Abstract Quinoa is a very versatile crop, amenable to the hot agronomical conditions of the Middle East, where it is cultivated under irrigation, frequently using saline water. This study aims to compare different approaches for early detection of the effect of salinity on the agronomic performance of this crop. A set of 20 genotypes was grown under drip irrigation in sandy soil at the International Center for Biosaline Agriculture (UAE). The crop was established using fresh water (0.3 dS m−1) for two weeks, after which half of the trial was submitted to irrigation with saline water, (15 dS m−1) and this was continued until crop maturity. After eight weeks of applying each specific irrigation, pigment contents were evaluated in fully expanded leaves. The same leaves were then harvested, dried and the stable carbon and nitrogen isotope compositions (δ13C and δ15N) and the total nitrogen and carbon content of the dry matter analyzed, together with the total content of K+, Na+, Mg2+, and Ca2+ ions. Genotypic and treatment effects existed for yield and biomass, as well as for the analytical traits above. The best traits in terms of correlation with biomass and yield within each irrigation regime were the Mg2+ and K+ contents and the δ15N. A stepwise model using different traits (mainly Mg2+, K+, and δ15N) explained 33.1 % of the variability in biomass and 56.0 % in seed yield, under saline irrigation, 52.4 % and 34.9 % under fresh water, and 42.4 % and 38.6 % under the combination of both irrigation regimes, respectively. Regardless of irrigation conditions, the results also showed that manure application causes salinity that is associated with high magnesium content. The combined analysis of ion concentrations and δ15N allows early evaluation of the effect of irrigation salinity and identification of the best performing genotypes under each irrigation condition.

中文翻译：

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沙漠地区灌溉藜麦的农艺性能：比较不同的盐胁迫早期评估方法

摘要 藜麦是一种用途广泛的作物，适合中东炎热的农艺条件，在灌溉下种植，经常使用盐水。本研究旨在比较早期检测盐度对这种作物农艺性能影响的不同方法。在国际生物盐农业中心 (UAE) 的沙质土壤中，在滴灌下种植了一组 20 个基因型。使用淡水 (0.3 dS m-1) 种植作物两周，然后将一半的试验提交给盐水灌溉 (15 dS m-1)，并持续到作物成熟。使用每种特定灌溉八周后，评估完全展开的叶子中的色素含量。然后收获同样的叶子，干燥和稳定的碳和氮同位素组成（δ13C 和 δ15N）和干物质的总氮和碳含量，以及 K+、Na+、Mg2+ 和 Ca2+ 离子的总含量。产量和生物量以及上述分析性状存在基因型和处理效应。在每个灌溉制度中，与生物量和产量相关的最佳性状是 Mg2+ 和 K+ 含量以及 δ15N。使用不同性状（主要是 Mg2+、K+ 和 δ15N）的逐步模型解释了 33.1% 的生物量变异和 56.0% 的种子产量，在盐水灌溉下，52.4% 和 34.9% 在淡水下，42.4% 和 38.6% 在淡水下分别结合两种灌溉方式。无论灌溉条件如何，结果还表明，施肥会导致盐度升高，而这与高镁含量有关。离子浓度和 δ15N 的组合分析允许早期评估灌溉盐度的影响并确定每种灌溉条件下表现最佳的基因型。