Seed Priming Enhances Germination and Morphological, Physio-Biochemical, and Yield Traits of Cucumber under Water-Deficit Stress

PurposeGrowth and productivity of high-value crops, such as cucumber (Cucumis sativus L.), are seriously threatened by irrigation water scarcity necessitating the adoption of climate-friendly drought mitigation practices. Seed priming has a proven role in enhancing seed germination, early seedling growth, reproductive development, and yield attributes under stressed conditions. The objective of this study was to assess the comparative effectiveness of different priming materials on morphological parameters, physio-biochemical traits, fruit yield, and irrigation water productivity of cucumber under water-deficit stress.MethodologyA factorial polyhouse experiment consisting of two factors, six priming treatments (non-primed control, hydropriming, and priming with potassium nitrate [KNO3], dipotassium phosphate [K2HPO4], gibberellic acid [GA(3)], and salicylic acid [SA]) and four soil moisture regimes (40%, 60%, 80%, and 100% field capacity [FC]), was conducted.ResultsDecreasing soil moisture level from 100 to 40% FC caused a 37-48% reduction in shoot dry matter, 30-51% reduction in fruit weight, 77-84% reduction in fruit yield, 41-48% reduction in membrane stability index, and 30-119% increase in electrolyte leakage across seed priming treatments. Seed priming improved all evaluated germination, morphological, fruit yield and quality, and physio-biochemical traits, where KNO3 was the most effective priming material, which caused more than three-fold increase in fruit yield and irrigation water productivity compared with the non-primed plants. Physio-biochemical performance in terms of free proline concentration, net photosynthetic rate, stomatal conductance, and transpiration rate was also enhanced in the KNO3-primed plants in comparison to the non-primed plants regardless of soil moisture regimes.ConclusionThe results imply that priming of cucumber seeds, especially with KNO3, protects plants against water loss and increases their dehydration tolerance. Seed priming with KNO3 could be recommended for cucumber production under limited soil moisture availability.