Genetic parameters for hydrocyanic acid content in forage sorghum (Sorghum bicolor L. Moench)

Six lines (IS 1003, IS 3504, IS 3541, IS 6354, CO 27 and CO 28) and four testers (IS 0030, AKSS 5, GSSV 1 and TNS 52) were crossed in line x tester design to produce 24 hybrid combinations. These hybrids along with their ten parents were grown in a randomized block design with three replications. The samples for estimation of hydrocyanic acid content were taken 32 days after sowing. The analysis of variance indicated significant differences for HCN content in all the genotypes. It also clearly shown that, the specific combining ability (SCA) variance for HCN content was higher than general combining ability (GCA) variance indicating the trait is controlled by non additive gene action. The parents IS 3541, CO 27 and IS 0030 were found to be the best ones based on GCA effects and the hybrids IS 1003 x TNS 52, IS 6354 x IS 0030 and IS 3541 x TNS 52 were found to have maximum negative SCA effects for HCN content. Heterosis breeding, recurrent selection and other population improvement procedures were suggested for getting varieties with reduced HCN contents.