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f63 G Cenirai Sc;ence
GCS Library
OCT 25 1989
GULF COAST RESEARCH & EDUCATION CENTER OCT 25 1989
IFAS, UNIVERSITY OF FLORIDA nivrsity of Florida
5007 60TH STREET EAST of orida
BRADENTON, FL 34203
Bradenton GCREC Research Report BRA1989-16 August 1989
Seedless Watermelon Variety Evaluation
Spring 1989
D. N. Maynard1
The concept of seedless watermelons was described first in the U.S.
literature by Kihara (1) in 1951 based on experimentation that began in
Japan in 1939. Seed for planting seedless watermelons results from a
cross between a selected tetraploid female parent and a selected diploid
(normal) male parent. Tetraploid lines are developed by treating diploid
lines with colchicine. The resulting triploid is sterile and does not
produce viable seed. However, small, white rudimentary seeds develop
which are eaten along with the fruit like immature cucumber seeds.
Fruit enlargement in normal fruit, including watermelon, is enhanced by
growth promoting hormones produced by the developing seed. Growth
hormones are lacking in seedless watermelons so those agents are provided
from pollen. Since flowers on triploid plants lack sufficient pollen,
normal watermelons are interplanted with triploids to serve as
pollenizers. An adequate bee population is necessary to insure that the
transfer of pollen occurs. Seedless fruit (from triploid plants) tend to
be triangular shaped unless sufficient pollenizer plants (normal
watermelons) and pollinators (bees) are present.
Although the procedure for production of seedless watermelons has been
known for almost 50 years and commercial varieties have been available for
almost 20 years, the interest in and acreage of seedless watermelons has
remained small. Erratic performance, poor seed germination, high seed
costs, and inadequate varieties caused the low interest in seedless
watermelon production.
Specialty vegetables are in high demand in the 1980's, and seedless
watermelons offer an attractive alternative for the up-scale consumer and
the food .service industry. Seedless watermelons are being actively
promoted by marketing organizations and seed companies to stimulate
demand. At the same time, new varieties are being developed that are
superior to those already available.
The object of these trials was to evaluate the performance of seedless
watermelon varieties and experimental lines under west central Florida
conditions.
1Professor of Vegetable Crops.
Materials and Methods
Seeds of 35 seedless watermelon varieties or experimental lines (Table 1)
were planted in a peat-lite growing mix in No. 150 Todd planter flats (1.5
x 1.5 x 2.5 in. cells) on February 2.
Soil in the experimental area was sampled before fertilization and
analyzed by the IFAS Extension Soil Testing Laboratory: pH = 7.3 and
Mehlich I extractable, P = 77, K = 25, Ca = 913, Mg = 116, Zn = 8.5, Mn =
4.2, and Cu = 2.7 ppm.
The EauGallie fine sand was prepared in January 1989 by incorporation of
0-2-0 Ib. N-P205-K20 per 100 linear bed feet (Ibf). Beds were formed and
fumigated with methyl bromide:chloropicrin (67:33) at 2 lb./100 Ibf.
Banded fertilizer was applied in shallow grooves on the bed shoulders at
3.3-0-6.6 lb N-P205-K20 per 100 Ibf after the beds were pressed and before
the black polyethylene mulch was applied. The final beds were 32 in. wide
and 8 in. high, and spaced on 9 ft. centers with seepage
irrigation/drainage ditches on 40.5 ft. centers or every 4 beds.
The watermelon transplants were set in holes punched in the polyethylene
at 3.5 ft. apart on March 1. The 24.5 ft. long plots had 7 plants each,
and were replicated 3 times in a randomized, complete block design in the
replicated trial. Individual plots were evaluated in the observational
trial. Icebox watermelons planted on each side of two seedless watermelon
beds served as pollenizers. Weed control in row middles was by
cultivation and applications of paraquat. Pesticides were applied as
needed for control of rindworm (Bacillis thuringiensis, esfenvalerate),
sweetpotato whitefly endosulfann, insecticidal soap), mites (dicofol),
downy mildew and gummy stem blight (metalaxyl + chlorothalonil), and
powdery mildew (triadimefon).
Watermelons were harvested three times beginning May 17 and ending June
19. Marketable (U.S. No. 1 or better) according to U.S. Grade Standards
(6), melons were separated from culls and counted and weighed
individually. Soluble solids determinations were made with a hand-held
refractometer on at least 12 fruit from each entry over two harvests and
notations on hollowheart and flesh color were recorded.
Results and Discussion
Temperature and rainfall (Table 2) during the experimental period from
March 1 through June 20 deviated somewhat from the 33-year averages (5) at
the Gulf Coast Research & Education Center. Average daily temperature in
March was three and four degrees higher than normal maximum and minimum,
respectively, and June maximum and minimum temperatures were four and
three degrees, respectively, above normal. The entire production period
was somewhat drier than normal.
Replicated Trial Results
Early yields, represented by the first of three harvests, ranged from 99
cwt/A for 'CFREC 89-1' to 306 cwt/A for 'HMX 7924' (Table 3). Early
yields of 'Tri X-313', 'XPH 9039' and 'CFREC 89-5' also were significantly
greater than 'CFREC 89-1'. Average fruit weight ranged from 11.0 lb for
'ACX 882322' to 17.6 lb for 'ACX 87B7026'. The incidence of hollowheart
at the early harvest was quite variable: 'HMX 7924', 'Tri X- 313' and
'NVH 4291' had no hollowheart, whereas 67% of 'ACX 87B7025', 59% of 'XPH
9039', and 58% of 'CFREC 88-4' fruit had some degree of hollowheart. It
should be noted that even minute cell separations that would not affect
consumer acceptance were recorded.
Total yields (Table 3) ranged from 461 cwt/A for 'CFREC 89-1' to 970 cwt/A
for 'HMX 7924'. Other high yielding varieties were 'CFREC 88-4', 'CFREC
88-2', and 'HMX 6920'. Average fruit weight ranged from 9.9 lb for 'FMX
28' to 16.3 lb for 'ACX 87B7026'. There was a general association between
large fruit size and high total yield. Soluble solids were uniformly high
ranging from 11.3% in 'PSR 49087' to 13.2% in 'CFREC 89-2'. Accordingly,
soluble solids of all varieties exceeded the 10% specified for opt onal
use in the U.S. Grade Standards for watermelon (6). As in 1988 (2,3)
seedless varieties had higher soluble solids than icebox watermelon
varieties in adjacent rows (4). The incidence of hollowheart was lower
for the entire crop than for the early harvest ranging from 0 in 'Tri X-
313' to 49% in 'XPH 9039'.
Since most seedless watermelons are packed in cartons, it is desirable to
have relatively uniformly sized fruit. All of the varieties in the
replicated trial, except for 'PSR 49087', had the largest proportion of
their fruit in the 10.1 to 15 lb weight class (Table 4). The proportion,
however, varied considerably from 40% for 'ACX 87B7026' to 71% for 'King
of Hearts'.
Observational Trial Results
Insufficient seed was received of five varieties (Table 1) to be included
in the replicated trial.
Early yield ranged from 213 cwt/A for 'ACX 87B7026' to 316 cwt/A for 'FMX
29' and total yields ranged from 449 cwt/A for 'ACX 88TK01' to 818 cwt/A
for 'ACX 87B7026 (Table 5). Yields of varieties in the observational
trial were therefore similar to those of varieties in the replicated
trial.
General Comments
Variety shape and rind patterns, based on observations in this trial, are
shown in Table 1. Varieties producing oval to oblong fruit may be more
suitable for boxing than varieties producing round melons. Generally, the
striped melons are more attractive for the U.S. market than those with
stripes on a very dark green background or those with a solid dark green
rind.
For the most part, internal quality of those fruit that were cut for
soluble solids determination was excellent. However, some fruit of 'FMX
28', 'Fengshan No. 1', 'ACX 882322', 'CFREC 89-10', 'Nova', and 'ACX
874503' were observed to have poor internal fruit color. Hard seed were
observed in only a very small number of fruit, and when present numbers of
seed were very few.
Because of the many new varieties of seedless watermelons being developed
and evaluated at the present time, it is difficult to identify those that
eventually will become standard in Florida. 'CFREC 88-4' and 'CFREC 88-2'
were among the highest yielding varieties in both 1988 (3) and 1989. 'Tri
X-313', the most popular variety in commerce for many years had high
yields in the 1989 trial.
Note
The information contained in this report is a summary of experimental
results and should not be used as recommendations for crop production.
Where trade names are used, no discrimination is intended and no
endorsement is implied.
Literature Cited
1. Kihara, H. 1951. Triploid watermelons. Proc. Amer. Soc. Hort. Sci.
58:217-230.
2. Maynard, D. N. and P. R. Gilreath. 1988. Icebox watermelon variety
evaluations, spring 1988. GCREC Res. Rept. BRA1988-17.
3. Maynard, D. N. and P. R. Gilreath. 1988. Seedless watermelon
variety evaluation, spring 1988. GCREC Res. Rept. BPA1988-18.
4. Maynard, D. N. 1989. Icebox watermelon variety evaluation, spring
1989. GCREC Res. Rept. BRA1989-00.
5. Stanley, C. D. 1988. Temperature and rainfall report for 1987.
GCREC Res. Rept. BRA1988-11.
6. U.S. Standards for Grades of Watermelon. 1978. USDA.
5
Table 1. Seedless watermelon varieties, description, and seed source.
Gulf Coast Research & Education Center. Spring 1989.
Variety Description Source
Replicated Trial
ACX 87B7025
ACX 87B7026
ACX 882321
ACX 882322
CFREC 88-2
CFREC 88-3
CFREC 88-4
CFREC 89-1
CFREC 89-2
Round-oval. Wide, indistinct,
medium-green stripe on light-
green background. Similar to
Jack of Hearts.
Oval. Indistinct, wide, medium-
green stripes on light-green
background. Similar to Tri X-313
Elongated. Distinct dark-green
stripe on medium to light-green
background.
Oval. Distinct dark-green
stripe on medium-green back-
ground. Queen of Hearts type.
Oval. Distinct dark-green stripe
on light to medium-green back-
Sround. Similar to Queen of
earts.
Oval. Thin, distinct dark-green
stripe on light-green back-
ground. Similar to Queen of
Hearts.
Blocky-elongated. Distinct very
dark-green stripe on dark-green
background, few with lighter
background.
Round-oval. Distinct dark-green
stripe on medium to light-green
background. Similar to Queen of
Hearts.
Blocky-elongated. Distinct
medium-green stripe on light-
green background, few with dark-
green background.
Abbott & Cobb
Abbott & Cobb
Abbott & Cobb
Abbott & Cobb
CFREC-Leesburg
CFREC-Leesburg
CFREC-Leesburg
CFREC-Leesburg
CFREC-Leesburg
Table 1 (continued).
Variety Description Source
CFREC 89-4
CFREC 89-5
CFREC 89-10
FMX 28
Farmer's Wonderful
Fengshen No. 1
Fummy
HMX 6920
HMX 7924
Jack of Hearts
King of Hearts
Oval. Distinct dark-green
stripe on light-green
background. Similar to Queen of
Hearts.
Round-oval. Indistinct, wide,
medium-green stripe on light-
green background. Similar to
Jack of Hearts.
Oval. Indistinct, wide, medium-
green stripe on light-green
background. Similar to Tri X-
313.
Round. Dark-green back-
ground with very dark-green
lines. Similar to Fengshen No. 1.
Round-oval. Distinct, wide,
dark-green stripes on medium-
green background.
Round. Dark-green with in-
distinct dark-green lines.
Round-oval. Distinct dark-
green stripe on medium-green
background.
Round-oval. Distinct, thin
dark-green stripe on light-
green background. Similar to
Queen of Hearts.
Oval. Indistinct wide dark-
green stripe on light-green
background. Similar to Tri X-313.
Oval-round. Wide-indistinct
medium-green stripe on light
green background.
Oval. Indistinct, wide, dark-
green stripes or light-green
background. Similar to Tri X-313.
CFREC-Leesburg
CFREC-Leesburg
CFREC-Leesburg
Ferry-Morse
Neuman
You)
(Known
Neuman (Known
You)
Twilley
Harris Moran
Harris Moran
Petoseed
Petoseed
Table 1 (continued).
Variety Description Source
Nova
NVH 4291
NVH 4292
NVH 4295
PSR 49087
PSR 49687
Honeyheart
Queen of Hearts
Sunrise
Tri X-313
XPH 9039
Round-oval. Distinct, very dark-
green stripe on medium-green
background.
Oval. Indistinct, wide, green
stripe on light-green back-
ground. Similar to Tri X-313.
Blocky-oval to blocky-elongated.
Gray back-ground with distinct
green lines.
Round-oval. Distinct, narrow,
dark-green stripe on light-green
background. Similar to Queen of
Hearts.
Round. Dark-green with fine
darker-green lines.
Round-oval. Distinct, narrow,
very dark-green stripe on medium
green background. Yellow flesh.
Oval. Distinct dark-green stripe
on medium-green background
Oval. Distinct dark-green stripe
on medium-green background.
Similar to Queen of Hearts.
Oval. Indistinct, wide, medium-
green stripe on light-green
background.
Round-oval. Wide,
dark-green stripe
green background.
indistinct,
on medium-
Abbott & Cobb
Northrup King
Northrup King
Northrup King
Petoseed
Petoseed
Petoseed
American
Sunmelon
American
Sunmelon
Asgrow
Observational Trial
ACX 874503
ACX 87B7026
Oval-round. Distinct, very
dark-green stripe on dark-
green background.
Oval. Indistinct, medium-green
stripe on light-green back-
ground. Similar to Tri X-313.
Abbott & Cobb
Abbott & Cobb
Table 1 (continued).
Variety Description Source
ACX 88TK01 Round. Distinct, very dark- Abbott & Cobb
green stripe on dark-green
background. Similar to Nova.
FMX 4-28 Round-oval. Dark green back- Ferry-Morse
ground with very dark-green
lines. Similar to Fengshen
No. 1.
FMX 29 Round-oval. Dark-green back- Ferry-Morse
ground with very dark-green
ines. Similar to Sugar Baby.
Table 2. Mean temperature and rainfall at the Gulf Coast Research &
Education Center from March 1, 1989 to June 20, 1989 and 33-year
average.
Average daily temperature (oF)
33-year Rainfall (in.)
1988-89 average 33-year
Month (date) Max. Min. Max. Min. 1988-89 average
March 80 59 77 55 2.97 3.39
April 83 60 82 60 1.38 1.59
May 88 64 87 64 2.44 3.14
June (1-20) 93 72 89 69
Table 3. Early and total yields, average fruit weight, percentage hollowheart, and soluble solids content
of seedless watermelon. Gulf Coast Research & Education Center. Spring 1989.
Early Yieldz Total Yield
Hollow- Soluble Hollow-
Weight Avg. Fruit heart Weight Avg. Fruit Solids heart
Variety No./AY (cwt/A) Wt. (lb.) (%) No./AY (cwt/A) Wt. (lb.) (%) (%)
HMX 7924 2041 ax 306 a 14.9 a-c OC 6585 a 970 a 14.8 a-c 12.2 b-d 2 d
CFREC 88-4 1778 ab 252 a-c 14.2 b-e 58 ab 6058 abc 926 ab 15.8 ab 12.6 a-d 39 ab
CFREC 88-2 1515 ab 208 a-c 13.6 b-f 21 a-c 6190 ab 824 a-c 13.4 c-f 12.7 a-c 17 b-d
HMX 6920 1580 ab 239 a-c 15.6 ab 13 bc 5466 a-d 785 a-d 14.5 a-d 12.3 a-d 15 b-d
Tri X-313 1910 ab 269 ab 14.1 b-d OC 5202 a-d 756 b-e 14.4 a-d 12.5 a-d 0 d
CFREC 89-4 1580 ab 233 a-c 14.9 a-c 11 bc 5268 a-d 742 b-e 14.2 a-d 12.3 a-d 10 b-d
XPH 9039 1910 ab 270 ab 13.8 b-f 59 ab 5400 a-d 730 b-f 13.5 c-f 13.0 ab 49 a
Sunrise 1778 ab 255 a-c 14.5 b-d 27 a-c 5334 a-d 723 b-f 13.7 b-e 12.4 a-d 24 a-d
CFREC 89-2 1317 ab 199 a-c 14.8 a-c 33 a-c 5136 a-d 720 b-f 14.1 a-e 13.2 a 35 a-c
NVH 4291 1449 ab 225 a-c 14.6 a-d OC 5268 a-d 704 c-f 14.4 a-d 12.3 a-d 7 cd
CFREC 89-5 1712 ab 256 ab 14.6 a-d 11 bc 5268 a-d 689 c-g 13.4 c-f 12.1 b-e 13 b-d
NVH 4292 1120 ab 166 a-c 14.9 a-c 30 a-c 5005 a-d 680 c-h 13.7 b-e 12.2 b-d 16 b-d
ACX 8787025 1185 ab 179 a-c 14.6 a-d 67 a 4741 b-d 676 c-h 14.2 a-d 12.0 c-e 34 a-c
King of Hearts 1317 ab 180 a-c 13.2 b-f 33 a-c 5268 a-d 666 c-h 12.6 c-g 12.2 b-d 19 a-d
ACX 87B7026 1120 ab 200 a-c 17.6 a 19 a-c 4083 d 664 c-h 16.3 a 12.7 a-c 22 a-d
Jack of Hearts 1515 ab 218 a-c 14.8 a-d 39 a-c 5202 a-d 643 c-h 12.5 c-g 11.7 de 28 a-d
CFREC 88-3 1383 ab 200 a-c 15.9 ab 39 a-c 5202 a-d 641 c-h 12.4 d-g 12.6 a-d 21 a-c
Farmer's Wonderful 1515 ab 220 a-c 13.2 b-f 9 c 4939 a-d 624 c-h 12.7 c-g 12.7 a-c 12 b-d
PSR 49087 1646 ab 187 a-c 11.2 ef 33 a-c 6190 ab 617 c-h 10.0 h 12.3 a-d 19 b-d
ACX 882321 1120 ab 162 a-c 14.2 b-e 33 a-c 4478 b-d 617 c-h 15.9 ab 11.3 e 36 a-c
Fummy 1515 ab 199 a-c 13.4 b-f 26 a-c 4939 a-d 603 c-h 12.3 d-g 12.7 a-d 12 b-d
NVH 4295 1515 ab 210 a-c 13.8 b-f 4 c 4873 a-d 571 d-h 11.8 e-h 12.8 a-c 17 b-d
PSR 49687 1120 ab 132 bc 11.7 d-f 11 bc 5071 a-d 559 d-h 11.0 gh 12.6 a-d 27 a-d
Nova 2107 a 244 a-c 11.7 d-f 32 a-c 4873 a-d 544 e-h 11.2 f-h 12.5 a-d 18 b-d
Fengshen No. 1 1778 ab 211 a-c 11.7 d-f 24 a-c 5136 a-d 538 e-h 10.5 gh 12.1 b-e 22 a-d
CFREC 89-10 988 ab 142 bc 14.5 b-d 21 a-c 4280 cd 535 e-h 12.8 c-g 12.5 a-d 33 a-c
Queen of Hearts 1844 ab 226 a-c 12.5 c-f 6 c 4479 b-d 527 e-h 11.8 e-h 12.4 a-d 12 b-d
FMX 28 1449 ab 162 a-c 11.3 ef 20 a-c 5071 a-d 503 f-h 9.9 h 12.1 b-e 8 cd
ACX 882322 1449 ab 159 a-c 11.0 f 12 bc 4479 b-d 472 gh 10.5 gh 12.1 b-e 17 b-d
CFREC 89-1 790 b 99 c 12.3 c-f 33 a-c 3951 d 461 h 11.8 c-h 13.0 a-c 27 a-d
ZEarly yield based on first harvest.
YAcre = 4840 Ibf.
XMean separation in columns by Duncan's Multiple range test, 5% level.
Table 4. Fruit size distribution of the total yield of seedless
watermelon varieties. Gulf Coast Research & Education Center.
Spring 1989.
Fruit Weight (Ib)
<5.0 5.1-10.0 10.1-15.0 15.1-20.0 >20.0
Variety Percentage of fruit
ACX 87B7025 0 cz 6 ij 55 a-g 33 a-d 5 c-e
ACX 87B7026 0 c 5 j 40 g 37 ab 18 a
ACX 882321 0 c 12 g-j 48 b-g 38 ab 3 c-e
ACX 882322 0 c 45 a-c 51 a-g 4 g 0 e
CFREC 88-2 0 c 13 g-j 63 a-e 20 a-g 4 c-e
CFREC 88-3 0 c 17 e-j 61 a-f 20 b-g 2 de
CFREC 88-4 0 c 7 ij 46 c-g 33 a-d 14 ab
CFREC 89-1 0 c 27 d-g 60 a-g 13 d-g 0 e
CFREC 89-2 0 c 9 h-j 54 a-g 35 a-c 3 de
CFREC 89-4 0 c 14 f-j 42 e-g 38 ab 5 c-e
CFREC 89-5 0 c 13 g-j 64 a-d 19 b-g 5 c-e
CFREC 89-10 0 c 16 e-j 54 a-g 28 a-f 2 de
Farmer's Wonderful 0 c 14 f-j 69 ab 15 c-g 2 de
Fengshen No. 1 0 c 31 c-f 47 c-g 20 b-g 3 de
FMX 28 2 a 47 ab 48 b-g 3 g 0 e
Fummy 0 c 25 d-h 60 a-g 15 c-g 0 e
HMX 6920 0 c 15 f-j 44 d-g 32 a-e 9 bc
HMX 7924 0 c 10 g-j 42 fg 41 a 7 cd
Jack of Hearts 0 c 22 d-i 65 a-c 12 e-g 0 e
King of Hearts 0 c 11 g-j 71 a 18 b-g 0 e
Nova 0 c 32 b-e 64 a-d 4 g 0 e
NVH 4291 0 c 2 j 61 a-f 34 a-c 2 de
NVH 4292 0 c 12 g-j 54 a-g 32 a-e 3 de
NVH 4295 0 c 30 c-f 57 a-g 11 fg 2 de
PSR 49087 1 b 52 a 43 d-g 3 g 0 e
PSR 49687 0 c 38 a-d 57 a-g 5 g 0 e
Queen of Hearts 0 c 26 d-g 63 a-d 10 fg 0 e
Sunrise 0 c 12 g-j 57 a-g 31 a-e 0 e
Tri-X 313 0 c 15 f-j 53 a-g 28 a-f 4 c-e
XPH 9039 0 c 17 e-j 47 c-g 31 a-f 5 c-e
Duncan's multiple range test, 5% level.
zMean separation in columns by
Table 5. Early and total yields, average fruit weight, incidence of hollowheart, and soluble solids of
seedless watermelons in an observational trial. Gulf Coast Research & Education Center.
Spring 1989.
Early Yieldz Total Yield
Hollow- Soluble Hollow-
Weight Avg. Fruit heart Weight Avg. Fruit Solids heart
Variety No./AY (cwt/A) Wt. (lb.) (%) No./A (cwt/A) Wt. (lb.) (%) (%)
ACX 87B7026 1383 213 15.5 33 5334 818 15.4 13.0 33
FMX 29 2963 316 10.7 0 7309 720 9.9 12.7 0
FMX 4-28 1976 232 11.8 23 6519 594 9.1 12.3 23
ACX 874503 1778 226 12.7 18 4939 550 11.2 12.6 18
ACX 88TK01 2371 299 12.6 36 3951 449 11.4 11.7 36
ZEarly yield based on
YAcre = 4840 Ibf.
first harvest.
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