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以超级杂交稻协优9308(协青早B/中恢9308)衍生的234个重组自交系(RIL)为材料,在正常水分和20%聚乙二醇(PEG-6000)模拟水分胁迫处理下对水稻苗期最长根长、总根长、根表面积、根体积、根平均直径、根尖数、根鲜重和根冠比进行QTL定位分析。采用复合区间作图法,共检测到影响8个根部性状的21个QTL,单个QTL可解释的表型变异介于4.80%～11.35%。其中,正常水分条件下检测到7个QTL,分布在第2、3、9、10、11染色体上;水分胁迫条件下检测到14个QTL,分布在第2、3、5、6、9染色体上。不同水分条件下检测到的QTL位点差异很大,表明不同水分条件下的遗传机制不同。在第3和第6染色体上各检测到1个根部性状的QTL簇,尤其在第3染色体RM6283-RM7370区间发现苗期根系性状与抗旱性及产量相关性状之间存在连锁关系,利用这些QTL紧密连锁的分子标记进行辅助选择,可望同时对多个相关性状进行遗传改良。
A total of 234 recombinant inbred lines (RILs) derived from the super hybrid rice Xieyou 9308 (Xieqingzao B / Zhonghui 9308) were used to study the effects of water stress and 20% polyethylene glycol (PEG-6000) The QTL mapping of longest root length, total root length, root surface area, root volume, root mean diameter, root number, root fresh weight and root / shoot ratio at seedling stage in rice was conducted. Twenty-one QTLs affecting 8 root traits were detected by composite interval mapping. The single-QTL explained phenotypic variation ranged from 4.80% to 11.35%. Seven QTLs were detected under normal water conditions on chromosomes 2, 3, 9, 10 and 11, and 14 QTLs were detected under water stress, distributed on chromosomes 2, 3, 5, 6 and 9 on. The differences in QTLs detected under different water conditions were quite different, indicating that the genetic mechanisms under different water conditions were different. A QTL cluster was detected on chromosomes 3 and 6, especially in the interval RM6283-RM7370 on chromosome 3, which showed that there was a linkage between root traits and drought-resistance and yield-related traits at seedling stage. Using these QTLs, Linkage of molecular markers for secondary selection, it is expected that multiple related traits at the same time genetic improvement.