Genetic Expression of Yellow Rust Resistance, Yield and Yield Related Traits in Wheat Using Griffing's Combining Ability Analysis

Knowledge of traits inheritance is a prerequisite for any plant breeding program. Wheat cultivars like Pirsabak-85, Khyber-87, Saleem-2000, Pirsabak-04, Pirsabak-05 and Shahkar-13 were crossed in 6 × 6 half diallel fashion during 201011 at the Cereal Crops Research Institute (CCRI), Pirsabak Nowshera, Pakistan. The F1 and F2 half diallel hybrids in comparison with parental genotypes were studied during 2011-12 and 2012-13, respectively. The aim of the present work was to explore the genetic basis of yellow rust (Puccinia striiformis West. f. sp. tritici) resistance, flag leaf area, 1000-grain weight and grain yield in F1 and F2 wheat hybrids through Griffing's combining ability approach. Significant (p≤0.01) differences were observed among the genotypes for all the traits. Mean squares due to general combining ability (GCA) and specific combining ability (SCA) were significant (p≤0.01) for majority of the traits in both the generations. Genetic components of variances due to GCA and SCA revealed that SCA variances excelled the GCA for majority of the traits, thus non-additive type of gene action controlled the inheritance of such traits. However, flag leaf area and 1000-grain weight in F1 generation showed preponderance of GCA variances and revealed additive type of gene action advocating those traits. Based on GCA effects, Pirsabak-05 was considered as the best general combiner for rust resistance and yield traits in F1 generation. However, in F2 generation, cultivar Shahkar-13 appeared to be the best general combiner for rust resistance and grain yield. The F1 hybrid Pirsabak-85 × Pirsabak-04 and F2 population Pirsabak-05 × Shahkar-13 performed better for majority of the traits. Therefore, these promising populations need to be further exploited for yellow rust resistance and grain yield in future breeding programmes.