COMBINING ABILITY ANALYSIS IN F1 AND F2 POPULATION FOR COTTON LEAF CURL VIRUS DISEASE AT MULTIPLE LOCATIONS

Abstract

Genetic studies were conducted to examine the heritage of resistant to cotton leaf curl virus. Genetic components of variance revealed higher σ2GCA and Additive (σ2A) than σ2SCA and Dominance (σ2D), which indicated additive genes were more reliable for inheritance of resistance to CLCV. The ratio of variances σ2gca/σ2sca was higher than unity (one) and further proved from degree of dominance [σ2A/σ2D]0.5 which was greater than one and confirmed supremacy of additive genes at both locations and generations. The heritability narrow sense (h2) and broad sense (H2) was found higher which suggested role of additive genes, which are fixable. Therefore selection would be effective in early segregating generation according to the symptoms of cotton leaf curl virus. The GCA effects for CLCV showed that among the parents, Mac-7 found as good general combiner with highest significant negative GCA effects at both locations in F1 and F2 which considered as CLCV resistant parent. The SCA effects exhibited that hybrid, Mac-7 x USD16-3058, CIM-602 x Mac-7 and NIA-Noori x Mac-7 showed significant negative SCA effect in both generations and locations. It was noted that cross combinations involved good x poor and poor x good general combiner with significant SCA effect was due to complementary gene action which produce desirable transgressive segregants, these can be further studies through bi-parental mating of diallel selective mating or any other form of recurrent selection in early generation with single plant selection to exploited both additive an non-additive gene action.

Keywords

• cotton leaf curl virus
• diallel analysis
• combining ability
• gene action
• locations