049 Thickness and Weight of Watermelon Seed Produced from a Cross Between Tetraploid and Diploid Plants

Abstract

Triploid watermelon seed are produced by crosses between tetraploid female and diploid male plants. When open-pollinated, the resultant seed can be either tetraploid due to self-pollination or triploid from pollination by a diploid. This work was done to test if triploid and tetraploid seed can be separated on the basis of seed thickness and weight. Open-pollinated seed from a 4n × 2n cross were separated by either thickness (grouped into 0.1-mm increments) or weight (5-mg increments). Seed were germinated in a greenhouse and transplanted into the field. Plants were scored as either triploid or tetraploid by use of a genetic marker system. When separated by either thickness or weight, triploid and tetraploid seed were found in essentially each size category. There were no significant differences between populations for thickness, and the mean weights were essentially equal between triploid and tetraploid seed.