Replication Data for: Chlorophyll concentration in leaves is an indicator of potato tuber yield in water-shortage conditions

The phenotyping of secondary characters is a common practice in breeding programs aiming at finding physiological mechanism related to drought tolerance. However, the dynamics of these characters depend on crop phenology, levels of water shortage, and other factors that affect their relationship with yield and limit their capacity to be used for predictive purposes. In this work, we compared tuber yield with the temporal trend (using accumulated thermal time) of chlorophyll concentration (ChlSPAD), osmotic potential, and relative water content under water restriction. UNICA, a potato variety characterized by its low drought susceptibility was tested under full irrigation (as a control) and different treatments of partial root-zone drying and deficit irrigation in greenhouse and field conditions. ChlSPAD was the only trait showing a concurrent changing trend (slope) with yields, particularly in field conditions. The rate of greenness loss or senescence was slower in the higher water restriction treatments, which indicates that the stay-green effect (delayed senescence) occurs in some potato varieties. ChlSPADat the loss of half the maximum plant cover during senescence (between 1040 and 1170◦C days) was high and nega-tively correlated with final yield in all irrigation treatments. Our findings suggest that during senescence, chlorophyll increment is not related to a rise of carbon assimilation (non-functional stay-green), but could be associated with an oxidative stress occurrence, ultimately reducing yield.

次级性状的表型鉴定（phenotyping）是育种项目中探寻与抗旱性相关生理机制的常规手段。然而，此类性状的动态变化受作物物候期、水分亏缺程度及其他多种因素制约——这些因素不仅会干扰性状与产量间的关联，还会限制其作为预测指标的应用潜力。本研究对比了水分胁迫条件下块茎产量与叶绿素浓度（ChlSPAD）、渗透势及相对含水量的时间变化趋势（以累积积温为量化基准）。本试验以抗旱敏感性较低的马铃薯品种‘UNICA’为试材，在温室与大田环境下设置全灌溉（对照组）、不同程度的局部根区干燥及亏缺灌溉处理开展试验。叶绿素SPAD值是唯一与产量呈现同步变化斜率的性状，该关联在大田环境中尤为显著。在水分亏缺程度更高的处理组中，叶片失绿（衰老）速率更慢，这表明部分马铃薯品种存在持绿效应（延迟衰老）。在衰老进程中植株最大覆盖度衰减至一半时（对应积温1040至1170℃·日）的叶绿素SPAD值处于较高水平，且在所有灌溉处理下均与最终产量呈显著负相关。本研究结果表明，衰老过程中叶绿素含量的提升与碳同化能力的提升并无关联（属于非功能性持绿），但可能与氧化应激的发生存在联系，并最终导致产量下降。