中国辽宁省杂草稻遗传多样性及群体分化研究

杂草稻是指在稻田间或周边作为杂草类型而伴随栽培稻生长的水稻植株, 现已严重发生于中国辽宁省。2003—2005年对中国辽宁稻区的杂草稻进行了初步的考察、收集和整理, 对其植物学特性进行了初步研究；利用收集到的部分杂草稻、栽培稻和野生稻, 采用SSR分子标记方法对其遗传多样性和群体分化进行了初步研究。发现杂草稻植物学特性变异较大。SSR分子标记结果表明, 中国辽宁杂草稻具有较高的遗传多样性, 30对SSR引物中有26对在杂草稻中扩增出多态产物, 多态性位点所占比例为86.67%, Shannon多样性指数平均为0.762。杂草稻群体的基因分化系数(GST)平均为0.843, 杂草稻群体间的遗传分化较大, 遗传差异明显。中国辽宁杂草稻与当地粳型栽培稻血缘关系很近, 与籼稻和野生稻的遗传关系较远, 很可能起源于当地栽培稻品种, 是栽培稻种个体间自然杂交、回复突变等产生的退化类型,远距离种子调运促进了它的进一步扩散。

Genetic Diversity and Population Differentiation of Weedy Rice in Liaoning Province of China

Weedy rice refers to rice plants growing in paddy field and its surrounding area as a weedy type, which is distributed in rice-transplanting areas in Liaoning Province of north China. Field surveys were conducted to define the distribution region of Chinese weedy rice, weedy rice resources were collected from the main rice-growing regions of Liaoning Province in the autumns 2003–2005, and the phenotypic diversity of weedy rice was tested at the Rice Research Institute of Shenyang Agricultural University in 2006. Weedy rice seeds were sown on 12 April and seedlings were transplanted to the field on 20 May 2006. Data were collected on various morphological variables of weedy rice. Samples of weedy rice were analysed with 30 SSR makers and compared with the collections of cultivated rice and wild rice O. rufipongon. The percentage of polymorphic loci was 86.67% and Shannon''s information index was 0.762, showing that the genetic diversity of Liaoning weedy rice is very high. The GST of 0.843 suggested that the main genetic variation of weedy rice resided among populations. Weedy rice populations in Liaoning were closely related to cultivated japonica rice but distantly related to O. rufipongon and cultivated indica rice. Weedy rice in Liaoning most probably originated from the local cultivated japonica rice through natural hybridization and natural mutation. The weakness of breeding and cultivation methods promoted the producing of Liaoning weedy rice.