Abstract
Performance test of diallel cross with five sugar beet strains showed that the high suger yield of single crosses were highly correlated with heterosis in root weight. General combining ability of these strains were estimated by grouping of the single crosses, and it was clarified that the regression coefficient of general combining ability on parental performance approached unity as the number of stratns were increased. Estimation of specific combining ability effects by using the linear regression equettion showed the importance of these effects in dete.rmining sugar yield of single crosses.
