Abstract: Variations in starch physical chemical properties were investigated between two waxy mutants and their parental lines. Waxy mutants showed higher GT (gelatinization temperature) and GC (gel consistency), and lower RVA (rapid visco analyzer) values than their parental lines. Three characters of RVA profile including setback, consistence and cool viscosity varied greatly between waxy mutants and their parental lines, while slight differences were observed in peak viscosity and breakdown. It suggested there was pleiotropy of Wx on GC, GT, and starch paste viscosity. In addition, variations in breakdown and peak viscosity of RVA profiles between two waxy mutants were even larger than those between the waxy mutant and their respective parental line. These results suggested that amylopectin besides AC was also a factor responsible for cooking and eating quality in rice grain. The Wx loci were characterized with both G/T single nulceotide polymorphism (SNP) at the putative leader intron 5′ splice site and (CT)_n microsatelliates in the leader sequence. Analysis of G/T SNP showed that Yangfunuo 4 differed from its parental line IR1529-68-3-2 by a subsitution of G by T, while Yangnuo 2 had the same nucleotide T with its parental line Kinmaze. Variations of (CT)_n repeat numbers were also observed both between Yangfunuo 4 and IR1529-68-3-2 and between Yangnuo 2 and Kinmaze.

Key words: rice, starch, physical chemical properties, gelatinization temperature, gel consistency, viscosity

摘要： 比较了籼、粳两个糯性突变品种与原亲本品种淀粉的理化特性。糯性突变后除了直链淀粉含量显著降低外，淀粉的糊化温度变高、胶稠度增大、RVA谱(rapid viscosity analyzer)参数下降。RVA谱参数降低的幅度从高到低依次是消减值>回复值>冷胶粘度>热浆粘度>最高粘度>崩解值，表明控制直链淀粉含量的Wx位点对淀粉糊化特性和粘滞性是有影响的，存在多效性。同时，两个糯稻品种之间的RVA谱差异较大，其中崩解值和最高粘度差值均大于糯性突变对它们的影响，说明除直链淀粉外，支链淀粉也影响淀粉的理化特性。对Wx位点鉴定的结果显示扬辐糯4号wx基因第一内含子剪切位点＋1位的碱基由原品种的G突变成了T，扬糯2号与其原品种相同(均为T)；两个糯稻突变品种wx基因前导区的(CT)n微卫星重复序列与原品种相比都发生了变化。

关键词: 水稻, 淀粉, 理化特性, 糊化温度, 胶稠度, 粘滞特性