Characterization of Quantitative Trait Loci for Leaf Rust Resistance in the Uzbekistani Wheat Landrace Teremai Bugdai

Abstract

Leaf rust, caused by Puccinia triticina Eriks. (Pt), is a major cause of wheat yield losses globally, and novel leaf rust resistance genes are needed to enhance wheat leaf rust resistance. Teremai Bugdai is a landrace from Uzebekistan that is highly resistant to many current races of Pt in the U.S.A. To unravel leaf rust resistance loci in Teremai Bugdai, a recombinant inbred line (RIL) population of Teremai Bugdai × TAM 110 was evaluated for response to Pt race Pt54-1 (TNBGJ) and genotyped using single nucleotide polymorphism (SNP) markers generated by genotyping-by-sequencing (GBS). Quantitative trait loci (QTL) analysis using 5,130 high quality GBS-SNPs revealed three QTLs, QLr-Stars-2DS, QLr-Stars-6BL, and QLr.stars-7BL, for leaf rust resistance in two experiments. QLr-Stars-2DS, which is either a new Lr2 allele or a new resistance locus, was delimited to a ~ 19.47 Mb interval between 46.4 Mb and 65.9 Mb on 2DS and explained 31.3% and 33.2% of the phenotypic variance in the two experiments. QLr-Stars-6BL was mapped in a ~84.0 Kb interval between 719.48 Mb and 719.56 Mb on 6BL, accounting for 33% to 36.8% of the phenotypic variance in two experiments. QLr.stars-7BL was placed in a 350 Kb interval between 762.41 Mb and 762.76 Mb on 7BL and explained 4.4% to 5.3% of the phenotypic variance. Nine GBS-SNPs flanking these QTLs were converted to kompetitive allele specific PCR (KASP) markers and these markers can be used to facilitate their introgression into locally adapted wheat lines.