Resistance of winter wheat varieties to pathogens in the conditions of the steppe zone of the Kabardino-Balkar Republic

Abstract

Results of the studies (2019-2021) of species composition of the disease complex under conditions of steppe arid zone of Kabardino-Balkaria are presented, which have scientific and practical significance for determining the degree of resistance of winter wheat varieties under study to phytopathogens. Phytosanitary monitoring was conducted on 10 released varieties of winter wheat. The following diseases and their pathogens were identified: pyrenophorosis (Pyrenophora tritici-repentis (Died.)), septoriosis (Septoria tritici Rob. et Desm.), powdery mildew (Erysiphe graminis DC. f. sp.tritici Em. Marchal), brown and yellow rusts (Puccinia recondite Rob. et Desm.f.sp.tritici; P. striiformis West), head smut (Tilletia tritici (Bjerk) Wint), fusarium blight (Fusarium graminearum Schw.) and glume mold (Alternaria tenuis Ness et Fr.; Cladosporium herbarum Fris.). According to the results of the analysis of digital lesion data, no potentially tolerant winter wheat varieties to the pathogens of these diseases were identified due to the aggressiveness of the existing strains of P. tritici-repentis (Died.), A. tenuis Ness et Fr., C. herbarum Fris. All tested varieties of winter wheat are resistant to the causative agents of septoriosis, rusts, head smut, but are susceptible to the causative agents of pyrenophorosis and glume mold. The average weighted percentage of leaf infestation with pyrenophorosis ranged from 20.5 to 59.6%. The most resistant to this disease were the varieties Memory of Shatilov and Cheget, and the susceptible varieties were Laureate, Korona, Graf, Moskvich and Tanya, in which the weighted average percentage of the disease was above 46.7%. The malignant disease glume mold, which manifests itself in the period of milky-wax ripeness of grain, was studied. The average weighted percentage of lesions from this disease was higher than 50% in varieties Alievich, Taulan, Tanya, Moskvich, Graf. The maximum percentage of grain infestation in the variety Cheget was 60.2%. Fusarium head blight was noted to be depressed as dry and hot weather set in during the period of grain formation. Rainy weather is a favorable condition for the development of this disease.