水稻糙米重金属Cd含量的QTL分析

镉(Cd²⁺)是一种分布较广泛、毒性较强的一种重金属, 文章利用韭菜青×IR26杂交衍生的一个重组自交系群体(Recombinant inbred lines, RIL)及构建的SSR分子遗传图谱, 对控制糙米中Cd²⁺含量的QTL进行分析, 为选育籽粒中Cd²⁺低吸收或低积累的水稻品种提供参考。结果表明, 在Cd²⁺胁迫(5 mg/kg)处理条件下, 共检测到2个与糙米Cd²⁺含量有关的QTLs, 分别位于水稻第11染色体上的标记RM6288-RM6544和RM167-RM5704之间, 其中qCCBR-11a对表型贡献率为11.17%, 加性效应0.089; qCCBR-11b对表型变异贡献率为7.66%, 加性效应0.075。相关分析显示, 糙米Cd²⁺含量与株高、每穗总粒数、每穗实粒数、结实率和千粒重等产量性状的相关性均不显著, 糙米中Cd²⁺含量是一个相对独立、由基因控制的遗传性状。

Mapping of QTLs of Cd2+ content in brown rice under Cd2+ stress in rice

A population of Fs recombinant inbred lines (RILs), derived from a cross between IR26 (Oryza sativa L. spp. indica) and Jiucaiqing (japonica), were used to identify the quantitative trait loci (QTLs) for Cd~(2+) content in brown rice under 5 mg/kg Cd + stress. Two QTLs, qCCBR-lla and qCCBR-llb, associated with the Cd + content in brown rice, were detected on chromosome 11. qCCBR-lla was located at the position between markers RM6288 and RM6544, accounting for 11.17% of the phenotypic variance with an additive effect value of 0.089. qCCBR-llb at the interval between markers RM167 and RM5704 explained 7.66% of the phenotypic variance with an additive effect value of 0.075. In addition, the correlation coefficients between Cd~(2+) content of brown rice and plant height, spikelets per panicle, filled grains per panicle, seed setting rate, and 1 000-grain weight were not significant. This suggested that the Cd~(2+) content in brown rice under Cd~(2+) stress was an independent genetic trait.