Heterosis in F2 –Hybrids of Soybean.

Abstract

Yield and yiel yield components of 11 F2 – hybrids of soybean were compared with their parents and the respective F3 progenies at Thailand National Corn and Sorghum Research Center during August-November 1984. Only F2 from Clark 63 x SJ 4 showed significant heterosis (~23%) above high parent, the other crosses did not display prominent yield heterobeltiosis. Number of pods per plant and seeds per pod exhibited low heterobeltiosis, while days to flower, days to harvest, seed weight, plant height and height of lowest pod were all shorter than or inferior to the higher parent. The latter five characters were found to lie around parental mean in most crosses. Variation between plants within cross was found in plant height but not in pod height. In most crosses, yield and yield components in the F3 were not different from F2 indicating that additive gene action played an important role in controlling traits in these crosses.