Inheritance of Leaf Rust and Stripe Rust Resistance in the Brazilian Wheat Cultivar 'Toropi'.

Leaf rust (Puccinia triticina) and stripe rust (P. striiformis f. tritici) affect wheat production worldwide. Brazilian 'Toropi' wheat has demonstrated durable leaf rust resistance in South America since its release in 1965. It was previously found to have up to two adult plant leaf rust resistance genes. The leaf and stripe rust resistance of Toropi were studied by analyzing a doubled-haploid population made by crossing with susceptible 'Thatcher'. Toropi expressed good resistance to leaf rust in Canada, Brazil, and New Zealand. Based on field and greenhouse testing, the leaf rust resistance of Toropi is conferred by two race-nonspecific complementary adult plant genes and a race-specific adult plant gene. The stripe rust resistance of Toropi analyzed in New Zealand and in Canada is based on up to two resistance genes. Toropi should provide an important contribution to rust resistance because it expressed good leaf rust and stripe rust resistance in different parts of the world.