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利用随机扩增多态性DNA技术(randomamplifiedpolymorphicDNA,RAPD)对广东省2001年度稻瘟病菌群体的遗传结构进行了分析。以相似性系数为0.70阈值时,可将采集于广东省三大生态稻作区、早稻和晚稻生长季节的96个菌株划分为12个遗传宗谱;其中宗谱8和9的菌株数各占总数的25%和18.8%,为优势宗谱。从稻作区来看,宗谱3和8为各个稻作区的共同宗谱;而宗谱1和2,7和11,以及9、10和12则依次是粤北、粤中和粤南稻作区的特异性宗谱。从生长季节来看,来源于早、晚季的菌株完全分属于宗谱图的上、下两个半区,彼此之间不存在共同的宗谱;而且两个优势宗谱都集中于晚季供试亚群体。结合前两次实验的结果,作者提出了如下两个假说来解释广东省稻瘟病菌群体所表现的遗传特性:一个地区或生长季节的病原菌群体,其优势宗谱所占的比例越高,该地区或生长季节病害发生就越严重;在长期的水稻栽培历史中,稻瘟病菌群体可能逐步地形成了早季宗谱(小种)和晚季宗谱(小种)的遗传分化。如何进一步验证上述两个假说是值得我们进一步探讨的重要课题。
The genetic structure of the rice blast population in 2001 in Guangdong Province was analyzed using random amplified polymorphic DNA (RAPD). When the similarity coefficient was 0.70, the 96 strains collected in the three major ecological rice growing areas of Guangdong Province and the growing season of early rice and late rice could be divided into 12 genetic lineages; The total number of 25% and 18.8%, as the dominant genealogy. From the rice area, genealogy 3 and 8 for each paddy area common lineage; and genealogy 1 and 2,7 and 11, and 9,10 and 12 followed by northern Guangdong, Guangdong and Guangdong Specific genealogy of rice fields. From the growth season point of view, from the early and late strains completely belong to the upper and lower half of the genealogy map, there is no common genealogy between each other; and the two dominant genealogies are concentrated in the late season Sub-test for the group. Combined with the results of the previous two experiments, the authors propose the following two hypotheses to explain the genetic characteristics exhibited by M. grisea population in Guangdong Province: the higher the proportion of dominant genealogies in a region or growing season, In the long-term history of rice cultivation, the populations of M. grisea may gradually form the genetic differentiation of the early season genealogy (races) and late season genera (races). How to further verify these two hypotheses is an important issue that deserves our further study.