Rapid mapping of a stripe rust resistance gene YrZl31 using bulked segregant analysis combined with high-throughput single-nucleotide polymorphism genotyping arrays

Abstract Stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most important diseases of wheat. Identification and utilization of new resistance genes is one of the most effective way for achieving durable disease control. Zhongliang 31, a cultivar of common wheat (Triticum aestivum L.), is highly resistant to Chinese predominant Pst races and has been grown widely in the Longnan region in Gansu Province, China. Inheritance analysis of F1, F2, and F2:3 populations indicated that the stripe rust resistance of Zhongliang 31 was controlled by a single dominant gene, temporarily designated as YrZl31. Bulked segregant analysis (BSA) combined with wheat 660K single-nucleotide polymorphism (SNP) array showed the highest proportion of polymorphic SNPs located on chromosome 2B. One hundred forty-one kompetitive allele-specific PCR (KASP) and 165 simple sequence repeat (SSR) markers on chromosome 2B were used to map YrZl31. Linkage analysis indicated that 31 markers were linked to YrZl31, and the genetic distances of the two closest flanking KASP markers AX-111650565 and AX-110196738 were 2.8 and 4.1 cM, respectively. YrZl31 was located on wheat chromosome 2BL. Pedigree, resistance specificity, chromosome location, molecular and allelism tests suggested that YrZl31 may be a new gene and can be pyramided with other effective stripe rust resistance genes using the closely linked KASP markers developed in this study in wheat breeding programs.