QTL analysis for internode elongation ability in deep-water rice

采用两个参数评价深水稻节间伸长能力；最低延长节间位置（LEI）和上升水位条件下节间延长率（RIE）。以粳稻非深水稻台中65 （T65）与籼稻典型深水稻Bhauda杂交的155株F_2群体为材料，进行了QTL分析。利用93个RFLP和21个SSR标记对F2群体进行基因分型。使用QTL Cartographer v. 1.16c进行QTL分析。采用了简单区间映射（SIM）和复合区间映射（CIM）两种方法。LEI位置和RIE的qtl在1%的阈值水平下被宣布为显著性，LOD评分高于3.4，由5000个排列给出。T65和Bhauda的LEI位置分别为13.7和6.4，RIE分别为1.3和8.1 cm day^<-1>。在3号和12号染色体上检测到两个LEI位置的qtl，解释了79.3%的表型变异。对于RIE，在1号和12号染色体上检测到两个qtl，解释了49.7%的表型变异。在所有qtl中，Bhadua等位基因均增强了节间伸长能力。利用SSR标记RM6703、RM8136、RM282、RM6832、RM5479和RM2197，从75株BC3F1植株中筛选出2株，得到2个BC3F2群体。群体BC3F2-A在qLEI3区域为杂合子，在其他QTL区域为T65纯合子。同样，在含有qLEI12/qRIE12的区间内选择另一个BC3F1杂合植株获得BC3F2-B群体。两个种群的LEI均落在4个LEI等级（10、11、12和13）内。然而，没有观察到明显的双峰偏析。也不可能将RIE在BC3F2-B中的分离划分为不同的类别。我们对这些人群进行了QTL分析。在标记RM282和fl03141之间的间隔，对BC3F2-A群体的LEI进行峰值LOD评分。在BC3F2-B中，LEI和RIE的LOD评分在标记RM5479和fl12163之间达到峰值。所有qtl均具有加性效应，并表现出轻微的显性效应。其他杂合区未检测到QTL。少

We used two parameters to evaluate the internode elongation ability in deep-water rice; position of the lowest elongated internode (LEI) and the rate of internodal elongation under rising water conditions (RIE). An F_2 population consisting of 155 plants derived from a cross between Taichung 65 (T65), a Japonica non-deep water rice, and Bhauda, an Indica typical deepwater rice, was used for QTL analysis. Genotyping of the F2 population was done using 93 RFLP and 21 SSR markers. QTL analysis was performed with QTL Cartographer v. 1.16c. Both simple interval mapping (SIM) and composite interval mapping (CIM) techniques were used. QTLs for the LEI position and RIE were declared significant at the threshold of 1% level with the LOD score higher than 3.4, given by 5000 permutations. The LEI position of T65 and Bhauda was 13.7 and 6.4, and RIE of them was 1.3 and 8.1 cm day^<-1>, respectively. Two QTLs for the LEI position were detected on chromosomes 3 and 12, and explained 79.3 % of phenot … More ypic variance. For RIE, two QTLs were detected on chromosomes 1 and 12, and explained 49.7 % phenotypic variance. In all QTLs, Bhadua alleles increased internode elongation ability. We selected two plants from 75 BC3F1 plants by using SSR markers RM6703, RM8136, RM282, RM6832, RM5479, and RM2197, and generated two BC3F2 populations. The population BC3F2-A was heterozygous for the qLEI3 region and fixed to T65 homozygous in the other QTL regions. Similarly, another BC3F1 plant that was heterozygous in the interval containing qLEI12/qRIE12 was selected to obtain the BC3F2-B population. The LEI of both populations fell within four LEI classes (10, 11, 12 and 13). However, no clear bimodal segregation was observed. It was also impossible to divide the segregation of RIE in BC3F2-B into distinct classes. We conducted QTL analyses in these populations. In the interval between the markers RM282 and fl03141, peak LOD was scored for LEI in the BC3F2-A population. In BC3F2-B, the LOD score peaked in the interval between markers RM5479 and fl12163 for both LEI and RIE. All the QTLs had additive effects and showed a slight dominance effect. In the other heterozygous regions, no QTL was detected. Less