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Copyright 2005, Board of Trustees, University
WATERMELON FIELD DAY
l- UTNIVERSTTY OF FLORIDA, IFAS
A(GI CULTURAL RESEARCH CNTIER, LEESBURG
GARY ELMSTROM, Center Director
JTune 1, 1981 1:3(0 PM
Earl Kelly, Lake County Extension director Moderator
Welcoming comments Gary Elmstrom, Director, Agricultural
Research Center, Leesburg
Discussions of Current Research
Warren Adlerz, Entomologist, Leesburg
Rindworm control on watermelon
Pickleworm control on squash
Watermelon mosaic virus studies
Don Hopkins, Plant Pathologist, Lccsburg
Watermelon disease control with fungicides
Muskmelon disease control with fungicides
Watermelon 'old land' studies
Sal Locascio, Horticulturist, (;alnesville
Mostella Myers, Agricultural Ellngrineer, Galnesville
Drip irrigation for watermelons
Gary Elmstrom, Associate Horticulturist, Leesburg
Cucurbit variety evaluation
Sugars in watermelon fruits
Seed priming for early melons
James Crall, Plant Pathologist, Leesburg
'Sugarlee' watermelon release
Fifty years of watermelon breeding
Refreshments (Courtesy of Foremost IFrt1lizer Company)
Tour of research plots, Bill Bodnaruk, Assistant County Agent,
HUMJ .iiE LUFBRAARY
.F.A.S.- Univ. of FPorida
Leesburg ARC Research Report ('1VT 3.-
The Institute of Food and Agricultural Sciences is an Equal Employment Opportunity Affirmative Actipn Employer authorized to provide research,
educational information and o '--- services only to individuals and institutions that function without regard to race, color, sex, or national origin.
1. Rindworm Control (Adlerz)
Purpose: To compare insecticides for control of rindworm on
watermelon. Typical rindworms are cabbage loopers, tobacco
budworms, and granulate cutworms.
Date of Planting: February 6, 1981
Procedure: Spray treatments were applied weekly beginning
April 30. They were applied in 100 gallons of water/acre at
about 150 psi with a boom sprayer.
A Pydrin 2.4E
B Pydrin 2.4E
C Pydrin 2.4E
D Pounce 3.2E
E Pounce 3.2E
F Pounce 3.2E
G Monitor 4E
H Monitor 14E
I Monitor 4E
J Nudrin 1.8
K Nudrin 1.8
L Nudrin 1.8
Pounds active ingredient
Results 1981: At this writing there is no rindworm infesta-
tion in the area of the control test. Residue studies for
labelling purposes are continuing this year on Monitor al-
though 24C labelling has been obtained.
1980 Rindworm populations were low, but significant control
was demonstrated with Pydrin, Pounce, Nudrin, and Monitor.
The rindworms were granulate cutworm, cabbage looper and
tobacco budworm in proportions that were not determined due
to low numbers of all worms.
Recommended Insecticide for Watermelon.
Materials and rate (amt/acre) to harvest
Bacillus thuringiensis NTL
Guthion 2s, 2 pts. NTL
Nudrin/Lannate 903P, 1 lb 3
Phosdrin 4EC, 1/2 pt. 1
Thiodan 2E, 1 qt. NTL
Monitor 4, 1-2 pts.2 7
Minimum number of days allowed between
the last foliar applications and har-
vest. NTL = no time limit.
2Recently approved 24(c) label, Florida
2. Pickleworm Control on jqiuash
Purpose: To comnpnar 1I:nnect1iidos ror control of pickleworm
Date of Plant ln: Augu:;gt 14, 1980
Variety: Burpee Hybrid Zucchini and Dixie.
Procedure: Insecticides were applied weekly beginning
September 23. They were applied in 100 gallons of water per
acre at 150 psi. Squash was harvested 1, 3, and 6 days after
Pounds active ingredient
Results: Burpee Hybrid Zucchini was more susceptible to
damage than Dixie. Yields from untreated zucchini plots
were nil. Pickleworms were controlled most effectively by
Pydrin, Monitor, and Lannate. Lannate had slightly better
residual effectiveness than the others.
Recommended Insecticides for Squash
Materials and rate (amt/acre)
Lannate/Nudrin 90SP, I/2 1 lb.
1/2 lb 1
over 1/2 lb 3
Carbaryl (Sevin) 80 WP, 1.25 lbs. NTL
1Minimum number of days allowed between the last foliar
application and harvest. NTL = no time limit.
3. Virus Control with Oil Sprays
Procedure: JMS stylet oil (JMS Flower Farms, Vero Beach,
Florida) was applied as a 0.75% emulsion in 100 gallons per
acre and 400 psi pressure with TX-5 brass-tipped nozzles.
Results: In 1978 and 1979 we treated watermelon plots with
no spray, weekly spray, and twice weekly spray. We made
weekly asse:;sments of spread of watermelon mosaic virus 2 by
aphids and concluded that mosaic control in watermelon was
poor. We found phytotoxicity on plants treated with Bravo
Experimental work in south Florida has shown that oil spray-
ing is effective in controlling virus spread in pepper and
tomato. It is less effective in controlling spread of water-
melon mosaic on squash and almost ineffective on watermelon.
Planting density seems the most likely factor to account for
these differences. Incompatibilities resulting in,phytotoxi-
city on crops other than watermelons have not been reported.
However, it is recommended that oil be applied alone.
Objective: Determine by direct observation what species of
aphids are most responsible for virus spread.
Procedure: Aphids are caught on a gray screen (5 ft high,
15 ft wide) or in pans painted yellow filled with water and
placed on the ground. Live aphids are transferred to the
cotyledens of squash plants In small vials. Aphids are
collected and identified to species. Plants are observed
for the development of mosaic.
Results: Little direct evidence of this kind has been col-
lected anywhere. Projects are underway at several locations,
for example in Illinois, Canada, England, and Israel. We
hope that identification of the most important vector species
and studies of their habits will help us gain a clearer under-
standing of virus spread.
In 1977 work, we found that Anuraphis middletonii was an
important local vector of watermelon mosaic virus 2. A.
middletonii is a root aphid that we found readily on cud-
weed, horseweed, tansymustard, Florida pusley, Virginia
pepperweed, mexicantea, dog fennel, and ragweed.
4. Watermelon Fungicides (Hopkins)
Date of Planting: February 19, 1980
Procedure: Spray application dates were May 2, 8, 12, 20, 29,
and June 5. Sprays were applied at a pressure of 150 psi and
in 100 gallons of dilute spray per acre, using a boom sprayer.
SN-66752 + Benlate
Benlate + Manzate 200
Dixie Flowable Maneb
Orthocide 50 + Sticker
Rate (Amt./100 gal./acre) Disease Rating1
2.'1 pbs. 3.2 a
2.5 pts. 3.3 a
1.3 pts. + 0.5 lb. 3.4 a
0.5 lb. + 1.5 ]bs. 3.4 a
4.0 pts. 3.5 a
1.5 lbs. 3.9 ab
2.5 lbs. 4.0 ab
2.0 qts. 5.0 b
4.0 lbs. + 0.5 pt. 5.2 b
Untreated U-- .4 C
Barratt Horsfall ratings system: 0 = no disease, 6 = 50%
disease, 11 = 100% disease. Diseases were gummy stem blight
and downy mildew.
Recommended Fungicides for Watermelon:
Min. days effectiveness
Materials and rate (amt./acre) to harvest GSB DM
Manzate D 80%, 1 1/2 2 lbs. 5 + ++
Dithane M-22 Special 80%
1 1/2 2 Ibs. 5 + ++
Dithane M-45 80%, 1 1/2 3 lbs. 5 + +++
Manzate 200 80%, 1 1/2 3 lbs. 5 + +++
Difolatan 4F, 2 1/2 5 pts. NTL +++ +
Bravo 500, 2 4 pts. NTL ++ ++
Benlate 50, 1/4 1/2 lb. NTL +++ 0
This is the minimum number of days allowed between the last
foliar application and harvest. NTL = no time limit.
+++ = highly effective; ++ = moderately effective; + = effec-
tive; 0 = not effective. GSB = gummy stem blight; DM = downy
5. Cantaloupe Fungicide Trial (Hopkins)
Procedure: Treatments were applied weekly beginning on
April 28, except for treatment (G) which was applied every
2 weeks and for treatments (D) and (F) which were applied
twice per week. They were applied in 100 gallons of dilute
spray using a boom sprayer.
A Difolatan 4F
B Bravo 500
C Manzate 200
D Dithane M-45 (2/wk)
Rate (amt./100 gal./acre)
E Manzate 200 + Benlate
F Bravo 500 (2/wk)
G Ridomil + Dithane M-45 (1i days)
H Soil Ridomil 10 G (Benlate)
I Previcur + Benlate
J Kocide 101
K Dithane M-45 Flowable M
L Difolatan 4F + Karathane
N Bravo 90 DG
0 Dithane M-45 + Karathano
P SN78-314 + Benlate
R Bravo 500
S Bravo 90 DG
2.0 lbs. + 0.5 lb.
0.8 lb. + 1.2 lbs.
5.0 lbs. (0.5 lb.)
1.5 pts. + 0.5 lb.
2.5 pts. + 0.5 lb.
2.0 lbs. + 0.5 lb.
2.5 lbs. + 0.5 lb.
Results: Results are not available yet. Plots will be
observed on the field tour.
Recommended Fungicides for Cantaloupe:
Materials and Min. days Effective on:
rate (amt./acre) to harvest DM GSB Alt. Anth. PM
Manzate 200 80%,
2-3 lbs. 5 + + + + -
Dithane M-45 80%,
2-3 lbs. 5 + + + + -
Bravo 500, 2-4 pts. NTL + + + + -
Difolatan 4F, 2 1/2 5 pts. NTL + + + + -
Karathane 25%, 6-8 oz. 7 +
Benlate 50W, 1/4 1/2 lb. NTL + + +
This is the minimum number of days allowed between the last foliar
application and harvest. NTL = no time limit.
+ = effective control; = insufficient control and in some cases
may provide no control.
6. Watermelon Rotation Trial (Hopkins & Elmstrom)
Purpose: To evaluate the effect of the length of rotation on
Varieties: Smokylee (highly wilt resistant), Charleston Gray
(moderately resistant), and Florida Giant (susceptible).
Results: (1980 Test)
% Wilt Yield
Rotat I on:;_ :t 1h1 nn .n ( tons/acre)
FG 5 4.4
FG-PG 58 0
FG-0-O-FG 33 0
CG 8 18.4
CG-CG 9 7.5
CG-O-O-CG 3 17.7
s 3 20.5
S-S 1 11.0
S-0-0-S 0 25.6
S = Smokylee; CG = Charleston Gray; FG =
Florida Giant; 0 = bahiagrass.
7. Buildup of Fusarium Wilt in the Soil (Hopkins and Elmstrom).
Purpose: To determine rate and extent of buildup of Fusarium
wilt on various watermelon varieties.
Procedure: Watermelon varieties with different levels of
resistance to wilt were planted in the same plots for 3 con-
% wilt to thinning
Variety 1979 1980 1979 1980
Crimson Sweet 3 20 13.9 10.7
Calhoun Gray 1 13 18.1 9.8
Smokylee 2 14 13.6 9.5
Charleston Gray 3 41 17.8 5.0
Jubilee 7 44 13.2 3.5
Dixielee 3 27 11.9 3.4
Congo 5 64 14.6 3.2
Sugarlee 0 35 13.0 2.8
Sugar Baby 3 62 6.9 0.7
Florida Giant 3 81 11.7 0
8. Watermelon Drip Irrigation Trial (Elmstrom, Locascio, Myers)
Purpose: To study watermelon growth and development using
Procedure: Drip irrigation using biwall tubing was compared
with no irrigation and with overhead irrigation. All ferti-
lizer was soil applied in the non-irrigated and in one of the
overhead irrigation treatments. A portion of the fertilizer
was applied through the irrigation system for the other over-
head irrigation treatment and with drip irrigation. In addi-
tion, two in-row plant spacings were used: 2.5 ft and 5 ft.
2.5' x 10'
5' x 10'
2.5' x 10'
r' x 10'
2.5' x 10'
5' x 10'
5' x 10'
Results: Incomplete. (First stop on field tour).
9. Watermelon Seed Priming/Earliness Trial (Elmstrom, Sachs)
Purpose: To hasten seed germination in the cold soil in
Procedure: Watermelon seeds were primed in 1.5% KNO3 + 1.5%
KH2PO4 for 5 days at 680F in aerated solution. After treat-
ment the seeds were rinsed thoroughly with water and dried
slowly at room temperature. A special slitted row cover was
used in some treatments (on display during tour of the re-
Results: Germination iin 'obruary was hastened by seed
priming and/or row cover. in Marc!h, when noil temperature
had increased, no differences were noted. Female blossoms
developed earlier on plants from primed seed and/or those
protected wlitl row c:nvOi.
10. Watermelon Variety Trial (Elmstrom, Crall, Hopkins)
Purpose: To compare promising breeding lines and new
varieties with : standard commercial varieties.
Procedure: Two-row plots were planted 19 February
randomized blocks with 3 replications.
Charleston Gray #5
Fla 78 SE
Fla 78 SE
Fla 80 SW
Fla 80 CW
Fla 79 SE
Calhoun Gray Seedless
Results: 1980. The earliest maturing cultivars were 'Smokylee',
'Crimsoni Sweet', and Au #3. The most productive were L390-2,
'Smokylee', Au #3, Fla. 78SW2, and 'Charleston Gray'. Average
soluble solids content exceeded 9% in 'Dixielee', 'Allsweet',
and 'Sweet Princess'.
'Charleston Gray', 'Jubilee', and 'Crimson Sweet' are still
the standard varieties for Florida. 'Crimson Sweet' has
been slowly increasing in popularity the last few years.
Growers have been receiving 14 to 1.5 more per pound for
'Jubilee' than the other variotioe,. Backcross lines from
Dr. Crall's breeding program have better Fusarium resistance
and quality than commerical seed of 'Jubilee' and 'Charleston
Gray'. Of' the three 'i ,- box' melons from the ARC, Leesburg
watermelon breeding program, Il'] a 81-2 and Fla 81-3 appear
superior to Pla 81-1. 1la 81-1 I susceptible to cracking;
Fla 81-3 is highly resistant to this problem. Presently
there are no ico box' v:,'i' i i : s;ui table for growing in
Florida on anythinLg lul, virgi',n l and. This small size is
ideal for shipment in cartons or overseas.
'Dixielee' was released in 1979 and is being grown commer-
cially on a- llmit-d :croeage this season. It is a high
quality melon but later maturing than Charleston Gray and
Crimson Sweet. 'Sugarlee', formerly tested as Fla 77-2,
will be available to commercial growers for the 1982 season.
Sugarlee also has high quality and is earlier maturing than
any of the three important commercial varieties.
Yellow Baby is a hybrid, yellow-fleshed variety that has
been very productive in trials at Leesburg. It is an 'ice
box' melon with yellow flesh.
Based on several years of evaluation, we have classified
the watermelon cultivars for Fusarium wilt resistance as
Highly Resistant Susceptible
Calhoun Gray Garrisonian
Smokylee Pe Ititor Sweet
Summit Tri X-313
Moderately Resistant Kl.ondike Blue Ribbon
Dixielee P"ugar Baby
Allsweet Peacock //67
Crimson Sweet Kleckley Sweet
Charleston Gray at
Louisiana ouocin New Hampshire Midget
Chilean, Black Seeded
11. Cantaloupe Variety Trial (Elmstrom)
Purpose: To compare promising breeding lines and new varie-
ties with ;:standard commercial vart' 1, i.es.
Procedure: Thirty varieties and brooding lines were planted
27 February in rep lic;atd, s il!nlo,-row plots. Twelve lines
were planted in s ing]o-row, observational plots.
1nrtrles, h'p I i cated :
1. PMR 45
2. PMR 6
5. Fla 93-71L1
6. Hyb 6000
Exp Hyb //1211-100
lixp 266 (IIoneybush)
Results: 1980. In a replicated trial of 18 cantaloupe
cultivars, the earliest maturing were 'Burpee Hybrid',
'Earlidew', and 'Summit'. 'The most productive were AC75-1,
'Mainstream', '"ummt' anrid 'Plalte,'rs Jumbo'. The culti-
vars with the highest soluble solids content were 'Earlidew',
'Planters Jumbo', Fla. 93-8 and AC 67-71.
'Saticoy' land 'Super Market', both hybrids, have been out-
standing over the years. Other varieties might have
higher yields but, as far as quality and consumer accep-
tance, these have been the best. 'Earlidew', a new, early
maturing, hybrid honeydew should be tried. It slips when
mature and has excellent qualLty. Foliar disease resis-
tance is greater than in the standard honeydew variety. It
has resistance similar to that of 'Super Market' and will
require a good fungicide spray program.
12. Watermelon Growth Regulator Trial (Elmstrom & Crall)
Purpose: To promote i-arlier female flowering and fruit
set on 'Dixiolo, o' watocrmeolon.
Date of Plantling: lFbruary 18, 1981
1,11:"(!, i () 1A
Chi f'ta in
',ar'! y Dawn
No. ''.ea ii iit,
1 Check, no treatment
2 Vine prt'uoing, 8-10( t.ii,-,I i 8;tage
3 Triba:s-c copper u, Ulfate, 6-8 ,rue leaf stage & week later
I Silver nl :i l, I 1" ) l1m
5 Silver nitrate 250 ppm
6 Gibberell c acid (iGA/y) 50 ppm
7 Curbislt 50 ppmi
8 Curbiset 100 ppm
9 Silver nitrate I 25 ppm, G';AII/ 50 ppm, Curblsot 50 ppm
10 Silver nitrate 250 ppm, ,A)//7 50 ppm, Curbiset 100 ppm
Treatment number 2 was pruned 3 April (main runner growing
point of all plants was removed). Silver nitrate, GA, and
curbiset were applied twice, 3 March and 6 April.
Results: 1980. Vine pruning and plant growth regulators
were employed in an attempt to promote early flowering of
'Dixielee' watermelon. The growing point of the main run-
ner was removed at the 4I true-leaf stage on some plants
and at the 7 to 8 true-leaf stage on other plants. Copper
sulfate (2,000 ppm, 2 applications) was applied to some of
the plants in the former treatment and to some plants which
did not have the growing point removed. Ethrel (200 ppm)
was also included as a treatment. Total fruit set was re-
corded May 22. Although differences among treatments were
not significant there were more fruit set on plants treated
with copper sulfate than on other plants. Removal of the
growing point at the 7 to 8 true-leaf stage was the only
treatment with a higher early yield than the untreated
check. Ethrel greatly reduced early yield of 'Dixielee'.
13. Watermelon Minor Element Trial (Elmstrom)
Purpose: To study the need for minor element supply in the
watermelon bed fertilizer and to compare two sources of
Date of Planting: February 18, 1981
Variety: ]'la 80 SW
Procedure: Minor elements were applied 30 January with the
bed fertilizer prior to bedding over a 3-ft wide band the
entire length of the plot. This was incorporated with a
disk prior to bedding.
No. Source Hate (lb./acre)
1 7'TE r;0 20
2 I'TE '03 110
3 FTE 503 60
)\I P'TI 'I)()' 80
5 TEM 300 20
6 T'EM 300 10
7 TEM 300 60
8 TEM 300 80
9 ltne --
Results: 1979 and 1980. There was no significant increase
in total yield as a result of the bed application of either
minor element source.
14. Watermelon Sugars (Elmstrom, Davis)
Purpose: To study qualitative and quantitative differences
in sugar content of various watermelon varieties.
Procedure: Watermelon fruits were selected at various
stages of maturity (days after anthesis), juice was extracted,
and analyzed 'or sugar content by Mr. Paul Davis at the U.S.D.A.
Horticultural Laboratory in Orlando.
Results: Wide variation in the ratio of total reducing sugar,
fructose and glucose, to the nonreducing sugar, sucrose,- was
found in selected mature fruit of I watermelon varieties in
1976. Fructose content was higher and sucrose content lower
in 'Smokylee' and 'Dixielee' than in 'Charleston Gray' and
In 1979, sugars were determined at 4-day intervals from 12 to
36 days after anthesis. (See Table 1) Sucrose did not appear
until after 20 days. Fructose content was highest 24 days
after anthesis for all cultivars except 'Dixielee' and
'Calhoun Gray' which peaked at 32 days. The continued in-
crease of fructose in maturing fruits is important because
of the greater relative sweetness of fructose.
15. Cantaloupe Breeding (Elmstrom)
Purpose: To evaluate the combining ability of some varie-
ties and breeding lines and to develop parental lines with
genetic properties suitable foi' Fl hybrid seed production.
Procedure: A number of P1 lines are being evaluated includ-
ing three that are entered in the 1981 Southern Cooperative
Muskmelon Variety Trial. At present, I am attempting to in-
corporate various character us into the parent lines which
would make them more suitable for parent lines, ie. reduce
Content of fructose (F), glucose (G), and sucrose (S), and relative range of
sweetness in melons harvested at 7 stages of maturity in 1979.
Sugar content (g/100 ml juice) Sugar content (g/100 ml juice)
Cultivar Age F G S F+G+S Cultivar Age F G S F+3+S
Dixielee 12 1.6dY 1.5c 0.Ob 3.1 Jubilee 12 2.0d 1.9e 0.Oc 3.9
16 2.9c 3.0b 0.Ob 5.9 16 2.4c 2.2de O.Oc 4.6
20 3.8b 3.6a 0.Ob 7.4 20 3.3b 2.8b 0.Oc 6.1
24 4.3ab 3.7a 0.Ob 8.0 24 3.8a 3.2a 0.3bc 7.3
28 4.5a 3.6a 0.lb 8.2 28 3.7a 2.6bc C.7b 7.3
32 4.7a 3.3ab 0.8a 8.8 32 3.8a 2.4cd 2.0a 8.2
36 4.2a 2.8b 1.3a 8.3 36 3.5ab 2.0e 2.la 7.
Charleston 12 1.8d i.8d 0.Oc 3.6 Crimson 12 1.8b 1.8d ;.0c 3
ray 16 2.0d 1.9cd O.Oc 3.9 Swee 16 2.4c 2.3c .c
20 2.9c 2.6b O.Oc 5.5 20 3.4b 3.0b .0c 6.
2 3.7a 3.1a 0.4c 7.2 24 4.2a 3.6a .3c .
2 3. 5a 2.6b 2.2b S.3 28 4.0a 3.0b 1.4
32 3.3ac 2.2bc 3.3a 8.8 32 4.0a 3.lb .la .
3.6 3.bc 1.8d 1.Oa 8.8 36 3.4b 2.4c .3a
Suaarlee 12 2.6 2.4cd 0.0c 5. Yieic-. 12 2.4c 2.3b 3d
16 2.6c 2.4cd 0.Oc 5. Baby: 16 3.0c 2.7b .d .
2 3.5 3.2ab .O c 6. 20 4.0b 3.6a C.d
2 4.2a 3.6a C.7b 8.5 24 4.4a 3.6a C.Id .
23 4.1a 3.3ab l.lb 8.5 28 4.lb 2.4b 2.0c.5
-32 ab 3.0bc 2.6a 9. 32 .0Ob 2.3b 2.8b 9.1
36 3.5b 2.2d 2.5a 8.2 36 3.7b 1.8c 3.5a 9.0
Calhoun 12 2.0d 2.0c 0.Oc 4.0 Smokylee 12 1.4d 1.3d 0.Od 2.7
Gray 16 2.7c 2.5ab 0.Oc 5.2 16 2.3c 2.0c 0.Od 4.3
20 3.4b 2.9a 0.Oc 6.3 20 3.8a 3.3ab 0.Od 7.1
24 3.8ab 2.9a 0.2c 6.9 24 4.2a 3.5a 0.3d 8.0
28 4.Oa 2.7a 1.6b 8.3 28 4.0a 3.3ab 1.2c 8.5
32 4.2a 2.6ab 1.9ab 8.7 32 .3.8a 3.Ob 1.8b 8.6
36 3.8ab 2.2bc 2.4c 8.1 36 3.1b 2.0c .Oa 8.1
ZNumber of days
YMean separation within columns for each cultivar by Duncan's mul
tile range test, 5-
the cost o' liyblrd seed wli. clh 1; now abotu $1l0/pound. Some
of these characters include the monoecious flowering habit,
male sterility, and :lhoi-rt Internode or dwarf vine habit. T
attempt to get 3 generations of cantaloupe a year, one in
the spring, one in the rall, nnd one during the winter in
16. FiftV Years or Watermeol n Broeedin g at ARC Leesburg (Crall)
This unit of the Florida Agricultural Experiment Stations
was established by an act of the 1929 legislature. Forty
acres of land were leased and 10 acres of it were planted
with 104 varieties In 1930 to study their reaction to Fusar-
ium wilt, the main reason for the establishment of a research
facility at this location. The first breeding work was be-
gun in 1931, just 50 years ago. This program, with emphasis
on disease resistance, has continued to the present time,
and additional goals have been added from time to time.
Among them are the breeding for resistance to anthracnose,
downy mildew, watermelon mosaic, and more recently, gummy
stem blight. Important goals of the program over the years
have been the development of varieties with multiple disease
resistance In vigorous and prolific vines producing melons
with desirable eating and shipping qualities.
The watermelon breoed-ii n program here was begun under Dr.
Marion N. Walker. He resigned in January 1945 to accept a
position in guayule research to develop rubber substitutes
as part of the war effort, and was succeeded by Dr. Keith
Parris, who directed the program until his resignation in
June 1951. 1 accepted the position as watermelon breeder
and director of the station in October 1952.
Varieties released from the program here are: Leesburg
(1936), Blacklee (1914), Ironsides (1952), Jubilee (1963),
Smokylee (1971), Dixielee (1979), and, most recently,
Sugarlee (1981). One of the most significant contributions
from our program to the improvement of watermelons was the
development by Walker of breeding lines incorporating anthrac-
nose and wilt resistance in horticulturally desirable types.
A number of these lines were furnished to the Southeastern
Vegetable Breeding Labotoatory in Charleston, SC in 1941.
Charleston Gray, Fairfax, Congo, and various other varie-
ties from the Charleston Laboratory obtained their anthrac-
nose and wilt resistances from Walker's lines. A line identi-
fied as Florida Seedling 124 (Prom a Leesburg x Hawkesbury
cross), ha:; been IdentifIled as the ultimate source of the
high level resistance to Fusarlum wilt found in Calhoun Gray,
Smokylee, and several other varieties.
The current program continues its emphasis on high levels of
resistance to Fusarium wilt, anthracnose, and other diseases
in horticulturally desirable types. All of our advanced lines
have resistance to races: 1 and 3 of anthracnose and most have
a high level i'e;l;t;Lantice t 'o u'iusarlium wilt.
Evaluation of mon:;sa r'-i:::;.tance .1 n ill or the then available
Plant Introduction accessions was initiated here in 1964 and
attempts to incorpor;ite resistance into horticulturally de-
sirable types were continued through 1977, at which time the
program was discontinued. Recently, an African accession
reported to have resistance to WMV-2 has been obtained and
crosses are being made this year between our lines and F2, Fl, and
parent lines of this accession. Two PI lines with resistance
to gummy stem blight are also being used this season in crosses
with some of our better varieties and advanced lines.
Emphasis in breeding better horticultural types in varieties
with anthracnose resistance and high level resistance to
Fusarium wilt is currently being placed on lines with four
distinct melon types: Charleston Gray types, Jubilee types
(both mostly by backcrossing), large round striped melons
(similar to Dixielee and Sugarlee), and small fruited lines
(mostly with light green rind color). In addition, we have
recently began a program to develop short internode (dwarf)
lines with resistances to anthracnose and Fusarium wilt and
fruits similar to those in our main breeding program.
The various types of melons being developed currently can be
seen in this year's field. The 1981 field is arranged in 3
main sections. In the middle section, Ranges M through O,
is a replicated trial of 8 Charleston Gray backcross progenies
(including Charleston Gray and Calhoun Gray as checks), 8
Jubilee backcross progenies (with both commercial Jubilee and
breeder seed Jubilee as checks), 12 large round-fruited
progenies (with Black Diamond, Crimson Sweet, Dixielee, and
Sugarlee as checks), and 12 small-fruited progenies (with
Petite Sweet and Sugar Baby as checks).
In the south section, Ranges E through J, are additional breed-
ing lines of the four main fruit types. Additional selfing
and selection are being carried out in these progenies. In
Ranges K and L of the south section are progenies being
utilized for additional crossing. In this part of the field
may be found mosaic resistant lines (Kl-6), gummy stem
blight resistant lines (K9-12), dwarf lines (L21-40), triploid
lines (Ll-7), tetraploid lines (L10-12), and other miscel-