中文摘要：

【目的】已克隆的稻瘟病抗性基因Pi1、Pik-p、Pik-h、Pi2、Pi9、Piz-t、Pita、Pii对不同稻区的稻瘟病菌表现较广谱的抗性，被广泛应用于水稻抗瘟性育种。为了明确上述抗性基因在华南稻区杂交稻组合中的分布及其组合的抗病有效性,【方法】利用上述8个抗病基因的功能标记，对华南328个杂交稻组合进行了抗瘟基因型分子检测。【结果】抗性基因Pita和Pii分布频率最高，在测试组合中检出率分别为84.76%与67.68%；其次是Pi2与Pik-p，分别为22.87%与13.72%；检出频率较低的是Pi1、Piz-t和Pik-h，分别为5.18%、3.35%与2.13%，检测的品种都不携带抗性基因Pi9。在单个杂交稻组合中，检出的抗瘟基因数量最多是4个。抗病性评价结果表明，杂交稻组合中检出的抗病基因数量越多，其表现为抗病品种的频率就越高；含4个抗病基因的杂交稻组合中，抗病品种所占比率达91.67%。含有不同抗瘟基因的组合表现出不同水平的抗瘟性，其中Pi2与Pi1对华南稻区稻瘟病的抗病性贡献最大，其他抗病基因的贡献大小依次是Pik-h、Pik-p、Pita、Pii与Piz-t。【结论】本研究为华南稻区杂交稻抗病品种基因型的合理布局以及抗瘟基因的应用提供了科学依据。

英文摘要：

【Objective】The cloned rice blast resistant genes,Pi1,Pik-p,Pik-h,Pi2,Pi9,Piz-t,Pita and Pii,which showed broad-spectrum blast resistance in different rice growing regions,have been widely used in rice breeding for blast resistance.To clarify the distribution of these genes in hybrid rice in South China,【Method】the genotypes of resistance genes Pi1,Pik-p,Pik-h,Pi2,Pi9,Piz-t,Pita and Pii in328hybrid rice combinations were detected with functional markers.【Result】The distribution frequency of Pita and Pii was the highest,reaching84.76%and67.68%in the tested rice combinations,respectively;followed by Pi2and Pik-p with the proportion of22.87%and13.72%,respectively;Pi1,Piz-t and Pik-h had the lowest distribution frequency,accounting for5.18%,3.35%and2.13%of total;all of these varieties didn't carry resistance gene Pi9.The number of blast resistance genes detected in hybrid rice combinations were at most four.The resistance evaluation showed that the frequency of resistant varieties rose with increasing number of resistance genes in hybrid combinations.In a hybrid combinations with four resistance genes,the distribution frequency of resistant varieties was91.67%.Blast resistance contribution assay of the eight resistance genes revealed that Pi2and Pi1displayed the greatest resistance contribution in the local rice in South China,followed by Pik-h,Pik-p,Pita,Pii and Piz-t.【Conclusion】This study provided a scientific basis for the rational distribution of resistant varieties with different genotypes in South China.