利用Ⅱ-32B/A7444组合CSSL群体定位水稻7个穗部性状QTL

Mapping QTLs for Seven Panicle Traits in Rice(Oryza sativa L.) Using Chromosome Segment Substitution Lines Derived from Ⅱ-32B/A7444

为发掘水稻穗部性状有利等位变异,构建了以籼稻保持系II-32B为遗传背景的A7444染色体片段置换系群体;利用QTL Ici Mapping 4.1软件对该群体7个穗部性状进行了QTL定位。结果 2年共检测到26个QTL。2年均检测到的13个QTL中,控制一次枝梗数的4个QTL位于第1、第6、第8和第9染色体,平均贡献率分别为15.16%、13.10%、29.74%和11.21%,平均加性效应分别为-1.40、1.01、1.11和0.77。控制二次枝梗数的2个QTL位于第6和第8染色体,平均贡献率分别为10.97%和21.39%,平均加性效应分别为5.45和6.36。控制每穗总粒数的3个QTL位于第2、第6和第8染色体,平均贡献率分别为8.65%、12.52%和31.22%,平均加性效应分别为-18.61、22.23和31.87。控制每穗实粒数的1个QTL位于第8染色体,平均贡献率为28.06%,平均加性效应30.85。控制千粒重的2个QTL位于第2染色体,平均贡献率分别为44.65%和17.51%,平均加性效应分别为2.88和-2.51。控制粒宽的1个QTL位于第10染色体,平均贡献率为21.96%,平均加性效应为0.11。第2、第6和第8染色体分别存在同时控制二次枝梗数、每穗总粒数和每穗实粒数QTL的区段。qSBN6和qSBN8所在区间与Hd1和DTH8的相同,但分别存在16处和1处碱基差异,推测为Hd1和DTH8的不同等位基因。qSBN2为新检测到的控制二次枝梗数位点。研究结果为实施分子标记聚合育种提供了有用信息。

For mining elite alleles controlling panicle traits in rice, a mapping population was constructed with chromosome segment substitution lines（CSSLs） by crossing and back crossing the indica variety II-32B（receptor parent） and the japonica variety A7444（donor parent）. A total of 26 QTLs associated with seven panicle traits were detected across two years using the QTL IciMapping 4.1 software, and 13 QTLs were identified repeatedly in both years. Among them, the four QTLs for primary branch number（PBN） were located on chromosomes 1, 6, 8, and 9 with average phenotypic variation explained（PVE） of 15.16%, 13.10%, 29.74%, and 11.21%, and average additive effect（AE） of -1.40, 1.01, 1.11, and 0.77, respectively; the two QTLs for secondary branch number（SBN） were located on chromosomes 6 and 8 with average PVE of 10.97% and 21.39%, and average AE of 5.45 and 6.36, respectively; the three QTLs for spikelet number per panicle（SPP） were located on chromosomes 2, 6, and 8 with average PVE of 8.65%, 12.52%, and 31.22%, and average AE of -18.61, 22.23, and 31.87, respectively; the unique locus for grains per panicle（GPP） was located on chromosome 8 with average PVE of 28.06% and average AE of 30.85; the two QTLs for 1000-grain weight（TGW） were located on chromosome 2 with average PVE of 44.65% and 17.51%, and average AE of 2.88 and -2.51, respectively; and only one QTL for grain width（GW） was located on chromosome 10 with average PVE of 21.96% and average AE of 0.11. Segments simultaneously controlling SBN, SPP and GPP were found on chromosomes 2, 6, and 8. According to bi-parent DNA sequence comparison, QTLs qSBN6 and qSBN8 were speculated to be different from Hd1 and DTH8 because 16 and 1 base difference were found, respectively. QTL qSBN2 seems to be a novel locus that controlling secondary branch number. These results are valuable for pyramiding breeding through marker-assisted selection.