Molecular Breeding for Multiple Pest Resistance in Wheat

Abstract

The development of wheat genetic maps based on microsatellite (SSR) markers is giving researchers an unprecedented view into genome organization and breeding population structure. When this DNA-based technology is coupled with phenotypic data, QTL analysis and trait mapping are facilitated. This ultimately enables design of experiments to assemble complex genotypes that pyramid multiple traits. Our research team worked to pyramid multiple pest resistance together into elite Canadian wheat lines through marker-assisted backcrossing. This program included six Fusarium resistance QTL, Lr21 and Sm1 (wheat midge resistance). Further, the strategy made use of high throughput genotyping and whole genome analysis which lead to an accelerated recovery of the elite genetic background. Disease nursery results testing 120 homozygous BC2F3 lines carrying varying numbers of FHB resistance QTL clearly showed the introgression of FHB resistance QTL markedly reduced infection symptoms and DON levels by 45-80%. This report will include the strategy and technology used to introgress multiple pest resistance in wheat and field results for disease and performance evaluation. The report will also introduce how molecular breeding of wheat can be augmented with association mapping studies and how bioinformatics supports and accelerates molecular breeding research.