Diversity analysis for resistance of rice (Oryza sativa L.) to blast disease [Magnaporthe grisea (Hebert) Barr.] using differential isolates from the Philippines |
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Authors: | M J Telebanco-Yanoria R Ohsawa S Senoo N Kobayashi and Y Fukuta |
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Institution: | International Rice Research Institute (IRRI), DAPO Box 7777, Metro Manila, Philippines;;Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan;;Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba 305-8686, Japan;;Corresponding author, E-mail: |
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Abstract: | A wide variation in resistance to blast disease caused by Magnaporthe grisea (Hebert) Barr. ( Rossman et al. 1992 ) was found using 922 rice ( Oryza sativa L.) varieties collected mainly from Asia. These were classified into six varietal groups, termed clusters A–F, according to Ward's hierarchical cluster analysis, based on the reaction pattern to 20 standard differential blast isolates from the Philippines. The most susceptible two clusters, B and C, dominated in varieties from the Far East (Japan). Varieties from East Asia and Southeast Asia occurred less frequently in B and C clusters than those of Japan, and more frequently in E and F clusters, which were the most resistant of the cluster groups. Varieties from South Asia showed the widest variation, occurring in all clusters but less frequently in cluster B. The cluster B varieties dominated in Japan and showed a high frequency of isozyme type VI, corresponding to Japonica type. In contrast, the frequency of cluster B was low in the groups with isozyme types I, II, III and V, which dominated in South Asia. Isozyme type I corresponds to Indica type varieties. The distribution of resistance corresponded to the geographical distribution of rice varieties and might be related to differentiation into Indica and Japonica types. These findings will provide useful information for understanding the variation in blast resistance at the global level. |
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Keywords: | rice (Oryza sativa L ) blast [Magnaporthe grisea (Hebert) Barr ] differential system genetic diversity resistance cluster analysis |
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