Mapping And Analysis Of QTL For Yield-Related Traits In Rice

Rice,as one of the world's most important food crops,can be said to meet about one-half of the world's population.China is not only a large producer of rice,but also a large consumer of rice,although in China's rice history research,there have been two significant increase in rice production experience,but the increase in rice production or catch up with the rate of population growth,We must import many rice rice every year in order to meet people's production and living needs,therefore,to study how to improve rice production is imminent.In this study,a wild type AZU was obtained under natural conditions.The main phenotype was a large change in the size of the hull,and the 1000-grain weight was significantly increased(about 1000 liters of grain weight,about 214% of the wild type).After hybridization of the mutant plants for 6 generations,the F1 generation was obtained by hybridization with the parent and another parental indica rice variety 93-11.F1 self-intersection to get F2 large groups.The F2 population was used as the isolated population for the study,and the target trait was mapped and analyzed by the composite interval mapping method and BSA(mixed grouping method).The results are as follows:(1)The total grain weight of 3454 plant seeds in F2 large population was counted,And randomly selected 384 F2 small groups as QTL mapping group experimental material,The grain length,grain width,grain thickness and grain weight of 384 plantlets were counted,It is found that these traits,whether large or small,are continuously normal distribution and are characteristic of quantitative inheritance.(2)A total of 119 SSR primers were screened on the molecular markers of polymorphism between the two parents.384 samples of this F2 population were constructed by genetic linkage map,and the total length was 2003.36 cM.The average distance between markers For 16.83 cM,covering the rice genome 12 chromosomes linkage map.(3)The QTL of grain length,grain width,grain thickness and 1000-grain weight of 384 samples were then mapped into QTL by QTL IciMapping3.0 software to obtain QTL with grain length,grain width,grain thickness and 1000-grain weight.A total of 33 QTL loci were detected,including 6 grain length QTL loci,10 grain width QTL loci,8 grain QTL loci,and 9 QTLs for 1000-grain weight;qGL8,qGW4,qGW12,qGT9-2,qGT12,qTGW9 have positive additive effect,qTGW3,qTGW3,qTGW3,qTGW3,qTGW3,qTGW3,qTGW3,qTGW3,qTGW3,qTGW3,qTGW3,qTGW3,qTGW3-1,qTGW3-2,qTGW3-3,qTGW3-4,qTGW5,qTGW8 and so on have obvious negative additive effect,the positive additive effect is derived from the mutant parent Mutant,the negative additive effect is derived from the parental parent 9311;And in the 33 QTL loci The contribution rates of qTL3-2,qGL3-3,qGW2-1,qGW5-1,qGT2,qGT5 and qTGW3-2 were higher than those of QTLs,and the contribution rates were 25.798%,11.447% and 10.801%,12.445%,18.720%,14.65% and 24.046% respectively.(4)When QTL mapping was performed with QTL IciMapping3.0 software,we used BSA to isolate the pool of extremely large and extremely small and two parents' DNA in a mixed-group separation method for high-throughput sequencing.The SNPs were detected by SNP loci,and 1,596,346 SNP loci were obtained.SNPs with polymorphism were screened.The SNPs of 640,595 polymorphisms were obtained.Then the extreme trait was selected as the reference,and the SNP-index(ie SNP frequency)of 640,595 marker sites in the parent was calculated and analyzed.Then the SNP frequency difference distribution of the offspring was made,and the SNP frequency of the whole genome Manhattan distribution map.The 95% confidence level was chosen as the threshold of screening,and the confidence interval was found to be consistent with the QTL locus obtained by QTL IciMapping3.0 software and composite interval locating method,which indicated the scientificity and accuracy of the experiment.(5)To validate the candidate genes obtained from the high-throughput sequencing results,a candidate gene was found,which was different on the base of AZU and Mutant.The mutation position was in the exon region,and the amino acid changed,and it was completely linked with the grain width.