vines as rootstocks, to be duly grafted
with scarce scion-wood from Spanish cultivars (Adams, 1978).
A widespread common name for V. caribaea on the mainland is agras.
The term was applied in Spain to special purpose acidic grapes. In the
northern part of the peninsula, acid juice was obtained from wild grapes
as a culinary and medicinal substitute for vinegar and sour orange, while
in the south such grapes were regularly needed to balance the chronically
acid-deficient wine musts of the hot climate. If suitable wild grapes
were unavailable, a late crop that would not ripen was intentionally
induced on cultivated vines by summer pruning. It seems likely,
therefore, that wild Caribbean grapes would have been planted in, and
tolerated near, colonial vineyards for supplementary must as well as for
rootstocks and improved fecundation.
The vicinity of native vines in field-border hedgerows is a
condition sufficient for cross-pollination between wild and cultivated
grapes. All grape species of the major subgenus (Euvitis) have the same
number of chromosome pairs (2n=38) and will produce fertile hybrids if
cross-pollinated (Rives, 1974). The blooming periods of many species
often overlap, more so if synchronized by pruning (by either human or
An abundance of interspecific hybrid grape seeds was a likely
occurrence in colonial vineyards, whether or not intentional breeding was
practiced. Seedling vines with exceptional "hybrid vigor," productivity
(in part through expression of hermaphroditism), and adaptedness (notably,
appropriate daylength programming) to environmental conditions would have
been recognized, selected and propagated. Adaptively superior hybrid
vines would have gradually replaced the short lived V. vinifera as they
Despite a ban on commercial viticulture in the Spanish colonies by
Philip II in 1595, the religious orders were exempted and vineyards
continued to be planted, especially in the frontier mission settlements
(Adams, 1978). Elsewhere, grapes became dooryard garden plants.
Eventually hybrid "creole" or "mission" cultivars have been handed down
and achieved economic prominence in every viticultural region of the
Hispanic New World, including each of the three latitudinal regions
represented in this study.
To summarize, it has been proposed in this chapter that the
geographical limiting condition in the diffusion of viticulture toward the
equator is the diminishing calendar range of photo-inductive daylength,
which is reflected in the phenological responses of cultivars originating
beyond the tropics, where the range is progressively greater and
phenological adaptation critical to survival. The condition is enhanced
on one hand by the additional seasonal reduction of effective daylength
resulting from periods of persistent cloud cover (tolda), and on the other
hand by the basic physiology of grapevines which uses daylength under
twelve hours to store metabolites for future growth, and daylength beyond
that threshold for productive phenology (i.e., flowering and fruiting).
The above proposition is grounded in the findings of researchers
from ancient times to the present. The introduction of viticulture to the
tropics has relied on three distinct adaptive techniques, all empirically
based on the underlying need to optimize the interaction of grapevine
physiology with the variable daylength environment. Historically, the
most primitive technique appears to be adaptive insolation optimization,
to which later was added the complementary techniques of adaptive pruning
and adaptive hybridization.
Historical analysis suggests that none of the two latter techniques
have evolutionary precedence, nor are they incompatible. However, in the
following chapters it will be shown that fortuitous geographical
circumstances (geo-environmental and cultural) have favored the
development of either approach on a regional basis, to the exclusion and
virtual banning of the other!
Chapter 3 seeks to clarify the obscure origins of modern adaptive
hybridization in the New World (specifically in Florida), and its
curiously limited geographical diffusion as an institutionalized
scientific approach. Chapter 4 examines the more recent establishment of
the alternative technique, adaptive pruning, as a comparably sophisticated
approach that has likewise failed to spread appreciably beyond its area
of origin. Chapter 5 raises the question of whether the two approaches,
paradigmatically entrenched in scientific institutions, can be reconciled.
1. "Heat summation" differentiates climatic regions by computing the
sum of mean daily temperatures above 50F (10C) during the growing
season. Its opposite term, the so-called "chilling requirement,"
presupposes that a certain number of hours under the same threshold
is needed to fulfill a required period of dormancy.
2. Tropical rainfall tends to follow a predictable seasonal and diurnal
course which is most intense during the high sun period (Ramage,
1971), thereby restricting the daily duration of photo-effective
daylight between the spring and fall equinoxes. In the tropics,
effective daylengths may be longer during brief equinoctial and
winter solstice dry (i.e. cloudless) periods when calendar days are
relatively short, especially so by comparison with daylengths of the
growing season in higher latitudes.
3. All true grape species are native to the Northern Hemisphere
(Levadoux et al., 1962). In the New World the number of recognized
forms diminishes dramatically toward the equator. Apparently, none
have spread naturally across the equatorial line.
4. Certain vinifera cultivars commonly grown in the tropics are
exceptionally tolerant to low latitude daylengths. Several
cultivars that have been successful were selected for "forcing" in
19th century European greenhouses (Miller, 1963). They appear to
have derived largely from Persian and Arabian lineages selected
since ancient times south of latitude 30N and beyond the Tropic of
Cancer possibly as far south as the Gulf of Aden at latitude 150N
(Levadoux, 1956). Well known are the characteristic "Muscats."
However, these "desert" grapes are generally intolerant of high
5. In Florida, where warm winter weather allows vegetal growth, the
custom of early pruning may be responsible for freeze damage and
subsequent infection with Pierce's disease, the most important
"natural barrier" to viticultural adaptation in Florida (Crall and
6. On the islands, however, two or three successive crops (of uneven
quality) are possible with some cultivars, a fact noted as early as
1582 in a "state of the colony" report on Puerto Rico for the King
of Spain (Latorre, 1919).
7. Cowan's (1976) Arabic-English Dictionary defines talkih as either
plant pollen/pollination, or animal (and human) sperm/insemination.
The Arabic terms for horticultural budding and grafting are derived
from the same root.
A common colloquial expression in Puerto Rico, and other Hispanic
lands, refers to human sexual intercourse, specifically
insemination, as "echar un polvo," literally: "To (throw a) dust."
The original meaning has been lost but the derivation seems clear.
8. Although Vernet (1978) affirms that Herrera took his notions of
applied plant sexuality from Arabic texts, early settlers in the
Hispanic Caribbean gave common names to a few native trees which
reflect continuity of the folk belief that small differences between
otherwise similar forms (actually related species) imply separate
sexes of the same species (Gilormini, 1979). By contrast, common
awareness of plant sexuality in most of Europe had to wait for
experimental confirmation by Bobart, Camerarius and Grew in the 17th
century (Wolf, 1952).
9. Herrera may have thought that hybrids associated with grafts are
graft or vegetative hybrids, actually quite rare (Hartmann and
Kester, 1968). Graft failure on intended native rootstocks would
thus augment interspecific "intimacy" and consequent production of
ADAPTIVE HYBRIDIZATION IN FLORIDA: ORIGINS AND DIFFUSION
The present chapter elaborates on a previous investigation which
suggested that early Spanish colonial Florida had a particular
significance in the introduction of viticulture to the New World
(Watlington-Linares, 1983). In that report, the author proposed a
thorough examination of grape seeds as archaeobotanical evidence to
determine whether adaptive hybridization had taken place in the first
European settlements. Eventually, the opportunity arose to examine a
significant sample obtained from a late 18th century mission village in
east central Florida which offered important clues. Thus, the sources for
this inquiry include archaeological grape seeds, as well as available
documents, direct observations in the field, and the first-hand testimony
of modern pioneers in adaptive grape breeding.
Modern adaptive viticulture in the southeastern United States is
based largely on native interspecific hybrids, including foundlings of
antique origin and their descendants. Sauer (1969, 1971) suspected
prehistoric aboriginal domestication. Others (Munson, 1909; Fennell,
1941; Bailey, 1948; Rives, 1963) have generally assumed that such vines
originated as natural hybrids of wild species, or between native grapes
and European cultivars. It is possible that some of the vines in question
may represent survivals of adaptive hybridization in early Spanish
Domesticated grapes appear to have evolved originally in the Old
World from discovery, collection and vegetative propagation of natural
hybrids combining fruit and vine traits of separate forms in advantageous
ways (De Candolle, 1886; Sauer, 1971). Replication of such an origin was
observed by Olmo (1970) in an ethnographic context in northwestern India.
Comparative studies of archaeological and living seeds suggest that the
cultigen continued to develop and spread as primitive selections were
taken to new geo-environmental areas and interbred with local wild and
cultivated ecotypes (Levadoux, 1956; Negrul, 1960; Rives, 1974; Janusevich
and Nikolaenko, 1979).(1)
C. 0. Sauer (1969) may have been the first to propose continuity of
Amerindian grape cultigens from prehistory to the present. The prominence
of grape seeds in archaeobotanical samples obtained by flotation since the
early 1970s (Watson, 1976) suggests that some aboriginal peoples may
indeed have practiced incipient viticulture between the late Archaic
period (4500 2500 BP) and the 18th century. Sauer's conjecture has
apparently not been seriously investigated previously.
Surprisingly, the existence of mission vineyards tended by Indian
labor from the late 16th to late 18th century was overlooked by Sauer, and
likewise ignored by archaeological researchers of Hispanic agriculture.
Most notably, grapes were left out of Ford's "Hispanic Complex" of
cultivated plants introduced by the Spanish and adopted by Southeastern
Indians (Ford, 1981). Since they were already avid consumers of fresh and
dried native grapes, there is little reason to believe the Indians did not
accept European grapes as readily as they did oranges, peaches, figs,
pomegranates and watermelons, all of them Old World fruit crops (Smith,
1956; Mason, 1963; Blake, 1981; Ford, 1981; Newsom, 1986; Reitz and
The Florida Mission Graves
Grapevines from Spain were introduced to the Caribbean region with
Columbus' second voyage (1493) when a vineyard was planted on the island
of Hispaniola (Sauer, 1966). Viticulture followed Spanish colonization
throughout the New World. Vineyards were planted and in many cases
maintained against environmental odds to assure a regular supply of wine,
a cultural staple vital to the social solidarity of the conquistadors.
Moreover, documentary and material evidence supports the proposition that
the process of adaptive hybridization postulated for Old World viticulture
continued in the New World, specifically in early Hispanic Florida.
In Florida, hybrid grapes may have first appeared in settlements
established by Spanish colonists in the late 16th century. During that
period also, the seasonally migrant Guale Indians were sedentized in
mission controlled villages on the Atlantic coastal Sea Islands from the
northern Spanish outpost of Santa Elena to St. Augustine in the South
(Gannon, 1965).(2) Of necessity, Spanish and Indian crop systems became
integrated in a new, "mestizo," agricultural complex (Matter, 1973).
Excavation (South, 1980) has confirmed historical reports that the
first Spanish vineyard in Contact Florida was planted at Santa Elena, on
what is now Parris Island, South Carolina, in 1566 (Watlington-Linares,
1983). The colony initially surpassed St. Augustine, until its
destruction in 1576 (Lyon, 1976). Although quickly rebuilt and
refortified, the vineyard replanted, the outpost lost its pre-eminence to
the more secure southern position. Officially abandoned eleven years
later (1587) under threat of Indian rebellion, apparently the settlement
did not disappear entirely.
Waring (1970) noted that a Captain William Hilton of Barbados
visited Santa Elena in 1663. He found "Spanish" Indians living there,
seventy-six years after the presumed abandonment of the former mission
village. They lived amid artifacts that included a standing wooden cross,
and orchards of peaches, figs and grapes. That these were not relics but
actively cultivated there can be little doubt. With the exception of
native grapevines and their adapted hybrids, capable of self renewal by
spontaneous layering, the exotic peach, fig and European grape are
reputedly short lived in the Southeast without skilled husbandry.(3)
In 1735, Francis Moore, an English visitor to Georgia, accurately
described the two common native wild grape species, V. aestivalis Michx.
and V. rotundifolia Michx. He then commented on a curiosity he had seen
on St. Simon's Island, site of the mission of Santo Domingo de Asaho:
But there is on St. Simon's, a wild Grape much nearer the Europe
Vine, the Fruit being exactly the same as the common white Grape,
though the Leaf is something different. The Birds and wild Animals
like it so well, that they suffer it seldom to ripen. All the Vine
Kinds seem natural to the Country. (Moore, 1744: p. 55)
Similarly, late 18th century settlers discovered feral grapes of
apparent V. aestivalis x vinifera hybridity (Rea, 1941; Mishkin, 1975),
growing within the former Hispanic/mission, and subsequent Anglo-Indian,
borderland in South Carolina, Georgia, and Alabama. This buffer zone,
then populated by remnant Indian tribal communities, included Hispanicized
villages forcibly relocated by the English upon destruction of the Spanish
west Florida province of Apalache at the beginning of the century (Jones,
San Francisco de Oconi was one mission community that may have
accepted relocation rather than the alternatives of enslavement or
slaughter. Those that went along with the English were settled amid the
Creeks, probably somewhere in the upper basin of the Altamaha River, and
most likely soon assimilated. Eventually, the northern branch of the
Altamaha came to be known as the Oconee.(4) Despite English encroachment,
the area remained under nominal Indian control until 1775 (De Vorsey,
In 1773, while traveling between the Oconee and Savannah rivers,
naturalist William Bartram observed that grapes and other orchard fruits
were cultivated in an Indian village that he visited. He later wrote:
The present nations that inhabit these lands seem very fond of all
kinds of eatable [sic] fruits and nuts and take great care to
cultivate peaches, grapes, plums, & etc. (Bartram, 1775: p. 142)
A few years later, in an ethnographic paper on the Creek of the Oconee,
Bartram again made reference to the cultivated grapes he had seen in their
Vitis vinifera: I call them so because they approach, as respects
the largeness of their fruit and their shape and flavor, much nearer
to the grapes of Europe and Asia, of which wine is made, and are
specifically different from the fox or bull grape of Pennsylvania
and Carolina (Bartram, 1789: p. 49).
By the time of Bartram's visit some Creek had moved out of Georgia
and into northern Florida. A group that had lived on the Oconee River
became established, between 1733 and 1750, in the Alachua region (Tebeau,
1980). The Micosuki, as this people came to be known, was gradually
forced southward, and in the 1820s briefly granted much of central Florida
from Ocala south to latitude 27 N. Isolated groups survived later
campaigns to remove them. It may be that many were gradually absorbed
into the dominant culture of later immigrants.
Feral grapes that appear to be "escapes" from cultivation or
abandoned cultivars from earlier occupation have been recovered in south-
central Florida, as in other Southeastern frontier zones where the Indian
presence lingered.(5) However, the original systemic or behavioral
context of such finds has not been as clearly established as certain
documented survivals from the preceding Spanish period.
In 1823 a surveyor preparing a site plan for the Florida state
capital at Tallahassee discovered the ruins of Fort San Luis, abandoned
one-hundred-nineteen years earlier. It was later reported that "within
the outerworks of this fort, are to be seen grape arbors in parallel
lines, which still maintain their pristine regularity." (quoted in Boyd,
1939: p. 4). Another contemporary observer described a vestigial street
grid nearby, with shade trees and "grape arbors of more or less
regularity." (Ibid.: p. 5). Unless the vines in question were overgrown
rootstocks of native species, their unusual longevity suggests the
possibility of hybrid cultivars.
It is interesting to note that toward the end of the century French
winemaker Emile Dubois established a winegrowing estate on the Fort San
Luis property (Paisely, 1968). Unlike many immigrants who brought in
muscadines (V. rotundifolia) from Georgia and the Carolinas, or introduced
V. labrusca cultivars from farther north (Lewis, 1979), Dubois planted
hybrid V. aestivalis x V. vinifera selections of the "Florida mission"
type. It is unclear what varieties he used to make the red wine that won
recognition at the Paris Exposition of 1900.
An Archaeological Clue
The widespread occurrence of feral hybrid grapevines is not
unequivocal proof that intentional hybrid viticulture, much less grape
breeding, took place in colonial Florida. It has been suggested that the
conventional botanical classification of grape species and supposed
subspecies is "illusory" (Rives, 1971) because of the observed frequency
of spontaneous hybrids between geographically coterminous forms. Another
researcher proposed "indefinite specific limits" (Bailey, 1948).
Intermediate forms have been noted as especially common in the
anthropogenic environments produced by fire, cultivation and grazing
(Rives, 1963, 1971; See also: Chapman, et al., 1982). It has also been
proposed that central Florida is a likely center of origin of new
botanical forms emerging in the interface of formerly isolated peninsular
species (Woodson, 1947).(6)
A cultural context has not been definitely established for the
origin of any foundling Florida grapevine adopted as a cultivar or proto-
cultivar (for breeding purposes) in modern times. However, because
natural hybridization is an ephemeral phenomenon (Rives, 1963; Anderson,
1949), the survival and diffusion of a hybrid grapevine may denote both
environmental and cultural favor. A natural hybrid may easily become an
artifact of material culture by means of asexual vegetative propagation.
Grape seeds of apparently hybrid morphology were recovered from a
historical archaeological context in Hontoon Island, central Florida
(latitude 2910'N, longitude 8130'W) by Purdy and Newsom (Newsom, 1987)
in 1982. The site comprises a sequence of aboriginal occupations
culminating in an agricultural (mission) settlement during the Spanish
colonial period. Charred grape seeds are among the more common floristic
remains at all levels. This is not surprising in view of the fact that
large scale smoke-drying of grapes was practiced by Indians in the
Southeast from prehistory through Contact (Sauer, 1971) to the late 18th
century (Bartram, 1775).(7)
Following Rogers and Mortensen (1979), most of the grape seeds from
Hontoon were tentatively identified as belonging to five broadly defined
species found in central Florida, and a few incidental hybrids.(8) The
most notable find is a substantial sample of 51 well preserved, apparently
charred, specimens which has been dated to the historic period, ca 1775-
1800 (Volumetric Sample 5, obtained 40 to 50 cm below the surface of the
dig). The sample is composed exclusively of relatively large bunch grape
seeds (Euvitis) of extraordinary and uniform appearance (Figure 2).
Interpretation of the VS 5 sample, provisionally named "Vitis x
hontunensis," was possible only after a considerable search for comparable
herbarium and living specimens.(9) No survey was made of grapes presently
found on Hontoon Island. The V. x hontunensis seeds have been found to
closely resemble the shape and dimensions of two supposed taxonomical
species, V. simpsoni Munson, otherwise known as "Simpson's Grape," and V.
gigAs Fennell, the "Florida Blue Grape."
The two forms share the horticultural attribute of bearing
relatively large clusters of comparatively large berries. This
combination of traits is rare in nature, but can occur when a small
Hontoon Grape seed (Vitis x hontunensis), enlarged
approximately ten times. Drawn by the author.
cluster, large seed, large berry form, specifically V. shuttleworthi House
of southern Florida (syn. V. coriacea Shuttleworth), hybridizes with large
cluster, small berry species such as V. vulpina L. (V. cordifolia Michx)
or V. aestivalis Michx. of wider distribution. Both "gigAs" and
"simpsoni" have been alternately described by the creators of the taxa and
by others as possible hybrids of such origin. V. x hontunensis may
represent a similar hybrid form.
A pioneer of modern adaptive grape breeding, T.V. Munson recognized
and made extensive practical and promotional use of such forms. In the
late 19th century, Munson grew in his vineyard at Denison, Texas (latitude
3345' N), propagules of several central Florida grapes supposed by the
collectors to be natural hybrids of V. coriacea (V. shuttleworthi) with
other species, namely V. cinerea, V. cordifolia (V. vulpina) and V.
aestivalis (Munson, 1909). However, such finds which continue to occur
(10), were common enough before large scale destruction of the native
vegetation to result in the elevation to specific status of some
foundlings by Munson. In 1887 he described taxonomically a V. simpsoni,
honoring the collector J. H. Simpson of Manatee, Florida (Munson, 1887).
Ten years later Munson established a second "Simpsoni," of more promising
horticultural appearance (Bailey, 1934).
Munson eventually downgraded his first simpsoni to V. cinerea var.
floridana (Munson, 1909). The ensuing taxonomical confusion has occupied
subsequent ampelographers from Viala (1889) and Bailey (1934) to Rogers
and Mortensen (1979). Bailey, in particular, compounded the problem by
renaming the second "Simpsoni," V. smalliana, and insisting that his
description applied to Simpson's intended "Simpsoni":
This is undoubtedly the plant understood as Simpsoni by Simpson
himself in a communication of Nov. 8, 1898, in which he says,
"bearing vines [i.e. female clones] seldom found except on shell
mounds near salt water." (Bailey, 1934: p. 207)
Meanwhile, in 1888 a French mission led by Viala examined Munson's
collection of "Simpsoni." Later Viala (1889) described what he saw as a
hybrid "mel~nge" of V. coriacea (shuttleworthi).(11) The "type" that he
returned with to France was identified as "Nash no. 399" from Lake County,
central Florida. A plate and measurements by Bonnet (1902), and a plate
by Gillet published years later by Viala and Vermorel (1910) are
presumably representative of the Viala accession in the Montpellier
collection. All are in agreement with Munson's (1909) brief description
of V. simpsoni. Both descriptions are congruous with the recovered
V. x hontunensis. A comparable sample of 49 seeds was obtained as a
medium (15 cm) cluster of fruits from a vine in the Leesburg (Lake County)
Agricultural Research Center germplasm collection. The medium cluster,
large-medium berry clone is listed as "Florida no. 399, V. smalliana
A second comparable sample comprises 20 seed specimens from the
original and only known botanical type of V. Sigcas Fennell (1940): Sample
no. 2216242 in the U.S. National Herbarium (Smithsonian Institution).
Fennell described an isolated population of vines which seemed akin to V.
aestivalis, and bore impressively large clusters of large berries with
meaty, sweet and tangy pulp. Proclaiming his find a new species: V.
Sjicis, Fennell described its habitat as restricted to "the dry shelly
banks of brackish waterways and lagoons" on the Sebastian River, ca.
latitude 27*50' N (Fennell, 1940: p. 17).
Fennell implicitly admitted the possibility of a hybrid origin for
his "Florida Blue Grape":
In a few cases it takes close observation to distinguish by foliage
alone the Florida blue grape from some of the natural hybrids of V.
shuttleworthi or of V. simpsoni (V. cinerea floridana). (Fennell,
1940: p. 17)
Fennell has never published his retrospective suspicion that his
foundling might be a remnant of antique viticulture (Fennel, p.c. 1984).
A collector of native grape hybrids in the wilds of southern Florida in
the 1930s, he was lured to ajgs by reports of exceptional dooryard bunch
grapes in the vicinity of the hamlet of Mico (an Indian word for chief).
Recently he read of archaeological digs in the same area (Tequesta) and
reflected that his best finds had been associated with Indian shell
mounds. This coincides with Bailey's observation concerning a similar
habitat for Simpson's Grape.
Comparative measurements of V. x hontunensis and the living forms:
Florida no. 399 (Simpson's Grape or VS), and V. gigqs (henceforth
Fennell's Grape or VG) are summarized in Tables 1, 2, and 3.(13) Despite
overall resemblance among the three types, the absolute and relative
measurements of each sample reveal distinctive differences as well as
similarities. Although seed morphology suggests the three forms are
closely related, their dimensions are indicative that they have separate
The V. x hontunensis (henceforth Hontoon Grape, or VH) seeds appear
to be in the same size category as Simpson's Grape (VS). Newsom (p.c.
1988) believes the degree of carbonization of the VH sample is open to
question. If compared directly, the absolute dimensions of VH fall into
the size range of the smaller VS, except for one feature, the chalaza,
which averages 16% larger in the VH seeds.
If 18% shrinkage is allowed for in the archaeological sample, and
the VS similarly "reduced," the longest (i.e. the "largest") VS become
equivalent in length to the mean for the "large" VH. (14) In addition,
31% of the VH seeds represent potentially greater live lengths, roughly
7 to 7.2 mm. All together, the longer VH seeds (43.75%) appear wider by
14.7% and thicker by 10% than their VS counterpart (the "largest" VS
comprise 18.36% of their sample).
The chalaza of the VH appears much larger than the shrinkage
adjusted value for all the VS. The mean is 31% larger, but the largest
VH seeds have chalazas 35% wider than the widest VS (surprisingly the
"small medium" seeds). The mean "diameter" of chalaza for all the VH is
also 31% larger than the adjusted mean for the largest chalaza of
Fennell's Grape (VG). The advantage is 17% for the unadjusted
measurement. Curiously, the "median" VG seeds have the largest chalaza.
Comparison of the relative dimensions for VH and VS tends to confirm
the visual similarity of proportions between the two forms. Small VS
seeds (2.24%) have a mean L/W ratio of 1.25, identical to the value for
"large" VH. The "small medium" VS (28.5%) have an L/T ratio of 1.82,
identical with the value for the largest VH. The whole VS sample has an
L/T value of 1.81, virtually the same as the "largest" VH. The L/W ratio
of the chalaza for all VS is 1.22, almost the same as the mean for all the
Table 1. Hontoon Grape Seeds, Summary of Comparative Measurements (mm)
Mean Mean Mean chalaza
Category Sample Length Width Thickness L/W L/T 5/W L/W
Largest (longest) # %
(5.85-5.975) 6 12.50 5.92 4.56 3.25 1.29 1.82 1.76 1.15
(5.62-5.75) 9 18.75 5.67 4.57 3.41 1.24 1.66 1.62 1.19
(5.50-5.57) 6 12.50 5.53 4.52 3.15 1.22 1.75 1.52 1.30
All Large 21 43.75 5.70 4.55 3.27 1.25 1.74 1.63 1.21
(5.40-5.475) 10 20.80 5.45 4.54 3.04 1.20 1.79 1.54 1.23
Small Med. (lgth.)
(5.07-5.35) 12 25.00 5.23 4.34 3.43 1.20 1.52 1.58 1.18
All Medium 22 45.83 5.34 4.44 3.23 1.20 1.65 1.56 1.20
(4.75-4.975) 5 10.41 4.88 4.27 3.12 1.14 1.56 1.47 1.19
All Seeds 48 100.00 5.45 4.47 3.23 1.21 1.68 1.58 1.20
Source: Direct measurements by Lee A. Newsom (1985), Department of Anthropology, University of
Florida, Gainesville, with "Manostat" dial type 6921 caliper. Classification, means and
ratios by the author.
Table 2. Simpson's Grape (Fla. 399) Seeds. Summary of Comparative Measurements (mm)
Direct measurements by Lee A. Newsom (1985), Department of Anthropology, University of
Florida, Gainesville, with "Manostat" dial type 6921 caliper. Classification, means and
ratios by the author.
Table 3. Fennell's Grape Seeds, Summary of Comparative Measurements (mm)
Largest (longest) # %
(6.025-6.20) 7 35.00 6.08 3.92 2.98 1.55 2.04 1.20 1.38
(5.80-5.95) 5 25.00 5.86 4.00 2.89 1.46 2.02 1.21 1.30
(5.625-5.75) 6 30.00 5.67 3.95 2.86 1.43 1.98 1.14 1.35
(5.475) 2 10.00 5.47 3.83 2.77 1.43 1.97 1.12 1.47
All Seeds 20 100.00 5.77 3.92 2.87 1.47 2.00 1.17 1.37
Direct measurements by Lee A. Newsom (1985), Department of Anthropology, University of
Florida, Gainesville, with "Manostat" dial type 6921 caliper. Classification, means and
ratios by the author.
Comparison of the Hontoon seeds with those of VG is limited by the
size and structure of the latter sample. Fennell apparently selected
representative seeds in terms of their number per fruit. The twenty seed
sample is based on two single seed berries (10%), three 4 seed berries
(60%), and one six seed berry (30%). There does not seem to be a clear
correlation between seed dimensions and number of seeds per berry.
Compared directly, (15) the longer VH seeds fall into the mean
length for VG (5.70 vs. 5.77) with a similar "median" of 5.67. The mean
width for all VH seeds, however, is 12.30% greater than that for the VG.
The mean thickness of the VH is also greater than that of the VG, by 11%.
The chalaza is 20% larger in the VH.
In relative dimensions there are corresponding differences that
belie the remarkable likeness between the VH and VG seeds. The L/W ratio
of VG is 17.7% higher (indicating a somewhat narrower form), and the L/T
ratio 16% higher (somewhat thinner), than the VH. The L/W value for the
VG chalaza is 12.4% higher, indicating a relatively elongated outline.
In general, the compared measurements show that seeds of the Hontoon
Grape are morphologically akin to those of Simpson's Grape and Fennell's
Grape. At the same time they are clearly distinct, individually and
collectively. Yet all three types were found in the same anthropogenic
context (shell middens), and within the same geographic area of south
central Florida. Is the archaeological grape a precursor of the two
living forms with similar seeds, that share horticultural attributes?
The possibility that the Hontoon Grape seeds represent an
archaeological cultivar raises further questions. The seeds of the three
forms compared do not suggest hybridization between a native type and
European V. vinifera, but rather between native American species.
Foundling "mission grape" cultivars such as Herbemont and Black Spanish
have seeds readily discernable as intermediate in form between V.
aestivalis, a likely parental species of VH, and V. vinifera. Two
characteristic features of the European Grape, namely: 1) pronounced beak;
and, 2) chalaza located well above the center of the dorsal face, are
present in the "mission" foundlings, but absent in the three samples
Elucidation of the ancestry of Simpson's and Fennell's foundlings
will have to await more sophisticated techniques of genetic analysis.
However, mention of Sauer's proposition of aboriginal grape cultivars is
relevant at this point. Sauer (1971) inferred that three modern American
cultigens V. rotundifolia, V. labrusca, and V. aestivalis were of pre-
colonial origin. The historical record supports reasonably well the case
for Indian muscadine (V. rotundifolia) viticulture (Mishkin, 1975; Gohdes,
1982). The evidence in favor of V. labrusca is at best tenuous.
The argument for V. aestivalis is complicated by the extensive range
of the species, taxonomic recognition of several geographic subspecific
forms, and widespread evidence of hybridization with other species. For
example, after a survey of herbaria, germplasm collections and the field,
Rogers and Mortensen (1979) recognized five subspecies of V. aestivalis
in Florida: 1) aestivalis; 2) sola; 3) divergens; 4) smalliana; and,
5) simpsoni. Following Anderson (1949), Rives (1963), and others, it is
likely that some or all of the subspecific forms could represent hybrid
"swarms" or "men~ges" resulting from interbreeding of the "true"
aestivalis with other species, including the introduced European cultigen.
The territory of V. aestivalis proper covers most of southeastern
North America (Bailey, 1934). In the northern reaches and higher
elevations of its range it gives way to a hardier variant, V. argentifolia
or bicolor. West of the Mississippi River, from eastern Texas and western
Louisiana north to the Ozark highlands of southern Missouri, the
subspecific Post-Oak or Caddoan Grape prevails. Often considered a
separate species, V. lincecumi Buckley, the Caddoan Grape has been
suspected variously as a natural hybrid swarm (Rives, 1963) and as a horde
of horticultural escapes from early mission vineyards (Branas, 1974).
V. lincecumi does suggest hybridity between V. aestivalis and the
large berry V. candicans which shares the southern part of its range and
is closely related to V. shuttleworthi of southern Florida. Sauer (1971)
pointed out that the first missionaries to visit the area (from the
Spanish colonies in Mexico and Florida) were surprised to find the Hasinai
and Caddoans tending grapes similar to theirs. In 1876, T. V. Munson, the
"father" of modern adaptive grape breeding chose to settle in Denison,
Texas on the Red River across from the Indian Territory of Oklahoma
(Munson, 1887, 1909).
Munson made the Caddoan Grape the focus of his breeding work. He
searched land the Indians had not long before vacated and collected
exceptional vines bearing large grapes (around an inch in diameter) in
heavy clusters. These he bred with cultivars of other species and
regions. His selections were widely disseminated. Taken to France, they
became the phylogenetic foundation of modern adaptive grape breeding in
Europe (Galet, 1956) and after World War II in the United States (Barrett,
Interestingly, the seeds of V. lincecumi (VL) described, illustrated
and measured by Bonnet (1902), Munson (1909), and later by Gleason and
Fernald (cited in Steyermark, 1963) appear very similar to those of VH,
VS and VG. Compared directly, the longest VH fits the lower range of
length for VL (7 to 7.25 mm). The mean L/W ratio for VS fits the middle
range for VL (1.40 to 1.33). Countering both Fernald and Gleason,
Steyermark found no correlation between seed size and berry size in the
modern feral population of "V. aestivalis" (i.e. lincecumi) from southern
Missouri. (16) On the other hand, he conceded that "the fruits are sweet
and edible and used for preserves and jelly" (Steyermark, 1963: p.
It is well documented that the Caddoans produced smoked raisins and
had a horticultural tradition that may have included clonal propagation
of selected grape varieties (Swanton, 1946; Griffith, 1954; Perttula et
al., 1982). Munson (1909) described two botanical varieties of the
Caddoan Grape. One was a smaller fruited, sweet and juicy type
appropriate for winemaking. The second was a larger fruited kind,
described as having tough, dry, very acid and astringent pulp, traits that
suggest the possibility of uncommonly good prune-like or apricot-like
raisins. If the large seeds are considered as "grape-nuts," it would seem
the Indians had a superior product by present standards.
A report on a late Woodland Period (ca 1,000 BP) grape seed find
from a typical Caddo site in northeastern Texas mentions the presence of
preserved dried pulp (Crane, 1982). Although the seeds are described as
identical to modern summer grape (V. aestivalis), a photo, inadequate for
lack of scale and resolution is suggestive of V. lincecumi, and of the
Hontoon Grape. Attempts to locate the author and the sample were
unsuccessful, as were efforts to obtain comparative seeds from Munson's
VL derived selections. Whether the Hontoon Grape is closely related to
modern VL or to archaeological Caddoan grapes could not be determined by
the researcher, and remains an open question.
It is not known what purpose was served by the Hontoon Grape,
presumably an Amerindian cultivar, in a settlement of Hispanicized Indians
of the late 18th century. At the time, Bartram observed that similarly
acculturated tribes in Georgia were still making smoked raisins in the
traditional manner, apparently with a cultivar unfamiliar to the
During our progress over this vast high forest, we crossed extensive
open plains, the soil gravelly, producing a few trees and shrubs or
undergrowth, which were entangled with grapevines of a peculiar
species. The bunches (racemes) were very large, as were the grapes
that composed them, though yet green and not fully grown, but when
ripe they are of various colors and their juice is sweet and rich.
The Indians gather great quantities of them, which they prepare for
keeping by first sweating them on hurdles over a gentle fire and
afterwards drying them on their bunches in the sun and air, and
store them up for provision. These grape vines do not climb into
high trees but creep along from one low shrub to another, extending
their branches to a great distance horizontally round about; and it
is very pleasing to behold the clusters pendant from the vines,
almost touching the earth, indeed some of them lie on the ground
(Bartram, 1775: p. 321).
The above quotation unequivocally indicates a non-vinifera bunch grape and
not, as has been recently claimed, a muscadine (Olien and Hegwood, 1990),
or even a labrusca or other native grape of the East, all of which were
familiar to Bartram. On the other hand, his description brings to mind
Munson's foundling Caddoan grapes (V. lincecumi) from Indian territory
west of the Mississippi River, a region unexplored by Bartram, who most
likely encountered a native cultivar, not a wild species.
Curiously, there is no record of transcultural Indian communities
having adopted grape winemaking. In the Spanish missions winemaking and
winegrowing were under religious control, and the use of wine by Indians
generally prohibited. The powerful ritual role of wine in Spanish culture
may indeed have been a reason for the non-adoption of winemaking by the
Indians. However, the possibility that aboriginal uses of grapes were
likewise of religious or ceremonial nature should also be considered.
Fruits such as grapes have been considered by anthropologists mainly
in the context of "gatherer" subsistence strategies, as nutritional
supplements, or "snack foods" (Ford, 1982: p. 304). The unique importance
of grapes as a high energy source, in particular for the lean winter
months, is supported by archaeologic as well as ethnographic data.
The most frequent grape seed finds have been carbonized specimens,
although they have been found in a variety of conditions, matrices and
sample sizes (Yarnell, 1969; Kay, et al., 1980). Although grapes are not
generally accepted as prehistoric domesticates, grape seed remains seem
rather consistently associated with recognized Amerindian cultigens and
horticulture from the late Archaic (Chomko and Crawford, 1978; Chapman and
Shea, 1981) through the Woodland (Pertula et al., 1982) and Mississippian
(Watson, 1980) to the historical periods (Newsom, 1986). (19)
On the other hand, evidence of possible non-subsistence uses of
grapes, such as ceremonial or "soul food" for the living and the deceased,
medicine and dyestuff, although sparsely documented is also available in
the archaeological record. The presence of grape seeds appears associated
in one early site (Late Archaic, ca 4,200 BP) with the presence of gourds,
suggesting a link with shamanist activities. (20) They also appear to be
characteristic of certain mortuary contexts. (21)
Medico-religious uses of grapes have survived in our own society as
a legacy of ancient Mediterranean culture. For example, the special
symbolism of dried fruits, including raisined grapes, in the celebration
of seasonal events is common to the Judeo-Christian and Islamic religious
traditions. Fresh grapes, and raisins also, can be used in effecting a
dietary "grape cure," or cleansing of the digestive tract in ritual
preparation for fasting. Did American Indians have similar traditions
four thousand years ago? If so, the presence and spread of hybrid grape
seeds would mirror the diffusion of early religious beliefs in a way
analogous to the diffusion of wine and winegrowing in the prehistoric
Mediterranean world (Stanislawski, 1975).
A Search for El Dorado
Florida has often been regarded a geographic corridor for biological
and cultural transferal between North America and the Caribbean tropics.
The subtropical native grapes of the peninsula, for example, because of
their adaptedness to hot and humid growing conditions, would be adapted
also, it has been reasoned, to similar conditions between the Tropics of
Cancer and Capricorn.
Modern adaptive grape breeding was emerging in Florida in 1935 (22)
when a visionary young botanist, Joseph Fennell, became enthralled by the
hybrid diversity and attractive cultivar-like traits of the native grapes
he found growing in apparently feral conditions in southern Florida. Like
Munson, whom he sought to emulate, Fennell collected horticulturally
appealing forms and bred them with each other and with cultivars from
other areas (Fennell, 1941, 1945). In the process, he conceived an
ambitious project for developing the foundation of a tropical viticulture.
In 1942 Fennell moved to Puerto Rico where Governor Tugwell offered
support. In 1943, frustrated by political and bureaucratic obstacles, he
moved with his vines from the federal experiment station in Mayaguez to
the Interamerican Institute of Agricultural Science (IICA) in Turrialba,
Costa Rica. Two years later, in 1945, he returned abruptly to Florida
where he continued breeding grapes privately on a limited scale. Fennell
ably memorialized his breeding work in search of a viticultural "El
Dorado" in articles written with contagious promotional enthusiasm
(Fennell, 1944-45, 1945).
Despite claims of success, Fennell's project came to a virtual
standstill in Costa Rica, for various reasons. Extreme cloud cover
(tolda) is characteristic of the growing season in Turrialba
(Schwerdtfeger, 1976) as it is in Mayaguez (Ravalo et al., 1986). (23)
Except for regional accessions of V. caribaea and V. popenoei, most of the
grapevines Fennell grew at the IICA he took there as hybrid seeds and
clones from Florida. Two growing seasons was insufficient time to fully
evaluate their performance.
Fennell (p.c. 1982) would recall that most of his material was
seriously affected by "rust," a mold which in grapes, as in peaches
(Prunus persica), appears mainly on senescent leaves (i.e., a "serious"
attack implies the vines were not growing properly). An exception was
two "true" species introduced from southernmost Florida. V. shuttleworthi
and V. cinerea var. floridana (V. aestivalis ssp. divergens). Both
developed as well as the native V. caribaea, according to Fennell.
Fennell's accounts mention the need to import and preserve pollen
of northern latitude parents as one of his difficulties in producing
hybrids at Turrialba. His known hybrid selections are described as having
originated in Florida, a very few from seeds obtained in Costa Rica.
Evidently, the greater part of Fennell's collection at the IICA was
abandoned by him as unpromising, and eventually died out or was destroyed
when its custodians arrived at the same conclusion. At the end, Fennell
(1947, 1948) hinted that he had become aware of the importance of
daylength as a critical parameter of adaptive viticulture in the tropics.
In 1950, some five years after Fennell's departure, a Brazilian
grape breeder, J. A. Santos-Neto obtained a handful of clones of dubious
phylogeny (24) from Fonnell's abandoned plot in Turrialba. The material
was planted at Fazenda Santa Eliza, the field station of the Instituto
Agron6mico de Campinas (IAC) in the state of Sao Paulo (latitude 22053'S)
a few miles north of the Tropic of Capricorn. These became the basis for
a vast succession of hybrids and backcrosses selected for adaptation to
the Brazilian tropics and subtropics over the next quarter century.
Santos-Neto (1955) deserves recognition for creating the first modern
grape hybrids in the tropics, for the tropics, with tropical (and
While Fennell was away in the Caribbean, viticulturist Loren Stover
of the agricultural experiment station in Leesburg, central Florida, was
visiting a nearby farm when a field hand walked by eating what appeared
to be unripe green grapes. Stover (p.c. 1982) was surprised to discover
that the grapes were not only ripe and quite sweet, but also wild from a
large vine eventually classed as V. simpsoni. (25) It was named Pixiola
and used by him as the female parent of the first hybrid selection
produced and released by the state's adaptive grape breeding program, the
Lake Emerald (Stover, 1960).
Stover, who had no formal training in plant breeding, expanded his
hybridization to include other foundling native grapevines. His work laid
the foundation for the present program, expanded considerably under his
successor, geneticist John Mortensen (Mortensen, 1971, 1980). The
development of adapted hybrid varieties for many uses has created a
diverse viticultural industry in Florida (Bates, et al., 1980).
In conclusion, it can be affirmed that the evidence articulated in
this chapter demonstrates the plausible evolution of adaptive grape
breeding in Florida from the Spanish mission settlements to the modern
state experiment station in Leesburg. However, the sequential pathway is
more often devious than direct, with many ramifications. The explanatory
scheme that is here presented is in the nature of a road map of a
territory that has considerable terra incognita.
On the basis of the archaeobotanical evidence, for example, the
Sauer grape theory of aboriginal cultivars cannot be decisively confirmed,
only elevated to a more sophisticated level of conjecture. Then also,
there are the apparent dead-ends of phylogenetic discontinuity. The
antebellum wine grapes Black Spanish and Herbemont, of presumptively
mission origin, were long eschewed as adaptive progenitors in Florida
(Mortensen, et al., 1977), probably because of a remnant prohibitionism
On the other hand, the above varieties were used in hybridization
by Munson and by later breeders in France. Some of their descendants have
returned to Florida where they have become the parents of more recent wine
grape hybrids (Mortensen, 1971; Mortensen and Andrews, 1981). Fennell's
V. gqas was lost for many years. Recovered in the early 1980s (Fennell,
p.c. 1984), it may yet be used in breeding new varieties. Simpson's grape
has been used to a limited extent in the Leesburg program (Mortensen, p.c.
The main contribution of the Florida mission grapes has been
ideographic. Their very existence and functional utility has been
responsible for the widespread adoption of adaptive breeding, both as a
dynamic grassroots tradition and as a practical scientific approach to
viticultural adaptation. Although Floridian grape cultivars have been
disseminated world-wide, few have proven adapted outside the narrow
latitudinal limits of the peninsula. However, as will be appreciated more
fully in the following chapters, Florida has played a key role in the
stimulus diffusion of adaptive hybridization to the New World tropics.
Nonetheless, the process has been hindered by the lack of adaptedness of
Florida cultivars to relatively short tropical daylengths.
1. These researchers have demonstrated that geographical and
archaeological series of grape seeds can be used to detect origin
and diffusion of somatic traits reflecting intra and interspecific
hybridization (See also: Olmo, 1942; Negral, 1957).
2. Subsequently, a second corridor was extended westward across the
peninsula, incorporating the peoples of Timucua and Apalache. At
its height the Spanish mission sphere embraced some forty principal
village communities (Gannon, 1965).
3. However, the location on the Atlantic Coast of Santa Elena and the
other Sea Island settlements provided long term protection from
lethal freeze damage for tender Mediterranean fruits (See "South
Carolina" and "Georgia" in Weather Atlas of The United States,
4. According to Marvin T. Smith (p.c. 1984), the upper branch appears
to have been considered the main Altamaha by natives of the area at
the time of De Soto's passage in the spring of 1540 (See also:
Hudson et al., 1984). Covington (1964) mentions a group of
Apalaches resettled on the Oconee until 1715.
5. It has been noted that the Creek were dedicated horticulturists who
insisted on planting and cultivating orchards even as they were
being dispossessed and forced to rely on less sedentary subsistence
strategies such as fishing, gathering and herding (Fairbanks, 1952;
Mason, 1963; Covington, 1964).
6. Woodson refers to the archipelagic condition of peninsular Florida
(Central Florida he calls "Orange Island") during the Pleistocene
7. The practice was widespread from the Late Archaic period (3,500 to
4,500 BP) on, as indicated by the abundant presence of charred seeds
in the archaeological record (Yarnell, 1976; Watson, 1980; Ford,
8. The species are: V. munsoniana, V. rotundifolia, V. aestivalis, V.
vulpina, and V. shuttleworthi (Rogers and Mortensen, 1979). A
number of seeds suggested intermediacy between vulpina and
aestivalis. Grapevines of phenotypically hybrid appearance have
been observed by the researcher as comprising perhaps 10% of the
wild Vitis population in some areas. This is in agreement with the
experience of viticultural botanists in other parts of the U.S.
southeast over the years (Bartram, 1804; Rafinesque, 1830;
Engelmann, 1883; Bailey, 1948; Munson, 1909; Fennell, 1945; Rives,
1963; Olmo, 1976; Duncan, 1975).
9. Sources included the University of Florida Herbarium, the living
collection of Vitis forms at the Leesburg Agricultural Research
Center (IFAS), the U.S. National Herbarium of the Smithsonian
Institution, the University of Tennessee Museum, the American Museum
of Natural History, Florida State University (Margaret Scarry), and
documentary sources featuring illustrations of grape seeds.
10. In reply to a classified advertisement placed in the July 15, 1983
edition of Florida Market Bulletin, several south central Florida
residents sent descriptions and samples of hybrid-like foundlings,
suggestive of both V. shuttleworthi and V. aestivalis.
11. Viala noted many similarities of "simpsoni" and coriacea. In
particular, that the very short beaked seeds of the first were
indistinguishable from those of certain forms of the latter. He
concluded that hybridization between diverse forms must be common
12. Slimpson's Grape according to Bailey, equivalent to Munson's revised
13. All seeds of the three samples were measured by Lee A. Newsom,
Department of Anthropology, University of Florida, Gainesville,
using a "Manostat" dial type 6921 caliper.
14. Coffee, for example, loses about 18% of its weight and presumably
reduces its proportions accordingly when roasted. See also, Shea
and Crites (1980), Minnis (1981).
15. Considerable shrinkage is assumed to have occurred in the herbarium
sample of V. gigas collected by Fennell in 1938, near Roseland,
Brevard County, Florida.
16. Fernald found a direct correlation between seed and berry size which
justified his separation of VL from aestivalis. Abandoned
cultivars, on the other hand, would presumably generate populations
of wild descendants in which their horticultural attributes would
tend to be genetically dispersed.
17. Very high soluble solids, mainly sugar, (over 20 Brix) has been
noted by this observer and others in some Florida forms of V.
aestivalis, in contrast to other local species, but in accordance
with V. vinifera.
18. That Bartram was puzzled is surprising. He has long been considered
a competent botanist and ampelographer. His father John Bartram
organized the first living collection of North American grapes in
his Philadelphia botanical garden. William authored a pioneer
American ampelography (Bartram, 1804).
19. Following Chapman et al. (1982), the Southeastern cultural periods
for prehistorical archaeological purposes is, in part, as follows:
Middle Archaic, 5,000 to 8,000 BP; Late Archaic, 2,500 to 4,500 BP;
Woodland, 1,000 to 2,000 BP; Mississippian, Contact (500 BP to 1,000
20. It has been proposed that the spread of the bottle gourd (Lagenaria)
in the Southeast is a likely indicator of an ideological (religious
and political) movement or "Great Tradition" that may have led to
the adoption of other plants for shamanist rather than subsistence
purposes (Hall, 1977).
In the so-called "squash and gourd" zone at Phillips Spring,
Missouri, uncarbonized grape seeds (preserved by saturation)
outnumbered seeds of the early cultigens by six to one (Kay et al.,
21. Early Woodland (ca 2,000 BP) grape seeds have been found in human
paleofeces from dry caves in Kentucky (Yarnell, 1969). The context
suggests they were ingested in preparation for death.
22. The ephemeral commercial success of several Munson hybrids in
central and west Florida led Charles Demko (of Altoona) to begin
breeding native peninsular grapes with American cultivars in 1927
23. The daylength shortening effect of tolda is enhanced by the location
of Turrialba. Nestled in the eastern piedmont of the Cordillera
Central, evening falls early in the rainy season as cumulo-nimbus
clouds pile against the mountains, thus "advancing" the westerly
setting of the sun.
24. This researcher observed in 1971 and subsequent visits to Campinas
that part of the Turrialba material in the IAC collection was
mislabeled. Two were species supposedly used by Fennell He claims
(p.c. 1984) he never took V. jgs or V. smalliana to Costa Rica.
25. An expedient that conveniently avoids the problem of origin of this
exceptional native clone with horticultural attributes.
ADAPTIVE PRUNING IN VENEZUELA:
EVOLUTION OF A PARADIGM
Venezuela provides a still unfolding epitome of a modern tropical
viticulture that is emerging from the largely empirical development of
traditional adaptive techniques. Although there are elements of
historical continuity from the early colonial period, it is largely a
recent phenomenon, arising from the geographic interface of diverse
cultural and geo-environmental factors during the latter part of the 20th
century. The process has generated a modest fund of documentary data and
direct sources of first-hand testimony that make possible the following
examination. Most of the information for this chapter was obtained in the
course of two visits to Venezuela, in April 1988 and in November 1989.
Before World War II grapevines were grown sporadically in gardens
and small vineyards throughout much of Venezuela between latitudes 8N and
120N (Eguiraun, 1945; Araque, 1969). After the war, a wave of immigrants
from Mediterranean Europe sparked an upsurge in planting and in public
interest concerning the possibility of viticulture as a viable agri-
industrial enterprise. In 1961, the first agricultural census to feature
grapes recorded only 4.75 hectares (MAC, 1970). Although probably
underreported, the figure is in stark contrast with the roughly 300
hectares reported for 1969, eight years later (Ibid.).
By 1975, the number had doubled to 600 ha. However, the spectacular
growth of the 1960s and 1970s was not distributed evenly among all the
geographic areas in which people were striving to establish vineyards.
This is made clear in Table 4, where grapevine areas are compared by state
between 1969 and 1975.
Table 4. Vineyard area in Venezuela, By State, 1969
Ha. % Ha. %
tegui (unlisted) 38.5 6.6
a 59 19.8 91 15.4
obo 6 2 6 1
21 7 61 10
a 7 2.3 3.5 .6
da 4 1.3 (unlisted)
11.5 3.8 5 .9
ra 11 3.7 4.5 .7
llo 17 5.7 (unlisted)
162 54.3 380 64.5
uela 298.5 100 589.5 100
e: MAC, 1969; and Ramirez-Soto, 1976.
The table shows that ten states had vineyards during the post-war "grape
rush." At the end of the period, however, plantings had declined or
disappeared in all but four states.
Only Zulia, Lara, Aragua, and Anzoategui (in descending order, and
from west to east) had experienced a "grape boom" by 1975. By 1980 total
hectareage for Venezuela had again doubled, to 1,200 ha. (Bautista and
Vargas, 1980). Half of the area, 600 ha, was planted in the districts of
Mara, Maracaibo and Urdaneta, in the immediate hinterland of the city of
Maracaibo, capital of the westernmost Venezuelan state of Zulia. The tide
receded in the early 1980s to about 1,000 ha in Zulia (Corzo, 1987). Lara
maintained a lagging second place with more or less 200 ha (20%) in
grapevines spread across five districts: Moran (El Tocuyo), Urdaneta
(Siquisique), Torres (Carora), Jimenez (Quibor), and Palavecino
(Tarabana), (Instituto de la Uva, 1988).
The two states, Zulia (capital Maracaibo) and Lara (capital
Barquisimeto), where viticulture has been relatively successful have in
common climatic conditions that assure maximum insolation for most of the
year (Figure 3). The traditional technique of adaptive insolation
optimization implicit in the selection of both regions by viticulturists
has been covered in detail in Chapter 2 and will only be dealt with
briefly in this chapter. Instead the following analysis compares the
development of the related techniques of adaptive pruning and adaptive
There are important differences as well as similarities between the
neighboring regions that imply alternative developmental constraints and
opportunities for viticulture. In both areas, the best land for vineyards
consists of nearly level alluvial terraces with well-drained, sandy
profiles at least one meter in depth (Vargas, p.c. 1989). However, the
so-called Maracaibo highland (altiplanicie) is really a peneplain raised
no more than fifty meters above its coastal periphery (Araujo, p.c. 1988).
In contrast, the inland fault valley depressions of Lara are elevated from
300 m at the foot of the Baragua escarpment in the north, to 700 m at the
edge of the Andes in the south (Guevara and Guevara, 1983).
0 20 40
VENEZUELAN ANDES i ,
.. ... o I Kilometer
Figure 3. Semiarid areas of western Venezuela, and approximate extent of
April-June and September-November tolda (6/8ths cloud cover).
Soure: After Guevara-Diaz, 1985; and MINIDEFENSA, 1984.
During the World War II years the importation of table grapes to
Venezuela was sharply curtailed, and cottage-scale growers of
comparatively poor quality fruit had a windfall. At the end of the war,
Italian and other South European immigrants settled in the hot, dry
coastal plain around Maracaibo, a landscape reminiscent of the
Mediterranean. There they became enthused by the prospect of a lucrative
crop that was familiar. Extensive varietal collections of Old World
grapes (V. vinifera) were introduced from Italy and elsewhere in an all-
out effort to find cultivars that would adapt to local conditions (Olmo,
1968; Araque, 1969; Melendez and Garassini, 1973).
By the early 1960s a handful of imported varieties had proven
reasonably productive as well as commercially attractive. The selected
cultivars could be pruned at any time of the year, and coaxed into
yielding two to three harvests yearly (Fregoni, 1977). However, the
foreign grapes had not been bred to withstand periodic spells of rainy
weather and high temperatures combined with high atmospheric humidity.
Such conditions, endemic to even the driest areas of Venezuela, brought
on mildews and other fungi that would disfigure fruit bunches and weaken
the vines by defoliation.
Thus, when commercial harvesting began in 1964, a promising market
for petroleum-derived fungicides, pesticides, growth regulators and
fertilizers began to unfold. Vineyards were included in the financial
credit program of the government's National Plan for Fructiculture
(FONDFRU, 1975). In 1965, FUSAGRI, the Shell Foundation for Agricultural
Services, began varietal trials at its experiment station in Coro (Falcon
As vineyard hectares multiplied, there seems to have been misgivings
in official circles concerning long term viability of the immigrant
temperate zone crop. The prevailing view among formally trained
agronomists was Winkler's (1962) authoritative dictum that without an
adequate low temperature period of rest V. vinifera vines in the tropics
could only be expected to produce small yields of poor quality fruit.
There was pressure also from the enduring viticultural community farther
inland, which began to feel left out of the incipient boom. FUDECO, the
government Foundation for Development of the West-Central Region, decided
to bring in an outside expert.
The choice was Dr. Harold Olmo (University of California, Davis),
renowned authority on grape genetics and geography. Olmo's 1968 survey
of Lara, Zulia, and neighboring areas identified prospective locations for
viticulture based on a subjective evaluation of geo-environmental
characteristics. He rejected the temperate zone tenet of "heat summation"
as inappropriate, and by implication laid to rest concern about the
chilling requirement, disregarding it altogether. Olmo also pointed the
way to a more scientific approach to adaptive pruning and adaptive
The Olmo report was officially presented at the First Symposium on
Production and Industrialization of the Grape in Venezuela (Maracaibo,
1969). In 1970, the grape growers of Zulia organized formally and
petitioned the government for protective legislation against imports,
which was enacted in 1971 (Millan, 1975). In 1973, FUSAGRI started a
broad program of research and technical assistance in viticulture, with
funding from CORPOZULIA, the state economic development agency.
Lara was not to be left behind. In 1974, an Instituto de la Uva
was established at the state university in Barquisimeto, capital of Lara.
A second viticultural symposium was sponsored by FONDEFRU and held in
Barquisimeto early that year. The agenda covered a comprehensive
assessment of the prospects for viticulture as an authentic agricultural
industry for Venezuela. Perhaps the most influential reports were the
supportive overviews of two additional outside experts, Professor Pierre
Galet (Montpellier, France), and Professor Luis Hidalgo (Madrid, Spain).
These led the way for visits by still other consultants: Alleweldt (1975,
Germany), Fregoni (1977, Italy), and Lider (1978, California). The door
was open for transferral of state-of-the-art technology from Europe, and
to a lesser extent from the United States.
Finally, in 1977, a Centro de Desarrollo de Viticultura Tropical
(Centro Viticola) was founded in Mara, near Maracaibo. The non-profit
foundation was jointly sponsored by CORPOZULIA, FUSAGRI, and AVEZ
(Association of Zulia Viticulturists). The Center sophisticated and
broadened the range of research and extension activities that had been
initiated by FUSAGRI.
By the turn of the decade, a number of young Venezuelan agronomists
were undertaking academic training in viticulture and allied subjects such
as enology in Argentina, California, Spain and France, as well as
Venezuela. In the 1980s a native corps of technicians was in the
forefront of research on adaptive tropical viticulture.
The Pruning Calendar
The pruning of grapevines in the tropics pursues adaptive goals
analogous to those at higher latitudes. Pruning is done to train vines
to a manageable framework, to optimize productivity, and to coordinate
critical stages in the fruiting cycle with adequate climatic conditions.
On the other hand, procedures introduced from higher latitudes and applied
without modification are often ineffective, and at worse counteradaptive
in the tropics (See Chapter 2).
Therefore, Venezuelan viticulturists have had to develop special
procedures for adaptive management of their immigrant crop. For example,
while long or cane pruning is productive at higher latitudes, only short,
or spur, pruning can deal with the problem of apical dominance and
consequent irregular, weaker budbreak of "unrested" vines under tropical
conditions (Bautista and Vargas, 1980). On the other hand, the more or
less continuously active vegetative state of adapted V. vinifera cultivars
at ca. latitude 10N allows training of the vine to a mature bearing
structure within a year, in contrast to the three or four years required
in places with discrete and shorter growing seasons (Simancas, 1988;
Vargas, p.c. 1989).
However, realization that pruning rather than repose (with or
without chilling) would renew the fruiting cycle marked the discovery of
tropical viticulture in the colonial period and its recurrent rediscovery
by immigrant growers and modern researchers (Bautista and Vargas, 1980).
For it is the prospect of two or more harvests yearly that has heartened
grape growers faced with the disappointing productivity of their imported
The crucial question of when to prune arises because of the
demanding climatic requisites of V. vinifera grapevines. Having evolved
originally in the arid Middle East (See Chapter 2), the cultigen generally
requires a very dry growing season, uninterrupted by rain or high
humidity. Ideal conditions are rarely encountered, even in its European
range, where its perimeter has shifted unceasingly over the centuries.
Nonetheless, in the Mediterranean basin a virtually rainless growing
season is more or less assured (Critchfield, 1974). Not so in the
seemingly dry environments of the Venezuelan tropics. According to
Guevara-Diaz (1985), the viticultural areas of Zulia and Lara (Figure 3)
as well as a promising development in the eastern state of Anzoategui, are
in regions climatically typified as "semiarid," or "BS" in Koppen's
classification. Tropical semiarid climates are characterized by
relatively high levels of insolation, hence high diurnal temperatures, and
evapotranspiration in excess over precipitation. Rainfall can be very
erratic, so that annual averages are of little help in delimiting
Moreover, relatively high levels of atmospheric humidity prevail.
In the semiarid areas mean relative humidity ranges from 70% to 76%
(Guevara-Diaz, Ibid.). (1) Only the widespread incidence of the trade
winds moderates diurnal temperature and keeps relative humidity around a
diurnal mean of 70% (Vargas, p.c. 1989). At night, when the trade wind
ceases and temperature drops, relative humidity in the semiarid regions
normally exceeds 80% (Vargas, Guevara-Diaz, Idem.). Although there are
wide varietal differences in tolerance to atmospheric humidity within V.
vinifera, the better adapted are precariously susceptible to breakdown
under environmental stress. When atmospheric moisture approaches the dew
point, all parts of the actively growing grapevine are subject to
infestation by various fungus maladies.
Mildews, for example, attack the leaves, progressively defoliating
and weakening the vine. However, damage can usually be allayed by timely
spraying with fungicides. Equally susceptible, and rather more difficult
to protect, are the fruiting clusters which are especially vulnerable
during flowering and fruit set, and again during ripening.(2)
Consequently, deciding when to prune requires detailed knowledge of local
seasonal rainfall patterns and of the phenology of the varieties that are
cultivated. The study of both subjects has become a central concern of
adaptive viticulture in Venezuela.
Overall, there are two major seasonal patterns of rainfall
distribution in Venezuela (Guevara-Diaz, Ibid.). A unimodal pattern with
maxima in June, July or August prevails in most of the country. Toward
the Andes in the west the pattern becomes bimodal with maxima in April or
May and in October. However, oceanic and topographic influences result
in intricate transitional and local patterns. In general, it is drier in
the coastal zone and inland rain shadow valleys, and wetter in the
northeast and higher elevations to the south and west.
In the first Venezuelan pruning manual, Eguiraun observed "an
incomplete recess" in grapevine vegetative activity during December and
January in some areas, and a "slight recess" in July and August, "as if
there were two vegetative cycles in a year" (Eguiraun, 1945: p. 6). He
then theorized that vine repose could be obtained either with low
temperatures or by withholding water, as was done in Belgian hothouses for
producing out of season table grapes. The problem in Venezuela, he
concluded, was to find varieties and pruning techniques that would yield
a crop within dry periods.
However, Eguiraun made no specific recommendation concerning when
to prune. Possibly he was constrained by his acceptance of the
theoretical need for a rest period by either chilling or drought. He did
not perceive the slowdown in vegetation as a response to shorter
daylength, both during the drier and cooler winter solstitial period and
again during the cloud covered summer rainfall climax. Apparently
attributing growth recesses to the lower temperatures that accompany the
increase in cloudiness, he rather expressed concern over the heat
summation required to complete the crop cycle.
Eguiraun carried out much of his work as a government horticulturist
in a coastal highland experiment station near Caracas (ca. 900 m ASL)
during the late 1930s and early 1940s. At the time many growers still
accepted temperate climate verities concerning the putative requirement
of cool weather. It is said that modern viticulture in Venezuela began
in 1938 when a home grown practitioner, Fortunato Gil, gave up trying to
grow grapes in the cool highland of Humocaro Alto (Lara) and established
a prize winning vineyard in the semiarid piedmont valley of Humocaro Bajo
(Araque, 1969; Vargas, p.c. 1989).
At any rate, in the early years the decision of when to prune
appears to have been highly subjective, based on each grower's
understanding of grapevine interaction with the local climate (Olmo,
1968). By the late 1960s regional patterns began to emerge. Araque
(1969) reported that in Zulia there were two pruning periods, one in
September to October for a December to January vintage, and another in
April for a July harvest. For Lara there was a single pruning in the
period from October to December for harvesting from January to April. In
the Andean state of Tachira on the Colombian border, and the north central
state of Aragua (just south of Caracas) pruning was done in July for a
vintage in December.
Interestingly, a two-crop pattern was mentioned only for Zulia,
which was already in the lead of vineyard expansion. The first complete
viticultural handbook, compiled by the growers of Zulia (Rojnic et al.,
1972) did not specify pruning dates but stated somewhat vaguely that
pruning should be programmed so that the ripening period would not
coincide with the rainy season of October-November. The first official
pruning manual published in Lara (Melendez, 1978) explicitly recommended
pruning toward the end of the rainy period. This appears to have been the
general rule of thumb (Raniery, 1969).
Subsequently, Galet (1973) coincided with Araque on the first
pruning period for Zulia (September-October), but assigned the second to
February and March rather than April. He also differed concerning
Tachira, where he found two prunings also, in May and January. He listed
the neighboring Andean states of Merida with pruning in March-April and
August-October, and Trujillo with pruning every four months beginning in
April. With a certain exasperation Galet added, "and even all year
around: in January, May, June, August, September, October, November, and
December" (Galet, 1973: p. 6).
Galet's report is one of the earliest to mention a phenological
event, blooming, as occurring fifteen to thirty days after pruning,
implicitly during dry weather. There may have been an error in
transcription, since it is budbreak which takes place roughly at that time
(Bautista and Vargas, 1981). Hidalgo (1974) offered a more explicit
statement of the need to correlate pruning with the phenological cycle.
Pruning should be done toward the end of the rainy season, he recommended.
In variety selection, he added, the duration of its fruiting cycle from
pruning to prospective date of harvest should be taken into consideration.
Long cycle varieties, requiring four or more months (120 or more days)
should be discarded in favor of short cycle varieties (ca. 90 days) that
would allow two or more crops per year.
Hidalgo proposed that viticultural sites in Venezuela be evaluated
and correlated with appropriate varieties by means of the "heliothermic
index" (HI). The HI is a European invention derived from Winkler's (1938,
1962) "heat summation" by Branas (et al., 1946) who added daylength as a
variable for measuring the calendar duration of appropriate (i.e. warm
and sunny) conditions for the fruiting cycle (See also: Santibafiez et
al., 1986). The formula for the HI is XH x 10-6, where X represents mean
degrees of effective heat per month, based on daily temperature over 10C
(50F), the threshold for vegetative activity in V. vinifera. H
represents the summation of hours of effective insolation per month. The
product is reduced to a manageable index on multiplication by 10-6.
The HI formula does not take into account the function of daylength
as a phenological regulator. Winkler, for example, observed that although
grapes in California would normally bloom when the mean daily temperature
reached 68F (20C), "in areas where a mean of 68F is not reached,
factors such as length of day seem to influence the time of blooming"
(Winkler, 1962: p. 106). Branas (1974) also was somewhat aware of
photoperiodicity in grapes. He noted that leaves became very large close
to the polar limits of cultivation, but were rather small in the
Regarding the HI, Branas had offered the caveat that in the lower
latitudes where ambient temperature is always above 10"C the HI formula
"loses all meaning" (Branas, 1974: p. 351). Nonetheless, to the nascent
research establishment Hidalgo's well articulated positivist prescription
must have seemed at once pragmatic and authoritatively "scientific."
Despite its flaws, the HI would become the cornerstone of adaptive
viticulture strategy in Venezuela in the 1980s. The pruning calendar
would evolve accordingly, as the principal instrument to implement that
Nineteen seventy five marks a watershed of institutionalization for
Venezuelan viticulture. Plans for research and development were being
drawn up and priorities established within a coalescing framework of
public and private organizations sharing the interest. Expert European
opinion corroborating Olmo's 1968 assessment and the Second Symposium
(1974) gave impetus to the process.
European consultants, Galet (1973), Hidalgo (1974), and Alleweldt
(1975), agreed on the priority of expanding the narrow cultivar base with
quarantined introduction of promising V. vinifera varieties. Hidalgo
thought that those varieties that did well in southern Europe would be
most likely to adapt. Galet suggested premium wine clones from France to
initiate diversification away from table grapes. All shared the long
standing officially sanctioned European aversion for North American
species hybrids, except as rootstocks.(4) Most echoed Olmo's (1968)
warning against importing such hybrids from the southeastern United States
for fear of introducing Pearce's disease and other maladies endemic to a
region with a growing season as hot and humid as that of Venezuela.
With existing humid environment hybrids eschewed, accurate
determination of pruning calendars became crucial, along with the
evaluation of V. vinifera selections in promising locations such as those
identified earlier by Olmo. Perhaps because of the geo-environmental
diversity of the viticultural areas of Lara and their relative
underdevelopment vis-a-vis the Maracaibo area, the new Grape Institute
led the way in studies of the measurement of grape phenology in the
context of local geographic conditions (Vargas and Freitez, 1982;
Economic concerns were foremost. According to a report by Millan
(1975), the state of Lara had decreased its share of the grape crop from
11.6% in 1969 to 1.3% in 1972. It had dropped from third place in
production to a poor fourth, almost tied with Trujillo. Yields had
declined from 3.4 metric tons per hectare to 2.96 t/ha as the national
average, between 1970 and 1972.(5) Imports of table grapes supplied over
85% of the market in 1972 and were rising despite restrictions.
Importation of concentrated must for winemaking had almost doubled during
the same two years.
In 1976, Professor Luis Garassini, Director of the Instituto de la
Uva, cited Millan's report, and added Hidalgo's (1974) warning that local
production of table grapes (mainly in Zulia) could more than cover the
local market within a very few years (Garassini, 1976). He reiterated
official concern that low yields and high production costs threatened the
long term viability of viticulture as an economic enterprise.
Following the advice of Galet and Hidalgo, Garassini proposed that
the Institute focus on research toward development of a wine industry as
a promising alternative to table grapes. Grape varieties should be
introduced and evaluated, he argued, in terms of their potential for wine
making. Stressing the need to increase funding for such research, he
pointed to the lack of adequately trained technicians and the prevalence
of viticultural practices inappropriate for Venezuelan environmental
Two years later, in 1978, an Institute faculty member, agronomist
Guillermo Vargas, submitted his thesis for a licentiate degree in
viticulture and enology from the Polytechnic University of Madrid, Spain,
where he studied under Hidalgo. The Vargas thesis developed a model
application of the HI to eight scattered viticultural zones in the state
of Lara, for comparative evaluation and correlation with European grape
varieties of known HI values. Vargas' work marked the beginning of
serious studies of climate and grape phenology in Venezuela. It was to
be highly influential in determining the dominant research trend of the
1980s in tropical viticulture. However, this early thesis dealt only with
Vargas' model can be summarily described as follows. All
prospective viticultural zones of Lara state and the capital Barquisimeto
were pinpointed on an outline map. Mean monthly rainfall for each
location was presented in bar chart form accompanied by data on latitude,
altitude and total precipitation. A thin line was drawn across each chart
at the 100 mm (approximately 4 inches) level, indicating the critical
threshold at which development of the V. vinifera fruiting cycle becomes
hazardous. Curiously, this empirical rule of thumb had been independently
arrived at by this researcher after many years of geographical
observations in Puerto Rico (See Chapter 5).
Vargas was careful to prequalify his eight prospective zones "with
viticultural vocation" according to the following criteria:
1. Mean annual rainfall not over 650 mm [25.6 in.];
2. Elevation not over 662 m ASL;
3. Dry periods of no less than four months duration;
4. Zones without limitations for grape cultivation.
(Vargas, 1978: p. 8).
Essentially, he is offering an empirical description of proven locations
within the state of Lara. However, his modification of Branas' HI is
innovative. He assumes that in the tropics pruning is equivalent to the
high latitude 10C (50'F) growing temperature baseline from which
effective heat (i.e., insolation) is accumulated.
The Vargas thesis proceeds as follows. HI formula data was
tabulated monthly for each zone, and two starting (pruning) dates assumed,
the premise being that two crops could be accommodated per year. In each
case, the first of December was chosen to initiate the first cycle. The
second cycle was initiated the first day of July in half of the locations
(the easternmost), and the first day of June in the other half (the
westernmost). The start of the cycles correlates in some locations with
the last month of a rainy season, and in others with the first dry month
thereafter. The end of the cycles coincides in every case with the end
of a dry period, April after pruning in December; September, October, or
November after pruning in June or July.
To complete his model, Vargas simply "fits" the zonal HIs with those
of grape varieties classified in Europe as early, midseason and late, to
thereby confirm Hidalgo's prediction that early to midseason (so-called
"first season") varieties could be double cropped in the preselected
viticultural zones. His conclusions include the admonition that during
periods of high rainfall the vines should be kept in a "repose"
characterized by cropless vegetation, during which new foliage is formed
and nutrient reserves are accumulated. Preventive control of fungi is
required (42 to 58 days depending on the zone) to avoid premature
defoliation and initiation of a new cycle while undesirable conditions
The assumption that reserves are accumulated in the vine during the
rainy season is in line with Eguiraun's (1945) "slight recess in
vegetation", previously cited, and with the popular designation of such
periods as "winter." However, it contradicts the theory initially
proposed by outside experts of continuous and exhaustive vine growth under
tropical conditions. The overcast or tolda produced during the rainy
season most likely shortens photoinductive daylength below the twelve hour
threshold, signaling the vine to stop growing and commence the
accumulation of reserves (See Chapter 2). Thus, the traditional allowance
for a rest period in the pruning calendar becomes functionally adaptive.
In a final conclusion Vargas advised that his theoretical exercise
should be the object of experimental field trials for verification, and
that other (geo-ecological) factors affecting viticulture be related to
the HI. Clues pointing to daylength (as a regulator of phenology) as one
of those factors continued to appear. Indeed, while Vargas was studying
in Madrid, an important evaluation of Venezuelan viticulture by the
Italian researcher Fregoni featured the observation that:
The difficulty of adaptation of Vitis vinifera in the tropics
is linked to photoperiodism; indeed, it may generally be
considered a long day species. A few varieties, however, can
adapt to short day areas (Fregoni, 1977: p. 27).
This comment by Fregoni appears to have gone unnoticed, probably
because daylength per se had not been recognized as a meaningful parameter
by Venezuelan researchers. However, a pioneer experimental study compared
varietal productivity during four successive calendar semester cycles
initiated by pruning in January and July (Bautista, 1975). Eight
relatively well adapted cultivars (featuring at least two reputed V.
vinifera-caribaea hybrids) responded similarly with respect to seasonal
productivity. Irrespective of varietal differences, all were considerably
more fertile (floriferous) after pruning in January than after pruning in
Bautista's results are consistent with the findings of previous work
(notably Kobayashi et al., 1966; Buttrose, 1969a, 1974) reported in
Chapter 2. That is, grapevine buds formed during relatively long days
(i.e., over 12 hours) produce more fertile canes and more flower clusters
per cane than those formed during relatively short days (i.e., under 12
hours). In other words, in Venezuela also, buds formed during the long
days after pruning in July are more productive than those formed during
the short days after pruning in January.
The data available from Bautista's (1975) study, although severely
limited (6), is suggestive of a measure that might be used to compare
varietal sensitivity to daylength in terms of fruitfulness. Two of his
tabulations are useful. The first compares the mean number of fertile
shoots (canes) developed by variety after pruning each semester. The
second compares mean number of flower clusters developed by variety for
each semester. If the difference between short and long day semester
yields of each variety in both tabulations are multiplied, the result is
an absolute indicator of "daylength inducted productivity" (DIP).
A comparable index can be obtained by using the integer one as a
common dividend and each DIP as divisors. The resulting "daylength
sensitivity index" (DSI) reflects the degree to which productivity is
dependent on daylength above the mean minimum at the latitude (as modified
by altitude) where the vines were grown. The results are summarized in
Table 5. Interpretation of Table 5 is as follows. The native hybrid
Villanueva (according to Olmo, 1968, an apparent second generation hybrid
of V. vinifera and V. caribaea) is the most sensitive of the tested
cultivars, having the lowest DSI. In second place is Muscat Hamburg, a
traditional European "forcing" variety, only slightly more tolerant of
relatively short daylengths. Another traditional hothouse variety, A.
Lavallee (also known as Ribier) is third, and Italia, also a "boutique"
quality table grape being somewhat less short day intolerant comes fourth.
Unexpectedly tied in fifth place are Cardinal, a very short cycle
European type, and the native Criolla Negra hybrid. Because the absolute
productivity of the latter is surpassed by Villanueva, it would seem a
contradiction that its productivity is less limited by suboptimal
daylength. Nonetheless, Bautista was at a loss to explain why Criolla was
virtually infertile during the July semester, after pruning in January.
Table 5. Evaluation of Fertility Differences in Grape Cultivars,
by Semester (Merida, Venezuela: lat. 830N)
Cultivar No. Fertile Canes Diff. No. Clusters/Cane Diff. DIP DSI
Dates: 7-11-72 1-6-73 (2-1) 7-11-72 1-6-73 (5-4) (3x6) ('1'/7)
Source: Bautista, 1975; additional computation by the
Note: DIP is "daylength inducted productivity;" DSI
is "daylength sensitivity index."
He concluded the variety was suitable only for annual cycle pruning. A
close sixth is Violeta (or Victoria), possibly also a native second
generation backcross hybrid, and a heavy bearer at lower elevation in Lara
(Diaz and Aguero, 1975). Last is Mustosa, similarly a heavy cropper in
Lara (Ibid.), but which performed irregularly at the trial site in Merida.
Bautista concluded that the first three varieties, Villanueva,
Muscat Hamburg and A. Lavallee, are the best adapted of those tested. He
also noted that the semester initiated by pruning in January is more
productive than the semester initiated in July. The explanation is, of
course, that buds fruiting after pruning in January were formed during the
relatively longer days of summer. Whether Villanueva would be much more
productive at higher latitudes remains to be determined.
A position paper by Bautista and Vargas (1980) summarized the status
of Venezuelan viticultural science at the turn of the decade. The infant
local research establishment had by then been inserted in the
informational network linking similar organizations world-wide.
Concurrently, environmental limitations to adaptation of viticulture in
the tropics had been reduced to rainfall, and the need to fill the heat-
insolation requirement of the heliothermic index (HI). Henceforth,
official viticultural research in Venezuela would conform by and large to
the European mainstream of applied viticultural theory.
Following the path initially proposed by Hidalgo (1974), adaptive
research in the 1980s would emphasize massive testing of imported
varieties for appropriate "fit" to specific local heliothermic
"microclimates." The vines would be mainly V. vinifera selections
introduced from "safe" (certified disease-free) sources.(7) On the other
hand, because correlation of the fruiting cycle with local weather is
critical, rainfall and eventually other climatic data would be recorded
Studies which, in fact, measured daylength controlled responses were
engaged as necessary evaluation of physiological differences between
European varieties in the tropics. For example, Bautista and Vargas
(1980) cite pertinent authority in recognition that floral induction and
differentiation is completed within newly formed buds of an actively
growing grapevine shoot (cane) by the time the currently expanding flower
clusters open (Lavee et al., 1967; Pratt and Coombe, 1978). They then
affirm, following Huglin (1958), that vine fertility varies according to
variety, in terms of the position of the buds on the cane, and more
ambiguously on the environment.
No mention was made of the equally pertinent fact that the number
of flower clusters "imprinted" in a formative bud is in direct relation
to photoinductive daylength (Kobayashi et al., 1966; Buttrose, 1969a,
1974). Subsequently, a report by the same researchers measuring the
"heliothermic requirements" of six cultivars, concluded interestingly
The duration of the cycle and its subperiods are affected by
daylength. Cycles initiated in short days tend to be more
prolonged than those initiated in long days. Therefore, it
is considered that the [semestral] cycles of the same year are
not homologous (Bautista and Vargas, 1981: p. 19).
The 1981 report by Bautista and Vargas was the first detailed study
of grapevine phenology in the tropics. Measurement of the fruiting cycle
covered four subperiods initiated by semestral pruning: 1) budbreak,
2) bloom, 3) veraison (beginning of fruit coloration), and, 4) harvest
(maturity). In the conclusion cited above, no attempt was made to elicit
broader implications by correlating, for instance, with Bautista's (1975)
earlier finding concerning semestral differences in fertility.
Consequently, the influence of seasonal daylength on fruit bud formation
continued to be ignored.
It appears that semestral pruning at the solstitial extremes does
not follow closely traditional empirical practice in Venezuela. Rather,
it may be a convenient administrative abstraction analogous to the use of
controlled environment "growth cabinets" in substitution of actual
geographic conditions in the field (Buttrose, 1974). Recognition of the
connection between changing seasonal daylength and potential grapevine
fertility would presumably lead to experimentation with pruning cycles
initiated in anticipation of the equinoxes, in order to assure that fruit
bud formation would take place close to the twelve hour threshold.
Bautista and Vargas (1981) had, indeed, established that less than
a month (19 to 26 days) of optimum daylength from budbreak to bloom would
suffice. However, such scheduling would occasionally run afoul of the 100
mm (4 in) mean monthly rainfall barrier which continued to rule the
pruning calendar (Ibid.). The question might then arise whether there was
not a better adaptive strategy than adaptive pruning.
During the 1980s the prevailing adaptive strategy, based on pruning,
remained unchallenged. Certain modifications did occur, spurred by the
gradual shift in emphasis from table to wine grapes. By 1984, researchers
at the Grape Institute had begun to realize that environmental conditions
in Lara held the promise of a competitive advantage over Zulia, which had
then completely dominated table grape production with over 80% of the crop
(versus about 15% for Lara). An Institute report outlining guidelines for
viticultural development in the west-central region of Venezuela,
discussed for the first time the implications on grape quality of
nighttime temperatures averaging 10C (18F) lower than daytime means
(Vargas et al., 1984).
At the same time, it had long been known empirically to growers in
Lara that imported varieties adapted best if grafted on the vigorous
native hybrid Criolla Negra (Olmo, 1968; Bautista, 1985). In Zulia,
however, vines were imported already grafted on foreign rootstocks (Corzo,
1987). Eventually the same rootstock varieties were imported and
propagated locally (Gallardo, 1988). Only near the end of the decade did
Zulian researchers cautiously begin to graft on native hybrids (Mielzarek,
1987). On the other hand, by 1986 the Zulia Center for Tropical
Viticulture had taken the lead by planting the first fifty of 3,000
proposed hectares of wine grapes (Corzo, 1988).(8) Two years later a
model experimental winery was inaugurated at the Center. Meanwhile,
evaluation of wine grape varieties was being stepped up in Lara (Vargas
and Bautista, 1987a).
In 1987, a decade after Garassini's initial proposal, Vargas
proclaimed that the wines of highest quality in all of Venezuela could be
produced in the state of Lara (Vargas, 1987). He identified six arid
zones with mean annual rainfall under 700 mm (27.5 in) and two well
defined dry periods of no less than 130 days each (4.3 months), delimited
by two rainfall peaks, generally in May and October.(9) He pointed out
that heliothermic values were moderately low, that is, with diurnal
temperatures not so high as to undo metabolic synthesis and accumulation
of qualitative components of wine must.
Vargas clinched his argument with the observation that temperatures
in the viticultural areas of Lara rarely rise above 28C (ca. 83F) during
the day. At night the mean is always close to 19C (66.5F), a
difference, on average, of 9C (16.36F). Such optimal conditions for
development of a balanced sugar to acid ratio (Kliewer, 1981) were
compared "rhetorically" (i.e., without empirical data) with those of
unnamed areas where constantly high day and night temperatures cancel
metabolic gains through excessive respiration. Thus, both synthesis of
color and aromatics and their accumulation in the grapes are adversely
affected (Kliewer, 1968; Buttrose et al., 1971, and with specific
reference to Zulia, van Balen, 1987).
Shortly thereafter, Vargas' proposal found a sponsor. Polar, the
major Venezuelan brewery, and Martel, the great Bordeaux winery, organized
a winemaking joint venture for Lara. Vargas took leave of absence from
the Institute to undertake a research and demonstration project for a
Master of Science degree, under auspices of the incipient enterprise
(Vargas p.c., 1989). By late 1989 Vargas was completing the draft of his
thesis while on the job as general manager of Bodegas Pomar, C.A. in the
central Lara town of Carora. The recently completed $1 million plus
winery was preparing its first vintage for market.
One hundred hectares of choice French and Spanish wine grape
varieties grafted on Criolla Negra had recently begun production in the
firm's vineyard at nearby Altagracia. The viticultural and oenological
technology being used was state-of-the-art in terms of adaptation to the
local environment. Various wines tasted by this researcher were
indistinguishable from the French archetypes. Vargas and his associates
have proved that wine growing on the European model can succeed in
Venezuela, with adaptive pruning--and native rootstocks. Whether the new
industry will be as competitive as its French counterpart remains to be
The principal weakness in the Vargas model is that dry periods in
the semiarid areas of Lara are not as well-defined in terms of calendar
incidence of rainy periods, and thus as reliable as he suggests. Yearly
deviation of critical rainfall maxima tend to be "averaged out" of long
term means. Unexpected shifts in seasonal rainfall cycles can add to the
difficulty of prediction (Caviedes, 1981). Vargas makes no use of daily
records which would be helpful in more accurately plotting characteristic
tropical precipitation, occurring mainly as torrential downpours. Such
records may be helpful also in detecting gaLa, a fine drizzle accompanied
by tolda (overcast) that can last for days, even weeks, with devastating
effects on V. vinifera, yet have little impact on monthly rainfall totals.
Whereas daily rainfall records in Venezuela are difficult to obtain,
the Institute's experimental station in El Tocuyo has maintained monthly
totals since 1978 that suggest a conceptual flaw in the Vargas model.
Vargas' (1978) Madrid thesis includes a 1973 FUDECO report in the
bibliography which is presumably the source (unspecified) of the long term
mean monthly rainfall data used for his graphs. His conclusion concerning
El Tocuyo, where he worked since 1975, is only partly in agreement with
his graph for the same area (Figure 4). Both are at variance with data
from the records of the Institute for the ten year period 1978-1988 (Table
According to Vargas (1978) the first rainy season is from April to
June at El Tocuyo, with a peak in May. This is supported by Figure 4.
However, Table 6 shows that critical maxima have occurred mainly in April
during the past decade, twice in March and only once in May. The second
rainy season is said to include October and November, with a peak in
October, that according to his graph is substantially under the 100 mm (4
in) critical limit. However, his conclusion is that the ensuing dry
season begins December first. Table 6 indicates that rainfall maxima in
excess of the critical threshold have occurred as often (three times) in
September as in October. Only in the anomalous year of 1988 was there a
protracted rainy season that began in August and actually ended in
December. In 1980 also, there was a brief near-critical peak in December.
The reason for the discrepancies can be explained in part as
follows. If the winter solstice dry season generally ends in April,
pruning at the beginning of December would allow a full four months for
the fruiting cycle to be completed under relatively dry conditions.
Similarly, pruning in late April would allow roughly four months before
the start of the next rainy period in September. However, as Bautista and
Vargas (1981) discovered, a difference of one hour and seven minutes
between the shortest and longest days of the year results in a difference
of up to fourteen days (for A. Lavallee) in the length of the fruiting
1 0 0 .....................
Feb Apr Jun Aug Oct Dec
Mean monthly rainfall in El Tocuyo, Lara, Venezuela.
Source: According to Vargas, 1978.
Table 6. Critical Maxima, Monthly Rainfall: El Tocuyo (Lara), Venezuela, 1978-1988
Month* 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 Mean
Mar. 91.5 91.5 91.5
(3.6) (3.6) (3.6)
Apr. 81 216 93.75 109.5 88.5 117.75
(3.2) (8.5) (3.69) (4.3) (3.5) (4.6)
May 75 75
July 93 93
Aug. 75 75
Sep. 133.5 138.75 183.75 76.5 133.12
(5.25) (5.46) (7.23) (3.01) (5.24)
Oct. 150 84 205.5 102 135.37
(5.9) (3.3) (8.1) (4.02) (5.32)
Nov. 115.5 115.5
Dec. 75 87 81
(2.95) (3.42) (3.59)
Source: Instituto de la Uva, El Tocuyo (Lara), Venezuela. 1989.
*Only values approximating 75 mm (3 in) or over are presented. All measurements are in millimeters.
Approximate equivalent in inches is in parenthesis.
Although cycles initiated during short days take longer to complete,
it appears that pruning for the first cycle should not be performed until
late November because of lingering conditions of tolda and caria (Vargas,
p.c. 1989). Similar conditions prevail from mid-April to mid-June and
explain why pruning for the long day cycle should be postponed until June
(Figure 3). The same pattern of cloud cover holds for the Maracaibo area
where torrential rainfall is minimal, exceeding the critical threshold
only in October (Figure 5). Thus, it is evident that Vargas has used the
100 mm rainfall limit as a surrogate for a more complex and subtle
barrier, involving the influence of tolda and arda on relative humidity
and most likely on effective daylength.
The Creole Hybrids
Hybrids between New World grape species and Old World V. vinifera
cultivars have been planted in Venezuela since well before the modern
viticultural boom. With rare exceptions (10), V. labrusca and V.
aestivalis hybrids from the eastern United States, as well as muscadines
(V. rotundifolia) and a few imports from Florida, have fared poorly,
despite being well-adapted in their latitudes of origin to hot and humid
On the other hand, early attempts to develop local viticulture were
based on a handful of vigorous, healthy and productive "creole" varieties
which Olmo (1968) recognized as hybrids between V. vinifera and the native
tropical species V. caribaea. The most widespread of these is the so-
called Criolla Negra (Black Creole). Capable of growing to enormous
proportions, with extraordinary yields of acceptable quality red