水稻糙米重金属Cd^(2+)含量的QTL分析

Mapping of QTLs of Cd^(2+) content in brown rice under Cd^(2+) stress in rice

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(5mg/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。

A population of F8 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^2＋stress.Two QTLs,qCCBR-11a and qCCBR-11b,associated with the Cd2＋content in brown rice,were detected on chromosome 11.qCCBR-11a 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-11b 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.