Phenotype Analysis And Gene Mapping Of A Single Segment Substitution Grain Weight Material

Rice is one of the most important food crops in the world,more than half of the world’s population live on rice as the staple food.At the same time,rice is also an important model plant of Gramineae.The research of rice functional genes provides a strong theoretical basis for rice breeding,the identification and mapping of quantitative trait loci in genetic research and breeding is very important.Sing segment substitution lines in Rice(Oryza sativa L.)contains only one from a donor parent chromosome segments,and eliminate the interference of genetic background is important genetic materials for quantitative trait loci identification and localization,which has characteristics of single,stability and efficiency.In this research,we use the indica cultivar 9311 as receptor,japonica rice varieties Nipponbare as donor,combined with molecular marker assistion selection,a set of single segment substition lines has been established.we found a grain weight of qGW11 material in these materials,the results of genetic analysis are as follows:1.We investigated the phenotype and agronomic traits of grain weight material qGW11 and 9311.It is found that compared with recipient parent 9311,the 1000 grain weight and grain thickness of single segment substitution lines qGWll is decreased,grain length shorter than 9311,but did not reach significant level,the grain width is no difference between qGW11 and 9311.It is indicated that the grain weight may caused by the decrease of grain thickness.The electron microscope observation on the grain glume epidermal cells showed that the cell length and width of qGW11 were smaller than 9311,but the number of outer epidermal cells increased.2.The grain weight QTL was located in the position between 1 269kb and 5414kb on chromosome 11 by the 9K-SNP-chip gentyping technology.We developed Indel polymorphism markers in this interval,combined with the fragment overlapping method,mapping the grain weight QTL in the 2273kb-4 772kb region.It is found that there are two loci in this region which may be linked to the control of grain weight.3.Containing GS3 and gw5 substitutions in this set of materials SSSL also screened,NIL-GS3 controlled grain length,NIL-gw5 controlled grain width.Using the two single segment substitution lines hybridized with qGWll,to research the interaction between the three genes.As the result,in NIL-gw5/GS3,the effeect of GS3 on grain weight was larger,and negative regulation of 1000 grain weight.gw5 has a positive effect on GS3,shorten the length of NIL-gw5/GS3,ultimately formation of short round grain.In NIL-gw5/qGWll,the effect of grain weight was the same as NIL-qGWll,but the effect of grain length was between NIL-qGW11 and NIL-gw5,the grain width effect by gw5.This indicates that the grain phenotype of NIL-gw5/qGW11 polymeric material may be due to the additive effect of gw5 and qGWll.In NIL-GS3/qGWll,the genetic effect value of 1000 grain weight was larger than NIL-GS3 and NIL-qGWll.qRT-PCR results show that GS3 and qGWll in polymeric materals have no interaction.The two genes produced by the polymerization of grain shape is an additive effect.