Pyramiding Yr genes via marker-assisted selection to improve stripe rust resistance in wheat cultivars WH711 and PBW343

Abstract In order to develop high yielding wheat genotypes resistant to yellow rust, marker-assisted selection (MAS) was utilized. The hard red spring wheat line Lassik was used as a donor, carrying three genes: high temperature adult plant resistance gene (Yr36), adult plant resistance gene (Yr18) and all stage plant resistance gene (Yr17). These genes were introduced into high yielding, but yellow rust susceptible wheat varieties i.e., WH711 and PBW343, through MABC. Specific markers (WKS1/ASA, csLv34, and URIC-LN2) were used for foreground selection for each of the three genes in BC2F7 and BC2F8 generation. Background selection involved the use of 100 and 101 simple sequence repeat (SSR) markers for the WH711 × Lassik and PBW343 × Lassik crosses, respectively, in their backcross generations. The WH711 × Lassik cross produced nine BC2F8 offspring, whereas PBW343 × Lassik cross produced five offspring with desirable Yr genes and up to 96.48% and 97.50% genetic similarity with the recipient parent, respectively. These lines showed significant resistance to yellow rust under epiphytotic conditions and were selected for field testing due to their high morphological and recurrent parent genome similarities, as well as their positive results for the Yr marker in the foreground. This study demonstrated that marker-assisted back crossing (MABC) can successfully introduce durable genes for yellow rust resistance into popular wheat varieties.