Journal of Plant Pathology & Microbiology

Abstract

Identification, Validation of a SSR Marker and Marker Assisted Selection for the Goat Grass Derived Seedling Resistance Gene Lr28 in Wheat

Pallavi JK, Anupam Singh, Usha Rao I and Prabhu KV

The goat grass (Aegilops speltoides) derived seedling leaf rust resistance gene Lr28 is effective in providing resistance against infection to leaf rust including its most virulent strain, 77-5 (121R63-1) of the pathogen. A polymorphic SSR marker specific to Lr28 was identified by employing bulk segregant analysis on an F2 population derived from the cross between PBW343-Lr28, a leaf rust resistant near isogenic line of the most cultivated variety PBW343 and CSP44-Lr48, the Australian cultivar Condor derived CSP44 line carrying the APR gene Lr48. The marker amplified a polymorphic fragment which was particular to the presence of the seedling resistance gene and it was mapped at a distance of 2.9 cM from the Lr28 resistance locus on chromosome 4AL. It was also validated on a set of 42 NILs which carried other potent leaf rust resistance genes of diverse origin. Such a polymorphic codominant SSR marker will be useful in wheat breeding programmes to differentiate plants homozygous at the Lr28 locus from those that are heterozygous.