Heritability, genetic gain and detection of gene action in hexaploid wheat for yield and its related attributes

Selection of promising genotypes from a diverse genetic pool and their utilization for hybridization is an important strategy for wheat crop improvement. The data from ten parents and their F1 progenies using line × tester mating scheme were analyzed to assess the effects of combining ability for yield and its cognate characters using randomized complete block design with three replications. Data were taken for grain yield and its associated characters like plant height, peduncle and spike length, flag leaf area, per plant tillers, spikelets spike−1, grains spike−1, spike density, thousand-grain weight and grain yield plant−1. Analysis of variance was used to statistically analyze the data. Line × tester analysis was used to find out association among traits and to estimate the effects of GCA and SCA. Highly significant differences were found among parents (lines, testers) and their F1 hybrids for all the parameters under study. Among parents, Line 9796 and tester 107 manifested as best general combiners and exhibited significant GCA effects for almost all the mentioned traits. In the case of F1 hybrids, 9793 × 118 and Punjab-2011 × 108 were recognized as best specific combiners exhibiting significant SCA effects. A higher value of SCA variance than the variance of GCA revealed the preponderance of non-additive genetic action. The degree of dominance revealed the involvement of both type of gene action for the traits under investigation. The deviations among total variation were mainly due to genotypes. Most of the yield associated traits were highly heritable with more than 80% heritability. These findings were confirmed by genetic gain. Thus, potential homozygous lines can be selected from transgressive segregants to improve yield and these crosses will be beneficial for commercial exploitation to heterosis.