Combining Ability Analyses of Net Photosynthesis Rate in Pepper (Capsicum annuum L.)

In perspective of breeding high-yield hybrid pepper varieties, combining ability analysis of net photosynthesis rate at different phases of flowering and fruit setting in pepper was made with 15 cross combinations from 6 parents by (1/2) n (n-1) diallel crosses. There are relatively large differences not only in general combining ability (GCA) effect among different parents and at different phases of flowering and fruit setting, but also in specific combining ability (SCA) effect among different hybrids. There are relatively large GCA effects in late parents but relatively less GCA effects in early parents. No obvious laws have been found in the relationship between SCA effects and maturity of hybrids. Variances of SCA are larger than those of GCA. Heritability is less but influence of environment is larger. Correlation analysis of combining ability between net photosynthesis rate and agronomic character or resistances to main diseases has showed that correlation coefficients of GCA are relatively large at the medium phase and the late phase of flowering and fruit setting. Net photosynthesis rate is more relative to leaf characters and fruit characters. Correlation coefficients of SCA are relatively large at the early phase and the late phase of flowering and fruit setting. Net photosynthesis rate is more relative to leaf characters and plant characters at the early phase but to plant characters and fruit characters at the late phase. Correlation coefficients of SCA between net photosynthesis rate and resistances to main diseases are larger than those of GCA. The combining abilities of net photosynthesis rate at different phases of flowering and fruit setting are positively correlated with those of yield per plant. The combining ability is an important parameter of breeding of high photosynthesis hybrid pepper varieties.