Seedless Watermelon Trial at Three Locations in Missouri

Project Summary
Seedless, triploid, watermelons are gourmet items that command high prices at both retail and wholesale markets. The recent surge in demand for locally grown vegetables has made the production of seedless watermelon attractive for small growers throughout Missouri. Traditional production of watermelons in Missouri involve regions with deep, sandy soils characteristic of alluvial areas near the two major rivers in our state. Indeed, yield estimates of most varieties of seedless watermelons are based on these soil conditions. Data concerning the performance of the seedless varieties on claypan soils characteristic of a goodly part of Missouri is sparse.

Project Approach
In the summer of 2009, a study was conducted to evaluate the performance of 15 seedless watermelon varieties at three sites in Missouri. The varieties evaluated included Amarillo, Buttercup, Harmony, Imagination, Indiana, Lamar, Matrix, Melody, Millenium, Palomar, Seedway 4502, Sugar Coat, Sugar Crisp, Sweet Delight, Triple Threat and Troubadour. Tests plots were located on the Bradford Research and Extension Center near Columbia, MO; the Carver Research Farm near Jefferson City, MO; and the Toby Detwieller farm near Lamar, MO.

Seeds were started in a greenhouse in a peat-lite germination medium and transplanted into the field on June 15th at the Lamar location and June 16th at the Columbia location. Plants were established on raised beds covered with black polyethylene plastic for weed and moisture control. Prior to transplanting the soil was amended with 80 pounds of actual nitrogen, 46 pounds of P2O5 and 60 pounds of K2O per acre. Four plants along with two pollinators were included per replication and each variety was replicated four times in a randomized manner. Plants were spaced two feet apart within rows spaced 10 feet apart. When warranted, supplemental irrigation was supplied via drip irrigation using polyethylene tape under the plastic mulch. At the Lincoln University site watermelon seedlings were transplanted in mid June and harvested in early September but data is not included because excessive rainfall in August severely reduced yield and quality.

Harvest was conducted on August 21 at the Lamar location and September 9th at the Columbia location. Data collected included total fruit number, average fruit weight, yield per plant, and sugar content measured as % Brix. The latter was based on two randomly selected fruit per plant from each replication. Data was presented by Dr. Sanjun Gu at the Great Plains Vegetable Conference at St. Joseph in January 2010 and is on the MU Bradford Web Page (http://aes.missouri.edu/bradford).

Goals and Outcomes:
It was our objective to determine if certain varieties of seedless watermelons performed better than others at various locations in Missouri. The data below is the mean of the Columbia and Lamar locations. The Lincoln University location had water logging issues late in the growing season which affected yield and quality and is not presented. At Columbia and Lamar the data was extremely close and we are very confident in the results.