广东不同时期水稻主栽品种抗病基因同源序列多态性分析

摘要

为掌握广东不同时期水稻主栽品种抗病基因同源序列(RGA)多态性变化,利用3对RGA标记分析了广东20世纪50年代初地方品种及1972、1980、1994和2008年主栽品种.按供试品种RGA-PCR指纹聚类,以相似系数0.81为标准,将171份品种分为20个类群.这五类品种分别分布于11、7、4、8和11个类群中,它们的Nei遗传多样性指数分别是0.801、0.682、0.493、0.603和0.527.相对于地方品种,1972、1980和1994年品种RGA多态性低是由于品种类群少及品种在各类群中分布均衡性差,2008年品种RGA多态性低是由于该年大多数品种属于同一类群,品种在各类群中分布均衡性差.因此保持品种抗性多样性,既要保证丰富类群,又要确保品种在各类群中分布均衡.近年来品种抗性背景趋同化是广东抗性多样性降低的主要原因,今后在新品种的选育上应均衡利用不同抗源.%In order to investigate the temporal diversity of resistance gene analogs (RGA) from major rice varieties in Guangdong,landraces from early 1950s and major varieties from 1972,1980,1994,and 2008 in Guangdong Province were selected and analyzed using three RGA primers.One hundred and seventy-one varieties were divided into twenty groups according to the DNA band data at the similarity index of 0.81.Landraces from early 1950s and varieties from 1972,1980,1994,and 2008 were distributed into eleven,seven,four,eight and eleven groups,with their Nei's polymorphism index of 0.801,0.682,0.493,0.603,and 0.527,respectively.The RGA polymorphism of landraces was the highest.Having a few group types and unevenly distributing in different groups were the reasons of low diversity for the varieties of 1972,1980,and 1994,while the low diversity for varieties of 2008 resulted from that major varieties distributed in one group and unevenly distributed among different groups.Thus,having various groups and evenly distribution is necessary for maintaining the resistance diversity of varieties.In recent years,the resistance diversity of rice varieties in Guangdong decreased as major varieties had similar genetic background in resistance.Thus,different resistant resources should be utilized equally in future rice breeding.