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WATERMELON AND GRAPE INVESTIGATIONS LABORATORY
AGRICULTURAL EXPERIMENT STATIONS
INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES
UNIVERSITY OF FLORIDA
Mimeo Report WGL 70-1 July 16, 1969
Grape Field Day Program
Welcome to the annual Grape Field Day.
J. M. Crall, Professor and Head
Tour of the experimental vineyards 2:05 3:20 P.M.
J. A. Mortensen, Assoc. Professor
C. F. Balerdi, Asst. Professor
Grape taste panel at barn 3:20 3:45 P.M.
(All interested persons please participate)
Questions and Answers 3:45 4:00 P.M.
UNIVERSITY OF FLORIDA, IFAS HUM
AGRICULTURAL RESEARC-I CENTER
P. o. BOX 338 JUL 24 1972
LEESBURG, FLORIDA 32748
175 copies Ui. f Florida
1FAS, Univ. of Florida
J. A. Mortensen, Assoc. Professor (Assoc. Geneticist)
PIERCE'S DISEASE VIRUS STUDIES (SCREENHOUSE)
1. Indexing for the presence of Pierce's disease virus in
resistant varieties has been under way since 1967. At least 1 out
of 10 vines of Lake Emerald and of Blue Lake have transmitted the
virus to susceptible Carignane by approach grafting. Stover and
Norris have both caused questionable symptoms on 2 out of 10
plants, but we are not sure it is Pierce's disease as yet. In
addition, the following clones have transmitted Pierce's disease
virus to Carignane variety by grafting: W987, D5-34, Delaware,
Bartel No. 1 and A3-43. Failing to transmit were D3-79 and Muench.
2. Selection A3-43 has proven to be a carrier of Pierce's
disease virus, though it has vigor enough each year to survive.
Possible use of this selection as a source of inoculum in screening
breeding selections is being investigated. It is hoped that
selections can be cleft-grafted to rooted plants of A3-43 in the
nursery row, and either develop symptoms if susceptible or remain
healthy scions if resistant. The following results were obtained
by grafting different selections to A3-43 in the screenhouse:
(1) died with Pierce's disease (susceptible): D3-52, Carignane.
(2) remained healthy (resistant): D2-26, D4-176, D5-21, D5-32,
3. The appearance of stunting and sudden wilting of vines
during the weeks shortly after spring bud burst have been noticed
on a number of bunch grape varieties: Blue Lake, W716, Stover,
and to a lesser extent, Lake Emerald and Norris. Tests as to
whether this is a manifestation of Pierce's disease or a completely
different disease are being initiated this year.
GRAPE BREEDING PROGRAM
Purpose: A program of careful crossing and selection of
bunch grapes was begun in 1944 by L. H. Stover at this Laboratory.
The program has been continued to the present, with the following
1. Early, midseason, and late varieties with purple juice
color suitable for processing into frozen concentrate (Concord type).
2. Early varieties that are firm-textured of high quality,
and with long shelf life for the table grape market; seedlessness
3. All varieties must be resistant to Pierce's disease and
fungi, be vigorous and long-lived in Florida, should have self-
fertile flowers, be productive, adaptable to mechanical harvesting,
and should ripen evenly on the clusters.
Results; Among juice types we have Blue Lake, released in
1960, and the following unreleased selections showing promise:
Ell-40 (cross of Norris x Concord), D5-157 and D5-167 (crosses of
Blue Lake x Concord), E12-59 (cross of Fla. 43-47 x Concord), and
D6-57 (cross of Fla. 399 x Concord). Ell-40 shows promise both as
a juice and table variety (others for juice only).
Among table types we have Norris, released in 1967, and Stover,
released early this year. Norris is a midseason, large, purple
variety, while Stover is early, neutral flavored and light colored.
Unreleased selections of merit are: E4-3 (Lake Emerald x W987),
D4-176, D5-10, and D5-68 (Norris x Schuyler); F4-11 and F4-30
(B3-90 x Exotic); F4-36, F4-47, and F4-54 (C5-49 x Exotic); F8-35
(Norris x Alden), Fll-30 (seedless, from W716 x NY35933), E18-63
(W1521 x Aurelia), and E14-29 (Norris x Stover).
Replicated tests of several of the most promising selections
are under way at Live Oak, Gainesville, Leesburg, Fort Pierce,
Hastings, and Jay, Fla.
BUNCH GRAPE ROOTSTOCK TRIALS
Purpose: to develop suitable rootstocks for Florida grapes
that have the following characteristics:
1. Resistance to Pierce's disease, fungi, and nematodes.
2. Vigorous and long-lived vines.
3. Good foraging ability in relatively infertile Florida
soils, producing high yield and quality in the scion variety.
4. Ready rooting ability as cuttings in the nursery.
5. Compatibility when grafted with various varieties, including
a freedom from excessive suckering before or after grafting, and
_-eedom from overgrowth at the union.
Results: Candidates for rootstock trial are first rooted as
cuttings in ground recently used for cutting nursery. Parasitic
nematodes and root rotting organisms are generally present in the
soil, and this furnishes us a test of the ease of rooting under
adverse soil conditions. A large percentage of potential rootstocks
are eliminated by this test.
The best rootstocks from the above test are planted out in the
vineyard as rooted plants to note their performance as vineyard
Rootstocks surviving both the above tests satisfactorily may
be placed in replicated yield tests, using the better bunch grape
varieties and selections as scions. Three such tests are under way:
(1) Old vineyard ground was replanted to the following rootstocks in
1963: W380, Dog Ridge, W1521, Lake Emerald, and Black Spanish.
Only Dog Ridge and Lake Emerald have been acceptable in this test.
(2) New ground not previously planted to grapes was planted with
12 rootstocks in 1964 for replicated test involving 6 scions. The
best rootstocks to date under these conditions have been Dog Ridge,
Duval, Lake Emerald, Fla. 449, and C4-46. (3) Fallow land previously
planted to grapes was planted in 1968 with 8 rootstocks in groups
of 5 plants each, and 15 observational rootstocks in groups of 2
plants each. It is too early for results on this test.
INHERITANCE STUDIES IN GRAPES
Inheritance studies have been undertaken since 1961 on resist-
ance to Pierce's disease, anthracnose, black rot, and downy mildew.
Other characters studied genetically are date of bud burst, cluster
and berry size, sex and flower types, seedlessness, and earliness
Resistance to Pierce's disease is conditioned by 3 dominant
genes, all of which must be present for satisfactory resistance.
Resistance to anthracnose was conditioned by a major recessive gene
and a number of minor dominant genes. Sex in grapes whether male,
hermaphrodite, or female is largely conditioned by a simple tri-
allelic series with male dominant to hermaphrodite, which, in turn,
is dominant to female.
Other characters have not been fully analyzed yet. There is
a linkage between femaleness and larger berry size, both in muscadines
and bunch grapes. Other linkages are also under study.
C. F. Balerdi, Assistant Professor (Asst. Horticulturist)
Purpose: To evaluate herbicides for the control of weeds in
young and mature vines, and in the cutting nursery.
Mature Vineyard Experiment: Ten year-old vines, mixed
selections. There are 10 treatments, 4 replications. Each plot
is 4 feet wide and 36 feet long. Treated March 28, 1969. Data
taken June 3, 1969.
1 Weed populations:
1 (few) to 6 (many).
2 BL = broad leaved weeds; G = grasses.
Conclusions: Karmex, Casoron, and Simazine gave good weed
control. There were 3 to 4 times as many weeds in the untreated
plots as in the treated. There was a little better broad leaf
weed control with Karmex and slightly better grass control with
Casoron. There was only a very slightly better weed control as
the rates of herbicides were increased, indicating that lower rates
were as effective as higher rates. This is especially true after
2 or 3 years of herbicide use.
Young Vineyard Experiment: Vines planted in 1967. Herbicides
applied after planting and every spring thereafter. Stover variety
used. There are 6 treatments and 3 replications. Each plot is
4 feet wide and 30 feet long. Treated on March 27, 1969. Data
taken June 3, 1969.
Lbs. Act. Weed populations1
Treatment Ingr./Acre Ratings Mean
Untreated 0 BL 6.0 4.2
Planavin 4 BL 3.4 2.4
TOK E-25 4 BL 3.7 2.5
Simazine 4 BL 1.3 2.3
Casoron 4 BL 1.2 1.9
Paraquat .5 BL 1.02 1.02
SRatings: 1 (few) to 6 (many).
Data taken 10 days after application.
Conclusions: All herbicide treatments had less weeds than
the untreated plots. There was better broad leaf weed control with
Simazine and Casoron, while Planavin and TOK E-25 gave better grass
control. Paraquat gives good weed control for 4 or 5 weeks. It
is strictly a contact herbicide which will burn any green tissue
that it contacts. It is applied at low rates and has no residual
Cutting Nursery Experiment: Cuttings were set in the nursery
and plots treated soon after setting. There are 6 treatments and
3 replications. Each plot is 4 feet wide and 20 feet long.
Cuttings set 9 inches apart. Treated on April 17, 1969. Data
taken on June 3, 1969.
1,2 See first table.
Conclusions: Black plastic, Ramrod Atrazine, and Planavin
were best for weed control. Since very few cuttings rooted (even
in the untreated and black plastic plots), these results are
SPROUT CONTROL TEST
Purpose: To inhibit the growth of sprouts at the base and
trunk of grape vines.
Procedure: Blue Lake, and selections 1521 and 716 are being
used in the test. There are 4 treatments 2 vines per treatment and
3 replications for each of the varieties. The trunk and base of the
vines were sprayed with the chemicals until run-off, on April 10,
1969. On June 3, 1969 the number of sprouts growing at the base
and trunk of 6 vines were counted and are shown below.
10,000 ppm +
1521 716 Blue Lake Total Total
Base Trunk Base Trunk Base Trunk Base Trunk All
2 3 9 19
2 1 0 0 2 1 3
1 0 0 0 3 0 3
3 27 8 11 16 44 60
Conclusions: Treatment of trunk and base of vines with 1000 ppm
of CIPC, and 10,000 ppm CIPC + 1500 ppm Paraquat prevented the growth
of sprouts for a period of 7 weeks. The effect of these two treat-
ments disappears soon after the 7 weeks. Apparently, Alar promoted
sprout growth. Sprouts are difficult to control in large stubs
from old trunks. CIPC is most promising as a sprout inhibitor.
CORRECTION OF MAGNESIUM DEFICIENCY
Purpose: To correct magnesium deficiency of grape vines
through soil applications of Emjeo.
Procedure: Emjeo (27% MgO) was applied to the soil in split
applications totaling 600 lbs/acre. Stover variety was used. There
were 2 treatments and 3 replications. Magnesium deficiency symptoms
on grape leaves were rated as to severity. Results are shown below.
Treatment Rep. I Rep. II Rep. III Mean
- Emjeo 2.8 4.5 1.8 3.0
+ Emjeo 1.5 1.3 1.0 1.3
1 Magnesium deficiency symptoms: 1 none; 2 slight; 3 medium;
4 severe; 5 very severe
Conclusions: Soil applications of Emjeo corrected magnesium
deficiency. Previous test showed also that fruit of Emjeo-treated
vines had higher soluble solids (sugar) content. No yield differ-
ences have been detected.
Purpose: To evaluate 3 trellises as to ease of harvest and
production of fruit.
Procedure: The Geneva Double Curtain, Munson, and 4-wire
horizontal trellis are being tested. Each trellis type replicated
Conclusions: The yields (in pounds/vine) for each of the 3
trellis types were: 2.3 for Munson, 7.9 for Geneva Double Curtain,
and 8.8 for 4-wire horizontal. Pickers preferred the latter over
the Munson as to ease of picking. Results are preliminary.
INDUCTION OF SEEDLESSNESS IN SEEDED VARIETIES
Purpose: To induce seedlessness in the seeded variety Stover.
Procedure: Vines were sprayed at bloom onset and after bloom-
ing. There were 5 treatments and 3 replications. The foliage and
inflorescences of treated vines were sprayed with different growth
regulators. Fruit will be checked for seedlessness. Vine yield
will also be taken. Treatments are given below. Data not available
2. Gibberellic acid (GA), 30 ppm, beginning bloom.
3. GA, 30 ppm + Alar (A), 2000 ppm, beginning bloom
4. GA, 30 ppm, beginning bloom plus GA, 30 ppm + benzyl adenine (BA)
600 ppm, post bloom
5. GA, 30 ppm, beginning bloom plus GA, 30 ppm + BA, 600 ppm + A,
2000 ppm, post bloom
Conclusions: Preliminary observations indicate that very few
berries are seedless. Only partial seedlessness was obtained during
the two previous seasons using gibberellic acid. Yields were reduced
and the number of seeds per berry decreased.
EVALUATION OF MUSCADINES FOR FLORIDA
Purpose: To evaluate varieties and outstanding selections of
muscadines for adaptability to Florida conditions.
Conclusions: Over 60 varieties and selections are being
evaluated. Among the varieties, Southland, Magoon, Chief, Dulcet
and Higgins appear to be well adapted and productive. Among the
selections USDA 4, Ml-2, Ga 23-35, NC 88-102, NC 276-108, NC 108-109,
NC 115-180, Ga 28, Ga 20-55, Ga 17-19, and USDA 42-12B were out-
standing. Further testing is required.
EVALUATION OF PEACHES FOR CENTRAL FLORIDA
Purpose: Several peach varieties and outstanding selections
from the University of Florida breeding program are being evaluated
and tested for adaptation to central Florida.
Conclusions: Varieties and selections fruited for the first
time this season. Varieties Flordasun, Early Amber, and Sunred
nectarine are well adapted. Flordasun is very early (last week of
April) while Early Amber and Sunred ripen during early and mid-May,
respectively. All these varieties must be thinned to get proper
size. Two selections have been recommended for naming and release
to growers during the 1969-1970 winter. Several other selections
look very promising but more evaluation is required. Selections
10-64, 16-33, W2-61, W9-11, 47-89, 18-15, 16-15, W13-19, W13-25,
W8-51, C-1251, and W18-32 look promising. Nectarine selections
47-22, 38-58, and 10-76 have very good quality but larger size is