Genetic diversity of blast resistance in rice


       A wide variation in resistance to blast disease caused by Magnaporthe grisea was found using 922 rice (Oryza sativa L.) varieties collected from Asia, Africa, and the Americas. These were classified into six varietal groups termed clusters A-F, according to Ward’s hierarchical cluster analysis, based on their reaction patterns to 20 standard differential blast isolates from the Philippines. The two most susceptible 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. American and African varieties showed similar distribution to those of East Asia. 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.

Figure, table

  1. Fig. 1. Frequencies of varieties’ groups

    Fig. 1. Frequencies of varieties’ groups
    A-F, characterized by resistant patterns to standard blast isolates from the Philippines in each area

  2. Figure 2. Frequencies of cluster groups in each isozyme type (No. of varieties)

Japan International Research Center for Agricultural Sciences Biological Resources Division


Technical A

Term of research


Responsible researcher

FUKUTA Yoshimichi ( Biological Resources Division )

KOBAYASHI Nobuya ( Biological Resources Division )

SENOH-NAMAI Sachiko ( Crop Production and Environment Division )

TELEBANCO-YANORIA Mary Jeanie Telebenco ( International Rice Research Institute )

OHSAWA Ryo ( University of Tsukuba )

Publication, etc.

Mary Jeanie Telebanco-Yanoria, Ryo Ohsawa, Sachiko Senoo, Nobuya Kobayashi, Yoshimichi Fukuta. Diversity analysis for resistance of rice (Oryza sativa L.) to blast disease (Magnaporthe grisea (Hebert) Barr.) using differential isolates from the Philippines. Plant Breeding (in press)

Japanese PDF

2007_seikajouhou_A4_ja_Part3.pdf505.25 KB

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