Inheritance of seedling reaction to stem rust race 15B was studied in the F, and F, generations of two crosses, Frontana × Mida-Kenya 117A and Kenya 58-Newthatch × Frontana, in the greenhouse at high temperatures (85° F.). Seedling reaction of the same F4 bulked lines to stem rust races 11, 17, 36, 38, and 56 and leaf rust races 5 and 15 were also studied. Stem and leaf rust reaction in the field to a collection of races was studied in the F3 generation.
Seedling resistance to stem rust race 15B was conditioned by three independent genes in both the crosses. Seedling reaction to each of the other races of stem and leaf rust appeared to be simply inherited.