Rice Quality Related Gene Polymorphism Analysis In Huang Huazhan Series Of Varieties

Rice is one of the most important food crops in the world. Because rice starch is the main component of milled rice, the formation of rice quality traits in essence can be regarded as a process of starch biosynthesis and accumulation in grains, while this process occurs in rice starch body, and catalysed under a series of enzymes.China is the world’s rice production and rice consuming countries, so the rice yield and quality raits is particularly important. Rice quality traits are usually divided into processing quality(milling quality), appearance quality, cooking and eating quality,nutritional quality. One of the most important and most researches are cooking and eating quality. Cooking and eating quality of rice were quantitative traits, and its genetic characteristics was very complex. We selected Guichao 2 、 Huang Huazhan and their derivative products as the research object,and hope to clear the cause of the differences of rice grain quality and the key genes or key sites influencing rice quality in Huang Huazhan series.First we observed the Huang Huazhan series varieties of rice grain phenotype.Differences on the appearance quality, this series of varieties, mainly on the grain shape, chalk white phenomenon.And Chang sizan as the boundary, the appearance quality is divided into two types,upstream varieties for short grain rice, high chalkiness degree;downstream varieties for long grain rice, less chalkiness.Rice grain shape and chalkiness has a negative correlation;when the ratio of length to width is high,chalkiness degree will be small; instead when the ratio is low, chalkiness degree will be large. In the rice endosperm starch granule structure, we find the differences mainly concentrated on the abdomen area and the transition zone which begin from abdomen to the central region. In the abdomen and the transition zone, Guichao2 and its parents showed spherical irregular starch grains; Huang Huazhan and its parents showed crystal structure. And since Chang sizhan,abdomen show the rules of the crystal structure, irregular structure is less.Starch granule structure and rice grainquality has an important relationship, when the starch granule is irregular quality then variation;When closely to rule the crystal structure of starch particles accumulate,relative to the quality is good.On the eating and cooking quality(ECQ), the difference among varieties mainly focus on the amylose content.Moreover,Chang sizan as the boundary,the varieties’ s quality were divided into two types,upstream varieties for high amylose content,downstream varieties for low amylose content,except Feng aizhan1. In Huang huazhan series varieties, Setback and gel consistency variation is not big.Analysis of starch synthesis related genes, we found that the variety’s mainly mutated gene were WX 、 SSII- 3 and SSIII- 2. WX gene is a granule bound starch synthase gene, and amylose synthesis is mainly under its control; SSII-3 and SSIII-2 are soluble starchsynthesis enzyme gene, the types of enzymes with a variety of the same activity enzyme,they participate in both the synthesis of amylose and amylopectin,the variation of single enzyme will have other isoformsupplement, so the impact is very little.Therefore we speculated that WX gene may be the main gene that influence Huang Huazhan series varieties’ rice quality. Also through the gene polymorphism analysis, we found that the difference of gene polymorphism among cultivars mainly at the-1251(CT) n repeat sequence and the first exon and intron splice G/T polymorphism sites of-1160. Also we found that the polymorphism of Chalk5 gene was similar with that of WX gene.This found also confirmed that chalkiness has some degree of correlation with amylose content.We still need further discussion and research for both the specific relationship.