EVALUATION OF WINTER WHEAT VARIETIES TO RESISTANCE TO BROWN RUST IN THE CONDITIONS OF THE FOOTHILL ZONE OF THE CENTRAL CAUCASUS

Abstract

The article presents the results of immunological studies of varieties of winter wheat. We considered the issues of resistance to brown rust, intrapopulation diversity of Puccinia tritici f. sp. tritici Eriks, and methods of evaluation and selection of initial selection material with a wide genetic basis of resistance to the pathogen. The research was carried out at the field of the FSBRI of North-Caucasian research institute of Hill and Foot-hill Agriculture of Russian national research centre RAS (RSO-Alania), located in the foothill zone of the Central Caucasus in 2019-2021. Twenty-five samples of soft winter wheat (Triticum aestivum L) from the collection of Vavilov Institute of Plant Industry and forty-seven isogenic lines (Thatcher) with Lr. genes were used as objects of research. Evaluation for non-specific resistance was carried out according to five criteria: the type of reaction (in points) and the degree of damage (in percentage points), the increase rate of the area under the curve (AUDPC), the stability and plant productivity indexes (SI and PPI, respectively). Studies of the racial composition of the pathogen populations were carried out using a universal set of wheat lines and varieties of differentiators with known resistance genes. We revealed that the effective genes of resistance to the local brown rust population included Lr9, Lr19, Lr24, Lr25, Lr30, Lr32, Lr34, Lr36, Lr39, Lr41, Lr42, Lr45, Lr47, Lr51, Lr53, Lr67. When analysing the phenotypic composition, six phenotypic groups were identified: MHTT, PGTT, RHTT, NHKP, ТQТР, QHKP. Phenotypes of the T-group, which are virulent to Lr9, Lr16, with an occurrence frequency of 40.0%, are characteristic of all grain-sowing regions of Russia and the world. They are dominant in the studied population of P. triticina. Phenotypes RHTT, QHKP, MHTT, which are avirulent to the Lr9, Lr24 genes, occur in the population with a frequency of 13.3, 3.3, 10.0%, respectively. The occurrence frequency of the phenotypic group PGTT and NHKP with an avirulence to the genes, Lr9, Lr24, Lr26, Lr2a, Lr3, is 33.3%. Genetic diversity according to Shannon's diversity index within the population is high, H = 2.51. According to the screening results, we identified winter wheat varieties, which are resistant to brown rust. They are ranked as follows: resistant – 11 samples, medium–resistant – 9, susceptible – 5. The following varieties of soft winter wheat of foreign selection – Dorota (France), Genoveva (Slovakia), Areal (Ukraine), Eltan (the USA), Verita (Slovakia), Muza (Poland), Alauda (Germany), Fenezja (Poland), Vatazbok (Ukraine), and Russian varieties Prima and Omskaya 5 – are proposed to use in breeding work as sources of non-specific resistance to Puccinia triticina. The selected sources of resistance are recommended for inclusion in wheat breeding programs for resistance to brown rust.

Keywords

• winter wheat
• brown rust
• sources of resistance
• population
• breeding