Timing of short period water stress determines potato plant growth, yield and tuber quality

Potato growth in humid climate regions is facing increasing challenges due to short period stresses in water deficit and excess. However, there is a lack of quantitative information on the effects of short period of water stress on potato plant growth and its implications on potato yield and tuber quality. In this study, we conducted a pot experiment to test the effects of short period (2weeks) of water deficit and water excess, respectively, applied at four different potato growth stages (sprouting, vegetative, tuberization and bulking stage) on potato vegetative development and tuber yield and quality. The results show that short period of water deficit overall had negative impacts while short period of water excess had slightly positive impacts on potato vegetative development and tuber yield and quality. For water deficit, the most sensitive periods were the vegetative and tuberization stage whereas for water excess, there were mostly no-significant differences between different potato growth stages. Although the impact of water deficit at the sprouting stage was minor, it was broad and long-lasting. These results confirm the benefits of supplemental irrigation and suggest the low risk of over-irrigation in well drained fields. They further suggest that when the availability of water for irrigation is limited, using water strategically during the period when potato needs water the most can maximize the benefits of supplemental irrigation.