Combining Ability and Narrow-Sense Heritability in Wheat (Triticum aestivum L.) under Rainfed Environment

Six advance wheat lines namely B4N11, B6N5, B6N12, BRF1, BRF3 and BRF17 and four wheat cultivars namely Zam-04 (ZM04), Kohat-10 (KT10), Pirsabak-08 (PS08) and Janbaz (JZ) were crossed in line × tester mating to develop 24 F1 hybrids. The resultant hybrids along with parents were evaluated during cropping season 2012-13 at Cereal Crops Research Institute (CCRI), Pirsabak, Nowshera, Pakistan under rainfed environment, using RCB design with 3 replications. General combining ability (GCA), specific combining ability (SCA) and narrow sense heritability for maturity and yield components traits were determined. The main objective of the research was identification and proper selection of best performing wheat parental genotypes and best F1 crosses, based on GCA and SCA estimates. Significant differences were observed among the wheat genotypes for all the studied traits. The estimates of σ²gca and σ²sca and its ratio (σ²gca/σ²sca) indicated that non-additive genetic expression were pre-dominant for most of traits studied. Line BRF3 and testers ZM04 were good general combiners for most of traits under consideration, while F1 hybrids B4N11 × PS08, B4N11 × JZ, BRF1 × ZM04, BRF1 × KT10 were best specific combiners observed for several important traits including grain yield plant-^1 which can be subsequently utilized in future wheat breeding to develop high yielding new wheat cultivars from transgressive segregants recovered in latter generations.