The Polymerization And Effect Analysis Of Sink-Source Pleiotropic Genes SS1,SS2,Ghd7 And Ghd8 In Rice

High yield is an eternal issue for rice breeding.Among the many high-yielding genes currently cloned,SS1,SS2,Gdh7,and Gdh8 are major genes that affect the sink-source traits on different chromosomes.These genes affect yield and sink-source traits,but they have different gene aggregation pairs so far.The phenotypic effects of yield and sink-source traits are poorly understood.In this research,we use four NILs carried respectively SS1,SS2,Ghd7 and Ghd8 to construct F₂ segregating population with different sink-source genes for evaluating the polymer effect of different sink-source genes.158 lines homozygous single plants with two different sink-source genes were selected out from F₂populations by MAS.The main agronomic traits of the F₃ generation of homozygous plants were investigated.The results show that the phenotype variation of pyramiding plants was abundant.Analysis of variance showed that SS1 and Ghd7 significantly increased the number of primary and secondary branches and total number of grains per panicle,resulting in a significant increase in yield per plant compared to the polymeric parent;SS1 and Ghd8 aggregates significantly increased secondary branch number,The length and width of flag leaves,plant height,number of effective panicles per plant,and total number of grains per panicle,extended the heading date and led to a very significant increase in the yield per plant.After Ghd7 and Ghd8polymerization,the number of primary branches,the number of panicles per plant and thousand grain weight increased significantly.but reduced plant height,led to a very significant increase in the yield per plant.The above three sets of double gene aggregates increased the yield per plant.The yield of the other three sets of dual gene aggregates was significantly reduced or equal to one of the parents.Specifically,the polymerization of SS2 and Ghd7 significantly increased the panicle length,reduced the number of primary branches,increased the plant height and the number of effective panicles per plant,reduced the total number of grains per panicle and the seed setting rate,and ultimately resulted in a yield per plant that was equal to that of the parent SS2,but significantly lower than the parent Ghd7;SS2 and Ghd8 after polymerization significantly increased the number of primary branches and flag leaf length,but significantly reduced the number of secondary branches and total grains per panicle,early heading date,and ultimately led to significantly lower yield per plant for both parents,SS1 and SS2 polymerization significantly increased the number of primary branches,decreased plant height and thousand grain weight,extended the heading date,and ultimately led to a single plant yield significantly lower than the parents.The results show that there are differences in the different polymerization effects produced by different high-yield gene aggregations,and it is necessary to reasonably and specifically use the polymerization of different favorable genes in the polymerization.Among the above results,SS1 and Ghd7,Ghd8 and Ghd7 and Ghd8have significant effects after polymerization.It is expected to breed excellent strains later.In order to identify and screen the excellent haplotypes of the four high-yielding genes,SS1,SS2,Ghd7,and Ghd8.630 haplotypes carrying different high-yield genes from 58 different countries or regions were selected from 3,000 germplasm resources.Among them,there were 360 copies of SS1 haplotypes and 16 different haplotypes.The haplotypes identified by phenotype identification were hap6 and hap10.The haplotypes of SS2 had a total of 425 cultivars and 13 haplotypes.The haplotypes of SS2 were hap5,hap6,hap11 and hap12.There are 445 haplotypes of Ghd7 gene,a total of 20 different haplotypes,among which the haplotypes with excellent performance are hap6,hap15 and hap18.The haplotypes of Ghd8 have a total of 481cultivars with 29 different haplotypes.The haplotypes of Ghd8 are hap1 and hap11.