Effectiveness of the influence of Sr and Lr genes on the field resistance of wheat to stem and leaf rust

Stem and leaf rust have a tremendous impact on wheat yields. The spread of these diseases can compromise any country’s food security. The Sr and Lr resistance genes, comprising ۶۰ and ۸۰ genes, respectively, are gradually losing their effectiveness due to the emergence of virulent populations of rust pathogens. The paper reports the results of field and molecular studies of resistance to the two types of rust in several varieties and lines of spring soft wheat. It is discovered that the Sr۲, Sr۲۱, Sr۳۲, and Sr۳۵ genes have virtually no effect on resistance to stem rust, as with an average plant disease severity of ۴۲.۲% the four genes prove ineffective. However, the area under the disease progress curve in the presence of Sr۲ is reliably lower by ۳.۲% (p≤۰.۰۱). Regarding the coefficient of infection, susceptibility in the presence of Sr۲۱ or Sr۳۵ is reliably lower by ۳.۵%. The Lr۱۹, Lr۲۴, Lr۲۷, and Lr۳۹ leaf rust genes retain their positive effect on wheat resistance to the disease. The Lr۱۹ and Lr۳۹ genotypes show moderate resistance in ۱۰۰% of the cases. The average coefficient of infection in the presence of both genes amounts to ۶.۵ units, with average plant disease severity equal to ۱۶.۳%. The Lr۳۹ gene reliably reduces the area under the disease progress curve by ۴.۵ units. The obtained findings indicate the need to identify donors of Sr resistance genes for their use in selection. There is also a need to study the influence and prevalence of the Lr۲۴ and Lr۲۷ genes in different varieties and lines of spring soft wheat.

کلیدواژه ها:

Wheat ، Stem and leaf rust ، Sr and Lr genes ، Resistance