Molecular Mapping of and Comparison with Other Genes for Resistance to Stripe Rust on Wheat Chromosome 1B.

Wheat stripe rust, caused by f. sp. , is one of the most serious plant diseases worldwide. Resistant cultivars are the most effective way to control the disease. is an important stripe rust resistance gene that has been used in wheat breeding programs and is represented in the host differential set to identify f. sp. races in the United States. To map , AvSYrTr1NIL was backcrossed to its recurrent parent Avocet S (AvS). Seedlings of BCF, BCF, and BCF populations were tested with -avirulent races under controlled conditions, and BCF plants were genotyped using simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers. was mapped to the short arm of chromosome 1B using four SSR and seven SNP markers. The genetic distances of from the nearest flanking markers and were 1.8 and 1.3 centimorgans (cM), respectively. DNA amplification of a set of 21 Chinese Spring (CS) nulli-tetrasomic lines and seven CS 1B deletion lines with three SSR markers confirmed the chromosome arm location and further placed the gene in chromosomal bin region 1BS18 (0.5). The gene was determined to be about 7.4 cM proximal to . Based on multirace response array and chromosomal location, was determined to be different from other permanently named stripe rust resistance genes in chromosome arm 1BS and was named .