Indian Phytopathology

Not AvailableA total of 263 accessions representing a cross section of the recently developed common wheat genotypes in India showing flag leaf tip necrosis (LTN) were characterized for the LTN-associated pleiotropic adult plant resistance (PAPR) genes, Lr34/Yr18/Sr57 (Lr34 +), Lr46/Yr29/Sr58 (Lr46 +), and Lr67/Yr46/Sr55 (Lr67 +) using closely linked molecular markers. They were evaluated for seedling resistance to important rust pathotypes, and for multi-environmental field resistance to the three rusts. About 79% of the genotypes carried the PAPR genes singly or in different two genes? combinations. The genes Lr67 + and Lr34 + occurred much more frequently than Lr46 + . While field resistance to leaf and stem rusts was usually associated with seedling resistance, that to stripe rust was based largely on the adult-plant resistance. Intermediate to low levels of resistance were provided by the three PAPR genes individually, and no clear-cut additive effects on rust resistance were apparent among the various gene combinations. Considerable diversity was observed for resistance to all the three wheat rusts. Additional genes for resistance were indicated in many genotypes which need to be characterized. The identified diverse sources of multiple rust resistance can be utilized in breeding for rust resistance along with desired agronomic traits