Salinity is a major environmental constraint affecting rice production in both irrigated and non-irrigated areas and threatening global food security. Development of salt-tolerant rice varieties with desirable agronomic traits is a logical approach to maintain high yield in saline areas. Here, we report development of two multi-parent advanced generation introgression line (MAGIL) rice populations in two US cultivar backgrounds and their physiological and morphological evaluation under salinity stress at germination and seedling stages. From the initial screening of 180 MAGILs in sand culture, 36 tolerant-to-moderately salt-tolerant lines were selected and further confirmed in hydroponics experiment. The selected MAGILs showed lower root and shoot Na⁺/K⁺ ratio compared with the recurrent parents. The principal component and cluster-based analysis using 12 morphophysiological traits revealed grouping of the selected lines with tolerant donors. Genotyping results with 100 polymorphic SSR markers indicated a low level of genetic diversity among these lines. Clustering based on molecular marker data separated the MAGILs from the salt tolerance donors in both populations but were grouped with the recurrent parents, suggesting genetic similarity of MAGILs with recurrent parents. The salt-tolerant MAGILs identified in this study are useful resource for investigating molecular and physiological bases of salt-tolerant mechanisms as well as for evaluating their yield potential for release as salt-tolerant rice varieties.

中文翻译：

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从水稻（Oryza sativa）两个多亲高代渐渗系群体中鉴定的耐盐育种系的遗传变异

盐度是影响灌溉和非灌溉地区水稻生产并威胁全球粮食安全的主要环境制约因素。开发具有良好农艺性状的耐盐水稻品种是保持盐碱地高产的合理途径。在这里，我们报告了两个美国栽培品种背景中两个多亲代基因渗入系 (MAGIL) 水稻群体的发展及其在发芽和幼苗阶段盐分胁迫下的生理和形态学评价。从沙培养的180个MAGILs的初步筛选中，选择了36个耐中度耐盐品系，并在水培实验中进一步证实。选定的 MAGIL 显示较低的根和茎 Na ⁺ /K ⁺与经常性父母的比例。使用 12 种形态生理学特征的主成分和基于聚类的分析揭示了所选品系与耐受供体的分组。100 个多态性 SSR 标记的基因分型结果表明这些品系之间的遗传多样性水平较低。基于分子标记数据的聚类将两个群体中的 MAGIL 与耐盐供体分开，但与轮回亲本分组，表明 MAGIL 与轮回亲本的遗传相似性。本研究中鉴定的耐盐 MAGIL 是研究耐盐机制的分子和生理基础以及评估其作为耐盐水稻品种释放的产量潜力的有用资源。