Inheritance and allelism of resistance to Russian wheat aphid, .Diuraphis noxia (Mordvilko) in Iranian wheat cultivars.

摘要

The Russian Wheat Aphid (RWA), Diuraphis noxia (Mordvilko) is one of the major pests on wheat and barley in some cereal growing regions of the world. The use of resistant cultivars is an effective strategy to control RWA. This genetic study was conducted to determine the inheritance of RWA resistance in two Iranian wheats. Azadi and Omid, and to determine the allelism relationship between their genes. The resistant cultivars were crossed with each other as well as with a susceptible cultivar, Sholeh.Seedlings of the parents, Fl, F2, BCS, and BCR were screened for resistance to RWA under greenhouse condition. The response of seedlings to RWA was scored 21 days after artificial infestation using a 1-9 scale for leaf chlorosis and a 0-3 scale for leafrolling. Unlike previous studies, leaf chlorosis and leaf rolling were considered as two separate traits. Several phenotypic segregation ratios were tested in the F2 populations for goodness of fit. The results for leaf chlorosis showed that one and twodominant genes control the resistance to RWA in Azadi and Omid, respectively. Leaf rolling measurement indicated that resistance in Azadi is governed by one recessive gene and in Omid is controlled by two genes, one dominant, and one recessive gene. Segregation observed in F2 population of a cross between two resistant cultivars indicated that their resistance genes are different for the two traits. These genes can be incorporated into an adopted wheat cultivar in order to produce a durable resistance.