More precise map position and origin of a durable non-specific adult plant disease resistance against stripe rust (Puccinia striiformis) in wheat

Recently a major gene determining non-specific adult plant disease resistance against stripe rust (Puccinia striiformis) designated Yrns-B1 was mapped in wheat Triticum aestivum L. by using a cross between 'Lgst. 79-74' (resistant) and 'Winzi' (susceptible). Linkage to five Gatersleben wheat microsatellite (GWM) markers was discovered, previously mapped on chromosome arm 3BS. In the present study this map was improved by the incorporation of four additional GWM markers. QTL-analysis revealed high LOD values for the resistance at all nine loci, whereas the largest LOD (20.76) was found for the newly mapped marker Xgwm1329. Microsatellite analysis and resistance tests of a collection of old German/UK wheat varieties, including probable ancestors of 'Lgst.79-74' were carried out. A high coincidence of non-specific adult plant disease resistance against stripe rust and the presence of 'Lgst.79-74' allele (117 bp) of the marker Xgwm533 was observed among the varieties tested. Linkage during the inheritance of both the resistance and the 117 bp allele of Xgwm533 was demonstrated. The probable origin of Yrns-B1 is discussed. Carriers of this resistance gene were grown on large areas since more than 100 years. To estimate the capability of Xgwm533 as a diagnostic marker for non-specific adult plant disease resistance against stripe rust, microsatellite analysis and resistance tests of a collection of Russian spring wheat varieties were performed. The 117 bp allele of Xgwm533 was found in about 35% of the Russian cultivars analysed, however, none of them possessed the expected disease resistance. Thus, the utilisation of Xgwm533 as diagnostic marker seems to be restricted to certain genepools.