Rapid transfer of the leaf rust resistance gene Lr52 for the improvement of bread wheat cultivar HD3086

For varietal improvement, parental genotypes are crossed and advanced to generate homozygous lines with selection for desirable traits like disease resistance and yield. In the current study, leaf rust resistance gene Lr52 from Lr52/Yr47/2∗Mace, the donor parent (DP), transferred to the recurrent parent (RP) HD3086, a popular Indian wheat cultivar, which has become susceptible to leaf rust. During the backcross breeding, the plants were grown sequentially under natural field conditions during the winter season and under controlled environmental conditions to take two crop generations during the summer season. Generations comprising F1, BC1F1, and BC2F1-3 plants were developed by crossing and successive backcrossing with RP HD3086 and further selfing to generate homozygous resistant lines. Plants with leaf rust resistance in backcross generations were selected phenotypically to identify the superior or similar plants as of RP HD3086. The Lr52/Yr47-linked SSR marker icg16c004_2 was initially utilized to confirm hybridity and foreground analysis in the BC1F1 generation but was found to be recombinant. Homozygous resistant (HR) lines in BC2F3 generation were selected based on leaf rust disease score and phenome recovery. Finally, the SSR markers unveiling parental polymorphism across the genome were employed to estimate the background recovery of phenotypically selected superior plants, revealing a recovery of 91.48–94.81 % of RP genome. The selected improved lines of HD3086+Lr52 displayed similar performance for most agro-morphological traits, and a few lines were also found to yield significantly superior to that of RP HD3086. Overall, the study shows the practical utility of phenotypic selection with intermittent selection under controlled and natural field conditions for improving popular cultivars with relatively higher speed and precision. •Improvement of mega variety HD3086 for leaf rust resistance by introgressing Lr52 resistance gene.•Modified backcross method was used with a combination of natural and RGA conditions for development of rust resistant lines.•Improved HD3086 lines have shown comparable or even superior agro-morphological characters for yield related traits.•The improved lines have shown resistance to diverse and prevalent Puccinia triticina pathotypes.