158 EIGSTI 



the better keeping quality, all are results of seedlessness and triploidy, adding 

 special value to this new hybrid. Also, certain superior specific combinations 

 have shown excellent hybrid vigor, thereby increasing the total fruit produc- 

 tion over a longer period of the season than the diploid (fig. 1). 



Fig. 1. Excellent fruit of seedless watermelon. {Photo by H. R. Knaiis.) 



The seed for the triploid plant does not germinate as readily as diploid, 

 particularly when the soil temperatures are below 85 °F. This difficulty has 

 been overcome by seedling culture in greenhouses or in covered and heated 

 beds. After 20-30 days, seedlings thus cultured may be transplanted to the 

 fields. Direct seeding into the field is not as successful, unless the daily soil 

 temperatures are above 85 °F. Usually, in early summer and late spring un- 

 favorable cold soil conditions occur. However, once the triploid seedlings are 



