Genetic Analysis And QTL Mapping Of γ-aminobutyric Acid Content In Rice

Utilizing the high performance liquid chromatography method to measure the y-aminobutyric acid content of seed in the 108 rice germplasm resources, and analysed correlation between y-aminobutyric acid content of seed and grain traits of different germplasm resources, and test the determination of y-aminobutyric acid content in rice parents、hybrids F1、F2 grains come from a hybrid combination of Gaoliangdao-1/Ningnongheijing with great different content of y-aminobutyric acid, and analysed the correlation between the content of seed and relative embryo weight、grain traits and coefficient of variation, and estimated the broad heritability for each trait; Construct the genetic linkage mapping of F2 population of Gaoliangdao-1/Ningnongheijing and detect the QTLs of controlling γ-aminobutyric acid content in rice grain、specific results were as follows:1. Rich γ-aminobutyric acid were selected from 108 rice germplasm resources,such as:Jupeidao, Jijing-88, Shengdao-14, Gaoliangdao-1, the γ-aminobutyric acid content of seed had an extremely significant negative correlativity with grain thickness、1000-grain weight, and had an negative correlativity with grain length、grain width, but the correlation coefficient was not significant.2. The study found that the grain in introduced species y-aminobutyric acid content was significantly lower than that in Ningxia local varieties; the y-aminobutyric acid content in colored rice was less than the white rice, waxy varieties was lower than the non-glutinous rice, the early varieties was lower than the late-maturing varieties.3. The content in hybrids Fi grains by Gaoliangdao-1 and Ningnongheijing was 8.39±0.11 mg/100g; testing a normal distribution of the y-aminobutyric acid content frequiency in F2 plant grains, the results showed that the y-aminobutyric acid content in hybrids F2 plant grains tend to skewed normal distribution and appear obvious transgressive phenomenon, and showed that the y-aminobutyric acid content in rice grains was quantitative trait with controlled by multiple genes.4. The y-aminobutyric acid content in hybrids F2 grains had an extremely significant positive correlativity with relative embryo weight, and had an extremely significant negative correlativity with grain thickness,1000-grain weight, and had an significant negative correlativity with grain length, the y-aminobutyric acid content, grain thickness and 1000-grain weight of F2 plant grain had relatively high broad heritability, respectively were 98.12%,91.99%,96.37%.5. Using 131 pairs of SSR primers constructting a linkage mapping of hybrid F2 population of Gaoliangdao-1/Ningnongheijing, covering a tatal length of 1606.9 cM in rice genome, two contribution rate of 10%,11%of QTL loci were detected in chromosome 8 (qGABA-8-1. qGABA-8-2), additive effect was 0.94mg/100g,0.87mg/100g.one contribution rate of 9%of QTL loci was detected in chromosome 9 (qGABA-9), additive effect was-0.86mg/100g. Wherein, the synergistic gene qGABA-8-1 and qGABA-8-2 mainly from Ningnongheijing, the synergistic gene qGABA-9 mainly from Gaoliangdao-1.