ARS | Publication request: Rice blast disease in Texas

Submitted to: Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: August 5, 2010
Publication Date: August 12, 2010
Repository URL: http://www.ars.usda.gov/SP2UserFiles/ad_hoc/622505005thInternationalRiceBlastConference/program-for-web-0809.pdf
Citation: Zhou, X.G., Mcclung, A.M., Jia, Y. 2010. Rice blast disease in Texas. Symposium Proceedings. IV-P-65.

Technical Abstract: Rice is an important agricultural commodity in Texas, with an economic impact of more than $1 billion annually. Rice blast, caused by Magnaporthe oryzae, is one of the most devastating diseases in rice. Texas Rice Belt provides a warm, humid climate favorable for the infection and reproduction of M. oryzae. Current agronomical practices including dense stands and excessive use of nitrogen fertilizer increase the likeliness of the epidemic of the disease. Blast poses a constant threat to Texas rice production. The objectives of this study are to update the occurrence of rice blast and the research on control of the disease in Texas. Rice blast has historically been a major disease in Texas. Prior to 1950’s, blast did not cause substantial yield and quality loss of rice. However, with the increased usage of nitrogen fertilizer following the World War II, blast became a major disease in rice. Increase in severity of the disease also coincided with the change in virulence of M. oryzae over time. The dominant races of M. oryzae in Texas have changed to IC-17, IB-19 and IE-1 from IG-1 during the 1960’s through 1970’s. Continued efforts in improving varietal disease resistance using major resistance genes including Pi-b, Pi-kh(m)/s and Pi-ta, and employing proper agronomical measures such as land and water management have contributed to the successful control of this disease. Currently, blast is not a widespread problem in Texas; severe blast has not been observed for many years. However, blast is highly adaptive to the host and potential race shifts could cause severe loss to the crop. The development of blast-resistant varieties and lines adapted to Texas and other southern states has been a major focus of plant pathology program in collaboration with rice geneticists and breeders at Beaumont, TX for many decades. An upland blast disease nursery has been established at the Beaumont Center since 1964. Approximately 200 varieties and lines were screened for resistance to blast each year. DNA marker-assisted selection has been used for incorporating major and minor blast resistance genes. As a result, many blast-resistant varieties and lines such as Madison (Pi-ta), Saber (Pi-b), and Jasmine 85 (resistant QTLs) have been released. In addition, a field research trial is under establishment at the Beaumont Center to allow the conduction of fungicide efficacy evaluation for control of blast under the Texas environment. References: 1. Tabien, R.E., Li, Z., Paterson, A.H., Marchetti, M.A., Stansel, J.W., and Pinson, S.R.M. 2002. Mapping QTLs for field resistance to the rice blast pathogen and evaluating their individual and combined utility in improved varieties. Theor. Appl. Genet. 105:313–324. 2. McClung, A. M., Marchetti, M.A., Webb, B.D., and Bollich, C.N. 1999. Registration of 'Madison' Rice. Crop Sci, 39:1256.