Wheat Resistance to Stripe and Leaf Rusts Conferred by Introgression of Slow Rusting Resistance Genes

Abstract

Twenty-three wheat genotypes were evaluated for stripe and leaf rusts, caused by Puccinia striiformis f. sp. tritici and Puccinia triticina f. sp. tritici, respectively, at seedling and adult stages under greenhouses and field conditions during the 2019/2020 and 2020/2021 growing seasons. The race analysis revealed that 250E254 and TTTST races for stripe and leaf rusts, respectively were the most aggressive. Eight wheat genotypes (Misr-3, Misr-4, Giza-171, Gemmeiza-12, Lr34/Yr18, Lr37/Yr17, Lr46/Yr29, and Lr67/Yr46) were resistant to stripe and leaf rusts at seedling and adult stages. This result was confirmed by identifying the resistance genes: Lr34/Yr18, Lr37/Yr17, Lr46/Yr29, and Lr67/Yr46 in these genotypes showing their role in the resistance. Sids-14 and Shandweel-1 genotypes were susceptible to stripe and leaf rusts. Twelve crosses between the two new susceptible wheat genotypes and the three slow rusting genes (Lr34/Yr18, Lr37/Yr17, and Lr67/Yr46) were conducted. The frequency distribution of disease severity (%) in F2 plants of the twelve crosses was ranged from 0 to 80%. Resistant F2 plants were selected and the resistance genes were detected. This study is important for introducing new active resistance genes into the breeding programs and preserving diversity among recently released wheat genotypes.

Mechanism of Wheat Leaf Rust Control Using Chitosan Nanoparticles and Salicylic Acid

“…Therefore, in the case of planting a highly susceptible variety, chemical resistance must be used to reduce the resulting losses [ 37 ]. This can also be achieved by developing rust resistant genotypes or by successful varietal manipulation of the available genotypes throughout the country to avoid heavy infection to the susceptible genotypes [ 1 ]. The emergence of new races capable of breaking the resistance in the new varieties, such as the emergence of the TTTST race on Shandweel-1, Sakha-94 and Sakha-95 varieties was reported [ 5 ].…”

“…tritici , and P. triticina f.sp. tritici , respectively, may attack wheat throughout the season [ 1 ]. Leaf rust is Egypt’s most frequent disease of wheat.…”

“…Wheat leaf rust disease has yet to be cured; therefore, the first line of defense in the resistance is the cultivation of resistant varieties. In recent years, the cultivation of more than one resistant variety was utilized [ 1 ]. The emergence of new disease races and the breaking of resistance in the varieties increase disease losses [ 5 ].…”

Genetic Characterization of Puccinia striiformis f. sp. tritici Populations from Different Wheat Cultivars Using Simple Sequence Repeats

“…In agricultural production systems, different disease management practices are used to control wheat stripe rust, including fungicides and genetic resistance. As an alternative to the use of fungicides, developing and growing resistant cultivars is considered a more economical and environmentally sound approach for the control of stripe rust [ 2 , 6 ]. Hence, planting resistant cultivars is recommended.…”

Detection and Introgression of Lr46 Gene-Conferring Partial Resistance to Leaf Rust (Puccinia triticina) in Wheat

“…Wheat breeders have generally relied on leaf rust genes for hypersensitivity tolerance (HR) to reduce the accumulation of epidemics and is easy to administer in breeding programmes. As a result, due to appearance of new virulent races that may breakdown the resistance of wheat cultivars, it must be knowing the resistance genes in parental germplasm to improve the effectiveness of developing new resistant germplasm (Omara et al, 2021). The number of leaf rust resistance genes (Lrs) has increased to over 74, and the majority of them are mapped on various chromosomes (McIntosh et al, 2013).…”