QTL Mapping of Adult-Plant Resistance to Leaf and Stripe Rust in Wheat Cross L224-3/Zhengzhou5389

Abstract

Abstract Wheat leaf rust and stripe rust are important diseases worldwide. Breading resistant cultivars is an effective means to control wheat leaf and stripe rust. Wheat line L224-3 currently has high resistance to wheat leaf and stripe rust in the field. In this study, 166 recombinant inbred lines (RILs) derived from the L224-3 × Zhengzhou 5389 cross were used to map quantitative trait locus (QTL) for leaf and stripe rust resistance. The population and two parents were phenotyped for leaf rust severity at Baoding in Hebei province and Zhoukou in Henan province in the 2015/2016 and 2016/2017 cropping seasons, and stripe rust severity at Baoding in Hebei Province and Mianyang in Sichuan Province in the 2015/2016 and 2016/2017 growth seasons. The population and parents were also genotyped with the 660K SNP array and simple sequence repeat (SSR) markers to screen for potential polymorphic markers associated with rust resistance. Four QTLs on chromosomes 1A, 2A, 4B and 7B, respectively, were detected using inclusive composite interval mapping (IciMapping). QLr.hbau-1A/QYr.hbau-1A, derived from susceptible parent Zhengzhou 5389, was pleiotropic for both leaf rust and stripe rust resistance and maybe a novel QTL. The second QTL on 2A in L224-3 for leaf and stripe rust resistance was the known gene Lr37/Yr17. QLr.hbau-4B/QYr.hbau-4B might be a new locus for leaf and stripe rust resistance. The last QTL for stripe rust resistance, tentatively designated as QYr.hbau-7B, was detected on 7B, and more tests are needed to confirm whether it is a new QTL. The QTL identified by their flanking markers in the present study could be used for candidate gene mining and marker-assisted selection (MAS) in wheat breeding programs for rust resistance.