摘要
[Objective] This study aimed to identify possible quantitative trait loci (QTL) for vegetative drought tolerance traits of rice (Oryza sativa L.). [Method] A total of 184 rice genotypes were field screened and 156 SSR markers randomly distributed at each 3 Mb bin were used through genome-wide scanning method and association analysis to detect QTLs for vegetative drought tolerance traits leaf rolling (LER), leaf drying (LED) and drought recovery rate (DRR). [Result] The experimental rice genotypes showed varied response under vegetative drought, LER, LED and DRR were highly correlated. Population structure was detected at K=3 and K=7, certain extent of admixture existed in the experimental rice genotypes, relative kinship of the rice genotypes ranged from 0 to 0.924 5. Significant linkage disequilibrium among SSR markers was detected. Sixteen SSR markers have been detected to be associated with vegetative drought tolerance traits, four for LER, eight for LED and four for DDR. Most of the markers were associated with more than one trait, indicating a single mechanism might involve in expression of several related traits, i.e. osmotic adjustment. RM107 (Chr.9) was associated with all the three traits and fell exactly within or closely nearby to previous reported regions, was a major QTL for vegetative drought tolerance, RM477 (Chr.8) was significantly associated with DRR and extremely significantly associated with LER was probably another major QTL for vegetative drought tolerance. [Conclusion] Association mapping is a very effective method for describing complex traits like drought tolerance.
[目的]此研究旨在检测水稻苗期抗旱性的数量性状位点。[方法]通过对 184 份水稻品种的田间苗期抗旱性鉴定,同时利用每 3Mb 为一区间随机分布于水稻 12 条染色体上的 156 个 SSR 标记子对卷叶、枯叶及复水恢复率 3 个苗期抗旱性性状进行标记,通过关联分析检测此 3 个性状的数量性状位点。[结果]水稻品种对苗期干旱具有不同的反应,卷叶、枯叶及复水恢复率这3个性状具有显著的相关性,对该群体在群体结构K=3 和 K=7 时进行了分析。[结果]该组水稻品种存在一定程度的遗传混杂,品种间的相互遗传相关性范围从 0 到 0.924 5。SSR 标记子间存在着明显的连锁不平衡。该试验共检测到与苗期抗旱性关联的16个SSR标记子,其中4个与卷叶性状,8个与枯叶性状,4个于复水恢复率紧密关联,而且大多数的标记子与2个以上的性状关联,表明某个单一抗性机理可能与多个不同性状的表达相关,如:渗透势调节。位于第九染色体上的RM107 标记子与所有 3 个苗期抗旱性性状关联,并且位于以前研究所报道的区间之内,为苗期抗旱性的主要位点,位于第八染色体上的 RM477与复水恢复率显著关联,且与卷叶性状的关联达到极显著水平,该位点可能是苗期抗旱性的另一个主要数量性状位点。[结论]关联分析是用于分析复杂性状(如抗旱性)非常有效的方法。
