Rhizoctonia Species and Anastomosis Groups from Corn Kernels in Turkey

In 1996, 165 samples of corn (Zea mays L.) kernels to be tested for seed-borne fungi were obtained from five provinces throughout the major corn-producing areas in the eastern Black Sea Region of Turkey: Artvin (41 samples), Rize (28 samples), Trabzon (32 samples), Giresun (30 samples), and Ordu (34 samples). A subsample of kernels (≈100 g each) from each sample was surface-disinfected in 3.5% NaOCl for 1 min. Kernels were washed in three changes of sterile water, and 100 kernels per subsample were placed in petri plates (5 kernels per plate) containing potato dextrose agar. After 5 to 7 days of incubation at 25°C in the dark, cultures were examined at 40× magnification for mycelia of Rhizoctonia spp. From 16,500 kernels examined, 40 isolates of Rhizoctonia spp. were recovered and characterized according to colony morphology and hyphal anastomosis using known tester isolates of Rhizoctonia spp. (1). Of these isolates, 10 were identified as R. solani, 18 as R. zeae, and 12 as binucleate Rhizoctonia sp. R. solani isolates were assigned to three anastomosis groups (AG): AG-4 (two isolates), AG-5 (two isolates), and AG-10 (six isolates). Binucleate Rhizoctonia sp. isolates were all assigned to AG-Ba. R. solani AG-4 and -5 and binucleate Rhizoctonia AG-Ba isolates were obtained from Artvin; R. solani AG-10 isolates were obtained from Ordu; and R. zeae isolates were obtained from Trabzon and Giresun. This is the first reported observation of Rhizoctonia spp. and anastomosis groups on corn kernels from Turkey. Reference: (1) B. Sneh et al. 1991. Identification of Rhizoctonia Species. The American Phytopathological Society, St. Paul, MN.