Sweet potato (Ipomoea batatas L.) is mostly grown in Asia, which accounts for 86% of global production. However, its production is under threat by salinity. Little is known about genotypic responses to salinity in sweet potato. Phenotypic responses or physiological processes linked to salt tolerance that could be developed into a reliable screening tool to assist breeding have not yet been developed for sweet potato. In a hydroponic cultivation system, 12 contrasting sweet potato genotypes were subjected to 0, 50, 100 and 150 mM root zone salinity (RZS). Genotypic thresholds for dry matter accumulation and the genotypic slopes for additional dry matter reduction when the RZS increased beyond the genotypic threshold were determined. Sodium, chlorine and potassium (K) were determined from above-ground biomass and correlated with the genotypic thresholds found. Genotypic threshold levels were linearly negatively correlated with the difference in tissue K content at 75 mM RZS and the tissue K content at control levels. Based on the genotypic ability to retain high tissue potassium levels under increasing RZS, we propose a screening tool based on these experimental data that can distinguish between salt-tolerant and salt-sensitive genotypes and indicate the potential yield level of the sweet potato genotypes.

中文翻译：

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钾含量是甘薯块茎形成前耐盐性的主要驱动因素

红薯 ( Ipomoea batatasL.) 主要生长在亚洲，占全球产量的 86%。然而，其生产受到盐度的威胁。对甘薯盐分的基因型反应知之甚少。与耐盐性相关的表型反应或生理过程可被开发成一种可靠的筛选工具以协助育种，但尚未开发出用于甘薯的表型反应或生理过程。在水培系统中，12 种不同的甘薯基因型分别受到 0、50、100 和 150 mM 根区盐度 (RZS) 的影响。确定了干物质积累的基因型阈值和当 RZS 增加超过基因型阈值时额外干物质减少的基因型斜率。钠、氯和钾 (K) 由地上生物量确定，并与发现的基因型阈值相关。基因型阈值水平与 75 mM RZS 的组织 K 含量差异和对照水平的组织 K 含量的差异呈线性负相关。基于在增加 RZS 下保留高组织钾水平的基因型能力，我们提出了一种基于这些实验数据的筛选工具，可以区分耐盐和盐敏感基因型，并指示甘薯基因型的潜在产量水平。