Genetics of adult plant resistance to stripe rust in ten spring bread wheats

Abstract

Nine Mexican spring bread wheat (Triticum aestivum L.) cultivars derived from CIMMYT germplasm and the U.S. spring wheat cultivar Wheaton were susceptible to the Mexican Puccinia striiformis pathotype 14E14 in seedling growth stage, but displayed different levels of adult plant resistances to the same pathotype when tested in the field. One hundred and eighteen random F 2 plant derived F3 and F5 lines from the crosses of these ten adult plant resistant wheats and susceptible cultivar Jupateco 73S were evaluated in the field . The moderate adult plant resistance of Penjamo 62, Lerma Rojo 64, Nacozari 76, Tesia 79, and Wheaton was under monogenic genetic control and was attributed to the adult plant stripe rust resistance gene Yr18 . The moderate resistances of Cleopatra 74, Zaragoza 75, and Apache 81 were also monogenic, but gene Yr18 was absent .Pavon 76 carried two partially effective additive genes ; and the adult plant resistance of Tonichi 81 was based on additive interaction involving Yr18 and two additional partially effective genes . Tonichi 81 does not carry any seedling resistance gene, however, the adult plant resistance is highly effective worldwide . This resistance, designated as the Yr18 complex, is of a durable nature . The partial adult plant resistance of Pavon 76 has also remained durable in Mexico and other countries where it is grown .

Breeding Disease-Resistant Wheats for Tropical Highlands and Lowlands

“…The Yr18 gene confers adult plant resistance and has proved to be durable. A goal of the program is to accumulate additional minor additive genes for adult plant resistance to stripe rust, which we believe will also be durable (42). Genetic and epidemiological studies in Mexico and Ecuador indicate that such genes, fairly common in CIMMYT germplasm, originate mostly from the cultivars Anza and Pavon or their derivatives.…”

Stripe rust reaction of 28 Canadian wheat cultivars1

“…'Glenlea' has the leaf rust resistance gene Lr34 (Dyck et al 1985), which is completely linked to the stripe rust resistance gene Yr18 (McIntosh 1992;Singh 1992a). The gene Yr18 provides racenonspecific resistance (also referred to as partial or slow rusting) in the adult plant stage and has been shown to have effective and durable resistance after use throughout the world over many years (Ma and Singh 1996;Singh and Rajaram 1994). Cultivars with Yr18 alone can become moderately infected with stripe rust, particularly toward maturity, and suffer some yield losses.…”

Genetic analysis of adult plant leaf rust resistance in three bread wheat (Triticum aestivum L.) cultivars

“…occurs through out the wheat growing regions of the world and it is so important in India that selection for leaf rust resistance has become an integral part of the strategic Indian wheat breeding programme. Rust resistance is mainly conferred by race specific hypersensitive seedling resistance genes and the genes that express best at adult plant stage such as hypersensitive as well as non-hypersensitive adult plant resistance genes (Dyck et al 1966;Kerber and Dyck, 1990;Singh and Rajaram, 1994;Saini et al, 2002). Among the released varieties of bread wheat in India, only a few posses effective seedling resistance genes that imparted complete resistance to all known pathotypes of leaf rust in India .…”