Inheritance of leaf rust and stripe rust resistance genes transferred into bread wheat from diverse progenitor and non-progenitor wheat relatives Abstract uri icon

abstract

  • Wheat is a staple food crop for 40% of the world’s population. But in recent years, the global production of wheat and its quality have been diminished due to abiotic and biotic stresses. The three rust diseases of wheat are prominent biotic stresses as these expected to cause loses as high as 10-100% by stem rust (Puccinia graminis), 10-70% by leaf rust (P. triticina) and 20-100% by stripe rust (P. striiformis). In a race to exploit the resistance gene for providing effective resistance, the cultivated germplasm is left with almost no diversity due to monoculture of few cultivars at global level. However wild species of wheat still has that abundance of novel alleles that can act as perpetual source of resistance for multitude years. About 1,500 accessions of wild wheat from different progenitor and non-progenitor species are being maintained at Punjab Agricultural University, Ludhiana. In this study resistant Introgression lines (ILs) developed from three progenitor (Aegilops speltoides, Triticum. dicoccoides, T. monococcum) and four non-progenitor species (Ae. kotschyi, Ae. umbellulata, Ae. ovata, Ae. peregrina) for the leaf rust (LR) and stripe rust (YR) resistance have been explored by transferring them to cultivated wheat. To examine the genetics of these transferred resistances, the mapping populations were generated by crossing the ILs with LR and YR susceptible cultivars. Furthermore, the F2/3/4/5 mapping populations were screened against Indian predominant pathotypes of LR and YR at seedling and adult plant stage and genetic ratios were calculated. Inheritance studies of F2 mapping populations developed from Ae. umbellulata, Ae. kotschyi, Ae. ovata, and Ae. variabilis segregated for a single dominant LR and YR resistance, as indicated by the theoretically expected ratio of 3 Resistant (R) : 1 Susceptible (S) plants. Similarly mapping population derived from Ae. peregrina IL, showed complementary gene interaction (9R:7S) for LR and a single dominant gene segregation for YR resistance. The F4:5 mapping populations from progenitor wild species T. monococcum, Ae. speltoides and T. dicoccoides indicated a single dominant LR all stage resistance gene effective in these ILs. Mapping and utilization of LR and YR resistance genes derived from these seven wild species will help to widen the rust resistance base of wheat crop.

publication date

  • September 2022