The 2011 ASHS Annual Conference

Growers in Central Missouri usually transplant watermelons in mid- to late-May. In the past three years, however, the frequent rainfalls had made this normal transplanting difficult.   The objective of this preliminary study was to test the yield and fruit quality of late-transplanted watermelons and to identify varieties that might suitable for late planting. Thirteen triploid watermelon varieties were chosen in this study. Seeds were started in a greenhouse on June 1; seedlings were transplanted on July 15 in raised beds covered with black plastic on George W. Carver Farm in Jefferson City, Missouri. Vines of diploid variety “sidekick” were planted as pollenizers. The experiment was conducted as a completely randomized design with four replications. There were 4 plants in each replication. Watermelons were harvested only once on September 21. Fruit weight, sugar content and sensory quality were measured shortly after harvesting. Results showed that all varieties grew vigorously and produced ripen fruit. Marketable yield ranged from 20.3 to 40.3 tons/acre.  ‘Yellow Buttercup’ had the highest yield although some fruit did not ripen enough. All other varieties are red-flesh with similar yield per vine. ‘Yellow Buttercup’ produced the highest number of fruit (seven per vine), but with relatively light fruit, an average of 11.6 pounds/fruit. ‘Tri-X313’, ‘Tomcat’, ‘Intruder’, ‘7167’, ‘ACX 7125T’, ‘Summer Sweet 5244’ and ‘4674’ had similar average fruit weight, about 13.5-15.9 pounds/fruit. The sugar contents (°Brix) were not different among varieties, ranged from 10.9 to 12.4. In conclusion, almost all tested red flesh variety performed well. ‘Tri-X314’ seemed to be the overall winner. The two solid dark-green varieties ‘SSX 7402’ and 9601 were excellent. The yellow flesh variety, ‘Yellow Buttercup’ tended to produce too many fruit. Its rind was thicker and some fruit was over- or under-ripen, which might be corrected by doing a series of harvests. The late-transplanting may be a good way for Farmers’ Market vendors to provide a continuous supply of watermelons.