Submitted to: Arkansas Agricultural Experiment Station Research Series
Publication Type: Experiment Station
Publication Acceptance Date: 6/17/2005
Publication Date: 8/9/2005
Citation: Wamishe, Y.A., Jia, Y., Singh, P., Cartwright, R.D. 2005. Studies on isolates of Rhizoctonia solani from Arkansas for management of rice sheath. Arkansas Agricultural Experiment Station Research Series 529. p. 142-148. Interpretive Summary:
Technical Abstract: The quantitative nature of the resistance to rice sheath blight caused by Rhizoctonia solani has made screening for resistance difficult. Studying field isolates may facilitate resistance screening. Among 200 Rhizoctonia-like fungi obtained from infected rice and two grass species from 19 counties in Arkansas, 102 isolates were identified as R. solani using ribosomal DNA internal transcribed spacers’ marker. Fourteen isolates were tested for anastomosis grouping and all fitted in AG1-IA. In vitro hyphal growth rate ranged from 1.17 to 1.89 mm/h with no significant difference among most of the isolates. The fastest growing isolates caused longer lesion length on detached rice leaves, rice plants at V-11, and 18-day-old rice seedlings (V4 to V5) than did the slowest growing isolates. The fast growing isolate in the seedling tests showed disease levels not significantly different from the susceptible control, M202 on 71.4% of the cultivars known to be tolerant to sheath blight in the field. The slow growing isolate conferred results relatively consistent with the disease reactions observed in the field for 90.9% of the cultivars. The results indicated the possibility of detecting resistance to sheath blight by combining appropriate evaluation techniques with the pathogen isolates.