Effect Of Rice Genes Related To Starch Synthesis On Rice Eating And Cooking Qualities

More than half of the world’s population used rice as a staple food, so the quality of the rice attracts a lot of people’s attention. The eating and cooking quality is the most important character in the evaluation of the rice quality. Because it determines the quality of rice taste. In recent years, the researches about the effects of rice starch synthesis-related genes on rice quality have been carried out. In this study, we used glutinous rice(javanica 22) and a restorer with high amylose content CG133 R as parents and crossed to produce a separating population. On the one hand the relationship between the variation of eating and cooking quality indice and the separation of the Wx and SSSII-3 gene in F2 were analyzed. On the other hand, we constructed backcross inbred line(BILs) with indica PTGMS line Guangzhan 63 S and potential restorer CG173 R as material, which had the same major genes for Wx and SSSII-3 gene. The effect of their minor genes in starch synthesis pathway of non-glutinous(PUL, SSSIII-1, SSSI, AGPlar, and their interaction) were analyzed on eating and cooking qualities of rice during separation of progeny. The main results were as follows:1. The eating and cooking quality indexes showed widely separation in F2 population, that came from a cross between javanica and indica rice. In their variation distribution, the maximum coefficient of variation is the setback value(SBV), CV=110.13%, with a range of variation-122.04~207.08 RVU. The CV of pasting temperature(PaT) was the smallest, CV=4.35% with a range of variation 70.65~84.17 ℃. The variation sequence sized down for each trait SBV> GC>AAC>ASV>CSV>CPV> BDV>HPV>PeT>PKV>PaT.2.The relationship among the RVA profile characteristics and eating and cooking qualities for different amylose content materials were different. There was no significant correlation in the materials with high amylose content. For the middle and low amylose content materials, there was significant correlation between AAC, GC, ASV and RVA profiles. In contrast, there was no significant correlation between RVA profile characteristics and ASV, but with significant correlation between RVA indices(CPV, SBV, CSV, PeT) and AAC, GC, ASV in glutinous.3.In F2 population, the separation ratio of Wxa gene and SSSII-3 gene didn’t conform to the ration of 1:2:1, and the chi-square test were above the critical value 0.04. Because Wxa and SSSII-3 genes were expressed in endosperm as triploid tissue in inheritance, there are difference in the isolation and expression compared with the diploid. Segregation direction of molecular marker Wxa gene matched with SSSII-3 gene, with less javanica rice genotypes and more CG133 R genotypes. Meanwhile, the heterozygous ratio is normal.4.Different types of soluble starch synthase gene had different influence on rice eating and cooking quality. The SSSI gene had a significant effect on AAC, HPV, BDV and SBV indices at 1% level, with a significant effect on GC and PKV indices at 5% level; SSSIII-1 gene had a significant effect on GT, PKV, BDV and PeT indices. The interaction effect between SSSIII-1 and SSSI gene arrived at extremely significant level on GT, and with significant effect on AAC, GC, PKV and SBV indices. It indicated that the interaction between SSSIII-1 and SSSⅠ gene has a significant influence on GT at the background of the co-expression of Wxb gene and SSSII-3 gene.5.PUL gene had significant influence on the gel consistency and consistence value. The different combination of AGPLar and PUL gene had no significant effect on AAC, GC, CPV, SBV and PaT indices. However, they had significant effects on ASV, PKV, HPV, BDV, CSV and PaT indices at 0.05 level or 0.01 level. It indicated that the interaction between AGPLar gene and PUL gene had significant or extremely significant effect on ASV, PKV, HPV, BDV, CSV and PaT indices.The studies have proved that rice eating and cooking qualities(ECQs) are not only controlled by major genes, but also by minor genes in pathway of starch synthesis, which have important effect on rice quality. Especially, Minor genes and their interaction effects are key factors controlling ECQs when the major genes are same.