水稻主要抗瘟基因对福建稻瘟菌群体的抗性分析

Resistance of rice major Pi-genes to the Magnaporthe grisea population in Fujian, China

用1995-2003年间在福建省水稻产区采集的稻瘟菌代表菌系的108个分离菌,它们在CO39近等基因系上测定被 划分为30个毒性类型,用它们在30个水稻抗稻瘟病近等基因系或单基因系品种上进行抗病性测定。结果表明水稻抗稻 瘟病基因Pi-kh抗性最强,抗性频率高达98．15％,Pi-1和Pi-9(t)也具有较高的抗性频率,是较好的抗源;对2个和3个Pi 基因的联合抗性频率的分析,发现一些联合抗性频率极高,甚至有达到100％的组合,表明抗瘟育种采用多个Pi基因聚合, 易于获得抗性强的品种。根据抗病基因与供试菌株互作的亲和性,对供试30个Pi基因可能的系统关系分析得到的初步信 息可为抗病基因的聚合与布局策略提供参考。

To provide breeders with desired resistant resources and utilize these resources for improvement of the resistance, the resistance of 30 rice varieties with single Pi-genes were assayed by using 108 blast isolates which were collected from rice paddy-fields during 1995 to 2003 in Fujian Province, Southeast of China. The isolates were originally grouped into 30 virulence types based on their virulence on the near isogenic lines with the single resistance genes： Pil ,P/2, P/3, Pi4a, Pi4b, in which CO39 is used as the recurrent parent. The results showed that Pi-khis the most resistant followed by Pi-1 and Pi-9（t） with the resistance frequency of 98.15% ,87.04% and 84.26%, respectively, suggesting that these Pi-genes could be directly introgressed into current elite cultivars. We further calculated the resistance frequency of any two or three Pi gene combinations and found that most of these Pi-gene combinations provided very high resistance frequency, even no virulent isolates identified. The results indicated that pyramiding Pi-genes in the same cultivar will be the most effective way in breeding for resistance varieties. The phylogenetic relationship of the Pi-genes tested based on their compatibility with the isolates tested by clustering analysis will provide information for resistance gene pyramiding and deolovment in integrated management of the rice blast disease.