STUDY OF BREAD WHEAT LINES WITH GENETIC MATERIAL OF Triticum SPECIES FOR RESISTANCE TO FUNGAL DISEASES

Abstract

Triticum aestivum L. yield losses caused by phytopathogens can reach 40-80 % in epiphytotic years. Wild and cultivated relatives of common wheat are promising sources of broadening the genetic diversity of resistance loci for modern varieties. For the first time differences in the degree of infection by fungal pathogens of wheat lines obtained from crossing with Triticum dicoccoides, T. dicoccum, T. durum, T. kiharae were shown on the basis of long-term monitoring under conditions of the natural infectious background of Belarus. In our work, we studied the resistance of bread wheat lines with Triticumspecies introgressions to powdery mildew (Blumeria graminis), septoria (Zymoseptoria tritici), and leaf rust (Puccinia triticina) in a natural infectious background. We studied 30 introgression lines obtained in the Institute of genetics and cytology NAS of Belarus from crossing of six varieties of common wheat (Rassvet, Saratovskaya 29, Festivalnaya, Chinese Spring, Belorusskaya 80, Pitic S62) with accessions of tetraploid species T. dicoccoides, T. dicoccum, T. durum (ААВВ, 2n = 28) and with hexaploid synthetic variety T. kiharae (AtAtGGDD, 2n = 42). Twelve of the studied wheat lines were obtained with T. durum contribution, 7 — with T. dicoccoides, 6 – with T. kiharae, 5 — with T. dicoccum. The evaluation of resistance to the diseases was performed in a naturally occurring infectious background on the experimental fields of the Institute of Genetics and Cytology of the NAS of Belarus during 2012, 2014-2016, 2018, 2019 field seasons using Geshele’s scale. We used the extent of flag leaf damage in the milky-wax ripeness phase as an indicator of resistance: 0-5 % — highly resistant plants, 5-10 % — resistant, 10-15 % — medium resistant, 15-25 % — medium susceptible, 25-40 % — susceptible. Statistica 10.0 software package was used for statistics (Kruskal-Wallis test, box-and-whiskers diagram, two-way ANOVA). The extent of flag leaf damage for the susceptible spring bread wheat variety Thatcher accounted 40-60 % by B. graminis and 15-25 % by Z. tritici during studied period. P. triticina, which causes wheat leaf rust, was detected only in 2012 and 2014 in a naturally occurring infectious background of Belarus (the degree of damage of susceptible control was 50 %). ANOVA confirmed the differences in the average degree of damage to wheat plants by fungal pathogens under weather conditions of six field seasons (p < 0,01). The highest sensitivity of wheat lines to powdery mildew and leaf rust was noted in 2014, to septoria blight — in 2012. The weather conditions of these years contributed to the intensive development of diseases (high precipitation, relatively low average daily air temperatures, Selyaninov's hydrothermal coefficient above 1.5). The least favorable conditions for the development of fungal pathogens were recorded in dry 2015 year (hydrothermal coefficient = 0.7). The species of genus Triticum were superior to common wheat varieties in resistance to fungal diseases. It was found that 60.0 % of introgression lines showed a high level of resistance to leaf rust, 56.7 % to septoria, and 36.7 % to powdery mildew. The highest number of highly resistant to powdery mildew and septoria genotypes were noted among the lines created on the base of T. dicoccoides (71.4 % and 85.7 %, respectively). Resistance to leaf rust (80 %) was common among lines with T. dicoccum genetic material. A significant statistical difference in the degree of damage by powdery mildew and septoria was shown between the groups of lines created using the species T. dicoccoides, T. dicoccum, T. durum, T. kiharae, and under different weather conditions. A total of 26.7 % of introgression lines demonstrated resistant to two diseases (lines 11-1, 13-3, 15-7-2, 16-5, 34-1, 34-2, 183/2-2, 184/1-6), 23.3 % — to three infections (lines 29, 8, 15-7-1, 1-3, 2-7, 19, 25-2). These lines are of interest in breeding for fungal disease resistance.