Characterization of wheat germplasm for stripe rust ('Puccini striiformis' f. sp. 'tritici') resistance

Abstract

Stripe rust or yellow rust caused by Puccinia striiformis f. sp. tritici is an important disease of wheat causing considerable yield losses in wheat growing areas worldwide. The pathogen is one of the very important yield limiting factors in Pakistan. Present study was carried out to identify wheat genetic resources for stripe rust resistance to enhance cultivar improvement efforts. Wheat germplasm consisting of 20 Chinese cultivars, 95 synthetic hexaploids and 85 advanced breeding lines were evaluated under field conditions at two hot spot locations (Pirsabak and Islamabad) in Pakistan during 2007-08 and 2008-09 wheat growing seasons. Same germplasm were also evaluated at seedling stage under controlled greenhouse conditions. Seedling testing revealed that synthetic hexaploids have seedling resistance with likely presence of stripe rust resistance genes; Yr3, Yr5, Yr10, Yr15, YrSP and YrCV. Advanced lines and Chinese cultivars showed adult plant resistance under field conditions wherein most of the genotypes were susceptible at seedling stage. Both types of seedling and adult plant resistance identified in wheat germplasm offer promising genetic stocks for accumulating both resistances to acquire durable resistance and long lasting control against stripe rust pathogen in Pakistan.