Gene discovery and pre-breeding for Russian wheat aphid resistance in wheat

Abstract

Pre-breeding research has a significant role in linking between genetic resources and breeding as it shortens the time frame between genetic enhancement and the development of new, improved crop varieties. The Russian wheat aphid (RWA), Diuraphis noxia, is one of the most damaging insect pests of wheat throughout the World. Although it is not yet present, its incursion to Australia is expected to cause substantial loses to the grains industry and therefore prebreeding research against this insect is seen as a high priority in Australia. The objectives of the study are to: 1) Identify available RWA resistant wheat germplasm from around the world and characterize against available RWA biotypes in various countries, 2) develop genomic tools for marker-assisted breeding, and 3) introgress new RWA resistance genes into Australian wheat and barley cultivars. We have evaluated a wide range of wheat lines from various parts of the world against a number of RWA biotypes from USA, Argentina, Mexico, Hungary, South Africa, France, Chile, Iran, and Syria. Wheat lines with moderate to good levels of resistance were identified. Genetic analysis of RWA resistant wheat lines has revealed significant diversity. To date, with the use of F2 and DH populations we have mapped genes for RWA resistance on chromosomes iDS and 7D. Closely linked SSR and DArT have been identified. These markers are also being used to identify wheat contigs potentially carrying the resistance genes. Introgression of resistance genes to adapted wheat lines have progressed up to BC4 generation. As we have identified some wheat lines that are resistant to both RWA and Ug99 in Kenya, crosses were also established to introgress resistance genes to both pests