Abstract: Salt stress is one of the abiotic stress factors repressed rice yield. With the increase of soil salinization, the breeding of new salt-tolerance rice varieties has become the effective method for improving rice yield. Compared with the hybrid breeding method, molecular marker-assisted breeding could improve the selection effect and accuracy. Taking high salt-tolerance Indica rice ST1050 and salt-sensitive Japonica variety Koshihikari as materials,   under the salt stress of 150 mmol/L NaCl liquid for one week and recovery for another one week, the survival rate of seedling was selected as the index of salt-tolerance, and 463 SSR markers uniform distributed on rice chromosomes were selected for the analysis of polymorphism of two parents to  identify  the popucations  genetic type and construct QTL mapping F2 generation. The seedling of two parents, ST1050 and Koshihikari, showed significant difference of survival rate  under salt stress with 60% and 18.75%, respectively. Among the 463 SSR markers, 121 SSR markers displayed clear codominance difference between two parents and the percentage of polymorphism reached 26.13%. The genotype of F2 population of 138 individuals was analyzed by software IciMapping 4.1. Finally, a genetic linkage map covering 1 160.09 cM genetic distance was obtained. Furthermore, combined with the phenotype of F2 population under salt stress, two QTLs, named qSR-8 and qSR-12, were identified on chromosomes 8 and 12, respectively, and explained 13.57% and 6.91% of total phenotypic variance. The study showed that Indica rice ST1050, which contained two QTL of salt-tolerance during seedling, could make a major contribution to improving salt-tolerance progress in rice breeding programs.

Key words: salt tolerance, survival rate, SSR molecular marker, quantitative trait locus, genetic linkage map

摘要： 盐胁迫是制约水稻产量的重要非生物胁迫因素。随着土壤盐碱化日益加重，培育适宜于盐碱地种植的水稻耐盐新品种是提高水稻产量的有效方法。相较于传统杂交育种，分子标记辅助育种能够提高选育的效率和精确度。选择高度耐盐籼型恢复系ST1050和盐敏感优质粳稻品种越光作为研究材料，用含有150 mmol/L NaCl的营养液处理三叶期幼苗1周，再用普通营养液恢复处理1周后，以幼苗的存活率作为苗期耐盐指标，选取均匀分布于水稻染色体的463个SSR标记对亲本进行多态性分析，鉴定ST1050与越光杂交产生的F2代群体基因型，构建遗传图谱并进行QTL定位。结果显示，籼型恢复系ST1050、粳稻品种越光的存活率分别为60%和18.75%，差异显著。463个SSR标记中有121个在ST1050和越光之间表现出较好的共显性差异, 多态性达26.13%。利用软件IciMapping 4.1分析ST1050×越光138个F2个体的基因型，最终获得了一张覆盖总遗传距离为1 160.09 cM，标记间平均距离9.59 cM的遗传图谱。结合F3代群体在盐胁迫后的存活率验证，在水稻8号、12号染色体上分别检测到1个苗期耐盐QTL，命名为qSR-8和qSR-12，贡献率分别为13.57%和6.91%。研究表明，籼型恢复系ST1050存在2个苗期耐盐QTL，对提高水稻的耐盐性发挥重要的作用，可以作为苗期耐盐供体用于标记辅助选择耐盐育种。

关键词: 耐盐, 存活率, SSR分子标记, 数量性状位点, 遗传图谱