Authors: Mehdi FazelNajafabadi Junhua Peng Frank B Peairs Hana Simkova Andrzej Kilian Nora L V Lapitan
Publish Date: 2014/11/05
Volume: 203, Issue: 3, Pages: 607-614
Abstract
The RWA Diuraphis noxia Kurdjumov is a devastating insect pest of wheat Triticum aestivum L and barley Hordeum vulgare in the United States and in many parts of the world The use of D noxiaresistant cultivars is an economically useful approach for protecting cereals from this aphid However there are few genes conferring resistance to the most predominant US biotype Biotype RWA2 Wheat line CI2401 originating from Tajikistan has been identified to be resistant to RWA2 An F2derived F3 F23 segregating population developed from a cross between CI2401 and Glupro a high quality susceptible wheat cultivar was used to genetically map the resistance in CI2401 Seedlings from F2 individuals and F3 families were infested with RWA2 aphids Seedling reactions were scored as resistant or susceptible based on the degrees of leaf rolling and chlorosis The observed segregation ratios in the F2 and F3 generations indicate the presence of a major dominant gene controlling resistance to RWA2 The gene named Dn2401 was genetically mapped to the short arm of chromosome 7D Xbarc214 mapped 11 cM and Xgwm473 mapped 18 cM distal and proximal respectively to the gene Association studies using more than 12000 SNPs and SilicoDArTs confirmed the presence of a major signal associated with resistance on chromosome 7DS In addition a minor signal was detected in chromosome 1D The markers developed in this study will be useful for markerassistedbreeding for resistance to RWA2The Russian wheat aphid RWA Diuraphis noxia Kurdjumov Homoptera Aphididae is a major pest of wheat T aestivum L and barley Hordeum vulgare L RWA was introduced into the USA in 1986 and by 1993 had caused direct and indirect losses to US growers estimated at US 893 million Morrison and Peairs 1998Plant damage from RWA infestations includes reduction of plant height shoot weight number of spikes and yield Girma et al 1993 Susceptible symptoms include chlorosis streaking along the entire leaf blade leaf rolling head trapping and in severe cases plant death Burton and Webster 1993 These symptoms typically appear within seven days after the initial infestation Once leaf rolling develops it can hinder the effectiveness of contact insecticides by sheltering the insect colonies The use of resistant varieties has been the most effective means of controlling this pest
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