Determination of Disease Severity of Rhizoctonia solani Kühn (Telemorph: Thanatephorus cucumeris (Frank) Donk) Isolates from Bean, Sugar Beet and Potato Planting Areas in Konya

This study was carried out to determine the disease severity of Rhizoctonia solani isolates isolated from plant samples collected from bean, sugar beet and potato cultivation areas in Konya in 2020 and the anastomosis groups of the most virulent isolates. A total of 40 R. solani isolates were obtained as a result of the isolations made from 86 plant samples (36 beans, 25 sugar beets and 25 potatoes) showing root rot symptoms in general appearance. The number of R. solani isolates obtained from these plants, respectively; 10 isolates from beans, 15 from potatoes and 15 from sugar beets. Nine of the bean isolates and 14 of the potato and sugar beet isolates were determined as multinucleic. One isolate each isolated from the bean, sugar beet and potato was determined as binucleic. As a result, a total of 37 multinucleate (MN) and 3 binucleate (BN) isolates were obtained from all plants. As a result of pathogenicity tests, 3 R. solani isolates with the highest disease severity for each plant were amplified using ITS1F and ITS4B primers and anastomosis groups were determined. Accordingly, the anastomosis groups of Fa 3.2 (97%), Fa 2.2 (89%) and Fa 1 (86%) in beans were characterized as AG 4HGI. The isolates with the highest disease severity in potatoes (Pa 10, Pa 12.1 and Pa 15.2) were determined as AG 3 group. Disease severity was determined as 50% of Pa 15.2, 44% of Pa 10 and 42% of Pa 12.1. The disease severity of 9 of the isolates obtained from sugar beet was determined as 100%. The anastomosis group of 3 randomly selected isolates from these isolates was characterized as AG 2-2.