Abstract: The phenotypically uniform indica rice variety IR64 was chosen for study of the source and inheritance of within cultivar residual variation using a set of SSR markers.Molecular heterogeneity in IR64 was identified on the short arm of chromosome 2 involving at least five SSR loci spanning nearly 30 cM.The SSR variations originated from the parental lines of IR64(IR5657-33-2 /IR2061-465-1-5-5)and were segregating in the selfed bulk seed stock in a Mendelian manner for more than 20 years.This study was one of few examples to verify successfully that within cultivar variations of SSR in morphologically uniform selfing crops came from its parental lines,which has immediate and commercial applications including test of seed purity,varietal fingerprinting,and curation and propagation of germplasm collections.

Key words: rice, residual variation, heterogeneity, simple sequence repeat

摘要： 用SSR标记对个体间表型一致的籼稻IR64（由育种家提供的种子，简称S0）品种内的残余遗传变异的来源以及变异的遗传模式进行了研究。发现第2染色体短臂上存在残余变异，该变异区间包含5个SSR座位，大小约为30 cM。进一步研究显示，变异存在于1989年种质库保存的IR64种子中，而变异的根源为IR64的原始亲本（母本IR5657332为1990年的库存，父本为1979年的库存）。S0中存在的变异均能在亲本中检测到。另外，对S0连续套袋自交后代分析表明残余变异以孟德尔方式稳定遗传。验证了在自花授粉作物中，推广品种内的残余变异源于亲本，对种子纯度鉴定、品种指纹图谱的构建、种质资源的保存具有借鉴意义。

关键词: 水稻, 残余变异, 异质性, 微卫星标记