Introgression and genetic mapping of leaf rust and stripe rust resistance in Aegilops triuncialis

Abstract

The growing and cultivating resistant wheat crop varieties is important to meet the demands of the growing population and minimizing the yield losses due to foliar diseases. More important is the identification of novel resistance sources and transfer of resistance in ready to use form. In the current study, leaf rust (LR) and stripe rust (YR) resistant tetraploid nonprogenitors of wheat Aegilops triuncialis (UtUtCtCt) acc pau 3462 was crossed and backcrossed susceptible cultivar WL711(NN) by inducing homeologous pairing using CS ph1. Recurrent parent type plants were selected in subsequent generation with resistance to LR and YR and BC2F7 introgression line (2n=42) named ILtri have been developed. To understand the nature and inheritance of LR and YR resistance genes and to map their genomic location, F2 and F2:3 mapping populations were developed by crossing ILtri with WL711(NN). In F2 and F2:3, the seedlings and adult plants segregated into 3R:1S and 1HR:2Seg:1HS ratios, respectively for both LR and YR, indicating inheritance of single dominant all stage resistance gene working against both the rusts. These genes were temporary designated as Lrtri and Yrtri and were inherited independently.Molecular mapping of 614 SSR markers mapped the Lrtri at a distance of 11.2 cM from SSR marker Xwmc606.