Genetic diversity of promising accessions of spring soft wheat of russian and kazakh breeding for resistance to leaf and yellow rust

Abstract

The study was carried out to characterize the resistance to leaf and yellow rust in promising spring common wheat accessions and to assess their diversity by Lr and Yr resistance genes for searching of promising genotypes. The material included 36 new varieties and lines, 23 of them of Russian and 13 of Kazakh breeding. Juvenile resistance to leaf and yellow rust was evaluated in the laboratory using test-clones and populations differing in virulence. Resistance to leaf rust at the seedling stage was characterized by 42 % of the accessions. 20 Lr genes were identified using specific PCR markers. Thatcher isogenic lines with identifiable genes served as positive controls. Highly effective genes Lr24 (3 accessions), LrAgi2 (3), partially effective genes Lr9 (4), Lr19 (6), ineffective genes Lr1 (7), Lr3 (13), Lr10 (4), Lr26 (12) and Lr34 (4), and wheat-rye translocation 1AL.1RS with genes of resistance to leaf, stem and yellow rust were identified in spring accessions. Resistant accessions carried two or more Lr genes. According to phytopathological analysis, no highly resistant samples to all used regional populations of the yellow rust pathogen were found. When using molecular markers, no samples with highly effective genes Yr5, Yr10, Yr15, Yr17, Yr24 were detected. Ineffective Lr9 and Yr18 genes were identified in 30 % and 8 % of the lines, respectively. The analysis indicates success in breeding for resistance to leaf rust and the need for advanced breeding for resistance to yellow rust with the involvement of genetically diverse donors.