关键词: 糊化温度;支链淀粉, SSⅡa, QTL定位;单核苷酸多态性

Abstract:

Gelatinization temperature (GT) is an important quality predictor that determines the cooking quality of rice. Low GT rice needs less energy input during cooking than high GT rice. The structure of amylopectin, especially its side-chain length distribution, has close relation to GT. The more amount of short chains, the lower starch GT. The quantitative trait locus (QTL) mapping has identified the alkali degenerate (alk) gene located on chromosome 6 as a major gene underlying the GT, which encodes the starch synthase IIa (SSⅡa). Functional single nucleotide polymorphisms (SNPs) found in SSⅡa are closely associated with GT and amylopectin structure. These SNPs are being used for marker assisted selection to improve rice quality. A molecular mechanism to control the variation in gelatinization temperature of rice starch by SSⅡa has also been put forward.

Key words: gelatinization temperature, amylopectin, starch synthase Ⅱa, quantitative trait locus, single nucleotide polymorphism