Characteristics of brown leaf rust virulence on winter durum wheat varieties in the Rostov region

Abstract

The purpose of this work was to characterize the virulence of the P. triticina population on durum wheat in the Rostov region and to assess the leaf rust resistance in the promising winter durum wheat varieties selected by the “ARC “Donskoy”. The joint studies were conducted in the laboratories of FSBSI “Agricultural Research Center “Donskoy” and FSBSI All-Russian Research Institute of Plant Protection. The samples of pathogen populations were collected on durum wheat varieties “Donchanka”, “Lazurit”, “Donskoy Yantar” and “Prikumskaya 142” and propagated on the susceptible soft and durum wheat varieties in the laboratory. There were studied 64 mono pustular isolate. The studied isolates were avirulent to the Thatcher lines with the genes Lr2a, Lr2b, Lr2c, Lr9, Lr15, Lr16, Lr19, Lr20 and Lr24 and were virulent to Lr3a, Lr3bg, Lr3ka, Lr10, Lr11, Lr14a, Lr14b, Lr18, Lr26, Lr30 и Lr44. All samples of populations propagated on durum wheat were characterized by avirulence to the TcLr17 line, and those propagated on soft wheat were mainly characterized by virulence. In general, the conducted analysis revealed significant differences in the composition of pathogen populations on durum and soft wheat. The isolates from durum wheat had a significantly smaller number of virulence alleles, compared with the isolates from soft wheat. In addition, there were observed differences in the latent period of isolates developing on soft and durum wheat (it was less on soft wheat). In 2015-2017 there were studied 17 varieties of winter durum wheat in the laboratory and field conditions. The variety “Arena” and line KS-586/13 were characterized with a high level of resistance in the field (0-5% of infestation) and laboratory conditions (score 0-2). There were identified the weakly susceptible varieties “Yubilyarka”, “Lazurit”, “Kurant”, “Aksinit”. A moderate infestation throughout all years of study was established on the varieties “Yakhont”, “Terra”, “Diona”, “Kristella”, “Agat Donskoy” (10-20%). The variety “Donchanka” (50-60% in 2015-2016; 40-50% in 2017) belongs to the susceptible group. The varieties “Donskoy Yantar”, “Gelios”, “Yantarina” and “Amazonka” were of medium susceptibility (20-40%).