Analysis And QTL Mapping Of Quality-Related Traits In Rice

Rice is an important grain crop in China.With the improvement of people’s living standard,the requirements for rice quality are getting higher and higher.Therefore,the basic research on rice quality traits is particularly important.In this study,78 indica rice varieties,157 japonica rice varieties,and 8 indica-japonica hybrid rice seedling lines,as well as 64 strains of chromosome fragment replacement line population with IR24 as background and Asominori as donor were used as test materials,and correlation analysis was conducted to investigate the relationship between each quality trait separately,and the chromosome fragment replacement line population was mapped using the compound interval mapping method for QTL detection,with the following main results:1.The variation in aspect ratio values was small for japonica rice,indica-japonica hybrid rice,and chromosome fragment replacement lines,while the variation in aspect ratio values was larger for indica rice.The variation in chalkiness was larger for both japonica and indica rice,while the variation in chalkiness was smaller for indica-japonica hybrid rice,ranging from 1.34 to 9.4 only;for the chromosome fragment replacement line population,chalkiness was low in the Sanya,Hainan growing environment,while chalkiness was higher in the Nanchang,Jiangxi environment.The viscosity characteristics were higher for both indica and Hainan Sanya-grown chromosome fragment replacement line populations and lower for the remaining types of rice varieties.The gum consistency was lower in the indica and chromosome fragment substitution line populations and higher in the remaining types of rice varieties.The straight-chain amylose of both japonica and indica rice had a large variation,and the variation of straight-chain amylose of indica-japonica hybrid rice was smaller,ranging from 15.46% to 23.68%,and the variation of straight-chain amylose of chromosome fragment substitution line groups was also larger.2.The correlation analysis of quality traits was conducted for indica rice varieties,japonica rice varieties and indica-japonica hybrid rice seedling lines,etc.It was found that the results of the correlation analysis for indica rice were basically consistent,and the results of the partial correlation analysis for other types of rice varieties were different.In the correlation study of quality traits of japonica rice,it can be concluded that there is a highly significant positive correlation between aspect ratio and grain length,a highly significant negative correlation between aspect ratio and grain width,a highly significant negative correlation between grain length and chalkiness,a non-significant relationship between grain width and chalkiness,a highly significant negative correlation between chalkiness and straight-chain starch content,a significant negative correlation between chalkiness and aspect ratio,and a significant positive correlation between straight-chain starch and abatement value.In the correlation study of quality traits of indica rice,it can be concluded that there is a highly significant negative correlation between grain length and grain width,a highly significant positive correlation between aspect ratio and grain length,a highly significant negative correlation between aspect ratio and grain width,a significant negative correlation between grain length and chalk,a significant positive correlation between grain width and chalk,a highly significant negative correlation between chalk and straight-chain starch content,a highly significant negative correlation between straight-chain starch content and gum consistency,and a highly significant positive correlation between aspect ratio and whole refined rice percentage.In the correlation study of quality traits of indica-japonica hybrid rice,it can be concluded that there is a significant positive correlation between grain length and grain width,a highly significant positive correlation between aspect ratio and grain length,a significant positive correlation between aspect ratio and grain width,a significant positive correlation between chalkiness and grain length and width,a highly significant negative correlation between straight-chain starch content and chalkiness,and a highly significant positive correlation between aspect ratio and whole finishing rice percentage.3.A total of 59 QTL were detected for processing quality,taste quality,and appearance quality,including 1 QTL for grain length,4 QTL for whole-grain length,4 QTL for grain width,3 QTL for whole-grain width,2 QTL for aspect ratio and 8 QTL for chalkiness;3QTL for brown rice percentage and 11 QTL for finishing rice percentage for processing quality;1 QTL for straight chain starch,5 QTL for gum consistency and 17 QTL for taste quality.The two loci of aspect ratio q LWR3 and chalkiness q CR5 were detected in two different environments in Nanchang,Jiangxi and Sanya,Hainan,indicating good reproducibility and stability of the loci.