Genetic study of resistance to Russian Wheat Aphid (Diuraphis nexia (Morduilko)) in advanced durum wheat (Triticum turgidum var. durum) lines

Six advanced durum wheat lines with different levels of resistance to Russian wheat aphid (RWA) were crossed in half-diallel method. Seedlings of F1 and their parents were grown in greenhouse and artificially infected with RWA. Analysis of variance and diallel analysis using Griffing, and Jinks and Hayman methods were performed for leaf rolling and chlorosis (percentage of leaf rolling and chlorosis) traits. General and specific combining abilities for resistance to Russian Wheat Aphid were significant for both traits indicating the role of additive and non-additive gene effects in controlling these traits. Jinks and Hayman analysis revealed higher additive gene effect as compared to non-additive gene effects. Non-additive gene effects were of partial dominance type for both traits. Less leaf rolling and chlorosis (greater resistance) were under control of recessive and dominant alleles, respectively. Broad and narrow sense heritability for resistance to RWA based on leaf chlorosis damage were 58 and 45 percent and for leaf rolling were 86 and 62 percent, respectively implying potential for improving resistance to RWA based on leaf rolling as compared to leaf chlorosis trait.