Expression of Two Wheat Leaf Rust Resistance Gene Combinations InvolvingLr34

The effects of temperature and different isolates of Puccinia recondita f. sp. tritici on the expression of leaf rust resistance genes Lr33, LrT3, and Lr34 and gene combinations Lr33 + Lr34 and LrT3 + Lr34, all in Thatcher wheat background, were studied in seedling and adult plants. In reaction to isolates 3SA122, 3SA132, and 3SA135, the expression of low infection type by the individual genes and the two combinations in the seedling stage was best expressed at 7 C. These low infection types were largely negated at 15, 20, and 25 C. All three individual host genes, as well as the two combinations, expressed race-specific characteristics (.)