Inheritance of resistance to russian wheat aphid, diuraphis noxia (mordvilko), based on leaf rolling in wheat

The present study was conducted to determine the inheritance of resistance to Russian wheat aphid (RWA) in two Iranian resistant wheat cultivars, Azadi and amid. The resistant cultivars were crossed with each other and with a susceptible cultivar, Sholeh. Seedling of both parents, F1, F2, BCS and BCR were screened for resistance to RWA under greenhouse condition. Twenty one days after infestation, the damage of aphid was measured quantitatively (percentage of leaf rolling) and qualitatively (scale 0-3).Inheritance of resistance to RWA, based on leaf rolling, was studied by Mendelian segregation ratios as a qualitative method, and mean and variance analysis of generations as a quantitative method. Mendelian ratios showed that one and two major genes in Azadi and amid, respectively control leaf rolling. Quantitative variations of this trait and presence of epistasis (based on generation mean analysis) indicated that I some minor genes have significant role in its control. Additive and dominance components and duplicate interactions (i, j and I) had also significant effects on controlling leaf rolling in cultivar Azadi. In amid cultivar, only additive component had significant effect. Leaf rolling showed high and moderate heritability in Azadi and amid, respectiveley. No allelism relationship was observed between major genes of two resistant cultivars. These different genes therefore, can be incorporated into adapted wheat cultivars to provide a durable resistance.