水稻苗期耐Cd胁迫的QTL定位分析

[目的]进行水稻苗期耐Cd胁迫的QTL初步定位。[方法]（1）以Lemont（美国）和Dular（印度）杂交建立的重组自交系（RILs）群体，包括123个家系和亲本在内，用含有0.2mg/L镉的水培液进行处理，以不加镉培养的水培液作为对照，考察了叶绿素含量、根长、株高、叶长等4个性状，并转换成抗性指数，用于评价水稻对Cd污染的抗性指标。（2）在已构建的以109个引物为基础的遗传图谱上进行复合区间定位。[结果]（1）共检测到9个加性QTLs，涉及1，2，3，11等4条染色体，其中，以叶绿素抗性指数为指标，检测到3个与耐Cd有关的QTLs 分别位于第2，3，11染色体上，解释了14%，9%，9%的表型变异；（2）以根长抗性指数为评价指标，只定到1个位于第1染色体上控制耐Cd的QTLs，解释了9%的表型变异; （3）用株高抗性指数进行定位，共有3个与耐Cd相关的QTLs，位于1，1，11染色体上，分别解释了10%，27%，10%的表型变异；（4）而以叶长抗性指数进行水稻秧苗耐Cd性表现的QTL定位，结果发现也有2个QTLs与其耐Cd 反应有关，它们分别位于1，11染色体上，解释了21%，12%的表型变异。分析表明，在采用不同评价指标所检测到的9个与耐Cd相关的QTLs中，有7个集中于第1和第11染色体上，其中第1染色体上有4个，第11染色体上有3个。（结论）以株高和叶绿素抗性指数为评价指标，检测到的QTLs最多，根长抗性指数为评价指标的最少。研究还发现在第1和第11染色体上的相同区间内同时检测到以不同抗性指数为评价指标的多个与耐Cd相关的QTLs，推测它们可能是功能相同的几个紧密连锁的非等位基因，也可能就是同一等位基因的不同表现形式，从而也说明了该评价指标用于基因定位的准确性和可行性。

QTL Mapping for Cadmium Tolerance in Rice (Oryza sativa L.) Seedling

[Objective]Research was done to detect the QTLs of tolerance to heavy metal cadmium in rice accessions.[Method](1) A recombinant inbred lines (RILs) including the population of 123 F10, which were derived from a cross between Indica rice Lemont（Cd Tolerance，USA）and Japonica rice Dular（Cd sensitive rice, India）was employed to investigate the genes in rice related to heavy metal cadmium (Cd) stress. All rice lines including parents were grown in Hoaglland solution with 0.2mg/L additional cadmium, and all entries grown in Hoaglland solution without additional cadmium were serviced as control. (2)The chlorophyll content (CC), root length (RL), shoot heigh (SH), leaf length (LL) were determined and transformed to Index of Cd Tolerance (ICT) for QTL location involving 109 SSR markers by composite interval mapping (CIM). Nine additive QTLs were detected and mapped to chromosome 1, 2, 3, 11, respectively. Three QTLs, which were evaluated by ICT from the CC and located on chromosome 2, 3 and 11, explained 14%, 9% and 9% of the phenotypic variation, respectively. One QTL, which was detected by ICT from the RL and mapped to chromosomes 1, accounted for 9% of the phenotypic variation. Three QTLs, which were evaluated by ICT from the SH and mapped to chromosomes 1,1,11, contributed 10%, 27%, 10% to the total phenotypic variation. Two QTLs by the ICT from the LL were located on chromosome1 and 11, and accounted for 21% and 12% of the phenotypic variation. The result showed that seven out of nine QTLs associated with Cd tolerance were located on chromosome 1 and 11, of which 4 QTLs were on chromosome 1 and 3 QTLs were on chromosome 11. （Conclusion）It was found that that some QTLs associated with Cd tolerance were located in the same marker intervals on chromosome 1 and 11, implying that they maybe different alleles with the same functions or may be the same gene in different performent manners. At the same time, it suggested that the indexes was approciate and feasible.