QTLs Mapping Of Yield Dominant In Northern Japonica Restorer Line C418 And Cluster Analysis Of Japonica Rice Resources

The theoretical research of rice heterosis is lagging behind the application of breeding practice.Although it has been reported that the genetic basis of rice heterosis has been studied by QTL mapping in Indica and wild rice,the genetic mechanism of rice heterosis is still unclear.In this project,the strong dominant hybrid Japonica rice combination?Liaoyou 5218?and the recombinant inbred line?BC₁F₆,167 lines?with one backcross of the female parent of the japonica backbone restorer line C418 and the population?F₁?of the population and its female parent were used as the locating population.Statistical analysis of 6 yield factors of recombinant inbred lines,test F₁group,F₁and parents was carried out to explore yield dominance loci and gene interaction effects in Japanese backbone restorer line C418 in order to reveal the genetic basis of Heterosis in Japonica rice and enrich the theory of Heterosis in rice.Further,genetic cluster analysis was carried out on the strong dominant lines of recombinant inbred lines and different types of Japonica rice resources.Different dominant groups were classified according to production practice,and matching patterns suitable for different ecological regions were put forward,which provided new ideas for the application of heterosis group theory in rice.The results showed that the yield of F₁was mainly influenced byeffective panicle number and grain number per panicle,and the effective panicle number,total grain number per panicle,grain number per panicle,seed setting rate,1000-grain weight and yeild per plant were significantly positively correlated with paternal parent,especially the correlation between total grain number per panicle and seed setting rate was more close.The heterosis of F₁and male parent compared with primary F₁general trend of dominant change is basically the same,but it does not show a linear change with the paternal parent,indicating that some F₁shows a different trend from the paternal parent due to the higher positive or negative superparental advantage.When the paternal traits were at a high level,F₁generally had a mesophilic advantage,but the superhydrophilic advantage was not obvious,and the additive effect was dominant in all traits.As the paternal trait level gradually decreased,At the middle and high level,the superparental dominance of F₁gradually became obvious,and the phenotypic values of many traits were higher than that of F₁at the high level of the fathers.At this time,the dominant effect of heterozygous dominant sites was significantly higher thanadditive effect.When the phenotypic value of the male parent was lower than that of the female parent,the majority of F₁showed a mesophilic dominance,and some traits were still significantly superior to the male parent.In some traits,a high level of paternal should be the aggregation of multiple excellent genes of the parent,or the original heterozygous dominant locus has been replaced by the mother,and then cannot form effective heterozygous dominant locus when hybridizing with the mother.The location of C418 heterosis-related QTLs was significantly different between 167 F₁lines and Liaoyou 5218 and C418.The RAD-seq method was used to excavate high-quality SNPs in 167 F₁breeding lines.Totally,40968 SNP markers were screened on 12chromosomes of rice.As the basis of genetic linkage map construction and QTL mapping,the results showed that there are 3 QTLs related to plant height advantage,two chromosomes 3and one chromosome 5.There are two QTLs associated with the advantage of ear length,both on chromosome 4.There are two real QTLs associated with the number of chromosomes on chromosomes 5 and 11.There are 4 QTLs associated with 1000-grain weight,and on Q1,4,6,and 10 chromosomes,among them the contribution of QTL on chromosome 10 is the largest.There are 3 QTLs related to effective panicle number,and on the 5th,10th,and 11th chromosomes,the contribution of QDL on chromosome 10 is the largest.There are 4 QTLs associated with yield of per plant,two on chromosome 5 and very close,and one on chromosomes 10 and 11.No QTLs were found to be significantly correlated with total grain number and seed setting rate.Finally,9 QTLs related to 5 agronomic traits were predicted.Among the 9 QTLs related to yield,4 were located on chr03,and 2were located on chr10.Among yield-related genes,ITPK3 and EGY3 were related to plant height,CYP724B1,GAPC2,TRS120,BADH1,AOX1a,AOX1b and COLD1 were related to average panicle length.;ACT2 and BAMY1 were associated with 1000-grain weight and number of tillers per plant,respectively.We believe that these 9 yield-related QTLs may be of great value for the identification and marker-assisted selection of candidate genes in rice breeding.INDEL and SSR markers were used to preliminarily analyze 74 Japonica Rice Resources in Northeast China.The materials were clustered and clustered by Structure and Powermarker v3.25 software.The results showed that the test materials could be divided into four small groups.In the cluster analysis chart,Longjing 30,Japonica 20,Tong 823 and other varieties of Heilongjiang and Jilin varieties were combined with the indica type control variety 9311and the hemiplegic material C418.The other japonica rice varieties were distributed in threedifferent groups.The genetic differences of Japonica rice materials in the three groups were small and their genetic relationships were close.The results were consistent with the field performance and results.In practical breeding,indica materials with distant genetic relationships could be selected for cross matching by referring to the information in cluster map.Furthermore,the results of cluster analysis of RIL medium-strong dominant lines and japonica rice resources at home and abroad were further selected,divided 202 materials into 9groups.Among them,The first groups are the female parent group in the northern rice area,which is characterized by a scorpion-type background,a light-light insensibility,and a small scorpion-type.The fifth group is the female group of the Huanghuai rice area,which is characterized by a scorpion-type background,sensitized or medium-sensing,and a small scorpion-type.The second group is the partial japonica parent group,which is characterized by thick rod,large spike,low temperature resistance and premature aging resistance in later stage.The seventh group is the paternal group,which is characterized by a partial background,a temperature-sensing type,and a large-sized type.The Liaoyou 5218 backcross recombination system is mainly distributed in the 9th groups.According to this,the grouping model can be divided into three parts:one is the dominant group of genetic interactions;the other is the temperature-sensitive and photosensitive interaction group of ecological response;the third is the yield component factor?panicle-tillering complementary?mutual dominant group.