Drought Stress Impact on Potato Growth

Soil moisture directly influences potato yield traits and quality indicators like tuber free amino acid content. Water deficiency during critical growth stages can lead to tuber deformities, while severe drought significantly reduces yields. However, moderate drought may improve tuber formation rate.

Research highlights that potato tuber formation and enlargement stages are highly sensitive to water stress. Drought during these periods significantly reduces total and economic yields while increasing the proportion of small tubers. Short-term water deficiency during tuber enlargement often causes deformities such as tumors, dumbbell shapes, or pointed ends.

Studies on rewatering after different drought levels show that moderate water deficiency followed by rewatering during tuber enlargement can significantly improve water use efficiency, resulting in compensatory or over-compensatory effects on final yield. Mild drought followed by rewatering increases both water use efficiency and yield compared to full irrigation; moderate drought followed by rewatering maintains similar yields to full irrigation with improved water use efficiency; while severe drought shows no yield compensation after rewatering.

Additionally, drought stress affects carbohydrate and nitrogen assimilation accumulation and distribution in tubers. Drought-treated tubers have significantly lower sucrose and starch contents but higher total nitrogen, free amino acids, and soluble protein contents compared to well-watered ones, leading to a significant decrease in the carbon-nitrogen ratio. Drought stress increases tuber free amino acid levels, particularly L-proline, L-hydroxyproline, L-arginine, L-glutamate, and L-leucine, while reducing L-tyrosine content.