Phytosanitary assessment of resistance of wheat varieties and lines bred at the Donskoy Agricultural Research Centre to major leaf diseases
Abstract
The study was conducted in 2021-2023 in Krasnodar Region under artificial infection conditions to screen winter wheat varieties for resistance to brown, yellow, and stem rusts, as well as yellow leaf spot, to identify genotypes with group-specific disease resistance that could be used for immune selection. Plants were inoculated with rust pathogens using a dry method (spraying a mixture of urediniospores and talc at a ratio of 1:100, 5 mg/m2) and with the yellow leaf spot pathogen using a wet method (spraying with an aqueous-conidial suspension, 3-5×103 spores/ml, 70-100 ml/m2). Counts were conducted according to the CIMMYT (International Maize and Wheat Improvement Centre) scale at 10-12-day intervals until the milky-wax ripeness stage. The study involved 30 winter wheat varieties and lines bred by the Donskoy Agricultural Research Centre. Tanya served as the standard for susceptibility to yellow spot, Kaw as the standard for susceptibility to yellow rust, Michigan Amber as the standard for susceptibility to brown rust, and Helios as the standard for susceptibility to stem rust. Fifty percent of the varieties demonstrated stable resistance to yellow rust (R-MR) over three years. In 23% of the varieties, the reaction type varied from R to S depending on the hydrothermal conditions of the year. 53.3% of genotypes were resistant to stem rust, and 43.3% to brown rust. Most varieties (53.3%) were susceptible to yellow leaf spot, while 46.7% were resistant or moderately resistant. Varieties with group resistance were identified. Lines 1908/16, 375/17, and 315/18 are resistant to two types of rust (yellow and stem rust); lines 1908/16 and 370/17 are resistant to stem and leaf rust; and lines 1908/16, 542/15, and 623/16 are resistant to yellow and leaf rust. In the juvenile phase, 23 varieties demonstrated resistance to stem rust, 22 to leaf rust, and 25 genotypes to yellow spot. Six varieties with group resistance are recommended as valuable source material for breeding wheat for immunity.