Comparing Biparental and Association Mapping Techniques to Find New Leaf Rust Resistance Genes from 3,200 Diverse Wheat Accessions

Leaf rust is common in wheat, consistently reducing yields by 5-15% with higher losses recorded.  In hard red spring wheat growing regions of the U.S., farmers spray fungicides annually to mitigate crop losses, but genetic resistance can provide protection at lower cost to the farmer and environment. Our objectives are to identify and map leaf rust resistance genes and evaluate the effectiveness of association or biparental mapping approaches for mapping leaf rust resistance loci. Currently, 10 populations developed from selections of 3,200 diverse lines from the National Small Grains Collection are being evaluated for seedling resistance, which will be mapped using bulk segregant analysis, and adult plant resistance, which will be mapped using at least 120 recombinant inbred lines. Criteria including number of genes detected, type of resistance (seedling or adult plant), and whether previously identified or novel will be used to compare biparental and association mapping techniques.