Seedless Watermelon Variety Trial - 2003

Timothy Elkner, Penn State Extension, Lancaster County

Introduction
Many new seedless watermelons were examined in 2003, the third year for watermelon trials in Lancaster County. Several "standard" varieties were included in the trial as well. Two varieties of "mini-melons" were in the trial this season along with a pollinator specific for these melons. There were six varieties that were in the trials all three years and the harvest data for these varieties is included in this report.

Procedures
A planting of seedless watermelons was established at the Penn State Southeast Research and Extension Center in Landisville on June 13 using commercially produced transplants. The variety listing and seed sources can be found in Table 1. The experimental design was a randomized complete block with three replications. Each replication contained 10 plants. Transplants were set at 3 feet in-row spacing on raised beds covered with black plastic. Water was supplied through trickle irrigation. Fertilizer (50 lbs./acre N) was broadcast and disked into the soil prior to plant establishment. Two additional fertilizations of 10 lbs./acre of N were applied through the drip system on July 10 and July 31. The pollinator varieties were WX-262, WX-263, Summer Flavor 790 HQ, HSR-2942, and "Minipol" for the mini-melons.

The watermelons were harvested on August 21, 29 and September 8. Each melon was individually weighed. On the August 21 harvest, 10 randomly selected melons per plot were cut and evaluated for hollow heart and soluble solids. On August 29, between 3 and 5 melons were cut and evaluated. Soluble solids were determined using a hand-held refractometer. The growing season was wet. Diseases and insects were controlled following recommendations in the 2003 Pennsylvania Commercial Vegetable Production Guide.

Results
Overall, germination percentages were good with only three varieties below 80% (Table 1). Total yield/variety, early, mid and late harvest yields, number of melons/variety, average soluble solids and average weight per melon are listed in Table 2. The wet growing season resulted in a higher percentage of melons with hollow heart than in previous trials (Table 3). Varieties with 20% or less hollow heart were Millennium, Amarillo, Fenway, Millionaire and Lilliput. Weight distribution for the total yield by weight class is found in Table 4. Characteristics of the individual varieties are listed in Table 5.

The highest yielding seedless variety overall in the trial was Olympia, followed by 6033 "Sagi", then Wrigley. The highest yield for the first harvest was Sugar Slice, the second harvest was EX-9020, and the third harvest was Vertigo. The highest yielding dark-rinded melon was Millennium. The best mini-melon was 5116.

Data for melons that were in all three trials are found in Tables 6 and 7. Millionaire, 5244 and Tri-X Palomar had higher yields in the hot, dry growing season of 2002 than in the cooler, wet 2003 season. Yields for Revolution, an oblong, larger melon, were similar both seasons. Soluble solids varied with variety and season. For the dark-rinded melons (Table 7), Millennium had reduced yields in 2003 versus 2002, while Imagination was not as affected by the weather.

Table 1: Watermelon varieties in 2003 variety trial, source of seed and germination percentages.

*Mini-melon

Table 2: Number of replications, early, mid and late harvest yields, total yield/variety, total number of melons/variety, and average weight per melon and average soluble solids for 25 seedless watermelons in 2003.

*Mini-melon

Table 3: Number of seedless watermelons cut, number with hollow heart and % of melons cut with hollow heart from variety trial in 2003.

*Mini-melon

Table 4: Weight distribution of seedless watermelons in variety trial in 2003.

*Mini-melon