Screening Winter Wheat Genotypes for Resistance Traits against <i>Rhizoctonia cerealis</i> and <i>Rhizoctonia solani</i> Infection

<i>Rhizoctonia cerealis</i> and <i>Rhizoctonia solani</i> are considered to be among the most harmful soil-borne pathogens for crop plants globally. The lack of effective protection and the requirement to minimize the use of chemical pesticides necessitate the need to develop alternative protective methods. One such method is resistance breeding against biotic and abiotic stresses. Here, we present studies on the presence of resistance traits in winter wheat genotypes that evaluate the plants’ resistance to the above two pathogens, in both field and laboratory environments. In the field environment, the incidence and severity of sharp eyespot were studied using 132 winter wheat cultivars, where random samples at the BBCH 75–77 were collected for analysis. The degree of the intensity of sharp eyespot was determined, applying the 0–4° scale. The susceptibility of the 132 cultivars of winter wheat to <i>R. cerealis</i> (AG-D subgroup I) and <i>R. solani</i> (AG-5) was also studied under laboratory conditions. In the laboratory, test pieces of potato dextrose agar colonized by the test isolates were placed onto filter paper soaked with distilled water and then placed into Petri dish. Infection on the roots, coleoptiles and leaves was then assessed after 15 days for <i>R. cerealis</i> and after 10 days for <i>R. solani</i>. None of the tested winter wheat genotypes were found to be asymptomatic to the pathogens. A moderate susceptibility was observed for such genotypes as Anthus, Baryton, Bellenus, Borderland Benatka, Blonde, Cubus, Estero, and Flairway. However, the classification of those associated with moderate susceptibility in laboratory tests resulted in severe symptoms in field tests. Hence, field experiments provide the most reliable measurements to determine the effects of pathogens on the plants.