Inheritance of Stem Rust Resistance in ‘Webster’ Wheat1

Abstract

Inheritance of seedling resistance to stem rust (Puccinia graminis f. sp. tritici Eriks. & E. Henri.) in ‘Webster’ wheat (Triticum aestivum L.) was studied in testcrosses and in crosses with the ‘Chinese Spring’ monosomics. Studies in Canada and Australia showed that its resistance to several North American and Australian races of stem rust is controlled by the same nearly recessive gene, which is designated Sr30. Analysis of the monosomic crosses indicated that Sr30 is on chromosome 5D.The cultivar ‘Festiguay’, which also carries Sr30, was crossed with a Chinese Spring 5DL ditelocentric line, a 5DL ditelocentric line in which the telesomes carried Lrl, and a euploid marker stock homozygous for Lrl and Pm2. The results of these crosses indicated that Sr30 is on the long arm of chromosome 5D and is probably independent of the centromere, Lrl and Pm2. Pm is presumed to be on the short arm, with the order being Pm2 — the centromere — Lrl — Sr30.