Development And Application Of Grain Shape Functional Markers In Rice

Rice is one of the most important food crops in the worldwide.More than 50%of the world's population uses rice as a staple food.With the changes in people's diet structure and improvement of living standards,the synergy of high yield and quality of rice has become the main goal of rice breeding.The research and application of rice grain shape genes and the cultivation of hybrid rice between indica and japonica subspecies will be important approaches to achieve this goal.In this study,we analyzed the gene sequences of GLW7,TGW6,GS2,and IPA1 in 28 parental materials used in our laboratory for construction of single-substitution lines,and then developed functional markers of these genes.The phenotype identification was performed using the single-segment substitution material and then the genetic effects of different haplotypes of these genes were analyzed.This study also used hybrid materials between indica and japonica subspecies to construct the F₁ population.Genotypes and grain shape of the parents and F₁ populations were detected,and the effects of different genotypes in these materials were also analysed.1.The results of base sequence analysis of GLW7?Os07g0505200?show that 5 kinds of haploid genotype are detected in 28 materials,and 3 of them carry functional variation locus.We developed functional markers based on the above locus and screened the SSSL materials with this functional variation.The results showed that the length of SSSL material with functional variation was shorter,the length and width ratio decreased,and the thousand seed weight decreased.2.The results of base sequence analysis of TGW6?Os06g0623700?show that 4 kinds of haploid genotype are detected in 28 materials,and 3 of them carry functional variation loucus.We developed functional markers based on the above locus and screened the SSSL materials with this functional variation.However,phenotypic studies showed that there was no significant difference between the grain length and thousand seed weight of SSSL material carrying functional variation locus and the recipient parent,which may be related to the genetic background of the material.3.The results of base sequence analysis of GS2?Os02g0701300?show that 4 kinds of haploid genotype are detected in 28 materials,but all the tested materials do not have the functional variation locus of TC?AA on the third exon.There was a significant difference between the grain width and the thousand seed weigh between different haplotypes which were differentiated by a sequence variation in GS2 coding region.Functional variation locus were not detected in 28 materials for IPA1?Os01g0350900?.4.A total of 185 F1 combinations were constructed using 15 indica rice restorer lines male parent and 24 japonica sterile lines female parent.The genes of the male parent and female parent were tested with the alleles of GW5,gw8,gs3,GW7,GLW7,GL3.1,TGW6and GS2.The results showed that the GW7 has a much more pronounced grain effect in our material,and it has a more pronounced genetic effect in the development of the indica-japonica hybrid rice.The gene combination of gs3,gw8 and GW7 is more conducive to the grain shape improvement of indica-japonica hybrid rice,which is of great value for the synergism of rice yield and quality.