Fodder yield and quality in forage sorghum: scope for improvement through diverse male sterile cytoplasms

Cytoplasmic male sterility (CMS) has proved to be an effective and efficient genetic tool in sorghum (Sorghum bicolor (L.) Moench) hybrid breeding programs. The A(1) (milo cytoplasm) CMS type has been widely exploited to produce both commercial grain and forage sorghum hybrids. To explore the possibility of using alternative CMS (non- milo cytoplasm) sources, we studied the effect of cytoplasm on forage yield and quality in sorghum. Nine female (CMS) lines (representing three each in A(1), A(2), and A(3) cytoplasms) and five male lines were used to generate 45 hybrids, which were evaluated in three environments. Cytoplasm and its first-order interaction with location and male and female lines showed the presence of a cytoplasmic effect on the majority of fodder yield and quality traits examined. The CMS lines possessing A(3) cytoplasm (A(3)N213 and A(3)N193) were good combiners for important fodder yield and quality traits. For hydrocyanic acid, the CMS lines possessing A(1) cytoplasm were good combiners. Mean performance of hybrids and combining ability analysis of parents revealed that A(3) cytoplasm can be used along with the widely used A(1) cytoplasm, which helps in the diversification of the male sterile base of forage sorghum hybrids.