• TABLE OF CONTENTS
HIDE
 Front Cover
 Front Matter
 Introduction
 General methods and materials
 Required rest period of seeds
 Seed shape
 Seed coat color and yellow...
 Valencia plant type
 Brachytic dwarf plants
 Regression tests
 Summary and conclusions
 Acknowledgement
 Literature cited






Group Title: Bulletin - University of Florida Agricultural Experiment Station ; 314
Title: Inheritance of rest period of seeds and certain other characters in the peanut
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00026684/00001
 Material Information
Title: Inheritance of rest period of seeds and certain other characters in the peanut
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 46 p. : charts ; 23 cm.
Language: English
Creator: Hull, Fred H ( Fred Harold ), b. 1898
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville Fla
Publication Date: 1937
 Subjects
Subject: Peanuts -- Genetics   ( lcsh )
Peanuts -- Seeds -- Dormancy   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Bibliography: p. 46.
Statement of Responsibility: by Fred H. Hull.
General Note: Cover title.
General Note: Originally presented as: Thesis (Ph.D.) -- Iowa State College, 1934.
Funding: This collection includes items related to Florida’s environments, ecosystems, and species. It includes the subcollections of Florida Cooperative Fish and Wildlife Research Unit project documents, the Florida Sea Grant technical series, the Florida Geological Survey series, the Howard T. Odum Center for Wetland technical reports, and other entities devoted to the study and preservation of Florida's natural resources.
 Record Information
Bibliographic ID: UF00026684
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 000924539
oclc - 18213195
notis - AEN5166

Table of Contents
    Front Cover
        Page 1
    Front Matter
        Page 2
    Introduction
        Page 3
        Page 4
        Page 5
    General methods and materials
        Page 6
    Required rest period of seeds
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
        Page 23
        Page 24
        Page 25
    Seed shape
        Page 26
    Seed coat color and yellow seedlings
        Page 27
        Page 28
        Page 29
        Page 30
        Page 31
        Page 32
        Page 33
        Page 34
    Valencia plant type
        Page 35
        Page 36
    Brachytic dwarf plants
        Page 37
    Regression tests
        Page 38
        Page 39
        Page 40
        Page 41
        Page 42
    Summary and conclusions
        Page 43
        Page 44
    Acknowledgement
        Page 45
    Literature cited
        Page 46
Full Text



September, 1937


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATION
GAINESVILLE, FLORIDA
WILMON NEWELL, Director








INHERITANCE OF REST PERIOD

OF SEEDS

AND CERTAIN OTHER CHARACTERS

IN THE PEANUT



By FRED H. HULL






TECHNICAL BULLETIN






Bulletins will be sent free to Florida residents upon application to
AGRICULTURAL EXPERIMENT STATION
GAINESVILLE, FLORIDA


Bulletin 314










EXECUTIVE STAFF
John J. Tigert, M.A., LL.D., President of
the University
Wilmon Newell, D.Sc., Director
H. Harold Hume, D.Sc., Asst. Dir., Research
Harold Mowry, M.S.A., Asst. Dir., Adm.
J. Francis Cooper, M.S.A., Editor
Jefferson Thomas, Assistant Editor
Clyde Beale, A.B.J., Assistant Editor
Ida Keeling Cresap, Librarian
Ruby Newhall, Administrative Manager
K. H. Graham, Business Manager
Rachel McQuarrie, Accountant

MAIN STATION, GAINESVILLE
AGRONOMY
W. E. Stokes, M.S., Agronomist**
W. A. Leukel, Ph.D., Agronomist
G. E. Ritchey, M.S., Associate*
Fred H. Hull, Ph.D., Associate
W. A. Carver, Ph.D., Associate
John P. Camp, M.S., Assistant
Roy E. Blaser, M.S., Assistant
ANIMAL HUSBANDRY
A. L. Shealy, D.V.M., Animal Husbandman**
R. B. Becker, Ph.D., Dairy Husbandman
L. M. Thurston, Ph.D., Dairy Technologist
W. M. Neal, Ph.D., Asso. in An. Nutrition
D. A. Sanders, D.V.M., Veterinarian
M. W. Emmel, D.V.M., Veterinarian
N. R. Mehrhof, M.Agr., Poultry Husbandman
W. W. Henley, B.S.A., Asst. An. Husb.*
W. G. Kirk, Ph.D., Asst. An. Husbandman
R. M. Crown, B.S.A., Asst. An. Husbandman
P. T. Dix Arnold, M.S.A., Assistant Dairy
Husbandman
L L. Rusoff, M.S., Asst. in An. Nutrition
Jeanette Shaw, M.S., Laboratory Technician
CHEMISTRY AND SOILS
R. V. Allison, Ph.D., Chemist**
R. W. Ruprecht, Ph.D., Chemist
R. M. Barnette, Ph.D., Chemist
C. E. Bell, Ph.D., Associate
R. B. French, Ph.D., Associate
H. W. Winsor, B.S.A., Assistant
ECONOMICS, AGRICULTURAL
C. V. Noble, Ph.D., Agricultural Economist**
Bruce McKinley, A.B., B.S.A., Associate
Zach Savage, M.S.A., Associate
A. H. Spurlock, M.S.A., Assistant
ECONOMICS, HOME
Ouida Davis Abbott, Ph.D., Specialist**
ENTOMOLOGY
J. R. Watson, A.M., Entomologist**
A. N. Tissot, Ph.D., Associate
H. E. Bratley, M.S.A., Assistant
HORTICULTURE
G. H. Blackmon, M.S.A., Horticulturist and
Acting Head of Department
A. L. Stahl, Ph.D., Associate
F. S. Jamison, Ph.D., Truck Horticulturist
R. J. Wilmot. M.S.A., Specialist, Fumigation
Research
R. D. Dickey, B.S.A., Assistant Horticulturist
PLANT PATHOLOGY
W. B. Tisdale, Ph.D., Plant Pathologist**
George F. Weber, Ph.D., Plant Pathologist
R. K. Vorhees, M.S., Assistant
Erdman West, M.S., Mycologist
Lillian E. Arnold, M.S., Assistant Botanist
SPECTROGRAPHIC LABORATORY
L. W. Gaddum, Ph.D., Biochemist
L. H. Rogers, M.A., Spectroscopic Analyst


BOARD OF CONTROL
Geo. H. Baldwin, Chairman, Jacksonville
Oliver J. Semmes, Pensacola
Harry C. Duncan, Tavares
Thomas W. Bryant, Lakeland
R. P. Terry, Miami
J. T. Diamond, Secretary, Tallahassee

BRANCH STATIONS
NORTH FLORIDA STATION, QUINCY
L. O. Gratz, Ph.D., Plant Pathologist in
Charge
R. R. Kincaid, Ph.D., Asso. Plant Pathologist
J. D. Warner, M.S., Agronomist
Jesse Reeves, Farm Superintendent
CITRUS STATION, LAKE ALFRED
A. F. Camp, Ph.D., Horticulturist in Charge
John H. Jefferies, Superintendent
W. A. Kuntz, A.M., Assoc. Plant Pathologist
Michael Peech, Ph.D., Soils Chemist
B. R. Fudge, Ph.D., Associate Chemist
W. L. Thompson, B.S., Asst. Entomologist
Walter Reuther, B.S., Asst. Horticulturist
EVERGLADES STATION, BELLE GLADE
J. R. Neller, Ph.D., Biochemist, Acting in
Charge
R. N. Lobdell, M.S., Entomologist
F. D. Stevens, B.S., Sugarcane Agronomist
Thomas Bregger, Ph.D., Sugarcane Physiologist
G. R. Townsend, Ph.D., Assistant Plant
Pathologist
R. W. Kid 'er, B.S., Asst. Animal Husbandman
Ross E. Robertson, B.S., Assistant Chemist
W. T. Foresee, Ph.D., Asst. Chemist
B. S. Clayton, B.S.C.E., Drainage Engineer*
SUB-TROPICAL STATION, HOMESTEAD
H. S. Wolfe, Ph.D., Horticulturist in Charge
W. M. Fifield, M.S., Asst. Horticulturist
Geo. D. Ruehle, Ph.D., Associate Plant
Pathologist
W. CENTRAL FLA. STA., BROOKSVILLE
W. F. Ward, M.S., Asst. An. Husbandman
in Charge*

FIELD STATIONS
Leesburg
M. N. Walker, Ph.D., Plant Pathologist in
Charge
W. B. Shippy, Ph.D., Asso. Plant Pathologist
K. W. Loucks, M.S., Asst. Plant Pathologist
J. W. Wilson, Sc.D., Associate Entomologist
C. C. Goff, M.S., Assistant Entomologist
Plant City
A. N. Brooks, Ph.D., Plant Pathologist
Cocoa
A. S. Rhoads, Ph.D., Plant Pathologist
Hastings
A. H. Eddins, Ph.D., Plant Pathologist
Monticello
Sam O. Hill, B.S., Asst. Entomologist*
Bradenton
David G. Kelbert, Asst. Plant Pathologist
Sanford
E. R. Purvis, Ph.D., Assistant Chemist,
Celery Investigations
Lakeland
E. S. Ellison, Ph.D., Meteorologist*
B. H. Moore, A.B., Asst. Meteorologist*

In cooperation with U.S.D.A.
** Head of Department.









INHERITANCE OF REST PERIOD OF SEEDS AND

CERTAIN OTHER CHARACTERS IN THE PEANUT1

By FRED H. HULL

CONTENTS
Page
Introduction ................................. ..................... ................ 3
General Methods and Materials ................................ ........ 6
Required Rest Period of Seeds ......................................... 7
Seed Shape ............................................................................. 26
Seed Coat Color ................................................ ..... ............. 27
Yellow Seedlings ................................................. ........... 27
Valencia Plant Type .............................................. ........... 35
Brachytic Dwarf Plants ................................. ........... ... 37
Regression Tests .............................................. ............... 38
Summary and Conclusions .................................. ......... ... 43
Acknowledgments .......................................... .................... 45
Literature Cited ................................................... ............ ..... 46


INTRODUCTION

Genetic studies of the required rest period of seeds, seed
shape, seed coat color, yellow seedlings, Valencia plant type,
and a brachytic form of dwarfing in the common peanut (Ara-
chis hypogaea L.) are reported in this paper. Biometric tests
for associations of the first five of these characters among them-
selves and with 17 others also are presented. The above named
characters with the exception of rest period of seeds were the
only ones of 23 which gave evident Mendelian ratios in a num-
ber of crosses of different varieties of cultivated peanuts.
All of the varieties were American types which seemed to
fall naturally into three groups: runner, Spanish and Valencia.
This classification is not entirely in agreement with the earlier
systems of Chevalier (1933) and Hayes (1933), but is the only
grouping which seemed satisfactory for the present purpose.
The runner group includes Virginia and common runner
varieties which are definitely prostrate, except Virginia Bunch
which is semi-erect. This group has dark green foliage, occa-
sionally three seeds in a pod, long seeds, russet seed coats, and
its seeds require a rest period of at least several weeks after
maturity before germinating under average field conditions.
The Spanish group, known sometimes as Little White Spanish,
consists of erect types, with light green foliage, very rarely if

1A thesis presented to the graduate faculty of Iowa State College in
partial fulfillment of the requirements for the degree of doctor of philoso-
phy, December 20, 1934. Revised for publication and to review recent
publications August 1, 1936.







Florida Agricultural Experiment Station


ever more than two seeds in a pod, short seeds, tan seed coats,
and most'of the seeds require no rest period at all. The Valencia
group includes also the varieties Tennessee Red, Tennessee
White, and Porto Alegre. This group is characterized by many
three- and four-seeded pods and by a very sparse branching
habit. The varieties named are all erect but Chevalier (2)2
describes two African forms which possess the same distinguish-
ing characters and are fully prostrate. The foliage is dark
green, seeds are short or long, seed coat is purple, red, russet
or tan, and most seeds require no rest period. This classification
of the varieties of Arachis hypogaea is further supported by
the genetic evidence of duplicate genes to be discussed later.
Two other species of peanuts, Arachis Nambyquarae and A.
Rasteiro, are cultivated to a limited extent in Brazil and a
selected strain of each was included in the present studies.
Chevalier (2) states that these two species are merely distinct
races of A. hypogaea.
This view of Chevalier has not been contradicted by cytological
evidence as reviewed and reported by Husted (8). There seems
to be little doubt that the three cultivated species of peanuts
have typically 40 diploid or 20 haploid chromosomes. Husted's
report of secondary pairing and of irregularities in meiosis
with the 'occurrence of univalents, trivalents, quadrivalents, and
rings of as many as six indicates polyploidy, probably tetra-
ploidy. Tetraploidy is also indicated by several pairs of dupli-
cate genes, reported by Hayes (6) and in the present paper.
The probable occurrence of types with 20 chromosomes among
the wild species of South America is thus suggested. If irregu-
lar associations at meiosis are frequent, unusual ratios will be
found with some characters. The statement of Badami (1)
that some characters give simple ratios in certain crosses and
complex series in others, is suggestive.
Other inheritance studies with peanuts may be summarized
thus:
1. Red seed dominant to russet or tan (3:1), Van der Stok
(18), Badami (1), Stokes and Hull (16), Hayes (6). Four
colors purple, red, rose, and white, with genes Pp, Rdrd, Rirl,
R2r2, Patel (14).
2. Prostrate habit dominant to erect, two factors, Badami
(1); (15:1) Hayes (6); duplicate genes, Patel (14).
2Italic figures in parentheses refer to "Literature Cited" in the back
of this bulletin.







Inheritance of Rest Period of Seeds in the Peanut


3. Chlorophyll; three factors with triple dominant dark green
and triple recessive albino, Badami (1); two genes, Patel (14).
4. Dark red stem dominant to light red (3:1), Hayes (6).
Violet tinge dominant, appears to be associated with hardiness,
Badami (1). Purple stem, duplicate genes, Patel (14).
5. Long seed dominant to short (15:1), Hayes (6).
6. Fertile dominant to sterile, complementary3 (15:1), Hayes
(6).
7. Normal leaf dominant to crinkleld leaf, complementary3
(15:1), Hayes (6).
8. Leaf rachis presence dominant to absence, complementary3
(15:1), Hayes (6).
9. No constriction on pods, double dominant, two factors,
Badami (1).
10. Leaflet size intermediate in F1 and wide range in F2,
Badami (1).
11. Large pod dominant to small, three factors, Badami (1).
12. Pericarp thickness, five factors, thin pericarp linked with
pygmy seed, Badami (1).
13. Deep reticulations on pericarp dominant to shallow, at
least four factors, Badami (1).
14. Hairy stem dominant to less hairy, Badami (1); 3:1,
Patel (14).
15. Three- or many-seeded pods dominant to less than three-
seeded, at least three factors, Badami (1).
16. Long growing season dominant to short, Badami (1);
3:1, Patel (14).
17. Early fading flowers dominant to late, Hayes (6).
18. Deeply colored corolla dominant to light, Hayes (6).
19. Red color on leaflet vein dominant to its absence, Hayes
(6).
20. Sine leaf shape dominant to Valencia shape, Hayes (6).
21. Required rest period of ds p lly dmnn ts
absence, Stokes and Hulll-().
22. Variegated seed due to rupture of seed coat as found in
A. Nambyquarae partially dominant to its absence in A. hypo-
gaea, Stokes and Hull (16).
23. Sterile dwarf, 15:1, Patel (14).
24. Branching over non-branching, 3:1, Patel (14).

3Hayes evidently uses the term complementary to describe the inter-
action of two pairs of genes which are ordinarily termed duplicates.







Florida Agricultural Experiment Station


Badami found drought resistance associated with dark green
leaf. Hayes states, "No characters that exhibit clean-cut segre-
gation show any connection with one another." He reports
that eight characters; length of leaves, length of petiole, length
of rachis (leaf), length of sheath, width of leaves, corolla color,
hairs on petiole, and number of seeds, all showed marked cor-
relations with each other.

GENERAL METHODS AND MATERIALS
Natural cross-pollination is generally conceded to be rare in
peanuts. No plants of hybrid appearance have been found
among pure strains of diverse type grown together at the Flor-
ida Experiment Station for a number of years. New strains
from selection of single plants have been uniform and constant.
A group of pure strains was obtained by isolating single plants
from each of the distinct American varieties or types of cul-
tivated peanuts. Hybrids were secured by hand pollination
and grown in field cultures with the parent strains. Records
were made of 23 characters in the different lots. If no definite
classification of a character were possible, numerical grades
were used. The experiments were designed primarily to study
inheritance of the required rest period of seeds which was some-
times detrimental to the study of other characters. Rest period
is of first importance in peanut improvement work in Florida,
for which purpose this experiment was conducted.
Pedigree numbers of the selected strains of peanuts and the
stock from which they originated are listed below.
No. 1 from an improved strain of Spanish peanuts fur-
nished by Mr. J. H. Beattie of the U. S. D. A.
No. 3 from a selected strain of Spanish originated at the
Florida Station by a single plant selection in 1921.
No. 4 from Tennessee Red.
No. 6 from Tennessee White.
No. 7 from Valencia.
No. 8 from Florida Runner.
No. 9 from Virginia Runner.
No. 11 from Virginia Bunch.
No. 12 from Spanish.
No. 13 from Spanish, variety Macspan from the Texas Ex-
periment Station.
No. 14 from Jumbo Runner.
No. 15 from the subspecies Nambyquarae.







Inheritance of Rest Period of Seeds in the Peanut


No. 21 from the subspecies Rasteiro.
No. 221 from Dixie Giant, an unusually large-seeded strain
of Jumbo Runner type selected by Mr. J. H. Beattie of the
U. S. D. A.

REQUIRED REST PERIOD OF SEEDS
Delayed germination is frequently observed in seeds of many
wild and cultivated plant species. It may be due to an im-
pervious or tough seed coat, an immature embryo, or to the
internal physiological condition of the seed. In the latter case
the time of delay is called the required rest period and the
process which terminates it is known as after-ripening (Miller,
13). That the peanut belongs to the latter class is indicated
by rapid absorption of water by seeds which may then con-
tinue dormant for some time, as was observed by Stokes and
Hull (16).
Physiology of after-ripening has been studied extensively with
no very definite conclusions. Genetic investigations have been
few. Stokes and Hull planted seeds of runner, Spanish and
Valencia peanuts and hybrids of runner and Spanish in moist
sand soon after maturity. Spanish and Valencia seeds germin-
ated immediately. Runner seeds remained dormant several
weeks. Seeds produced on Spanish plants with runner pollen
were intermediate to the parents and in the second generation
a complex series was observed. It was concluded from the F
test that rest period is largely controlled by the genotype of
the embryo and not by maternal impression and from the F2
that inheiance of restperiod is complex.
Deming and Robertson (3) found marked differences among
common strains of wheat, oats, and barley in ability of seeds
to germinate 10 days after harvest. An F1 hybrid of Marquis
and Federation wheats was more like the dormant Marquis
parent. Garber and Quisenberry (5) and Johnson (11) studied
the inheritance of delayed germination in wild oats, Avena fatua,
and immediate germination in the cultivated species, Avena
sativa. Their conclusions agree very well and may be stated
from the later and more comprehensive work of Johnson who
suggests three dominant genes for germinability, one of which
is linked with the factor for grain type.
Inheritance of premature germination in maize has been ex-
tensively studied by several workers, notably Mangelsdorf (12).
At least 15 recessive genes were found to affect premature







Florida Agricultural Experiment Station


germination. Some of the genes were complementary in action
while others behaved as duplicates, triplicates, or quadruplicates.
Delayed germination after maturity is apparently unknown in
maize while premature germination has not been definitely iden-
tified in peanuts but is suspected to occur occasionally.
Inheritance of required rest period of peanut seeds has been
studied with selected strains of the several groups and hybrids
between them. Rest periods were measured by harvesting in-
dividual plants when a characteristic stage of maturity was
reached, planting shelled seeds 10 days later in a greenhouse,
and recording dates of emergence. Considerable variation in
stage of maturity of seeds on a single plant usually existed.
Those used for tests of rest period were selected within a nar-
row range judged by the color developed on the inner surface
of the pod. By selecting older seeds of plants slightly immature
and younger seeds of those fully mature it was possible to secure
samples well balanced in that respect. Tests of rest period in
seedso-f different ages indicated that rest requirement increases
slowly up to a point where the seed may be judged fully mature
and then gradually declines.
Seeds were planted in clean sand to a depth of one-half inch
and watered thoroughly at regular intervals. Sand tempera-
tures were maintained near 250 C. except in rare cases when
extremes of 100 C. and 350 C. were reached. Tests of effects
of moisture and temperature variations on rate of after-
ripening were conducted supplementary to inheritance studies
with seeds of Florida Runner and Spanish peanuts. Large sam-
ples of each kind were placed in different storage conditions
soon after harvest and small sub-samples were planted from
each lot at intervals of two to seven days. Progress of after-
ripening with different conditions of storage was thus indirectly
measured by time required to complete the process in the green-
house. There were no significant differences in rate of after-
ripening in Florida Runner seeds stored over a drying agent,
open to the outside air, and over water. Moisture contents of
the stored seeds were 7 percent, 9 percent and 16 percent, re-
spectively.
Rest requirements dropped rapidly in Florida Runner peanuts
stored in an open shed at 20-250 C. (Figure 1, curve "b") and
more rapidly in storage at 400 C. (curve "a"). At 3 C. pro-
gress of after-ripening was greatly retarded (curves "c" and
"d"). Storage at 3 C. increased the rest requirement of Span-







Inheritance of Rest Period of Seeds in the Peanut


ish peanuts for a time, Figure 2. These variations in rate of
after-ripening at different temperatures emphasize the need for
control in critical comparisons, however, it does not appear that
serious error from lack of temperature control has appeared
in inheritance records reported below. Incidentally, as a result
of these and similar tests it has become a regular practice to
store hybrid seeds at 300 C. for 30 days after harvest when
quick germination is desired.



280

240o

I 200

S 160

q 120

o80 b
a
40


35 70 105 140 175 210 245 280 315 350

Days after harvest when planted
Fig. 1.-Progress of after-ripening measured by time from planting
to emergence in Florida Runner peanuts with different conditions of stor-
age: (a) Storage in covered container at 40' C., continuously after harvest;
(b) Shed storage at mean temperature of 20-25* C.; (c) Shed storage 12
days after harvest, then at 3o C.; (d) Storage at 3o C. continuously after
harvest.

Time from planting to emergence of the seedling is treated
in inheritance studies as a satisfactory measure of required
rest period. Strictly, the few days occupied by germination
processes should be subtracted and the decrease of rest require-
ment during the 10 days between harvest and planting should
be added to the total. These two corrections would tend to
cancel one another. Time required for germination could not
be measured in many samples but in a goodly number an early
emerging group of seedlings appeared simultaneously. In some







Florida Agricultural Experiment Station


samples the first group appeared as early as the sixth day and
in others it was as late as the 12th day. No adjustment has
been made for this discrepancy but all seeds in early emerging
groups have been segregated in the first class of frequency
distributions by setting the upper limit of that class at 17 days
after planting where a minimum of daily emergence occurred.
The first class has an interval of 11 days because the time re-
quired for germination was not constant. Ideally its interval
is zero and actually it is composed almost wholly of seeds which
required no rest period. The upper limit of the first class might
have been set at 13 or 25 days with no appreciable variation
of class frequencies.


8o
0



5 20
0


r&
0




1 0
0


5 70 105 14o 175 210 245

Days after harvest when planted
Fig. 2.-Progress of after-ripening measured by time from planting
to emergence in Spanish peanuts, Strain No. 1, with different conditions
of storage: (a) Shed storage at mean temperature of 20-25* C., continu-
ously after harvest; (b) Shed storage 48 hours after harvest, then at
3 C.; (c) Shed storage ten days after harvest, then at 3 C.

It was not feasible to grow many plants to maturity from
seeds germinating in rest period tests and F1 and F2 seeds were
not easily obtained in large numbers. Consequently, most of
the tests were run in later generations. Records on pure strains









TABLE 1.-FREQUENCY DISTRIBUTIONS, MEANS, STANDARD ERRORS, AND VARIANCES OF DAYS FROM PLANTING TO EMERGENCE
WITH NUMBERS TESTED AND GERMINATION PERCENTAGES IN REST PERIOD TESTS ON LESS DORMANT, PURE STRAINS OF
PEANUTS.
(Frequencies expressed by percentage.)


Class limits-days
6 17 37 57 77 97 117

98.9 1.1
100.0
97.0 1.0 1.0
91.7 8.3
92.7 2.8 1.8 1.8
92.3 7.7
92.9 2.0 1.0 2.0 1.0
90.0 10.0
90.2 6.5 1.1 1.1 1.1
100.0
96.5 1.2
90.0 10.0
79.6 3.1 1.0 7.1 4.1 2.0
40.0 50.0 10.0
75.8 5.3 3.2 1.1 5.3 1.1
30.0 40.0 30.0
63.6 2.0 5.1 5.1 2.0
10.0 30.0 20.0 30.0 10.0


Pedigree
numbers

1*-31**

1-32

7-32

12-31

6-31

4-31

3-31

7-31

13-31


137 157



1.0






2.3

2.0

S3.2

8.1


Num- |
Sober JMean
|tested

88 9
10
105 11
12
109 11
13
99 12
10
92 12
10
86 14
10
98 24
10
95 28
10
99 50
10


S. E.


1

2

2

2

2

3

4

4

2


Vari-
ance

132

360

381

254

210

589

1190

1543

427


Germin-
ation
%

91

88

90

99

92

86

98

96

99


*Origin of different pedigrees given on page 6.
**The second figure of each pedigree indicates the year of the test, e. g. 1-31 refers to the 1931 crop of strain No. 1.
The first line after each pedigree number includes the data on single seeds; the second line includes the same data
averaged by mother plants.


--







Florida Agricultural Experiment Station


and hybrids are summarized in Tables 1 to 6 with frequency
distributions, means, standard errors, variances, numbers tested,
and percent of germination. It was originally planned to study
F2 segregation by characterizing each F, and F3 plant with the
mean record of its progeny. Large variance of rest period in
pure strains indicated that such a plan might be desirable. How-
ever, asymmetric distribution of rest period in many samples
made that plan unsatisfactory. As is well known, averaging
distorts asymmetric data. Frequency distributions of single
seeds and means of samples from single plants are presented
together in the tables. Distortion from averaging may be seen
in many of them, e. g. in the large sample of F4 seeds at the
bottom of Table 4. The lower entry is the distribution of single
seeds. Immediately above, the same data are classified by F3
plant means, each mean being calculated from a sample of F4
seeds produced by a single F3 plant. Averaging has shifted the
mode from the first to the second class and has thus obliterated
the critical evidence for the interpretation of rest period be-
havior given below.
Referring only to distributions of single seeds in a general
view of the several tables it is first apparent that rest period
is a multigenic character. If the first class, the class of zero
rest period of each distribution, is neglected and attention is
confined to the remaining classes the picture coincides very
nicely with a little more than the right one-half of the classical
picture of quantitative or multigenic inheritance. A little less
than the left one-half is seemingly compressed in the first class.
This behavior of rest period may be plausibly explained by
the nature of the character itself. Rest period is necessarily
a reflection of some variable condition of seeds at maturity.
That basic seed condition is a complex character which physi-
ological studies in other species have failed to identify. It is
transformed by after-ripening to a state where germination
will occur if the outer environment is favorable. Peanut seeds
lie fully dormant in rest period tests until germination begins
suddenly and proceeds at a normal rate. An abrupt threshold
of germination is indicated. Germination threshold on the
range of seed condition and zero on the range of rest period
are coincident points. They coincide ideally with the first class
in the present records, and this class has breadth only as an
expression of imperfect experimental technic in measuring zero
rest period. Zero is a lower limit of rest period but there is











TABLE 2(a).-FREQUENCY DISTRIBUTIONS, MEANS, STANDARD ERRORS, AND VARIANCES OF DAYS FROM PLANTING TO EMERGENCE
WITH NUMBERS TESTED AND GERMINATION PERCENTAGES IN REST PERIOD TESTS ON MORE DORMANT, PURE STRAINS OF
PEANUTS.
(Frequencies expressed by percentage.)
Pedi- | V Ger-
gree IClass limits-days Num- Va- mina-
num- ber Mean S. E. ance tion 4
bers 6 17 57 97 137 177 217 257 297 337 377 417 457 497 Itested % /
35 112 11 3942 63
21*-32** 8.6 5.7 20.0 51.4 8.6 2.9 2.9
50.0 33.3 16.7 6
14-32 0.8 6.9 47.3 26.0 16.0 3.1 131 136 4 2482 63
40.0 60.0 10
14-31 2.4 12.2 31.7 12.2 19.5 19.5 2.4 41 154 12 5721 91 ,
20.0 60.0 20.0 5
15-31 4.3 4.3 8.7 13.0 34.8 21.7 8.7 4.3 23 161 17 6792 77
16.7 50.0 33.3 6 CO
11-31 3.1 1.0 13.3 15.3 40.8 14.3 4.1 2.0 1.0 5.1 98 170 9 8066 98
30.0 40.0 30.0 10
8-31 1.0 1.0 3.0 10.1 20.2 40.4 7.1 9.1 1.0 2.0 3.0 4.0 99 210 11 12451 99
30.0 20.0 30.0 20.0 10

*Origin of the different pedigrees given on page 6. M
**The second figure of the pedigree indicates the year of the test, e. g. 21-32 refers to the 1932 crop of strain No. 21.
The first line after each pedigree number includes the data on single seeds; the second line includes the same data
averaged by mother plants.







Florida Agricultural Experiment Station


no evidence that seed condition is limited at the coincident point
of germination threshold or that after-ripening has an end point
there. Storage tests reported in Figure 2 indicate that after-
ripening may continue beyond the germination threshold. Cold
treatment induced rest requirement immediately (curve "b")
when after-ripening had just reached the germination level.
Ten days later (curve "c") approximately 10 additional days
of cold storage elapsed before rest requirement reappeared. It
is conceivable that the mean seed condition of some genetic
types of peanuts is already beyond the threshold of germination
when maturity is reached. Seed condition at maturity may be
a typical quantitative character with near normal frequency
distributions in homozygous and heterozygous samples. Some-
where near the mid-point of its range may be the critical point
of germination threshold which coincides with zero rest period.
On one side of that point the requirement for immediate ger-
mination is equaled or exceeded and rest period is uniformly
zero. On the other side the requirement is not met and the
varying degrees of deficiency are reflected in rest periods of
varying duration.
TABLE 2(b).-COMPARISONS OF MORE DORMANT STRAINS OF PEANUTS BY
MEAN DIFFERENCES AND THEIR STANDARD ERRORS.
(Differences in bold face type are thought to be significant as judged by
their standard errors and the germination of the two lots.)

Pedigree 14-32 14-31 15-31 11-31 8-31
21-32 24.0 11.4 42.4 15.9 49.1 20.2 58.9 13.9 98.5 15.4
14-32 25.1 17.7 34.9 10.0 74.5 12.0
14-31 6.7 20.8 16.5 14.9 56.1 16.3
15-31 9.8 19.4 49.4 20.5
11-31 _____39.6 14.4

Such relation between rest period and seed condition with
a large non-genetic variance of seed condition would produce
frequency distributions of rest period in a series of types like
that obtained. A sample with mean seed condition far beyond
the germination threshold might have one end of its distribu-
tion, due either to genetic or non-genetic variance, extending
across the threshold and exhibit short rest periods in a few
seeds. Most of its frequency would be in the first class. A
sample with mean seed condition at the germination threshold









TABLE 3.-FREQUENCY DISTRIBUTIONS, MEANS, STANDARD ERRORS, AND VARIANCES OF DAYS FROM PLANTING TO EMERGENCE
WITH NUMBERS TESTED AND GERMINATION PERCENTAGES IN REST PERIOD TESTS ON LESS DORMANT AND MORE DORMANT
PURE STRAINS OF PEANUTS AND THEIR F1 AND F2 HYBRIDS.
(Frequencies expressed by percentage.)


17 57


Pedigree
numbers

3X
221
(3X x 221)F,
7**-31

7-32

3-31

21-32

14-31

(7 x 21)F,

(7 x 14) F

(3 x 21)F2


Class limits-days
97 137 177

5.0

20.0 30.0
6.4 1.1

0.9

2.0 1.0

51.4 8.6
33.3 16.7
31.7 12.2
20.0 60.0
11.7

5.2

21.3 11.7


I ___ ~
16

75.0
No test

81.1
70.0
95.5
92.3
82.7
90.0
8.6

2.4

44.7

32.5
16.7
14.9


iNumber
| tested

20

10
95
10
109
13
98
10
35
6
41
5
94
5
191
6
94
3


Mean


25
(112-210)*
110
20

11

24

112

154

45
37

75


S. E.


12

12
4

2

4

11

12

4
2

5


Vari-
ance

2653

1333
1543

381

1190

3942

5721

1841
1083

2523


Germin-
ation
%10

100

100
96

90

98

62

91

79
86

76


10.0

50.0
6.4


6.1

20.0
50.0
12.2

19.1
20.0
16.8

27.7
66.7


217 257









2.9

i 19.5
)



i


*Estimated from the behavior of other dormant strains.
**Records of parent strains repeated from Tables 1 and 2.
The first line after each pedigree number includes the data on single seeds; the second line includes the same data
averaged by mother plants.









TABLE 4.-FREQUENCY DISTRIBUTIONS, MEANS, STANDARD ERRORS, AND VARIANCES OF DAYS FROM PLANTING TO EMERGENCE
WITH NUMBERS TESTED AND GERMINATION PERCENTAGES IN REST PERIOD TESTS ON F3 AND F. SEEDS IN CROSS 1 X 14.
(Frequencies expressed by percentage.)


Pedigree
numbers

1-31*

1-32

14-31*

14-32

1 x 14

F2; means of
FK progeny

F2; means of
F4 progeny

Fs; single seeds
F2; means of
F4 progeny

F4; single seeds


6 17 67

98.9 1.1
100.0

96.2 1.9 1
91.7 8.3

2.4 2.4 2S
2C

3.8 29
1C


34.7

18.1

60.2

30.3

49.6


9.7 4.2

19.4 2.8

11.7 5.4

14.7 3.8

9.8 8.3


Class limits-days
167 217 267 317 367 417 467 517 567

HHHHH.


0.4

0.3 0.7

0.5 0.3


617 667 717


Num- 1
ber I Mean
tested I

88 9
10

105 11
12

41 154
5

131 136
10


72

72

495

944

31029


*Records of the parent strains repeated from Tables 1 and 2.


S. E.


1

2

12

4








3



1


Vari-
ance

132

360

5721

2483




3889

1819

4937

3074

4172


Ger-
mina-
tion %

90 3

88

91

63








I9


--










TABLE 5.-FREQUENCY DISTRIBUTIONS AND MEANS OF DAYS FROM PLANTING TO EMERGENCE WITH NUMBERS TESTED AND .
GERMINATION PERCENTAGES IN REST PERIOD TESTS ON F4 SEEDS OF A REPRESENTATIVE SAMPLE OF F2 FAMILIES IN CROSS
1 x 14.
(Frequencies expressed by percentage.)
|Num- Germin-
F2 plant Class limits-days her Mean action a
numbers 6 17 67 117 167 217 267 317 367 417 467 517 567 617 tested i %

97 97.6 2.4 596 8 90.7
10 99.0 1.0 196 8 72.3
78 91.5 6.2 1.6 0.7 723 12 95.3
55 72.6 21.7 4.7 0.7 0.3 749 19 95.3
39 75.0 17.4 7.6 212 20 95.5
103 80.3 13.4 3.4 2.2 0.4 0.4 269 21 72.4 3.
21 72.8 19.2 6.4 1.5 0.1 781 23 97.0 0
98 56.6 34.3 7.4 1.4 0.2 0.2 566 27 84.1
56 72.0 12.0 7.6 6.2 1.4 0.2 0.5 784 30 95.7
71 60.6 22.3 12.3 4.4 0.2 0.2 942 35 91.8
66 49.4 35.7 6.6 6.0 1.1 0.2 0.4 0.6 545 39 97.2
69 39.9 28.6 13.0 17.6 0.8 607 44 95.4
94 30.2 45.4 15.4 6.9 1.3 0.5 0.2 632 51 86.8 co
46 28.9 41.6 11.6 15.9 1.6 0.2 0.3 895 60 95.5
60 32.5 31.6 12.6 16.5 2.2 0.3 2.0 0.8 0.8 0.6 357 71 93.2
27 19.0 30.1 17.2 26.9 5.0 1.1 0.3 0.3 379 77 76.4 -
24 20.4 39.8 15.0 14.3 4.2 2.6 0.3 0.8 0.5 0.5 0.8 622 90 92.2
53 20.8 8.7 10.3 37.4 13.7 4.7 2.9 0.8 0.3 0.3 384 115 96.3
75 5.3 23.7 19.8 33.5 9.6 3.0 0.9 0.9 0.7 1.0 0.4 565 123 92.9 5
77 6.7 4.8 10.3 17.9 10.9 5.1 6.7 7.1 4.2 8.3 4.5 6.1 4.5 2.6 312 265 84.9 s
____ __ __ ___ ___ ___ ___ __ ____ ____ ____ __L__ ___ ____<+








Florida Agricultural Experiment Station


would have 50 percent of its frequency in the first class and
the remainder tapering off in higher classes. At a somewhat
higher position with the mean in the third or fourth class a
bimodal distribution of rest period would be produced with one
mode in the first class, and the other mode coinciding with the
mean seed condition. Any sample whose range was entirely
above the germination threshold would produce an undistorted
and probably near normal distribution of rest period. On this
basis, the classical picture of quantitative inheritance is shown
in the frequency distributions of Tables 1 to 6 with approxi-
mately the left one-half compressed into the first class which
is the class of zero rest period. The right one-half of the picture
is shown undistorted in the higher classes.
TABLE 6.-SUMMARY OF MEANS OF DAYS FROM PLANTING TO EMERGENCE
IN REST PERIOD TESTS ON LESS DORMANT AND MORE DORMANT, PURE
STRAINS OF PEANUTS AND THEIR HYBRIDS.
Less More Mean
Cross dormant dormant of Fi F Fa F-
S parent parent parents I
3X* x 221 25 (112-210)** (68-118) 110
7 x 21 19 112 65 45
3 x 21 24 112 68 73
7 x 14 19 154 87 37
1 x 14 10 154 82 42 47
13 x 14 50 154 102 63
3 x 8 24 210 117 79
13 x 8 50 210 130 84
*Two sister plants from strain No. 3 were used as parents for the
ten Fi seeds and were labeled 3X. Origins of the different pedigrees are
given on page 6.
**No test was obtained on strain No. 221 due to constantly poor quality
of its seeds but it is undoubtedly a more dormant type.

This explanation agrees very well with the general aspects
of rest period behavior as has been indicated. Its most signifi-
cant and most doubtful feature is the extension of the range
of seed condition approximately as far below as above germina-
tion threshold and zero rest period. Rest period is a multigenic
character as evidenced by a distribution of mean values over
all portions of a wide range. The present theory requires also
that the range of genotype for rest period extend far below







Inheritance of Rest Period of Seeds in the Peanut


zero rest period. Rest period is thus expressed over only about
one-half of its genetic range. This possibility may be checked
in the breeding behavior of pure strains whose modal type is
zero and the entire theory may now be examined in this and
other details.
It seems desirable first, however, to consider briefly alterna-
tive explanations of rest period expression. One is that after-
ripening proceeds at a nearly constant rate until it is about
one-half completed. It then becomes, very suddenly, enormously
accelerated and rushes to completion in a time so short that
it cannot be distinguished from zero by the present methods.
Other explanations might involve complex gene interactions
which produce little or no effect with less than about 50 percent
of the total gene number and behave in a usual manner with
higher numbers. These possibilities cannot be entirely ignored.
They are dismissed for the present on the grounds of being
less plausible than the first plan outlined.
Extreme dominance of short rest period, coupled with the
one-sided expression of errors which must be obtained at or
near zero, might account for the apparent skewness of frequency
distributions of rest period. Any apparent necessity of the
genetic range of rest period transgressing below the zero point
of the physical character might thus be eliminated. Very
strong super-dominance or complete dominance with replicate
genes would be necessary to recover a parental phenotype in
50 percent or more of F3 and F4 seeds from a multigenic cross,
as is the case in the cross 1 x 14, Table 4. The case for dom-
inance breaks down in the further summary of that cross in
Table 5 where apparent skewness is highly correlated with
shorter rest period. Variable expression of dominance cannot
be easily accepted nor can dominance explain the regular and
greatly varied series of frequency distribution types. Tests of
rest period in F, seeds have been reported earlier, Stokes and
Hull (16), and additional tests are reported in Tables 3 and 6.
Slight dominance of long rest period or an intermediate F1 is
indicated. A total of 14 F1 seeds has been produced on Spanish
plants by pollination from runner plants and tested for rest
period. Every seed had a rest period of some length and con-
siderably in excess of the Spanish parents. Every seed was
harvested at the proper stage of maturity, was strong, plump,
and vigorous and was given a fair test. Earlier or later har-
vesting would have shortened the rest period. Time from plant-







Florida Agricultural Experiment Station


ing to emergence might have been lengthened by disease, low
temperature, or lack of moisture, but none of those factors
was operating. It cannot, therefore, be denied that every F,
seed had a considerable rest period and it is indicated that the
F1 rest period is slightly above the mean of parents. While
these tests are limited in number and precision, the very ex-
istence of F1 rest period is entirely adequate to disprove dom-
inance of short rest period in sufficient degree to recover the
parental phenotype in 50 percent of F4 seeds.
It remains to examine in some detail the behavior of rest
period in parent-offspring relations and in other respects. First
it is necessary to recognize the positive bias in mean rest period
which must be obtained from unequal expression of experi-
mental errors or random variation of any kind because the
range of variation extends to zero. It is noted that the range
of variation in the pure strain of Table 2 is sufficiently removed
from the limit to avoid most of the bias., The situation in Table
1 is quite different where the modal type of each strain is zero.
It is difficult to avoid the conclusion that mean rest period of
each strain in Table 1 is zero except for the bias of unequal
expression of experimental errors, i. e. random variations of
seed condition. If the present theory of the ranges of seed
condition and genotype extending beyond zero rest period is
correct a similar bias due to unequal reflection in rest period
will be similarly obtained. In both cases the bias is increased
as the position of the sample lies farther to the left or by an
increase of variance from genetic or non-genetic sources.
Other significant features of rest period behavior may be sum-
marized:
1. Less dormant parent strains in Table 1 all have zero as
the modal type but differ in means and variances. More dor-
mant parent strains in Table 2 differ significantly in mean rest
periods as judged by their standard errors, Table 2b.
2. Differences between parent strains are generally confirmed
in their hybrids, Table 6. Comparisons of 1 x 14 with 13 x 14,
3 x 8 with 13 x 8, and 13 x 14 with 13 x 8 are more reliable,
being based on much larger numbers.
3. Mean rest period of the F1, Table 6, is approximately equal
to the mean of parents. Later hybrids average not only con-
siderably less than the parental means but also considerably
less than one-half of the greater parents. This in spite of the
considerable positive bias which must occur in each hybrid mean







Inheritance of Rest Period of Seeds in the Peanut


with very little in the means of greater parents. Less dormant
parents have quite significantly negative average breeding values
as measured by means of crosses with more dormant types.
4. Transgressive segregation above the greater parent is evi-
dent in most crosses. Particularly, F2 family No. 77 listed at
the bottom of Table 5 has a mean gain over its greater parent
of 111 days with standard error of 15 days. Standard error of
gain is calculated from two near normal distributions. The gain
is seven times its standard error and equal to 72 percent of the
greater parent. Genetic variance in F2 family No. 77 is evident
from greater variance of its F4 seeds in comparison with the
pure strains of Table 2 and in analysis of its variance in Table
7. Decline of variance due to selfing of F3 plants is shown in
the ratio of variance of F4 seeds between F3 families to the vari-
ance within F3 families to be highly significant. Considerably
longer rest periods than the mean of No. 77 are easily possible
in its progeny. Yet the less dormant parent is strain No. 1
which produced more than 95 percent of seeds with zero rest
period and is the least dormant pure strain tested. It may be
said further that the mean of No. 77 is a highly significant gain
over that of any parent strain in the cultures and that it gives
unmistakable evidence of Spanish ancestry. No possibility of
admixture or random outcrossing can abrogate its evidence that
the less dormant parent strains possess considerable genic ma-
terial whose effect is in the direction of increasing rest period.
5. Transgressive segregation below the lesser parent is not
easily demonstrated. The best evidence is in the two F3 families
at the top of Table 5. With 792 seeds tested from both families
the latest seed emerged 48 days after planting. In the lesser
parent, top of Table 1, with 193 seeds tested one emerged at
68 and one at 132 days after planting.
6. Retaining attention on the same three strains, it is noted
that their variances are very small. Also, in Table 4, 30 percent
of the 944 F3 families averaged less than 17 days from planting
to emergence of their F4 seeds. Variances of such families are
necessarily small. It is not only necessary to explain how posi-
tive experimental errors become so drastically restricted in
these samples but also the failure of genetic variance to appear
in so many hybrid families. The extreme plus F2 family of the
same cross has been discussed and its large proportion of genetic
variance noted.








Florida Agricultural Experiment Station


TABLE 7.-ANALYSIS OF VARIANCE OF DAYS FROM PLANTING TO EMERGENCE
IN THE F. SEEDS OF TWO MOST DORMANT F2 FAMILIES FROM CROSS 1 x 14.
Degrees of Sum of Mean
Source of variation freedom squares square
F2 family No. 75
Total ................................... 564 4,541,066.62 8,051.54
Between F2 families ............ 16 978,490.15 61,155.63
Within .......... ............. .. 548 3,562,576.47 6,501.05

F* = 61,155.63/6,501.05 = 9.41; F(0.05) = 1.6, F(0.01) = 2.0

F2 family No. 77
Total ..................................... 311 10,085,143.59 32,428.11
Between Fs families ....... 12 850,112.33 70,842.69
W within ................................. 299 9,235,031.26 30,886.39

F* = 70,842.69/30,886.39 = 2.29; F(0.05) = 1.79, F(0.01) = 2.24
larger mean square
*F= Snedecor (15).
smaller mean square

7. Rest period behavior is unique among other quantitative
characters of the peanut. Seven other characters in the same
cultures, with one exception, have generally symmetrical dis-
tributions. Distributions of seed cells (ovules) per plant are
markedly skewed to the left but much less so than those of
rest period. Hayes (6) presents six distributions from the F2
generation of one cross, four of which are symmetrical. Num-
ber of seeds is distributed similarly as seed cells in the present
cultures.: Hayes classed number of hairs on petiole in six grades
by observation and derived a distribution slightly skewed to the
right but actual counts might have produced symmetry.
All of these features of rest period behavior are in close agree-
ment with expectation of the theory proposed above. Regression
of rest period on the underlying seed condition and consequently
on genotype becomes discontinuous at zero rest period and ger-
mination threshold near supposed mid-points of the ranges of
seed condition and genotype. The only argument that has ap-
peared against this interpretation is the absence of premature
germination which may be inhibited by a separate mechanism.
It may also be difficult to understand the economy of a system








Inheritance of Rest Period of Seeds in the Peanut


in which one-half of the genetic range is non-effective or how
such a system became established. It is equally difficult to
understand how varieties of the cultivated species came to be
separated into two distinct groups. An environment which
favored the short or no rest period type would probably allow
accumulation of mutations in either direction back of the ger-
mination threshold where selection pressure must be very weak.
A variable (tropical?) environment where growing conditions
prevailed continuously except for rare and irregular intervals
would favor a type which usually required no rest period but
required rest periods of varying lengths in a small proportion
of seeds to bridge unfavorable periods. The present system is
remarkably well adapted to provide that type, regardless of
degree of inbreeding. It would be disadvantageous if zero rest
period were a minimum genotype and hence a rare combination.
More dormant types may be relatively recent developments from
the above system segregated in response to increasing regularity
of unfavorable periods alternating with growing seasons as the
plant migrated to higher altitudes or latitudes.
No parallel cases of the rest period type of inheritance have
been reported and this type is not expected to appear with
vital characters nor with characters upon which selection is
never reversed. However, a sudden shift of environment with
no reversal of selection may produce the situation temporarily
even with characters as vital as reproductive capacity. A cross
of two heterozygous strains of corn (Zea mays) under observa-
tion by the writer shows the rest period type of inheritance
of tillers per plant under conditions where adapted varieties
produce about 30 bushels per acre. The non-tillering strain pro-
duces a single small tiller on 7 percent of its plants and none
on the remainder. There can be little doubt that in a more
favorable environment the same strain would produce tillers
on nearly every plant and that the highly skewed distribution
of F2 plants with mode in the zero class would be transformed
to near normal type. Similarly a cross of high. and low produc-
ing strains of a grain crop might be shifted to an environment
where the low producing strain and a large proportion of F2
plants produced no grain. The usual type of quantitative in-
heritance would be transformed to the rest period type but a
return to the normal type would eventually be effected by selec-
tion if the new environment continued.







Florida Agricultural Experiment Station


Whether required rest period of seeds is inherited in other
species as in the peanut is yet to be determined. The analysis
of inheritance of delayed germination in oats by Johnson (11)
and by Garber and Quisenberry (5), as noted previously, has
produced quite different conclusions, although the data appear
similar to the present data on peanuts. If peanut seeds had
been held 30-90 days in storage and then subjected to a germina-
tion test just long enough to determine what percent of each
sample would germinate immediately the methods with oats
would have been duplicated. F2 and F3 plants could then be
characterized by percent of seeds germinating in the test. Fre-
quency classifications of F2 and F3 plants on that basis would
parallel very closely Johnson's Table 2, page 371, and Garber
and Quisenberry's Table 1, page 272. Most of the plants would
have shown high germination and those with lesser germination
would have occurred with decreasing frequency exactly as in
the two oats tables. Critical evidence for the present theory of
rest period inheritance would have been almost entirely obscured.
For example, the regular series of distribution types would not
have been obtained and F1 seeds would probably have germin-
ated immediately after even 30 days storage. From the writer's
viewpoint, dominance of germinability in oats must remain
doubtful until germination tests are made very soon after
maturity. Investigations, at least as detailed as the work on
peanuts, would seem desirable with small grains and it is not
unlikely that when such investigations are completed the con-
clusions will parallel the present ones with respect to peanuts.
Physiological studies have shown that rest period in small grains
is broken by low temperatures and in peanuts by high tempera-
tures. That, however, does not constitute any argument against
similarity of genetic mechanisms. Also, if delayed germination
in oats is partially or wholly due to an impermeable seed cover-
ing rather than an internal physiological condition the possibility
of a germination threshold midway on the range of permeability
must not be neglected.
It will probably be safe to direct breeding operations as though
the present theory of rest period inheritance in peanuts were
definitely established. Peanut improvement may frequently in-
volve hybridization of Spanish or Valencia strains with runner
or other more dormant strains. Strains of hybrid origin may
be used also in further crossing. Usually it will be desired
to produce a rest period as long as or even longer than is found







Inheritance of Rest Period of Seeds in the Peanut


in the more dormant parent. Strains of the Spanish and Valen-
cia groups may be expected to have negative breeding values
as measured by means of crosses with more dormant types,
even though they exhibit mean rest periods up to 50 days or
more with the present accuracy of testing. On the contrary,
those strains may exhibit positive breeding values in that trans-
gressive segregation above the greater parent may appear in
their crosses with more dormant types. Relative breeding values
of both less dormant and more dormant strains may be expected
to follow the same order as the tests on their own seeds but
the possibility of some combinations proving particularly satis-
factory or unsatisfactory cannot be entirely overlooked.
Rest period tests usually will be deferred until later hybrid
generations when only a small proportion of selected lines is
still retained. The probability of recovering rest requirement
in satisfactory amounts in such lines is lessened by skewed
distributions. It is desirable to know what proportion of F2, F3,
and later generation families may be expected to retain satis-
factory rest requirement. A partial answer is found in Table
4, particularly with the distribution of F3 families. The 944
F3 plants were tested with an average of 30 F4 seeds. About 5
percent had rest periods as great as the greater parent. This
5 percent of satisfactory F3 plants came from 25 percent of F2
plants but 5 percent of F2 plants contributed nearly one-half
of them. It would seem that weak selection, such as might be
provided by delaying harvest two or three weeks after maturity,
would be helpful in eliminating less dormant types in the earlier
generations. However, such practice may not always be feasible.
Since 75 percent or more of genes affecting rest period are prob-
ably fixed in the F3 generation, it is clear that approximately
5 percent of later generation lines chosen at random from 1 x 14
crosses may be expected to have as long rest requirement as
the greater parent. Three other crosses have given very similar
results in F3, so it would appear that the same conclusion might
apply in most crosses of more dormant and less dormant strains.
The possibility of recovering longer rest periods in hybrid
strains than is found in the greater parent has been indicated
by marked segregation above the greater parents in several
crosses.








Florida Agricultural Experiment Station


SEED SHAPE
Spanish peanuts have short, nearly spherical seeds while the
seeds of runner peanuts are oblong. Varieties of the Valencia
group have seeds somewhat distorted in shape by being closely
packed in the many-seeded pods. Hayes (6) has reported long
seed dominant with a 15:1 ratio in a cross of Valencia with Sine.
Sine is a runner variety and was described as short-seeded,
which is certainly unusual in the runner group.


TABLE 8.-SUMMARY OF INHERITANCE OF SEED SHAPE
12 x 14, 3 x 8, and 13 x 8.


IN CROSSES 1 x 14,


I Short Inter-
Pedigree Short plus in- medi- Long N X2 P
S____ termed. ate

1 x 14 F2
Observed .................... 52 20 72
Theoretical (3:1) .... 54 18 0.30 0.59
F2 families
Observed .................. 25 29 18 72
Theoretical (1:2:1) 18 36 18 4.08 0.14
Fa
Observed .................... 596 348 944
Theoretical (5:3)* .. 590 354 0.18 0.66
13 x 14 F,
Observed .................. 16 32 16 64
Theoretical (1:2:1) 16 32 16 0.00 1.00
3 x 8 F2
Observed ................. 54 97 47 198
Theoretical (1:2:1) 49.5 99 49.5 0.58 0.75
13 x 8 F2
Observed .................. 31 60 30 121
Theoretical (1:2:1) 30.25 60.50 30.25 0.02 0.99


*The theoretical monogenic
2Aa: 3aa.


ratio in Fs with self-fertilization is 3AA:


The F2 and F3 plants 6f crosses 1 x 14, 13 x 14, 3 x 8, and
13 x 8 seemed to fall rather easily into three classes: short-
seeded, intermediate, and long-seeded. There was, however,
considerable variation in the shape of seeds from any one plant.
No attempt was made to classify single seeds because their
shape is often slightly distorted. The intermediate group of
plants was so truly intermediate that dominance of either shape
was not detected. Comparison of data of the several crosses
with an hypothesis of single gene inheritance and no dominance
is presented in Table 8. Agreement with the expected ratios
is quite satisfactory throughout.







Inheritance of Rest Period of Seeds in the Peanut


SEED COAT COLOR
Seed coat color of peanuts varies from the dark purple of
Porte Alegre through red, russet, and tan to nearly white in
White Pearl. Van der Stok, Badami, Stokes and Hull, and Hayes
have reported 3:1 ratios of red to russet or tan. Patel et al note
four colors, dark purple, red, rose, and white. They state,
"There are two duplicate factors for the rose colour. The factor
for red and the factor for purple are dominant to rose, but the
red and purple factors are expressed only in the presence of the
rose factor. The purple is dominant to red. The white seed
coat colour (pp rdrd rlrlr2r2) is recessive to the coloured seed
coats." The present study deals with russet and tan as they
occur in runner and Spanish peanuts. Patel apparently com-
bines those two colors as rose.
The F2 and F3 plants in cross 1 x 14 and the F2 plants of
crosses 13 x 14, 3 x 8, and 13 x 8 were classified as having
russet, intermediate, or tan seeds. The proportions of inter-
mediates obtained were so small that they were finally combined
with the russet classes which had the greater numbers. Russet
is clearly dominant but the difference between russet and tan
is so slight that correct classification is not easily accomplished
in every case. Samples of parent strains of the same year's
crop were kept at hand while the classifications were made,
since the color gradually darkens after the seeds are harvested.
Seeds which were as light as the darkest variations of Spanish
parents were classed as tan while the others were finally all
classed as russet. The data are summarized in Table 9 and
compared with an hypothesis of single gene inheritance with
russet dominant, which they fit very closely.

YELLOW SEEDLINGS
Badami (1) reported triplicate gene inheritance of chlorophyll
in peanuts with the triple dominant dark green and the triple
recessive albino. The statement suggests that double and single
dominants were lighter colored than the triple. Patel et al (14)
found albinos in a ratio of 15:1 in F2 generations of bunch and
spreading varieties. The character is probably identical with
the one discussed here, and the constant deficiency of albinos
is very suggestive in connection with this report. Yellow seed-
lings in the present case were distinctly yellow rather than
albino. They were probably controlled by duplicate genes with







Florida Agricultural Experiment Station


green fully dominant and yellow plants sometimes showing faint
traces of green.
Crosses involving five strains of Spanish, four of runner, four
from the Valencia group, and one each from A. Nambyquarae
and A. Rasteiro have been studied. All crosses of Spanish x
runner have produced some yellow F2 seedlings. No crosses
involving the Valencia group or A. Rasteiro have produced them.
A. Nambyquarae has behaved as the runner group. It has been
learned through correspondence with Dr. L. Husted, University
of Virginia, and Dr. B. B. Higgins, Georgia Experiment Sta-
tion, that these results have been confirmed with a number of
crosses involving the Spanish, runner, and Valencia groups in
their cultures. Hayes (6) reported a cross of Valencia with
a runner strain but noted no yellow plants.
TABLE 9.-SUMMARY OF INHERITANCE OF SEED COAT COLOR IN CROSSES
1 x 14, 13 x 14, 3 x 8, and 13 x 8.
Russet Inter-
Pedigree Russet plus in- medi- Tan N X2 p
termed, ate
1x 14 F,
Observed .................... 50 72
Theoretical (3:1) .... 54 18 1.20 0.28
FP families
Observed ................... 22 30 20 72
Theoretical (1:2:1) 18 36 18 1.44 0.49
F,
Observed .................... 564 380 944
Theoretical (5:3) .... 590 354 3.20 0.08
13 x 14 F,
Observed .................... 48 16 64
Theoretical (3:1) .... 48 16 0.00 1.00
3 x 8 F2
Observed .................... 147 51 198
Theoretical (3:1) .... 148.5 49.5 0.06 0.80r
13 x 8 F2
Observed .................... 92 29 121
Theoretical (3:1) .... 90.75 30.25 0.07 0.79


Yellow seedlings have not appeared in F, and only in low
frequency in F2 but with greater frequency in the F3 of some
families. This evidence strongly suggested duplicate gene in-
heritance with green dominant and also that the genotypes
LiL11212, lllL2L2, and LIL1L2L2 might be assigned respectively
to the Spanish, runner, and Valencia groups of peanuts. In-








Inheritance of Rest Period of Seeds in the Peanut


heritance studies of yellow seedlings have been made principally
in four crosses involving Spanish and runner strains. Data
of the cross 1 x 14 which was studied most extensively are
presented in Table 10. It soon became apparent that very few
families appeared in this or other crosses with ratios as low
as 3:1. Consequently a few F3 progenies were selected because
of low ratios in seedling progeny tests with the expectation that
only monohybrid plants would be included. These were con-
tinued another generation and seedling tests were made from
F4 plants. Ratios of true and segregating F4 families and green
and yellow F5 seedlings are shown in the last two entries of
the table. The deficiency of yellows in the F5 test is too great
to be ascribed to chance, nor can it be explained by differential
germination since the segregating families germinated equally
with their sibs. Since the deficiency appeared in monohybrid
families, it could not be due to linkage of duplicate genes. Other
possible causes, e. g. abnormal behavior at meiosis, must become
evident in unequal numbers of effective gametes or in differential
viability of zygotes.
An attempt was made to determine as closely as possible
gametic ratios of both sexes and differential viability of zygotes.
It was assumed after a preliminary inspection of the data that
gametes containing one or more dominant genes were produced
in equal numbers and were equally viable. The ratio of fully
recessive gametes to those of any one dominant class was defined
as q. The gametic proportion for one sex of the monohybrid
was then written
1 q
+ 1
1+q 1+q
and for the dihybrid
1 1 1 q
-- + -- + = 1.
3+q 3+q 3+q 3+q

Identical equations with q' served for the other sex in both
cases. It was further assumed that zygotes with one or more
dominant genes were equally viable and that the ratio of viabil-
ities of dominant and recessive zygotes was (1:w).
Defining:
T = recorded number of dominant progeny breeding true,
S = recorded number of dominant progeny segregating,
Y = recorded number of recessive progeny,







Florida Agricultural Experiment Station


and omitting intermediate steps, it is possible to write for the
case of self-fertilization of a monohybrid,

S
q + q' -
T
Y 1
qq' = -
T w
and for a dihybrid
7S 2
q + q =-- -
3T 3
7Y 1
qq' = --
T w
It is of no advantage to treat the dihybrid and monohybrid
progeny of the dihybrid separately, since they do not provide
independent equations. Also they cannot be separated accur-
ately without extensive progeny tests. They are combined in
S for this study. The best solutions obtained for these two
pairs of equations are the pairs of quadratic roots:

S / fS2 4Y
-- / --
T V T Tw
q or q'
2
and
7S 2 / 7S 212 28Y
3T 3 V 3T 3 Tw
q or q'
2
In neither case has the necessary third condition or equation
to solve for three unknowns been found but the situation is
not entirely hopeless. Since the roots cannot be complex the
discriminant cannot be less than zero. Setting it equal to zero
provides a minimum limit on w in each case. Also the maxi-
mum limit on the larger root may be reasonably taken at one,
thus setting a maximum limit on w. Taking these limits for
the monohybrid,
Y/T 4 Y/T
Max. w = Min. w
(S/T-1) (S/T)2
and for the dihybrid
21Y 28 Y/T
Max. w -- Min. w -
(7S 5T) (7S/3T 2/3)2





TABLE 10.-SUMMARY OF THE INHERITANCE OF YELLOW SEEDLINGS IN CROSS 1 X 14.


Pedigree and ratio


F2, Observed ......................
Theoretical corrected* ......
F2 families
Observed ...........................
Theoretical corrected* ......
Fa, 'Observed ...........................
Theoretical corrected* ......
F. from dihybrid F2
Observed ............................
Theoretical corrected* ......
Fa from monohybrid F2
Observed ............................
Theoretical corrected* ......
Fs families
Observed .........................
Theoretical corrected* ......
F,, Observed ......................
Theoretical corrected* .....
F4 families from selected
monohybrid Fs
Observed ...........................
Theoretical (1:2) ................
Theoretical corrected* ......
F, from selected F4
Observed .....................- ..
Theoretical (3:1) ................
Theoretical corrected* ......


*See text.


Dihybrid


Total
segre-
gating


Total
green


102.0
102.2


36.0 1


True
green


36.0
36.0











770.0
728.0





44.0
39.0
44.0


IMono-
I hybrid


12.0
17.1

















73.0
78.0
73.0


Yellow


4.0
3.8




92.0
96.2

34.0
32.0

58.0
64.3




635.0
1,152.0






430.0
680.0
442.4


174.0
216.0


106


72

2,818


898


395


944

30,466



117



2,720


2,726.0
2,721.8

864.0
866.0

337.0
330.7




29,831.0
29,314.0






2,290.0
2,040.0
2,277.6


0.01


2.93

0.19


0.13


0.73


10.58

241.00



0.96
0.00


122.54
0.42


0.92


0.24

0.65

C0
0.71

0
0.40
O


0.002

0.000
C+.


0.32
0.99+ -


0.00
0.53 M


g e n








Florida Agricultural Experiment Station


It should be noted, however, that these limits may be strictly
imposed only on expected values of w. Random deviations be-
yond the limits may readily occur. The entire mathematical
treatment given here deals expressly with the expected values.
Utility of the solutions obtained must be judged by their sam-
pling variances finally. These limits set on w have proven to
be of considerable value in the analysis of the present case
while further treatment has been fruitless. However, it seems
desirable to present the further treatment briefly because ac-
curate evaluations of q, q', and w should prove of great value
preliminary to cytological investigations of such cases as the
present one.
The segregating F2 plants from a dihybrid F, are dihybrids
and monohybrids in the proportions
2+q+q' 2(q + q')
+ -1.
2+q+q'+2(q+q') 2 + q+ q'+ 2(q+ q')

It seemed that this relation might provide the necessary third
condition for a definite solution for q, q', and w in the F3 gen-
eration. Such data were available with cross 1 x 14. However,
it was learned from the Jacobian determinant that no solution
was possible. This test was kindly made by Dr. L. W. Gaddum
of the Florida Experiment Station, who then suggested that a
combination of the data in three separate cases should provide
three independent equations and a definite solution for q, q',
and w. The first choice for this attack was the ratio of re-
cessives to the total number of progeny in each of three cases,
since the error involved in experimentally determining these
ratios is least. Classification into true breeding and segregating
is hazardous unless very large progenies are grown. The ratios
of recessive to total progenies in a monohybrid, a dihybrid, and
in the F3 progeny of segregating F2 plants from a dihybrid F,
were designated as a, b, and c respectively. Solution of the
three equations resulted in:
9b 8ab a 6ab
S+ q' =-- qq' =
a + 2ab 3b (a + 2ab 3b)w
c(b-2ab+a) (21b-20ab-a) b(a-2ac+c) (3b-4ab+a) -
W -
c(1-a) (1-b) (21b-20ab-a) b(1-c) (1-a) (3b-4ab+a) -
2a(b---2bc+c) (9b-8ab-a)
2a(1-c) (1-b) (9b--ab-a)







Inheritance of Rest Period of Seeds in the Peanut


These formulae are apparently correct mathematically. They
work perfectly with hypothetical cases when no deviations from
expected values are allowed. Deviations in any one of the ratios,
a, b, or c, which have 50 percent probability with samples of
500 to 1,000 throw the results entirely out of line. The formulae
are of very limited utility, presumably because of enormous size
of their sampling variances. Similar formulae might be cal-
culated from the ratios of segregating to total progeny, or to
true breeding progeny, or from any set of three independent
equations involving the three unknowns. None of these other
possibilities has been investigated fully as yet, but the prob-
ability of finding a more valuable set of formulae appears to
be very small.
Estimates of q, q', and w were obtained by calculating maxi-
mum and minimum w in the dihybrid F2 and the monohybrid
F4 families of cross 1 x 14 by the formulae given above. For
the F2 maximum w is 0.82 and minimum w is 0.79 while for
the monohybrid F4 families maximum w is 0.76 and minimum
w is 0.73. In either case, for maximum w, q = 1.00, q' 0.66;
while for minimum w, q = q' = 0.83. The corrected ratios in
Table 10 have been based on an hypothesis of q = q' = 0.83,
and w = 0.75. There is, unfortunately, no evidence for or
against equality of q and q'. The ratios of F2 seedlings, F2
families, F4 families, and F5 seedlings were used to build the
hypothesis and are not entirely independent of it. Tests of the
hypothesis lie in the ratios of F3 seedlings, F3 families, and F4
seedlings, which data were not used to calculate q, q', and w.
Theoretical ratios for later generations were also corrected
for random deviations and differential productivity in earlier
generations. The ratio of F3 families was, in addition, cor-
rected for the proportion of dihybrid families expected to pro-
duce no recessive progeny and apparently breed true because
of few progenies tested. Contributions of these factors to X2
must of course be eliminated if a fair test of the hypothetical
values of q, q', and w is to be obtained.
It was possible to make the above corrections on the theo-
retical F3 ratio with reasonable assurance. This ratio is pre-
sented in Table 11 for the entire population and for the progenies
of dihybrid and monohybrid F2 plants separately. Good fits
were obtained in all cases. The ratios of F3 families and F4
seedlings could not be corrected so accurately and the fits obtained
were hardly within the limits of random sampling. However,







Florida Agricultural Experiment Station


judging the data of Table 10 as a whole, there can be little
doubt that the hypothesis of duplicate genes with deficiencies
of recessive gametes and zygotes is correct. It is also indicated
that the calculated values of q, q', and w which are measures
of those deficiencies are not greatly in error, at least in their
resultant.
Records of yellow seedlings in the other three crosses are
available only for the F2 and F3 generations. These data are
sufficient only to set limits on w and to approximate q and q'.
In cross 13 x 14 there were 82 F2 seedlings of which 64 green
plants were grown to maturity and tested for segregation with
4,479 F3 seedlings. By the formulae given above for a dihybrid,
maximum w is 0.91 and minimum w is 0.84. Taking the maxi-
mum value of w, q = 1 and q' = 0.57. Taking the minimum
value of w, q = q' 0.78.
In cross 3 x 8 there were 212 F2 seedlings from three F1 plants
of which 198 were grown to maturity and tested for segregation
with 13,781 F3 seedlings. Maximum w is 0.727 and minimum
w is 0.723. For minimum w, q = q' = 1.08. In this cross
the proportion of segregating plants is slightly in excess of the
expected proportion with q = q' = 1. There is no evidence
of deficiency in q or q'.
In cross 13 x 8 there were 146 F2 seedlings of which only
two were yellow. However, the occurrence of yellow plants
among 6,174 F3 seedlings from 121 F2 plants is very similar to
that of the previous cross. The unusual F, result prevents
any reasonable determinations of limits on w as in previous
crosses. The proportion of segregating F2 plants is very close
to that expected with q = q' = 1. There is no evidence of
deficiency in q or q'. Two estimates of w have been made from
the ratios of green to yellow plants in the F3 derived from the
segregating F2 plants and in the total Fs. In these two cases
the proportions of yellow plants are 0.73 and 0.74 of that ex-
pected with q, q', and w equal to one. This deficiency must
be largely ascribed to w, and the ratios of yellow plants obtained
to the numbers expected with a hypothesis of w equal to one
may be considered estimates of w.
Values of q, q', and w obtained in the first two crosses are
quite similar. These crosses involve runner strain No. 14 crossed
with the Spanish strains No. 1 and No. 13. The latter two
crosses also behaved similarly but different from the first two.
They involve runner strain No. 8 crossed with Spanish strains







Inheritance of Rest Period of Seeds in the Peanut


No. 3 and No. 13. Deficiencies in q and q' would appear to be
associated with strain No. 14. The significance of these defi-
ciencies, especially in q and q', in relation to abnormal associa-
tions in meiosis noted by Husted (8) must not be overlooked.
However, they would seem to be adequately and more simply
explained by a weakening effect of the recessive genes in both
the gametic and zygotic stages. Examination of pollen in mono-
hybrid families has shown no plants with less than 95 percent
of normal appearing grains and little variation in the amount
of aborted pollen. Segregating plants are frequently slightly
less productive than true breeding, green plants. However,
no significant differences between true green, dihybrid, and
monohybrid F2 plants or families have been found. It is possible
that the indeterminate blooming and fruiting habit of the plant
enables it to eliminate largely the effect of a considerable pro-
portion of aborted ovules.

VALENCIA PLANT TYPE
It was stated previously that the Valencia group of peanuts
differs from other American types in its very sparse branching
habit and by commonly producing three or four seeds in a pod.
Chevalier (2) has assembled the varieties having many-seeded
pods into a principal variety, stenocarpa. He lists Tennessee
Red and Tennessee White but omits Valencia which, as known
in America,. should be included, as should Porte Alegre from
Brazil. Chevalier also describes two African forms with many-
seeded pods. One is stated to have few branches which are long,
slender, and prostrate. Both are low yielding, which is a com-
mon character of sparsely branched types. Perhaps both are
sparsely branched. If so, sparse branching and many-seeded
fruits are constantly associated in all known varieties which
possess either character. The two characters have appeared to
assort independently in crosses of Valencia or Tennessee Red
with Spanish or runner strains.
Sparsely branched peanuts frequently have a central stem
or rachis in the fruiting cluster several inches in length. Some-
times a few small leaves are found at the tip. Fruit stalks are
borne singly and alternately along this stem. The typical in-
florescence of peanuts as described by botanists and found in
other forms is a reduced head. The fruit cluster consists of
one to four ovary stalks with sessile attachment. Plants having
the central stem in the fruiting cluster and sparse branching








Florida Agricultural Experiment Station


habit have been found among the later generations of crosses
between Spanish and runner peanuts. Such plants do not have
many-seeded fruits necessarily. Their analogy with Valencia
type is not easily recognized at first because of their usually
long, slender, prostrate branches. Valencia and related vari-
eties except the African forms described by Chevalier have short,
thick, upright branches. The type of hybrid plants with sparse
branching and central stem in the fruit cluster has been named
Valencia plant type. There is no inference as to the number
of seeds per pod.
The inheritance of Valencia plant type has not been investi-
gated in crosses involving any varieties of the Valencia group
but the data of a cross of Spanish and Jumbo Runner, 1 x 14,
are summarized in Table 11. The record on the F2 is not known
exactly but it is certain that approximately 5 percent were
Valencia type, as was the case in other crosses of Spanish and
runner peanuts. When the F3 generation of cross 1 x 14 was
grown the significance of the sparsely branched plants was
recognized. Seventy-two F3 families were grown to maturity
with an average of 13 plants. The occurrence of Valencia type
plants suggested duplicate gene inheritance with Valencia type
recessive. Theoretical ratios based on that hypothesis are com-
pared with the experimental ratios in Table 12. Because of
the small number of F3 plants in the F2 families it was necessary
to correct the theoretical ratios. This was done by making use
of Warwick's tables (17). In the portion of the table dealing
with 13 progeny tested, it is recorded that 43 percent expected
to breed 15:1 would produce no recessive progeny while the
other 57 percent are expected to produce dominants and re-
cessives in a ratio of 8.085:1. These corrections were made on
the theoretical ratios in the first and second comparisons of
Table 11. No correction for the monohybrid families was neces-
sary. These corrections are not entirely accurate since the
number of F3 progeny per F2 was not constantly 13. A more
accurate correction could probably be made by treating each
F3 family separately and summing the corrections. However,
the error in the method used tends to increase X2 and no false
conclusions are likely.
Agreement of the data with the hypothesis is quite satis-
factory in three comparisons. It is concluded that Valencia type
is a recessive character controlled by duplicate genes. Peanut
varieties of the Valencia group are probably of the genotype








Inheritance of Rest Period of Seeds in the Peanut


val val vaa va2 while Spanish may be assigned Val Val va2 va2
and runner peanuts val vaa Va2 Va2. The classification of pea-
nut varieties proposed and used here may thus be given addi-
tional support.
TABLE 11.-SUMMARY OF THE INHERITANCE OF VALENCIA PLANT TYPE
FROM THE F3 GENERATION OF CROSS 1 x 14.

Breeding behavior of
F2 plants N X2 p
All Non-1 All
_Valencial 15:1 | 3:1 1 Valencial
Observed ............ 47.0 5 16 4.0
Theoretical* .. 39.5 10 18 4.5 72 4.03 0.25

Summary of F2 families
breeding 15:1
Non-valencia I Valencia
Observed ............. 92.0 7.0 99
Theoretical* ....... 88.1 10.9 99 1.57 0.21

Summary of FP families
breeding 3:1
Non-valencia Valencia ]
Observed .............. 174.0 47.0 221
Theoretical .......... 165.8 53.2 1.64 0.20

*Corrected for small numbers-see text.

Since the above paragraphs were written, John and Seshadri
(10) have described the Valencia type very accurately as it is
usually recovered from crosses of Spanish and runner peanuts.
They recovered it from a cross of bunch and spreading types
and found it bred true. They failed to note that the char-
acteristic elongated axis of the inflorescence is also characteristic
of the Valencia group as listed here and described this double
recessive as a new variety.

BRACHYTIC DWARF PLANTS
Brachytic dwarf plants were discovered in a field planting
of one F2 family of a cross of Virginia Runner with Tennessee
Red. Five other F0 families of the same cross did not show the
character nor has it appeared in any other cultures, although







Florida Agricultural Experiment Station


many related hybrids have been grown. Dwarf plants had
greatly shortened internodes, and the leaf rachis was shortened
so that the two pairs of leaflets were found in a cluster. This
was true of first seedling leaves and of later leaves on the plant.
Blossoms were reduced in size with anthers containing mostly
empty pollen grains. Occasionally a few fruit stalks developed
to a length of an inch or more but no fruit development was
found. This character is probably identical with the abnormal
dwarf described by Patel et al (14) and found to appear in a
ratio of 15:1 in F2 of a cross of spreading x a purple seeded
variety.
One of the segregating, normal sibs of the dwarf plants was
carried through another generation and seedling tests made on
17 of its progeny. Five of them bred true and 12 segregated.
The 12 segregating plants produced 393 normal to 114 dwarf
seedlings. For the test of this ratio against a theoretical 3:1,
X2 = 1.71, P = 0.18. One of these segregating plants was
tested a generation further, producing seven true breeding
progeny and 20 segregating. The 20 segregating plants pro-
duced 394 normal and 139 dwarf seedlings. For the test of
this ratio against a theoretical 3:1, X2 = 0.33, P = 0.58. Com-
bining the numbers breeding true and segregating in the two
tests produces a ratio of 12:32. Testing this ratio against a
theoretical 1:2, X2 = 0.73, P = 0.40. Brachytic dwarf be-
haved as a single recessive character.

REGRESSION TESTS
Records of the 22 characters listed in the first column of
Table 12 were taken in the F2, F3, or F4 generations of cross
1 x 14. Records on nearly all of the same characters were taken
in the F2 or F3 generations of crosses 13 x 14, 3 x 8, and 13 x 8.
Those characters which did not fall naturally into definite
classes were graded numerically. The F3 and F4 records were
then averaged by F2 families and only F2 values were used in
regression tests. The tests were made by the analysis of vari-
ance and z test of Fisher (4) as modified by Snedecor (15). Re-
gressions of the several characters listed on rest period, seed
shape, seed coat color, and yellow seedlings were tested in all
four crosses and, in addition, regressions on Valencia plant type
were tested in cross 1 x 14. Regression is used here in the broad
sense to refer to any type of association or dependence between
variables.







Inheritance of Rest Period of Seeds in the Peanut


The classification of rest period given above produced highly
*skewed distributions not well suited to analysis of variance
tests. That method of classifying was called "equal interval"
because all class intervals were equal except the first, which
was of indeterminate breadth in the genetic sense. Transforma-
tions of the distributions were made by two other methods of
classification. It was necessary in making these transformations
to assume that the relative rank of F2 mean rest periods was
measured with reasonable accuracy. However, no doubt need
be entertained of significant regressions on that account since
failure to classify correctly could hardly produce spurious re-
gression.
The first transformation was to a rectangular distribution by
taking classes of equal frequency throughout. This provided
tests of regression on rank. The second transformation was an
attempt to normalize the distributions by taking class frequen-
cies proportional to areas of equal breadth under the normal
curve. It was done by dividing a range of 2.6 standard devia-
tions plus or minus into equal sections and calculating the pro-
portionate frequencies from Fisher's Table I (4). The total
range of 5.2 standard deviations centered at the mean includes
a little more than 99 percent of the total area under the normal
curve. Justification for this transformation lies in the supposi-
tion that distributions of rest period genotypes are probably not
far from normal type.
Most of the tests on rest period were made with the trans-
formed rectangular distributions but a few tests with the other
distributions are also shown in Table 12. When rest period
served as the dependent variable only the actual data were
used with no transformation, and no transformations of distribu-
tions of other variables were made in any case.
Values of F for the several tests of regressions on rest period
in cross 1 x 14 are presented in Table 12. The F values for
tests of regression on seed shape, seed coat color, yellow seed-
lings, and Valencia plant type of the 22 recorded characters
in the four crosses have been omitted. As shown by the column
headings each series of F values is listed in two columns, "Be-
tween" and "Within", to indicate which was the larger mean
square in the ratio F. A significantly greater between mean
square indicates that group means of the dependent variable are
less alike than expected with random sampling. The increment
of variance is attributed to association with the independent










TABLE 12.-VALUES OF F* IN TESTS FOR REGRESSION OF VARIOUS CHARACTERS ON REST PERIOD IN CROSS 1 X 14, WITH
REST PERIOD CLASSIFIED IN GROUPS BY THREE DIFFERENT METHODS AS INDICATED.


Dependent variables



Rest period I

Percent yellow 12111l12 1

Seed length 1
]
Seed shape ]
Seed coat color ]
Indented seed 1
]
Ruptured testa ]
1
Black eyed seeds ]
Fill of seeds ]
]
Three-celled pods ]

Cells per pod ]


Independent variable rest period

Fs rest period by F2 families F4 rest period by F2 families

Equal interval Eq'l frequency I Normalized I Equal interval Eq'l frequency I Normalized


Be- *
tween


37.73


With-
in**


Be-
tween


11.99





2.25
1.15
1.10


2.00
2.74


I Be- I Be- I Be-
Within tween Within tween I Within tween

S90.47 6.00


22.60










1.16
1.92


2.56
13.40


1.65
1.65
1.65
1.35
1.75
2.55


1.15
1.10
1.75

2.50
2.65
1.45


*Ratio of mean squares, Snedecor (1934).
**The headings, "Between" and "Within" indicate which was the larger


1.00

1.15

1.25
1.30

3.10
1.18
1.80

1.15


Within




1.45
1.55

5.40

1.50

1.13


3.10
1.25


Be-
tween Within

20.29

1.08
1.00
1.16
1.26
1.11
11,48
1.94
1.40
2.15
2.41
1.60
1.61
1.44
2.72
1.32


mean square in the ratio, F.










TABLE 12.-VALUES OF F* IN TESTS FOR REGRESSION OF VARIOUS CHARACTERS ON REST PERIOD IN CROSS 1 X 14, WITH
REST PERIOD CLASSIFIED IN GROUPS BY THREE DIFFERENT METHODS AS INDICATED-COntinued.

Independent variable rest period
F. rest period by F. families F, rest period by F2 families
Dependent variables I I
Equal interval Eq'l frequency | Normalized Equal interval Eq'l frequency! Normalized 2
Be- ** With- Be- Be- I Be- Be- Be-
tween in** tween Within tween Within tween Within tween Within tween Within
Cells per plant F, 1.01 7.49 2.50 1.72 1.70 1.77
F, 2.39 3.00 1.05 1.01 3.30 1.28
Fertility F. 1.20 1.13 2.74
Pericarp thickness F, 7.35 1.90 1.30
F, 1.75 1.20 1.02 .
Pubescent pericarp F, 1.70 1.65 1.69 o
Plant weight F, 1.05 4.16 3.46 1.56 1.85 1.88
Weight nuts F, 1.14 4.11 2.54 2.62 2.65 1.90
Valencia type F3 1.40 1.00 1.07
Stipular spines F, 1.16 1.45 1.10 1.71 2.20 2.06
F. 1.46 1.36 1.13 5.48 1.50 1.94
Anthocyanin F, 1.90 1.40 1.41
F. 2.25 1.55 1.03
Length of season F, 1.61 1.10 1.19
F. 1.10 1.10 2.77
Angle of branches F2 1.85 1.60 1.70
F, 1.41 1.15 1.10
F, (P = 0.05) 2.16 3.35 2.16 3.35 2.16 3.35 2.16 3.35 2.16 3.35 2.16 3.35
F, (P = 0.01) 2.95 5.80 2.95 5.80 2.95 5.80 2.95 5.80 2.95 5.80 2.95 5.80 Z

*Ratio of mean squares, Snedecor (1934).
**The headings, "Between" and "Within" indicate which was the larger mean square in the ratio, F.







Florida Agricultural Experiment Station


variable. A greater within mean square indicates that the group
means of the dependent variable are more alike than expected
with random sampling. Values of F for the points of 5 and 1
percent probability, Snedecor (15), are given at the bottom of
each column and all values of F in the table which exceed the
5 percent point have been set in bold face type.
The F values of tests of the regressions of the two generation
measures of rest period on each other are highly significant with
each of the three methods of classification when judged by the
criteria applicable with normal distributions. That they are
really significant seems probable from a comparison with other
F values in the table which range much smaller generally. The
F values of the other tests which were not listed were also
much smaller. Significant regressions of the different genera-
tions of rest period on each other were to be expected, since
strong heritability of the character was already demonstrated.
Perhaps the principal value of these tests was to provide F
values derived from highly skewed distributions with strong
regressions to compare with other F values also derived from
highly skewed distributions where the order of regression was
unknown.
Some of the characters other than rest period also had highly
skewed distributions. Seed coat color was classified sometimes
in ratios approximating 1:2:1 and in other cases the ratios
approximated 3:1. Valencia plant type has a highly skewed
distribution in cross 1 x 14, as may be seen in the first experi-
mental ratio of Table 11. This character is controlled by dupli-
cate pairs of genes with one pair coming from each parent of
the cross; thus it is hardly expected that genetic regressions
involving Valencia plant type should be found in F2. The order
of F values obtained with characters having skewed distribu-
tions appears not different from that of characters with distribu-
tions generally symmetrical.
Only a few of the F values obtained in tests involving two
separate characters exceed the points of significance and those
few to no great extent. Results of the several tests on any pair
of characters are frequently inconsistent or contradictory. It
might appear, e. g. in Table 12, that greater between mean
squares were obtained too frequently with both plant weight
and weight of nuts to be ascribed to chance but in the other
three crosses no significant F values were obtained and the







Inheritance of Rest Period of Seeds in the Peanut


between mean squares were as often smaller as greater than
the within.
It is concluded that any regressions which exist between
the characters tested must be weak. The significant values of
F which appeared are more probably due to non-normal distribu-
tions, to errors which may have occurred in recording and cal-
culating the data, or to the sampling variance of F itself.
The probability of strong genetic regressions, especially with
quantitative characters, in the peanut must be small. The num-
ber of chromosomes is large, 20 haploid. Also polyploidy, prob-
ably tetraploidy, has been suggested by the cytological findings
of Husted (8) and by the several pairs of duplicate genes which
have been reported by Hayes (6) or in this bulletin. Since no
strong genetic regressions were uncovered it would seem that
rigid selection for rest period, seed shape, seed coat color, and
probably most other characters might be practiced with little
fear of accumulating undesirable genes. The possibility of find-
ing linked markers of rest period is almost entirely eliminated.

SUMMARY AND CONCLUSIONS
Peanut seeds planted soon after maturity in conditions near
optimum for germination frequently required rest periods rang-
ing up to two years before germinating. Rest periods were
apparently due to necessary physical or chemical changes within
the seeds which comprise a process commonly called "after-
ripening".
The average time to emergence of different strains from the
Spanish and Valencia groups of peanuts ranged from 9 to 50
days, while in a more dormant group including runner peanuts,
A7Nambyquarae, and A. Rasteiro, it ranged from 110 to 210
days. Genetic differences between strains within the two groups
were demonstrated to be very probable.
Frequency distributions of time to emergence in pure strains
and hybrid populations were highly skewed to the left with
modes at the point of zero days rest period in most cases. The
degree of skewness was greater in less dormant samples. Inter-
mediate samples had two modes, one of which was at zero,
Ele the most dormant samples had single modes near the
ters of nearly symmetrical distributions.
'he mean time to emergence of F1 seeds was intermediate
probably slightly greater than the average of the parents.







Florida Agricultural Experiment Station


Means of later generation hybrids were considerably below the
mid-point of their parents.
Marked transgressive segregation of F2 families above the
greater parents was found in four crosses of Spanish and run-
ner peanuts. These segregations were thought to indicate the
presence of considerably more genic material for long rest
period in the less dormant parents than was evident in their
own rest period tests and that a large part of this genic material
was different from any found in the more dormant parents.
Rest period behavior suggested and agreed closely with a
theory of multigenic inheritance with the zero point of rest
period coinciding with a germination threshold lying near the
mid-point of the range of the seed condition basic to rest period.
Seed condition may be a typical quantitative character. It is
complex and has not been identified by physiological studies.
Regression of rest period on seed condition and genotype be-
comes discontinuous at the lower limit of rest period. Presum-
ably the point of discontinuity is near the mid-points of the
ranges of seed condition and genotype. Approximately the left
one-half of a usual picture of quantitative inheritance is thus
compressed into a single class of zero rest period. The right
one-half is obtained with little or no distortion.
A single pair of major genes differentiating long and short
seeds with the heterozygote intermediate was demonstrated in
crosses of Spanish and runner peanuts. The results indicated
that seed shape was controlled largely by maternal impression
and very little by the genotype of the seed.
Russet seed coat color of runner peanuts behaved as a single
dominant to tan color of Spanish peanuts.
Yellow seedlings appearing among progenies of a number of
crosses indicated duplicate gene inheritance with green fully
dominant. It was also indicated that the genotypes L1L1212,
liliLL2 and L1L1LL2 might be assigned respectively to the
Spanish group, to the runner group and A. Nambyquarae, and
to the Valencia group and A. Rasteiro. Deficiencies of recessive
zygotes were found in both monohybrid and dihybrid progenies
in all crosses and in some cases deficiencies of segregating plants
in proportion to true breeding dominants also were found.
attempt to calculate deficiencies of recessive zygotes and gan
in both sexes was only partially successful. No explanatic
deficiencies other than lower vigor of recessive gametes
zygotes was discovered.











Inheritance of Rest Period of Seeds in the Peanut


Valencia plant type, so named from its similarity to the sparse
branching habit of Valencia peanuts, was found among pro-
genies of several crosses of Spanish and runner strains. It
behaved as a duplicate gene recessive, indicating that the parent
groups carry alternate pairs of duplicate genes in the recessive
and dominant conditions.
A division of the American varieties of A. hypogaea into three
principal groups-runner, Spanish, and Valencia-was proposed
and used in the present study. It was supported not only by
morphological characteristics but also by the distribution of
duplicate genes controlling yellow seedlings. Probability that
the distribution of duplicate genes controlling Valencia plant
type also supports the classification was indicated.
Male-sterile, brachytic, dwarf plants were discovered in one
F2 family of a cross of Virginia Runner and Tennessee Red.
The character behaved as a monogenic recessive.
Regression tests involved the 22 characters listed in the first
column of Table 12 as dependent variables and rest period of
seeds, seed shape, seed coat color, yellow seedlings, and Valencia
plant type as independent variables. The tests were made with
F2 plants or families in four crosses of Spanish and runner
peanuts. No significant regressions were found.

ACKNOWLEDGMENTS
A word of appreciation for friendly interest and criticism during the
progress of the work is due to Dr. E. W. Lindstrom, Dr. W. E. Loomis,
Dr. J. N. Martin, and Professor G. W. Snedecor of Iowa State College;
and Mr. W. E. Stokes of the Florida Agricultural Experiment Station.
Thanks are due to the administrative officers of the Florida station
for permission to present the data in a thesis to the Graduate Faculty of
Iowa State College.
Dr. L. W. Gaddum of the Florida station kindly checked the mathe-
matical theory involved in the discussion of yellow seedlings and offered
valuable suggestions during its development.
Seed stocks were generously furnished by Mr. J. H. Beattie and Mr.
Roland McKee of the United States Department of Agriculture, Dr. Paulo
Campos Porto, Jardim Botanico, Rio de Janeiro, Brasil; Dr. F. C. Hoehne,
Institute Biologico, Sao Paulo, Brasil; and Dr. Reynaldo Bolliger, Instituto
Agronomico do Estado de Sao Paulo, Campinas, Brasil.









Florida Agricultural Experiment Station


LITERATURE CITED

1. BADAMI, V. K. Unpublished thesis, University Library, Cambridge,
England.1 1928.
2. CHEVALIER, AUG. Monographie de l'Arachide, Rev. Bot. Appl. 13: 689-
789; 14: 565-632, 709-755. 1933.
3. DEMING, G. W., and D. W. ROBERTSON. Dormancy in small-grain seeds.
Colorado Agr. Exp. Sta. Tech. Bul. 5. 1933.
4. FISHER, R. A. Statistical methods for research workers. 5th edition.
Oliver and Boyd. 1934.
5. GARBER, R. J., and K. S. QUISENBERRY. Delayed germination and the
origin of false wild oats. Jour. Hered. 14: 267-274. 1923.
6. HAYES, T. R. The classification of groundnut varieties; with a pre-
liminary note on the inheritance of some characters. Trop. Agr.
10: 318-327. 1933.
7. HUNTER, H., and I. M. LEAKE. Recent advances in agricultural plant
breeding. P. Blakiston's Son and Co. 1933.
.8. HUSTED, L. Chromosome number in species of peanut, Arachis. Amer.
Nat. 65: 476-477. 1931.
9. ---- -. Cytological studies on the peanut, Arachis. 1. Chromo-
some number and morphology. Cytologia 5: 109-117. 1933.
10. JOHN, C. M., and C. R. SESHADRI. A new groundnut Arachis hypogaea,
Linn. Var. Gigantea Patel and Narayana (var. Nova.) Cur. Sci.
4: 737-738. 1936.
11. JOHNSON, L. V. P. The inheritance of delayed germination in hybrids
of Avena fatua and A. sativa. Canad. Jour. Res. 13: 367-387. 1935.
MANGELSDORF, P. C. The inheritance of dormancy and premature
germination in maize. Genetics 15: 462-494. 1930.
13. MILLER, E. C. Plant physiology. McGraw-Hill Book Company. 1931.
14. PATEL, J. S., C. M. JOHN, and C. R. SESHADRI. The inheritance of
characters in the groundnut Arachis hypogaea. Proc. Indian Acad.
of Sciences, 3: 214-233. 1936.
15. SNEDECOR, G. W. Calculation and interpretation of analysis of vari-
ance and covariance. Collegiate Press. 1934.
S16. STOKES, W. E., and FRED H. HULL. Peanut breeding. Jour. Amer.
Soc. Agron. 22: 1004-1019. 1930.
17. WARWICK, B. L. Probability ratios for Mendelian ratios with small
numbers. Texas Agr. Exp. Sta. Bul. 463. 1932.
18. VAN DER STOK, J. E. Onderzoekingen omtrent, Arachis hypogaea L.
(Katjang-tanah). Med. van het Dept. van Land. 12: 176-221. 1910.

'Seen by reference only, Hunter and Leake (7).




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