Mapping Of QTLs For Appearance Quality And Starch Shape In Rice

Rice is one of the main crops for production and consumption in China,and it is also a model plant commonly used in biological research.The appearance quality of rice is regulated by multiple genes,but the conventional breeding methods are difficult to rapidly select and polymerize genes.Therefore,when the genetic mechanism of traits is known,molecular marker-assisted selection can effectively improve breeding efficiency.In this study,two populations were used to study the genetic basis of rice appearance quality and starch grain shape related traits.We used them to locate the quantitative trait loci（QTLs）controlling rice grain shape,1000-grain weight,chalkiness and starch grain shape traits.The main results are as follows:1.F4 population was constructed,and there are 123 families.The genetic linkage map was constructed by SSR and InDel markers.A total of 143 pairs of polymorphic markers were designed and 108 pairs of good markers were selected for mapping,and 25QTLs were detected.There are 7 grain shape QTLs.Grain length and length-width rate repeatedly detected the locus of D11₅-DD11₂ on chromosome 11,explaining the genetic variation rates of 9.99%and 8.17%,respectively.Grain width and length-width rate repeatedly detected two loci（qGW2,qGW5）located on chromosomes 2 and 5,and the effect of qGW2 was larger,the interpretation of the genetic variation rate was 17.05%,and the interpretation of the genetic variation rate of qGW5 was 13.92%.There are two QTLs for grain weight,which are qTGW5 located on chromosome 5 and qTGW8 located on chromosome 8,the former overlaps with grain shape QTL（qGW5）.qTGW8 and qGW8are similar but do not overlap,and the genetic variation rate of qTGW8 is 8.97%.There are 5 QTLs for chalkiness,which are qWBR1,qWCR2,qCR2,qCR4 and qCR6,respectively.qWCR2 and qCR2 are the same locus.The effect of qCR2 is larger,explaining the genetic variation rate of 14.23%.The effect of qCR4 located on chromosome 4 is also large,explaining the genetic variation rate of 17.33%.There are 8QTLs for starch granules,which are located on chromosomes 5 and 11,respectively.There are two sites were located jointly for starch granule area,starch granules long axis,starch granules short axis and starch granules perimeter.They are D5₅-D5₉ and D11₂-RM287,the effect of D11₂-RM287 is larger,and the range of genetic variation rates is from 21.97%to 26.10%.These QTLs with large effects and high genetic variation rates can be used as candidate QTLs for further research.2.The genetic linkage map of F₂ and F_2:3 populations derived from Hua5178S/Hua611 was constructed by GBS technology,including 1985 markers,and 15QTLs were detected.Among them,there are 6 granular QTLs.The qdGL10 detected for the grain length overlaps with the qdLWR10 detected for the aspect ratio,and the genetic variation rate is 15%and 24%,respectively.Two QTLs（qdGL2,qdGL5）are also detected in the grain length.The interpretation of the genetic variation rates were 46%and 14%,respectively,and there are two QTLs for the grain width detected on chromosomes 6 and8.There are two QTLs for 1000-grain weight,and the effect of qdTGW8 on chromosome8 is larger,explaining the genetic variation rate of 24%.There are 7 QTLs in the chalkiness,and qdWCR6 and qdCR6 are similar to the interval of qdGW6,explaining the genetic variation rates of 24%,29%,and 21%,respectively.