Molecular marker assisted pyramiding of leaf rust resistance genes Lr19 and Lr28 in bread wheat (Triticum aestivum L.) variety HD2687

Backcross lines of high yielding cultivar HD2687 developed earlier carrying leaf rust resistance genes Lr19 and Lr28 were utilized to pyramid the two genes using marker assisted selection. Background analysis using 602 SSR markers was done to compare the genotypic background of backcrossed lines with recipient variety HD2687 as well as the donor genotypes Cook*6/C80-1 and CS2A/2M#4/2. Backcross lines of HD2687 with Lr19 and Lr28 i.e. HD2687+Lr19 and HD2687+ Lr28 showed 89 and 92.1 percent genomic similarity with HD2687. The two backcross lines were crossed and plants carrying both Lr19 and Lr28 were identified in F₂ generation. Background analysis of 51 plants carrying both Lr19 and Lr28 was undertaken using polymorphic SSR markers to identify plants with better recovery of HD2687 background. Although, Lr19 and Lr28 individually are ineffective against leaf rust pathotypes 77-8 and 77–10 but pyramided lines are expected to provide resistance against all the races.