Letters to Nature

Nature 406, 718-722 (17 August 2000) | doi:10.1038/35021046; Received 18 April 2000; Accepted 30 June 2000

Genetic diversity and disease control in rice

Youyong Zhu1, Hairu Chen1, Jinghua Fan1, Yunyue Wang1, Yan Li1, Jianbing Chen1, JinXiang Fan2, Shisheng Yang3, Lingping Hu4, Hei Leung5, Tom W. Mew5, Paul S. Teng5, Zonghua Wang5 & Christopher C. Mundt5,6

  1. The Phytopathology Laboratory of Yunnan Province, Yunnan Agricultural University, Kunming, Yunnan 650201, China
  2. Honghe Prefecture Plant Protection Station of Yunnan Province, Kaiyuan 661400, China
  3. Jianshui County Plant Protection Station of Yunnan Province, Jianshui 654300, China
  4. Shiping County Plant Protection Station of Yunnan Province, Shiping 662200, China
  5. Division of Entomology and Plant Pathology, International Rice Research Institute, MCPO Box 3127, 1271 Makati City, The Philippines
  6. Department of Botany and Plant Pathology, 2082 Cordley Hall, Oregon State University, Corvallis, Oregon 97331-2902, USA

Correspondence to: Christopher C. Mundt5,6 Correspondence and requests for materials should be addressed to C.C.M. (e-mail: Email: mundtc@bcc.orst.edu).

Crop heterogeneity is a possible solution to the vulnerability of monocultured crops to disease1, 2, 3. Both theory4 and observation2, 3 indicate that genetic heterogeneity provides greater disease suppression when used over large areas, though experimental data are lacking. Here we report a unique cooperation among farmers, researchers and extension personnel in Yunnan Province, China—genetically diversified rice crops were planted in all the rice fields in five townships in 1998 and ten townships in 1999. Control plots of monocultured crops allowed us to calculate the effect of diversity on the severity of rice blast, the major disease of rice5. Disease-susceptible rice varieties planted in mixtures with resistant varieties had 89% greater yield and blast was 94% less severe than when they were grown in monoculture. The experiment was so successful that fungicidal sprays were no longer applied by the end of the two-year programme. Our results support the view that intraspecific crop diversification provides an ecological approach to disease control that can be highly effective over a large area and contribute to the sustainability of crop production.