Combining ability and gene action for fodder quality improvement in brown midrib sorghum (Sorghum Bicolor (L.) Moench.)

Presence of brown midrib gene in sorghum is bringing an attention to utilize this crop in manipulating forage quality due to its low lignin content. Therefore efforts were taken to study the combing ability effects (general and specific) of white and brown midrib parents and F₁ crosses of sorghum and gene action involved in controlling fodder quality traits. The experiment consisted of 30 F₁ hybrids developed by crossing six white midrib and five brown midrib genotypes. Less than unity ratio for general and specific combining ability variances for most of the traits excluding days to 50 percent flowering revealed existence of non additive gene action involved in inheritance of these traits. High mean and desired gca effects for grain yield, fodder yield and its contributory characters was manifested in Parbhani Moti and CSV 29R among the lines and Bmr 7-4-1 and Bmr 7-2-2 among testers. Per se performance and gca effects for in vitro digestibility and acid detergent lignin was significantly better in brown midrib testers; Bmr 7-4-1 and Bmr 7-2-2 than white midrib lines. F₁ crosses viz., Parbhani Moti x Bmr 7-2-2, PMS 71B X Bmr 7-2-2MS 104 B x Bmr 7-4-1 and Phule Anuradha x Bmr 7-4-1 exhibited significant desirable sca effects and per se performance for grain yield, fodder yield, higher in-vitro digestibility and low lignin content indicating good opportunity for improving digestibility of fodder utilizing bmr genotypes in future breeding programme.