The Use of Rice Varietal Diversity for Rice Blast Control

<正> Field experiments of mixed- (intercropping) and pure-planting (monoculture) of four rice varieties, representing improved hybrid varieties (Shanyou63 and Shanyou22) and high-quality traditional varieties (Huangkenuo and Zigu) from Yunnan Province, were conducted based on their differences in genetic background and agro-economical characteristics. The results demonstrated that the mixed-planting of the hybrid rice and high-quality traditional rice varieties had a significantly greater effect on controlling rice blast disease than the monoculture of these varieties, particularly the traditional ones. It is evident for the highly susceptible traditional varieties in mixed-planting to achieve disease control, with significant decreases in blast incidences and severity indexes. The blast control efficiency reached up to 83-98% under such planting model. This suggests that an appropriate mixed-planting of rice varieties with diverse genetic background and agro-economical characteristics is an effective approa