Nature of gene action and combining ability analysis of yield and yield-related traits in chickpea (Cicer arietinum) under heat stress

Increasing incidence of heat stress (HS) is appearing as an important abiotic stress, limiting chickpea (Cicer arietinum L.) yield globally. Therefore, understanding of the nature of gene action of yield- related traits could help in breeding heat tolerant chickpea genotype for its sustainable production under HS. In the present investigation a total of six chickpea genotypes, viz. ICC 4958, ICC 92944, ICC 1205, DCP 92-3, ICC 96030 and KWR 108 were used as parents for 6 x 6 diallel analysis (excluding reciprocal crosses) to estimate gene action for various phenological and yield-related traits by growing them under normal sown (NS) and late sown (LS) conditions. Genetic analysis revealed the presence of both additive and non-additive genetic variances. However, higher magnitude of general combining ability (GCA) variance than specific combining ability (SCA) variance, with predictability ratio > 0.5 for most of the traits studied under both NS and LS conditions indicated preponderance of additive gene action. The estimates of GCA effects revealed that the parents ICC 92944 and KWR 108 were better general combiners for yield and yield- related traits, under both NS and LS conditions. Likewise, ICC 4958 x ICC 92944 (under both conditions) and DCP 92-3 x KWR 108 (under LS) F-1 crosses were the most suitable cross combinations for yield and yield-related traits. High estimates of broad sense heritability for most of the traits, and low to medium estimates of narrow sense heritability for the studied traits were noted under both conditions. Therefore, inclusion of parent with high GCA effect in crossbreeding programme could be a potential strategy for improving HS tolerance in chickpea.