Ecological and genetic characteristics of sulfonylurea-resistant Monochoria vagina us, a paddy weed

磺酰脲（SU）除草剂具有广谱的除草活性和相对较低的使用率，是日本水田使用最多的除草剂。日本共报道了12种抗苏生物型水稻杂草。其中，阴道单孢菌是危害最大的稻谷杂草之一。阐明抗苏生物型的生态适宜性，以及抗苏基因的起源和传播，对其防治具有重要意义。比较了日本耐苏生物型和敏感生物型的生物量和种子产量，阐明了日本耐苏生物型的遗传变异。为评价对苯甲磺隆、吡唑磺隆和吡唑磺隆的抗性，测定了9个群体在不同除草剂处理下的新根伸长。禅野治、神光良、Maizuru、Kasai-B和Ushiku生物型在处理下新根伸长，而Seika、Kameoka、kamisya和Kasai-A生物型在处理下新根没有伸长。前5种生物型对苏有抗性，后4种生物型对苏敏感。每7株对苏敏感和抗性生物型分别在1/10,000瓦格纳罐中生长。9月收获，干燥并称重。计算每株的种子数。在单株的干物质产量和种子数量上，苏氨酸敏感型和抗性生物型没有差异。抗苏生物型与敏感苏生物型的生态适应度似乎没有什么不同。利用RAPD（随机扩增多态性DNA）分析了群体内的遗传多样性和群体间的遗传关系。禅野寺、上津良、舞津、kasai b和福岛每个抗苏群体内20个个体间无遗传变异。在基于简单匹配系数的UPGMA树中，将抗苏种群划分为不同的支系。这些结果强烈表明抗苏生物型是独立起源的。少

Sulfonylurea (SU) herbicide is the most important herbicide used in paddy fields in Japan because of its broad spectrum of weed control activity and relatively low usage rates. A total of 12 SU-resistant biotypes of paddy weeds has been reported in Japan. Among them, Monochoria vaginalis is one of the most harmful paddy weeds. It is important to clarify the ecological fitness of SU-resistant biotypes of the weed, and the origin and spread of SU-resistant gene(s) for their control. The biomass and seed production of SU-resistant biotypes of M.vaginalis were compared with those of susceptible ones and clarified genetic variation of SU-resistant biotypes in Japan.To evaluate the resistance to bensulfuron-methyl, imazosulfuron and pyrazosulfuron-ethyl, elongation of new roots of nine populations under each herbicide treatment was measured. Zennoji, Kamitsuneyoshi, Maizuru, Kasai-B and Ushiku biotypes elongated new roots under the treatments, but Seika, Kameoka, Kamiseya and Kasai-A biotype … More s did not. The former five biotypes were SU-resistant and the latter four biotypes were SU-susceptible.Each seven plant of SU-susceptible and resistant biotypes was grown individually in a 1/10,000 a wagner pot. They were harvested in September, dried and weighed. Number of seeds per plant was counted. No differences were found in dry matter production and number of seeds produced per plant between SU-susceptible and resistant biotypes. Ecological fitness of SU-resistant biotypes seems not to be different from that of SU-susceptible biotypes.The genetic diversity within a population and relationship among populations were analyzed by RAPD(random amplified polymorphic DNA). There was no genetic variation among 20 individuals within each SU-resistant population of Zennoji, Kamitsuneyoshi, Maizuru, Kasai-B or Fukushima. In UPGMA tree based on simple matching coefficient, the SU-resistant populations were grouped into different clades. These results strongly suggest that SU-resistant biotypes originated independently. Less