Identification of Stripe Rust Resistance Genes in Wheat Genotypes Used to Differentiate North American Races ofPuccinia striiformis

Stripe rust, caused by Puccinia striiormis Westend f. sp. tritici, is one of the most important foliar diseases of wheat ( Triticum aestivum L.) worldwide. Stripe rust resistance genes Yr27, Yr31, YrSp, YrV23, and YrCN19 on chromosome 2BS confer resistance to some or all Chinese P. striiormis f. sp. tritici races CYR31, CYR32, SY11-4, and SY11-14 in the greenhouse. To screen microsatellite (SSR) markers linked with YrCN19, F1, F2, and F3 populations derived from cross Ch377/CN19 were screened with race CYR32 and 35 SSR primer pairs. Linkage analysis indicated that the single dominant gene YrCN19 in cultivar CN19 was linked with SSR markers Xgwm410, Xgwm374, Xwmc477, and Xgwm382 on chromosome 2BS with genetic distances of 0.3, 7.9, 12.3, and 21.2 cM, respectively. Crosses of CN19 with wheat lines carrying other genes on chromosome 2B showed that all were located at different loci. YrCN19 is thus different from the other reported Yr genes in chromosomal location and resistance response and was therefore named Yr41. Prospects and strategies of using Yr41 and other Yr genes in wheat improvement for stripe rust resistance are discussed.

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Molecular Marker Based Design for Breeding Wheat Lines with Multiple Resistance and Superior Quality

Plant Disease ◽

10.1094/pdis-02-20-0420-re ◽

2020 ◽

Vol 104 (10) ◽

pp. 2658-2664

Author(s):

Tao Liu ◽

George Fedak ◽

Lianquan Zhang ◽

Rangrang Zhou ◽

Dawn Chi ◽

...

Keyword(s):

Stripe Rust ◽

Resistance Genes ◽

High Resistance ◽

Stem Rust ◽

Rust Resistance ◽

Stripe Rust Resistance ◽

Multiple Resistance ◽

Wheat Stem Rust ◽

Wheat Production ◽

Rust Resistance Genes

There has not been a major wheat stem rust epidemic worldwide since the 1970s, but the emergence of race TTKSK of Puccinia graminis f. sp. tritici in 1998 presented a great threat to the world wheat production. Single disease-resistance genes are usually effective for only several years before the pathogen changes genetically to overcome the resistance. Stripe rust caused by Puccinia striiformis f. sp. tritici (Pst) is one of the most common and persistent wheat diseases worldwide. The development of varieties with multiple resistance is the most economical and effective strategy for preventing stripe rust and stem rust, the two main rust diseases constraining wheat production. Plateau 448 has been widely used in the spring wheat growing region in northwest China, but it has become susceptible to stripe rust and is susceptible to TTKSK. To produce more durable resistance to race TTKSK as well as to stripe rust, four stem rust resistance genes (Sr33, Sr36, Sr-Cad, and Sr43) and three stripe rust resistance genes (Yr5, Yr18, and Yr26) were simultaneously introgressed into Plateau 448 to improve its stem rust (Ug99) and stripe rust resistance using a marker-assisted backcrossing strategy combined with phenotypic selection. We obtained 131 BC1F5 lines that pyramided two to four Ug99 resistance genes and one to two Pst resistance genes simultaneously. Thirteen of these lines were selected for their TTKSK resistance, and all of them exhibited near immunity or high resistance to TTKSK. Among the 131 pyramided lines, 95 showed high resistance to mixed Pst races. Nine lines exhibited not only high resistance to TTKSK and Pst but also better agronomic traits and high-molecular-weight glutenin subunit compositions than Plateau 448.

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