| The rice in cold region has been favored by consumers because of its excellent quality.With the improvement of people's living standards,the demand for rice quality was also increasing.Analyzing the quality of rice germplasm resources in cold region and locating the genetic loci that control the quality of rice were of great significance in promoting the molecular assisted breeding of high quality rice in cold region.Linkage disequilibrium analysis was an effective way to obtain close linkage sites with target traits.In this study,158 germplasm resources of rice in cold region were used as the experimental material,variation analysis,correlation analysis and cluster analysis were carried out based on 8 quality traits which were the brown rice rate,the milled rice rate,the head milled rate,the grain length and width,the ratio of length and width of the grain,chalky grain rate and protein content,in order to clarify the characteristics of quality traits of rice germplasm resources in cold region and provide a theoretical basis for selection of parents for high quality cultivars breeding.The 267 SSR loci distributed on all 12 chromosomes of rice were used and association between these SSR loci and the above 8 quality traits were studied in order to obtaining SSR loci closely linked to the quality traits of rice in cold region,and providing selection tools for molecularly assisted breeding of rice in cold region.The main results were as follows:(1)The quality traits of 158 germplasm resources of rice in cold region were determined.The results showed,among the 8 quality traits,the coefficient of variation of chalky grain rate was highest(73.56%),followed by the ratio of length and width of the grain(12.44%);The coefficient of variation of remaining values were less than 10%,and the coefficient of variation of brown rice rate was lowest(1.93%).(2)The correlation analysis of the quality traits of 158 test materials were carried out.The results showed,there were significant positive correlation between the brown rice rate and the milled rice rate,chalky grain rate;The milled rice rate was significant positive related to the head milled rate,and significant negative related to the chalky grain rate;There were significant negative correlation between the head milled rate and the protein content;There were significant positive correlation between the grain length and the grain width,the ratio of length and width of the grain;There were significant negative correlation between the grain width and the ratio of length and width of the grain.(3)The cluster analysis based on characteristic traits were carried out.The results showed,158 test materials were divided into 7 groups.The average of the brown rice rate,the milled rice rate and the head milled rate of the rice in group I were highest;The average of the ratio of length and width of the grain of the rice in group V was highest and in group II was lowest;The average of chalky grain rate of the rice in group V was lowest(4.34%);The average of protein content of the rice in group VII was highest.(4)The association analysis between 267 SSR loci and quality traits of 158 rice germplasm resources in cold region shows follows,there were 7 SSR loci that were significantly associated with the brown rice rate,located on chromosomes 1,3,4,5,and 10,explaining 7.07% to 11.83% phenotypic variation;There were 7 SSR loci that were significantly associated with the milled rice rate,located on chromosomes 1,2,3,5,9,and 10,explaining 8.49% to 16.87% phenotypic variation;There were 10 SSR loci that were significantly associated with the head milled rate,located on chromosomes 1,4,5,9,and 10,explaining 7.42% to 16.19% phenotypic variation;There were 9 SSR loci that were significantly associated with the grain length,located on chromosomes 3,5,6,7,and 8,explaining 6.89% to 23.07% phenotypic variation;There were 5 SSR loci that were significantly associated with the grain width,located on chromosomes 1,7,9,and 12,explaining 7.26% to 19.94% phenotypic variation;There were 10 SSR loci that were significantly associated with the ratio of length and width of the grain,located on chromosomes 3,4,5,8,9,and 11,explaining 6.87% to 17.24% phenotypic variation;There were 5 SSR loci that were significantly associated with the chalky grain rate,located on chromosomes 1,6,8,and 11,explaining 6.42% to 21.45% phenotypic variation;There were 2 SSR loci that were significantly associated with the protein content,located on chromosomes 6,and 7,explaining 8.62% to 12.43% phenotypic variation. |
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