Characteristics of the gene pool of spring wheat (Triticum aestivum L.) for resistance to loose smut in the forest-steppe of Western Siberia

Abstract

Among the many diseases of spring wheat caused by pathogenic fungi, loose smut Ustilago tritici (Pers.) Jens. remains to be a dangerous disease with a wide range of distribution. In fields where there is no control over the emergence and spread of the disease, the yield reduction can be up to 10 %, and in the case of highly susceptible varieties, up to 40–50 %. Taking into account the increasing cost of seed protectants and their environmental damage, the cultivation of varieties resistant to loose smut is still the most affordable way to protect plants, reducing the pesticide load on agrocenoses. The crucial point in breeding for resistance is the use of resistant varieties as parental forms. The aim of our research was to isolate samples of spring wheat that are immune to loose smut against the background of artificial infection of plants with a population specific to the West Siberian region. The article presents the results of long-lasting studies of 350 genotypes of spring wheat of different ecological and geographical origin for resistance to disease. Physiological specialization of races was carried out on the basis of a differentiating set consisting of six varieties of soft wheat and three varieties of durum spring wheat. The obtained results in combination with literature data reveal changes in the racial composition of the pathogen population over the past 30–35 years. Varieties of foreign and domestic selection resistant to the West Siberian population of loose smut have been identified. Based on the analysis of pedigree samples, highly and practically resistant to loose smut, we concluded that in breeding for immunity to U. tritici, the same sources of resistance genes are most often used. Among the gene pool of spring wheat of foreign selection, the largest number of genotypes resistant to loose smut is assigned to the countries of the North American geographical zone (USA, Canada, Mexico). These are largely samples containing Ut1 genes, genes from spring wheat ‘Thatcher’ and its sister line ‘DC II-21-44’. Resistance genes in Russian wheat varieties can be traced from cultivars Beloturka, Poltavka, Selivanovsky Hare (using Saratovskaya 29 and its derivatives), and genes from wheatgrass lines AGIS 1 and Grecum 114.