Abstract: A single nucleotide length polymorphism (SNLP) was identified at the intron region of the Pi-ta gene to develop a codominant Pi-ta gene marker suitable for genotyping with an ABI automated machine. The DNA primer specific to the resistance Pi-ta allele was labeled with blue dye as a forward primer, the DNA primer specific to the susceptibility pi-ta allele was labeled with green dye as another forward primer and the DNA primer identical to both Pi-ta/pi-ta alleles was unlabeled as the reverse primer for polymerase chain reaction (PCR). Using these three primers, a 181 bp blue peak in homozygous resistant and a green peak of 183 bp in homozygous susceptible, and both peaks in heterozygous plants were produced by PCR. The utility of marker was verified using 12 plants coming from segregating F 2 population and 15 inbred varieties via dominant markers and pathogenicity test. A codominant Pi-ta marker is thus developed for effective Pi-ta assisted selection for rice disease resistance breeding program.

Key words: rice, blast resistance gene, single nucleotide length polymorphism, codominant marker

摘要： 根据抗病基因Pi-ta和感病等位基因pi-ta在DNA序列上的单核苷酸长度多态性（single nucleotide length polymorphisms，简称SNLP）设计了3个特异性引物YL155、YL183和YL200，并分别用蓝色和绿色染料将YL155和YL183进行标记，而YL200不标记。在一个PCR反应中同时加入这3对引物，并应用ABI自动分析仪对PCR产物进行分析，结果发现，抗病基因Pi-ta纯合的样品获得一个峰值为181 bp的图谱，感病等位基因pi-ta纯合的样品获得一个峰值为183 bp的图谱，而抗病基因Pi-ta处于杂合状态的样品出现两个峰。由此建立了水稻抗稻瘟病基因Pi-ta的共显性分子标记。以杂交组合Katy/RU9101001的12个F2单株和15个水稻品种为材料，利用已建立的显性分子标记和稻瘟病菌人工接种试验对共显性标记的正确性进行了验证，结果发现三者的实验结果完全吻合，因此该共显性标记可应用于水稻抗病基因Pi-ta的分子标记辅助选择。

关键词: 水稻, 抗稻瘟病基因, 单核苷酸长度多态性, 共显性分子标记