水稻耐盐萌发能力的遗传分析和QTL定位

One F2:9 recombinant inbred lines (RILs) population, derived from a cross between IR26 (Oryza sativa L. spp. indica) and Jiucaiqing (japonica), was used to construct a molecular linkage map and to identify the germination ability under 100 mmol/L NaCl for 10 d in this study. A major gene plus polygene mix inheritance model and a composite interval mapping approach were applied to conduct genetic analysis for germination ability. The frequency distributions of germination traits under salt stress in RILs population showed continuous segregation, suggesting these were quantitative traits controlled by several genes. The germination traits were complex regulated by two or three major genes plus polygene and the traits were mainly dominated by major genes, among the traits of germination rate, germination index, shoot length and seed vigor with high heritability value (over 60%). Five QTLs were identified on chromosome 2, 4, 6 and 9: two for imbibition rate (qIR-4 qIR-9), two for germination rate (qGR-2-1 qGR-2-2) and one for seed vigor (qSV-6) respectively. The phenotypic variance explained by a single QTL ranged 9.6 - 46.6% and one major QTL qGR-2-1 accounted for 46.6% of the phenotypic variation. The expression of QTLs were developmentally regulated and growth stage-specific. Most of QTLs observed here shared the similar regions of QTLs for rice salt tolerance reported previously, indicating these QTLs were reliable. However, qIR-4 was firstly reported here.