以优质粳型糯稻苏御糯为供体.品质较差的籼稻桂朝2号为轮回亲本,构建了BC2F4群体,通过发展分子标记,研究了淀粉合成相关基因Wx、SbeⅠ、Sbe3、Isa、Pul、SssⅠ等对稻米淀粉RVA谱特征的影响。结果表明,Wx基因对RVA谱8个特征值的表现均起主要作用,对支链淀粉合成相关基因SbeⅠ、SssⅠ、SssⅡ-3和风SssⅢ-1,表现明显的上位效应。在糯稻遗传背景下,分支酶基因SbeⅠ和可溶性淀粉合成酶基因SssⅠ、SssⅡ-3和SssⅢ-1,都可对RVA谱特征产生显著影响,其中尤以SssⅡ-3的作用最为明显。支链淀粉合成相关基因之间普遍存在着互作。根据淀粉合成相关基因对RVA谱特征作用的复杂性,对稻米淀粉黏性特征的遗传改良作了讨论。
RVA profile has been frequently used to evaluate rice cooking and eating quality. Starch content is up to 90% in milled rice, indicating that starch-synthesizing genes may have a correlation with rice cooking and eating quality. In order to investigate the effect of the starch-synthesizing genes Wx , SbeⅠ , Sbe3 , Sss Ⅰ, Sss Ⅱ-3, Sss Ⅲ-1, Sss Ⅲ-2 , SssⅣ-1 , lsa and Pul on the RVA profile characteristics in rice, a BC2 F4 population was developed in which Guichao 2 (a cuhivar of indica rice with relative poor quality)was served as recurrent parent and Suyunuo(a glutinous cuhivar of japonica rice with fine quality)as donor parent. Also, the gene-tagged molecular markers for all the genes were developed or cited. A total of 2 010 plants were identified from the BC2 F4 population and with a single starch-synthesizing gene of Guichao 2 being substituted by the allele of Suyunuo either in non-glutinous or in glutinous background, and a total of 15 genotypes were obtained to be in further investigation. Their RVA profiles consisting of five primary parameters: peak viscosity (PKV), hot viscosity ( HPV), cool viscosity ( CPV), paste temperature ( PaT), peak time (PET) and three secondary parameters: breakdown value (BDV, = PKV - HPV) , setback value (SBV = CPV - PKV) and consistency value (CSV = CPV - HPV) were evaluated. Data were analyzed using ANOVA. The results showed that Wx gene played the most important role on RVA profile characteristics. Significant epitasis effect of Wx gene to other starch-synthesizing genes was found in nonglutinous rice. In the lines of glutinous rice whose Wx was substituted by wx of Suyunuo, all the characteristics of RVA profile were greatly changed. The allele of Sss Ⅱ-3 derived from Suyunuo could further decrease the PKV, HPV and CPV of RVA profile in glutinous rice and other characteristics of RVA profile also changed accordingly. Besides, the alleles of Sbel, Sss Ⅰ and Sss Ⅲ-1 of Suyunuo showed similar effect on RVA profile