| With the improvement of rice yield and people have payed more and more attention on eating,improving rice quality has become an important issue,but thecontradiction between rice yield and quality"high but not excellent,excellentbut not high"is still prominent,so the fundamental way to solve the contradiction is improving the quality of high yielding varieties/population.This study selected Minghui 63 which is the restore line of the"trump card"hybrid rice“Xianyou63”as the recurrent parent,with a high-quality new lines AN72 as the donor parent,created a yield selected introgressed lines BC1F5.Hardness,head milled rice rate,chalky rice rate and chalkiness degree were analyzed,including phenotypic evaluation and QTL mapping analysis.The main results are as follows:1.Hardness,head milled rice rate,chalky rice rate and chalkiness degree are continuous distribution basically in yield selected introgressed lines BC1F5,indicating that these traits are controlled by multiple quantitative trait loci（QTLs）.This study use the yield selected introgressed lines BC1F5 groups as materials and the quality traits showed normal distribution basically,indicating that the heredity of yield traits and quality traits are independent,and it is feasible to carry out QTL analysis with the yield selected introgressed lines.2.Hardness is mainly controlled by the genotype,and environment has littleimpact on it;the heredity of chalky rice rate,chalkiness degree and head milled rice rate are mainly affected by genotype,but the environmental impact on them are larger,and among them,the head milled rice is largest who affected by the environment.Chalky rice rate and chalkiness degree was extremely significant positive correlation,the correlation of head milled rice rate with chalky rice rate and head milled rice with chalkiness degree were significant negative,hardness degree and chalky rice rate wase xtremely significant negative correlation,the correlation between hardness degree and head milled rice rate was extremely significant positive correlation.3.There are 15 QTLs are detected to controlling the hardness,22 QTLs control the head milled rice rate,34 QTLs control chalky rice rate and 29 QTLs chalkiness degree.There are 37 QTLswere repeatedly detected in two years,there are two QTLs control the hardness which closely linked with marker RM6275 and RM340;the4.re are seven QTL control the head milled rice,and the contribution rate of qHR1.3 and qHR1.4 which closely linked to RM1232 and RM5389 respectively are larger,6.31%and 7.75%,there are seventeen QTLs control the chalky rice rate,the contribution rate qPGWC2.1,qPGWC2.2,qPGWC2.4 and qPGWC8.2 which closely linked with RM145,RM262,RM1942and RM458 respectively are larger,3.71%,4.32%,3.35%,8.68%,there areeleven QTLs control the chalkiness degree,the contribution rate of qC D2.1,qCD2.2,qCD8.2 which closely linked with RM262,RM145 and RM458 respectively are larger,3.26%,3.24%and 8.49%.5.Among the 37 quality related QTLs that can be detected in two years,there are 14 QTLs control two or more than two traits.The contribution rate of qPGWC3.2 which control chalky rice rate and closely linked with RM3867 on chromosome thirdis larger,9.84%,the QTL can also control the head milled rice rate,and the enhancing alleles derived from the donor parent AN72;the contribution rate of qPGWC2.1 and qPGWC2.2 which control chalky rice rate and closely linked with RM145,RM262 on chromosome second respectively rate is larger,3.71%and 4.32%,and they can also control the chalkiness degree,the enhancing alleles of them were derived from the recurrent parent Minghui 63;The contribution rate of qPGWC8.2 which control chalky rice rate and closely linked with RM458 on chromosome eighth is larger,8.68%,and the QTL can control chalkiness degree closely linked with RM340 on chromosome sixth can control hard degree,chalky rice rate and chalkiness degree;the QTL which linked with RM494 on chromosome sixth can control chalky rice rate and chalkiness degree.5.The qHD6.1 and qHD6.2 which are closely linked with the marker RM6275 and RM340 respectively and stably expressed,have not been reported,they should be the new QTL.The RM145-RM1942 on chromosome second and RM340-RM494 onchromosome sixth are hot QTL regions which control rice chalkiness.There are 13QTLs were detected in two years in these regions,the numberof QTL is large and these QTL are centralized and the hot regions have not been reported previously.The genetic expression of the hot spot region is stable,its contribution rate is large,and it is less affected by the environment,so it can be further studied forfine mapping. |
