Studies on Combining Ability for Bio-energy Traits in Sweet Sorghum [Sorghum bicolor (L.) Moench]

An investigation was carried out to assess the nature of combining ability and gene action in respect of bio-energy traits in 72 new hybrids of sweet sorghum developed by crossing 4 male sterile lines and 18 testers in line × tester mating design and grown in Randomized Block Design with two replications during Kharif 2008 at ‘K’ Block of Zonal Agricultural Research Station, University of Agricultural Sciences, GKVK, Bengaluru. The variance among the lines (for juice yield and total sugars), testers (for juice yield) and line × tester interaction (for all the characters studied) in respect of their general combining ability were highly significant indicating predominance of non-additive gene action in genetic control of these traits. ICSA 84, ICSA 38 and ICSA 264 among the lines and NTJ 2, E 36-1 and GD 65008 among the testers, were identified as good general combiners indicating their ability in transmitting additive genes in the desirable direction to their progenies. Highly significant sca effects were observed for all the characters studied and good specific combiners for different characters involved parents with high × high, high × low, low × high and low × low general combinations.