Identification Of Genotype And Genetic Effect For Grain Shape Based On Single Segment Substitution Lines In Rice

Rice?Oryza sativa L.?is one of the three major grain crops.The requirements for rice quality,promote the development of rice breeding for high yield and good quality.Based on the single segment substitution lines and marker-assisted selection,near-isogenic lines with different alleles which control grain size and shape were identified.Then the genes pyramiding have been successfully practiced for developing new breeds or lines,and the genetic effect of different grain shape related genes was appraised.This study demonstrated that gene pyramiding is feasible in rice breeding.The results as follows:1.GL3.1 was divided into 4 kinds of haplotype based on the sequence information of 27different rice varieties.The functional markers were used to identify the SSSLs which carried gs3,GL3.1,gw8,GW7 and GW5 separately.And 27 two-gene-pyramiding lines and6 three-gene-pyramiding lines were developed by crossing and MAS.2.There are complex genetic interaction effects between different grain shape related genes.The results showed that GL3.1 is epistatic to gw8 and GW7,gw8 is epistatic to GW7,and GW5 can inhibit the effects of gw8,GW7 and gs3 strongly.Besides,there is a considerable additive effect between GW7 and gs3.3.All the two-gene-pyramiding lines of gs3/GW7,gs3/GL3.1 and gs3/gw8^amol performed slender grain shape and up to the high quality rice standard.The gs3 is important for obtaining slender rice grain in breeding.Moreover,the two-gene-pyramiding line NIL-gs3/GW7 not only has the high grain quality but also high-yielding.4.Based on the homozygote and heterozygote analysis of two-gene-pyramiding lines in F₂ population,we found that the lines carried GW7 perform better than other lines in heterozygote.