Abstract

The genetic effect of grain yield plant^-1 and its correlation with yield components were investigated in a 7 × 7 incomplete diallel cross of seven wheat parents during the crop season of 2009 to 2010. Mean square of general combining ability (GCA) effect was 2.90 for grain yield plant^-1, which was highly significant (P<0.01), indicating that additive effect played important role in the inheritance of the trait. Specific combining ability (SCA) effect was highly significant (P<0.01) for grain yield plant^-1 (0.68), suggesting that the trait was also controlled by non-additive effect. The estimates of GCA showed that the best combiner for grain yield plant^-1 was Ningmai 9. The additive-dominance model was partially adequate for grain yield plant^-1 and it was controlled by the over dominance type of gene action. Ningmai 8 possessed maximum dominant genes, whereas Yangmai 9 had maximum recessive genes. Grain yield plant^-1 might be controlled by two groups of genes and exhibited moderately high value of narrow sense heritability (h²_N=69.51%). The statistical analysis revealed that grain yield plant^-1 was positively and significantly correlated with tillers plant^-1 (r_p=0.584, r_g=0.595) and number of grains spike^-1 (r_p=0.528, r_g=0.507) at phenotypic and genotypic levels. The information obtained from the study might be helpful for wheat breeders trying to develop new varieties with high-yielding potential.

Key words: Combining ability, diallel cross, grain yield, inheritance, Triticum aestivum L.