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基因Pi-ta和Pi-b是最早被克隆的两个稻瘟病抗性基因,在粳稻中表现出持久稳定的稻瘟病抗性,因而被广泛用于稻瘟病抗性育种。为明确上述基因在江苏粳稻中的分布,为抗病育种提供依据,该研究利用Pi-ta和Pi-b的功能标记,对40个粳稻品种和665份粳稻新品系进行相关基因型的分子检测。结果表明,抗性基因Pi-ta和Pi-b在江苏粳稻品种中具有一定的分布,其中Pi-b的分布频率高于Pi-ta的频率,连粳系列品种大都不携带Pi-ta和Pi-b抗性基因,而武粳系列品种则基本含有上述抗性基因。粳稻新品系携带抗性基因Pi-ta的频率与推广品种相比变化不大,但携带抗性基因Pi-b的频率明显高于推广品种,这说明人工改良水稻品种有利于抗病基因Pib频率的提高。4种基因型中,Pi-ta/Pi-b的分布频率最高,为60.0%,其次为Pi-ta/Pi-b,占33.5%,基因型Pi-ta/Pi-b的分布频率为3.9%,而Pi-ta/Pi-b的分布频率最低,只占2.6%。从4个组合的抗性基因来源看,抗性基因Pi-ta则可能来自武香粳14、武粳15或南粳44,而Pib则可能来自武粳13、武香粳14、武粳15或南粳44。从4种基因型后代的获得频率看,以南粳44//武粳13/关东194获得抗性基因型Pi-ta/Pi-b后代的频率最高。
The genes Pi-ta and Pi-b, the earliest cloned two blast resistance genes, showed long-lasting and stable blast resistance in japonica rice and were therefore widely used in blast resistance breeding. In order to clarify the distribution of these genes in Jiangsu japonica rice and provide basis for disease-resistant breeding, the molecular markers of related genotypes were detected in 40 japonica rice varieties and 665 japonica new rice lines by using the functional markers of Pi-ta and Pi-b . The results showed that Pi-ta and Pi-b had some distribution in Jiangsu japonica rice, in which the distribution frequency of Pi-b was higher than that of Pi-ta, and most of the japonica rice varieties did not carry Pi-ta and Pi -b resistance genes, while the Wujing series basically contains the above resistance genes. The frequency of Pi-ta carrying resistant gene in new japonica rice lines did not change much compared with the promotion varieties, but the frequency of carrying resistant gene Pi-b was significantly higher than that of promoting varieties, which indicated that artificial improvement of rice varieties was beneficial to the frequency of Pib Improve. Among the four genotypes, Pi-ta / Pi-b had the highest frequency of 60.0%, followed by Pi-ta / Pi-b, accounting for 33.5% and genotype Pi-ta / Pi-b with frequency 3.9 %, While the Pi-ta / Pi-b distribution frequency is the lowest, accounting for only 2.6%. According to the four combinations of resistance genes, Pi-ta may be derived from Wuxiangjing 14, Wujing 15 or Nanjing 44, while Pib may be derived from Wujing 13, Wuxiangjing 14 and Wujing 15 Or Nanjing 44. According to the frequency of the four genotypes, Pi-ta / Pi-b progeny of Nanjing 44 / Wujing 13 / Guandong 194 had the highest frequencies.