水稻多基因型和单基因型品种抗病性及群体内稻瘟菌遗传多样性初析

利用多基因型集成品种群体(由多个类似表型的单基因型品种或品系组成)和单基因型品种群体,分析两种群体中的稻瘟菌群体遗传结构及发病情况。将这两种群体植株上所采集标样的菌株进行分离纯化,应用细菌基因组重复序列PCR技术(rep-PCR)获得各菌株指纹图谱,并将其划分为若干单元型进行多样性分析。结果显示,稻瘟菌多样性指数范围在集成品种群体内为0.521～0.603,在单一品种群体内为0.319～0.705,说明两种群体内的病菌多样性没有差异,稻瘟菌多样性在抗性弱的品种内低,抗性强的品种内高。病害调查结果表明,集成品种的实际病穗率低于预期发病率,差异极显著。由于集成品种群体中含有抗性强材料阻止了致病菌的扩散,从而控制了病害。进一步证实了种植集成品种是一条控制稻瘟病的有效途径。

Preliminary Analysis on Rice Blast Disease and Genetic Diversity of Its Pathogen in Multi-Genotype and Mono-Genotype Varieties

The haplotypes of rice blast disease (Magneaporthe grisea) were obtained and analyzed in the multi-genotype and mono-genotype variety groups by DNA fingerprinting with rep-PCR. The isolates of Magneaporthe grisea were classified into several haplotypes. It was found that the diversity index of blast pathogen ranged from 0.521 to 0.603 in multi-genotype varieties, and from 0.319 to 0.705 in mono-genotype varieties. The diversity index of blast pathogen was lower in susceptible varieties and higher in resistant ones. However, there was no difference in the diversity of rice blast fungi between the two variety groups. The disease rate of panicle-neck blast in multi-genotype varieties was remarkably lower than the weighed average value of disease rates in percentage of their components in mono-genotype varieties. The diversity of isolates in both multi-genotype varieties and mono-genotype varieties was not different, but the resistant component of the multi-genotype varieties blocked spore dispersal of the causal fungus and reduced the disease. So using the multi-genotype varieties is a good approach to control the rice blast.