Submitted to: Rice Technical Working Group Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: February 29, 2004
Publication Date: February 1, 2005
Citation: Singh, P., Jia, Y., Eizenga, G.C., Lee, F. 2005. Development of a detached leaf inoculation method for rapid evaluation of rice cultivar response to sheath blight pathogen. Rice Technical Working Group Meeting Proceedings. Abstract p. 117. Technical Abstract: Sheath blight caused by Rhizoctonia solani Kühn, is one of the most destructive fungal diseases of rice worldwide. To date no complete genetic resistance to the disease is available among cultivated rice. A better understanding of mechanisms of host defense responses to different field isolates would enhance development of sheath blight-resistant cultivars. However, a reliable and reproducible inoculation technique in the laboratory is not available to accurately determine virulence of isolates. In the present study, differential rice cultivar responses to R. solani were detected by an in vitro detached leaf inoculation method using 14 field isolates from Arkansas, the major rice-growing state of the United States. The second youngest leaves of greenhouse-grown rice plants were detached and inoculated with potato dextrose agar plugs containing mycelia and incubated in petri dishes. The total length of disease lesion was measured. Six rice cultivars, Cypress, Jasmine 85, Labelle, Lemont, Katy and M-202 were used to evaluate their responses. Jasmine 85 was significantly more resistant to R. solani when compared to the other cultivars tested. Katy and Lemont were moderately tolerant, whereas Cypress, M202 and Labelle were susceptible. The minor resistance responses to R. solani and minor pathogenecity differences of different isolates were determined by this method. Successful application of this assay should accelerate the identification and incorporation of minor sheath blight resistance genes into improved rice cultivars.