Saturation of the Yr34 region of wheat chromosome 5AL to identify closely linked SNP markers

Stripe rust of wheat, caused by Puccinia striiformis f. sp. tritici (Pst), is a major threat to global food security. Although stripe rust was detected for the first time in Eastern Australia in 1979, Western Australia (WA) remained free from stripe rust until 2002. The Pst incursion in WA was pathotyped as 134 E16A+ and differed from the most widely virulent pre-2002 group by combined virulence to Yr8 and Yr9 and avirulence for Yr3 and Yr4. An advanced breeding line, WAWHT2046, expressed resistant to moderately resistant (R-MR) response to 134 E16A+ under field conditions, and infection type (IT) 23C - 3C at the seedling stage. The resistance gene Yr34 that controlled stripe rust in WAWHT2046 was 12.2 cM distal to the awn inhibitor B1 in chromosome 5AL (Bariana et al. 2006; Theor Appl Genet 112:1143-1148) based on a Carnamah/WAWHT2046 doubled haploid (DH) population. The present investigation was planned to identify SNP markers closely linked with Yr34. Eight homozygous resistant and eight homozygous susceptible lines from the Carnamah/WAWHT2046 DH population were used for selective genotyping using SNP markers. Twenty four SNP markers were associated with resistance. Kompetitive allele-specific primers (KASP) were designed and SNP markers were genotyped on the DH population. SNP marker IWB80451 mapped 1.7 cM proximal to Yr34.

The University of Sydney Plant Breeding Institute, Australia
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