EFFICIENCY OF WHEAT RESISTANCE GENES TO BROWN RUST IN THE ROSTOV REGION

The purpose of the study is to monitor the efficiency of wheat resistance genes to the causative agent of brown rust (Lr-genes) in the Rostov region. Brown rust is the most widely spread and harmful wheat disease which annually occurs on the crops from poor development to epiphytoties. Soft wheat varieties grown in the region are variously resistant to this pathogen. To breed the brown rust resistant varieties, it is necessary to expand genetic basis of the varieties grown in the region and to attract new Lr-gene donors. Due to it the study of the monitoring of pathogen populations and the effectiveness of the known Lr-genes to the Rostov pathogen population is of great importance nowadays. For this purpose, the isogenic lines of the variety “Thatcher” with Lr-genes are annually studied in the Agricultural Research Center “Donskoy” on the infectious plots and in the laboratory conditions in the sprouting phase. This paper presents the monitoring results of the populations in the period of 2015–2017. The variety “Tarasovskaya 29” served as a universally susceptible variety. In this work, there were used generally accepted methods of working with brown rust pathogen in the “sprouting” and “grown-up” periods. It has been established that in the “grown-up” period, 10 lines showed a high resistance to the disease (0% of damage), 6 lines did not exceed 10%, and 11 lines had moderate susceptibility (30–40% of damage) to the pathogen. The remaining lines were susceptible to the pathogen population. The virulence analysis of the plants in the sprouting phase showed high efficiency of the Lr9, Lr19, Lr24, Lr28, Lr29, Lr41, Lr42, Lr45, Lr47, Lr50, Lr51, and Lr53 genes. The phenotypic (racial) composition of the Rostov fungus population was identified using 20 TcLr-lines. In 2016–2017 in the Rostov population there were identified 6 phenotypes. RNTH, RNTKG and TNTTH were common phenotypes in both years of research. The identified effective Lr-genes can be used to develop resistant wheat varieties, taking into account the plants’ ontogenesis.