VIEW ARTICLE

Inheritance of Stem and Leaf Rust Resistance in Agent and Agrus Cultivars of Triticum aestivum. F. J. Gough, Plant Pathologist, Plant Science Research Division, ARS, USDA, College Station, Texas 77843; O. G. Merkle, Agronomist, Plant Science Research Division, ARS, USDA, College Station, Texas 77843. Phytopathology 61:1501-1505. Accepted for publication 27 July 1971. DOI: 10.1094/Phyto-61-1501.

Tests of F₃ and selected F₄ families from crosses of Triticum aestivum cultivars, Agent and Agrus with Little Club, indicated that both Agent and Agrus have at least four genes for resistance to culture 111-SS2 (race 111) of Puccinia graminis f. sp. tritici. In Agent, resistance to culture 111-SS2 was inherited independently of resistance to prevalent genotypes of Puccinia recondita f. sp. tritici in the field. But in Agrus, a gene for resistance to culture 111-SS2 was linked with the gene (presumably Lr 19) for resistance to leaf rust on the Agropyron chromosome substituted for wheat chromosome 7D. In F₄ families, infection types conditioned by two genes for resistance to 111-SS2 from Agent and two from Agrus, including the one on the Agropyron chromosome, were most effective at 20 C, moderately effective at 25 C, and ineffective at 30 C. The resistance conditioned by each of the remaining two genes from Agent and two from Agrus changed only slightly, or not at all, under the different incubation temperatures.