Soil Water Stress Effects on Potato Tuber Starch Quality Formation

Soil water stress has a significant impact on crop physiology, however, the specific response of starch quality formation in potato tubers remains unreported. Here, two potato (Solanum tuberosum L.) varieties, one with high, and the other with low tuber starch content, were grown in pots under three different soil water stress treatments, maintaining 75, 50 and 25% of soil field capacity, respectively. Soil water stress restricted potato plant growth and development, and severe stress reduced tuber yield by 47.8% relative to the control. It also inhibited tuber starch biosynthesis, which declined by 62.4% (AGPase activity) relative to the control. Furthermore, water stress reduced tuber starch accumulation by 23.6% (total starch content) relative to the control, and finally, it shortened the tuber starch gelatinization process by 1.44% (pasting temperature) compared to the control. These results reflect the soil water stress regulation mechanism on starch formation and potato tuber quality. Moreover, the study provides a scientific basis for breeding of varieties with high starch content, for improving starch quality and high-efficiency cultivation in dryland potato production.