Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 6/30/2004
Publication Date: 7/30/2004
Citation: Wamishe, Y.A., Jia, Y., Singh, P., Cartwright, R.D. 2004. Characterization of Rhizoctonia solani isolates from rice in Arkansas. American Phytopathological Society Annual Meeting. Phytopathology. 94(6):107. Interpretive Summary:
Technical Abstract: Rhizoctonia solani causes sheath blight, one of the most serious diseases of rice. Over 200 isolates of Rhizoctonia-like fungi were obtained from infected rice samples in Arkansas, of which, 103 isolates were identified as R. solani using rDNA-ITS marker. The remaining isolates were either R. sativa oryzae or other sclerotia- forming fungi. To determine growth rates of R. solani isolates in vitro the isolates were grown on potato dextrose agar in a completely randomized design at 30 o C with three replications and hyphal growth after 24 + 3 h was recorded. There were significant differences among isolates for hyphal growth rate. Three fast, two intermediate, and three slow growing isolates were selected for a pathogenically test, and all eight produced necrotic lesions on detached rice leaves. The selected isolates produced typical sheath blight symptoms on whole plants when leaves were inoculated with hyphal agar disks (pressed with thumb). Preliminary greenhouse inoculations showed positive correlation of hyphal growth rate with lesion length in most cases. Further characterization of the selected isolates and development of an inoculation technique for screening rice cultivars for resistance are underway and will be reported.