abstract
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Stripe rust of wheat, caused by Puccinia striiformisf. sp. tritici (Pst), was estimated to cause A$127 million in losses annually in Australia and similar magnitude of losses have been reported in many other nations. It traditionally threatened wheat production in cooler wheat growing areas and has adapted to relatively warmer regions in the last two decades and these Pst pathotypes are now prevalent around the world. An exotic incursion from this high temperature adapted Pst pathotypes was detected in Western Australia in 2002 and was typed as 134 E16A+. It has since evolved to acquire virulence for wheat stripe rust resistance genes Yr10,Yr17, Yr24and Yr27. While fungicides are available for stripe rust control, release of resistant wheat cultivars is accepted to be an environmentally safe and economical method to combat this disease. The success of breeding for stripe rust resistance depends on availability of diverse sources of resistance and linked phenotype-neutral DNA markers for their pyramiding in future wheat cultivars. An adult plant stripe rust resistance (APR) gene Yr75was mapped on distal part of the long arm chromosome 7A of wheat cultivar Axe using BSA with 90K Infinium Array. To enrich the Yr75 region we tried other genomic approaches, tGBS markers, complexity reduction GBS and simple sequence repeat (SSR) markers. The linked SNPs were converted into kompetitive allele-specific PCR (KASP) markers. Yr75 was flanked by sunKASP_389(2.3 cM) and sunKASP_394(0.5 cM).These flanking markers were tested on F2population (Axe/Nyb3) consisting of 1032 plants. We identified 72 recombinants and flanking markers KASP_389 and KASP_394 covered 3.6 cM interval. These recombinants will be phenotyped in F3generation and will be used for further saturation. This study will provide tightly linked markers for marker assisted selection of APR gene Yr75in wheat breeding programs.