Polyform, Inc., Morrow, GA). Watermelon plants were transplanted and watered in by hand on 24 Apr. each year. Mickylee (BASF Nunhems) plants were used as pollinizers at a one pollinizer plant to three seedless plants ratio. The cotton variety DP1050B2RF
Several new seedlees watermelon cultivars have recently been released or tested by seed companies. Their greatest asset is their seed-lessness. Melon quality, as determined by consumer acceptance may be a greater challenge.
A consumer preference survey was conducted to determine the acceptability of ten seedless cultivars and breeding lines. All cultivars were rated as acceptable and significant differences were found among the cultivars. Comments expressed by consumers indicated that the seedless melons were not as flavorful as seeded cultivars. No correlations were found between soluble solids and preference nor firmness and preference. Further investigation will be made as to whether the convenience and flavor are worth the greater cost of the seedless watermelon.
that consumers were willing to pay 50% more for seedless watermelons. To produce seedless watermelons, techniques such as triploidy, hormonal treatment, and pollination with inactivated pollen have been tried. Seedlessness may affect fruit quality
Watermelon [ Citrullus lanatus (Thunb.) Matsum. & Nakai] is an important specialty crop in Florida, a leading watermelon producer in the United States, with an average production value exceeding $80 million each year ( USDA, 2017 ). Seedless
Cover crops offer an excellent source of nutritional requirements for production of vegetables in sustainable agricultural system. By using this concept, field experiments were conducted in l998 at three locations in Virginia; Petersburg, James City, and King and William County, and five cover crop treatments; Hairy Vetch (HV), Crimson Clover (CC), HV+Rye, CC+Rye, and a conventional bare-ground control were used for their potential support of nutritional requirements for production of a seedless watermelon crop. The results indicated that the yield levels of seedless watermelon following cover crop treatments had significantly higher number of fruits per acre and the crimson clover treatment had higher fruit size in one of the sites (King William County) as compared to the other four treatments and two sites suggesting that cover crop/crops alone have the potential to support nutritional requirements for seedless watermelon to sustain production, thus becoming a viable and profitable alternative to using inorganic nitrogen source. The effects of cover crops on chemical composition of seedless watermelon were generally not significant. The results also indicated that watermelons produced using sustainable crop production methods are comparable to those produced using conventional methods. Our studies support using seedless watermelon as a viable alternative and high-value cash crop for Virginia farmers' especially tobacco growers, other small-scale producers, and limited resource farmers.
Although there is increasing interest in reducing the use of nitrogen (N) fertilizers due to the potential of unused N causing pollution of surface and groundwater, N is a major nutrient for plant growth. Our objective was to determine the potential of using winter legume cover crops to meet the N needs of seedless watermelon (Citrullus lanatus), a potential cash crop for farmers in Virginia. Fruit number, fruit weight, fruit yield, and fruit quality traits (flesh to rind ratio, water content, total soluble solids, sugar content, and pH) of seedless watermelons were evaluated in replicated experiments in Virginia at three locations during 1997-98 and two locations during 1998-99 following cover crop treatments consisting of crimson clover (Trifolium incarnatum), hairy vetch (Vicia villosa), crimson clover + rye (Secale cereale), hairy vetch + rye, and a bareground control treatment that received 100 lb/acre (112 kg·ha-1) of N. At all five locations, the bareground control treatment resulted in fewer fruit [1803 fruit/acre (4454 fruit/ha)], lower fruit weight [9.8 lb (4.5 kg)], and lower fruit yield [8.9 tons/acre (20.0 t·ha-1)] compared to the four cover crop treatments. The crimson clover + rye and hairy vetch treatments resulted in highest numberof fruit [2866 and 2657 fruit/acre (7079 and 6563 fruit/ha), respectively], whereas the highest fruit yield was obtained following hairy vetch [21.2 tons/acre (49.8 t·ha-1)], hairy vetch + rye [20.3 tons/acre (45.5 t·ha-1)], and crimson clover + rye [19.6 tons/acre (43.9 t·ha-1)]. Cover crop treatments did not affect the quality of watermelon flesh. The seedless watermelon fruit averaged 1.4 flesh: 1 rind ratio, 90% water content, 9.5% total soluble solids, 8.0% sugar, and a pH value of 5.9. These results indicated that legume cover crops, such as crimson clover and hairy vetch, can be successfully used to produce seedless watermelons, in a no-till system, without any use of N fertilizers with dryland conditions.
Watermelons contain the carotenoids b-carotene, phytofluene, lycopene, and lutein. These carotenoids play an important role in plant oxidative protection and may serve to protect humans against oxidative assaults. Of the carotenoids, lycopene is the predominant pigment in red-fleshed melons (30-130 μg·g-1), b-carotene is present in small amounts (1-14 μg·g-1), and other carotenoids are present in minute amounts (1-3 μg·g-1). Seventy varieties were screened for lycopene content using scanning colorimetry, spectrophotometry, and HPLC techniques, and grouped as low, medium, high, or very high in lycopene. Pink-fleshed heirloom varieties such as Sweet Princess and Black Diamond contained low amounts of lycopene (<40 μg·g-1). A number of seeded and seedless varieties had medium amounts of lycopene (40-60 μg·g-1). Varieties in the high category (60-80 μg·g-1) were primarily seedless types, although `Dixie Lee', an open-pollinated, seeded variety had 69 μg·g-1, indicating that high lycopene content is not restricted to hybrid or seedless melon germplasm. Six selections were found to be very high in lycopene (>80 μg·g-1), including the minimelon Hazera 6008 (Extazy). Total carotenoids and carotenoid profiles were determined by HPLC for 23 varieties in 2003. Both seeded and seedless type melons had varieties high in bcarotene, lycopene, and total carotenoids. These results indicate that commercial watermelon varieties have a wide range in lycopene and b-carotene content, and that most commercially important varieties are high in lycopene and total carotenoids, providing important sources of phytonutrients to the human diet.
Watermelon fruit that results from pollination with pollen irradiated with soft-X-ray contains only empty seed, although the fruit develops to a normal size. In this study the processes of fertilization and embryo formation were compared between unirradiated and irradiated pollen in order to reveal the mechanisms by which seedless fruits are generated. The use of soft-X-irradiated pollen resulted in normal pollen tube penetration into the synergid and discharge of sperm cells. Two to three days after pollination, the sperm nucleus was present alongside the egg nucleus before fusion. The polar nuclei divided and the endosperm cell spread in the embryo sac before zygote division. A globular embryo was observed on day 7 to 10 after pollination. Subsequently, the embryo failed to differentiate to organ tissue and degenerated. These results indicate that double fertilization occurred after pollination with the irradiated pollen and that abortion of the embryo results from soft-X-ray induced chromosomal abnormalities in generative nucleus.
Due to the lack of viable pollen produced in seedless (triploid) watermelons, fruit set in seedless watermelons requires a standard seed (diploid) producing cultivar (hereafter referred to as a pollinizer) to be interplanted as a source of pollen. It is recommended that one row of pollinizer be planted for every two rows of seedless watermelon. There is little to no information available to growers comparing the effects of pollinizers on seedless watermelon yield and quality. We conducted a study to evaluate the effectiveness of three seeded pollinizers (`Crimson Sweet', `Fiesta', and `Royal Sweet') on yield and quality of four seedless watermelon hybrids (`Abbott and Cobb 5244', `Crimson Trio', `Millionaire', and `Tri-X 313'). `Royal Sweet' as a pollinizer tended to produce higher yields of small (<3.6 kg) and medium-sized seedless watermelons (3.6-7.3 kg) per acre compared to `Crimson Sweet' and `Fiesta'. `Crimson Sweet' produced a greater number of large (>7.3 kg) seedless watermelons compared to `Fiesta' and `Royal Sweet'. However, the number of marketable melons (>3.6 kg) did not differ among the three pollinizers evaluated. Two quality measurements taken (hollow heart and soluble sugars) were not influenced by the choice of pollinizer.
Medium-sized triploid watermelons were evaluated in southeast Pennsylvania in 2002 and 2003 to determine the best adapted cultivars for this region. The 2002 season was unusually hot and dry, while 2003 was unusually cool and wet. Yields and fruit quality were compared for the eight cultivars that were grown both seasons to determine the effect of weather on seedless watermelon. Cooler temperatures reduced total fruit number and total yield but not average fruit weight or soluble solids. Researchers evaluating triploid watermelons over several seasons can compare size and °Brix among cultivars, but will need to be cautious when predicting total yields.