Submitted to: Proceedings Southern Region American Phytopathology Society
Publication Type: Abstract Only
Publication Acceptance Date: November 17, 2010
Publication Date: February 6, 2011
Citation: Zhou, X.G., Mcclung, A.M. 2011. Disease severity and yield potential of rice cultivars in organic production systems. Proceedings Southern Region American Phytopathology Society. 101:S270. Technical Abstract: The market demand for organically produced rice has driven the steady increase in the acreage of organic rice in the U. S., with Texas and California being the largest states. Yield potential and disease management are among the principal challenges associated with organic rice production. We evaluated 27 rice cultivars and breeding lines to determine their responses to diseases and yield potential under organic production conditions in Texas over two years. Narrow brown leaf spot (Cercospora janseana) was a constant yield-limiting disease and was severe on Jazzman, Presidio, Sierra, and Cocodrie and its derived lines in both tilled, water seeded and no-tilled, dry seeded production systems. In the no-tilled production system with significant amount of previous cover crop residue, straighthead was another significant disease, occurring in all the cultivars and lines, with Cocodrie and its derived lines having the most severe symptoms. Brown spot (Cochliobolus miyabeanus) was also commonly present regardless of the production system used whereas sheath blight (Rhizoctonia solani), bacterial panicle blight (Burkholderia glumae), and leaf smut (Entyloma oryzae) were minor in severity on the majority of the cultivars and lines. The cultivars Tesanai 2, GP2, Rondo, PI312777, and PI338046 had the lowest levels of all these diseases and had yields that ranked among the highest. Tesanai 2 outperformed all other cultivars and lines in yield potential. These results can help identify the rice cultivars that perform best in managing diseases and increasing rice yield under organic management.