Improvement Of Rice Quality Traits By Functional Marker Of Wx And Fgr Gene

1.Wx genotypes of the 13 indica maintainer lines were detected by the Wx gene functional marker "484/485".The result showed that there was significant correlation between the Wx genotypes and amylose content(AC) of rice.Analysis of F_1-3 populations derived from "â…¡-32B/Yixiang 1B" suggested that "484/485" marker was tightly linked to and co-segregated with rice AC.After carrying out marker-assisted selection(MAS) in F₂ generation,the rate of plants with the Wx homozygote genotypeâ… selected from F₃ generation reached as high as 93.5%. Based on them,combined with selection of other traits(plant type,grain type, degree of endosperm chalkiness(DEC),grain endosperm transparency(GET), gelatinization temperature(GT) and so on) and molecular marker detection.As a result,114 plants with target Wx genotypeâ… ,good plant types,slender grain type, low DEC,high GET,medium GT and AC were successfully obtained from the F₆ generation.The AC in 92.1%selected plants were between 10-20%;Result of testcross showed 74.5-86.7%plants were maintainer lines.It suggested that developing indica maintainer lines with intermediate AC by "484/485" molecular marker was feasible and effective.2.fgr genotypes of the 13 indica maintainer lines were detected by the fgr gene functional molecular marker "fgr-1F/1R".The result showed that "Yixiang 1B" had the fgr genotypeâ… (fgr/fgr) with obvious fragrance,and others had fgr genotypeâ…¡(Fgr/Fgr)."fgr-1F/1R" was used to screen F_1-3 genernation derived from the cross "â…¡-32B/Yixiang 1B",and found that the "fgr-1F/1R" marker followed a one-gene segregation pattern.After carrying MAS in F₂,the homozygote rate of the marker "fgr-1F/1R" in F₃ reached as high as 96.0%.Based on the plants with fgr genotypeâ… together with investigation and selection of other traits,such as plant type,grain type,DEC,GET,GT and so on,we had obtained 85 advanced lines in F₆, and these plants showed good plant types,slender grain shape,low DEC,high GET, medium GT and AC.Among them,82 plants(96.5%) had the obvious fragrance, whereas the remaining three plants had no obvious fragrance or non-fragrance at all. This study indicated that marker assisted selection of aromatic rice by functional marker "fgr-1F/1R" was effective.3.Genotypes of 6 indica maintainer lines were detected by "484/485" and "fgr-1F/1R",while their grain quality was determined.These two markers were used to genotype the F₂ individuals derived from the "â…¡-32B/Yixiang 1B",and selected fine plants with fgr and Wx genotypeâ… andâ…¢.Then we carried out the detection in selected plants or individuals by "484/485" and "fgr-1F/1R" combiled with the selection of agronomic and quality characters in F₃-F₆ generation.In addition, "484/485" and "fgr-1F/1R" were aslo used to screen offsprings derived from the "D62 B/Yixiang 1B","Xieqinzao B/Yixiang 1B","Baifeng B/Yixiang 1B","Quanlong B/Yixiang 1B".In F₆ generation,we had obtained advanced quality plants which have the stable character,high homozygosity,good plant type,thus has provided the good foundation for breeding of high quality male-sterile line.4.Screening the individuals of the BC₁F₁ and BC₁F₂ derived from cross, backcross and self-cross of "Xieqingzao B/Yixiang 1B" by the Wx gene functional marker "484/485".Combined with the selection of low DEC and high GET.Finally, we had obtained a good quality CMS line "Zhenong 3A",which had stable and complete male sterility,good agronomic characters,low DEC,high GET,and intermediate AC."Zhenong 3A" was registered by the Zhejiang Provincial Crop Variety Appraisal Committee in 2009.