Identify And Map QTLs Of Grain Shape In Wild Rice Based On Single-segment Substitution Lines

Grain shape is closely related to rice yield and quality.It is meaningful to map and analyze genes of grain shape for breeding high yield and good quality rice varieties.Wild rice contains abundant genetic diversity and has accumulated many excellent alleles.Using wild rice as the donor to construct single segment substitution line(SSSL)and apply it to rice design breeding,which can increase the genetic diversity and enrich the germplasm resources of cultivated rice.At the same time,SSSL can eliminate the interference of wild rice’s genetic background,and it is a powerful tool for the isolation and identification of genes,especially the minor effect genes.In this study,new QTLs of rice grain shape were identified using wild rice SSSL materials,and two of these QTLs were primary mapped.The main results obtained by this study are as follows:1.Identified 20 grain length QTLs,11 grain width QTLs and 25 thousand grain weight QTLs in the SSSLs with four wild rice as donors,and there are no reported major effect genes controlling grain shape in the 24 QTLs among them.2.Using the single-segment substitution line GD50 derived from O.rufipogon to develop a mapping population,q GW7.1 was mapped to 311 kb between RM481～YJ7-10 on chromosome 7,which could regulates the grain width negatively.3.The single-segment substitution line GD59 derived from the O.meridionalis was used to develop a mapping population,and q GW8.1 was located in the interval of about2070 kb between RM6382～RM3153 on chromosome 8.q GW8.1 negatively regulates the grain width,and also have significant effect on grain length and plant height.This study enriched the understanding of the genetic regulatory loci of grain shape in wild rice,and laid a good foundation for the identification and localization of new genes.The preliminary mapping of q GW7.1 and q GW8.1 is helpful to further clone candidate genes of these loci,uncover their genetic mechanism,and improve our understanding of the genetic regulation network of grain shape.