Tuber Growth and Nutritional Traits in Deficit Irrigated Potatoes

Knowledge of tuber growth and nutritional traits response of early potatoes to dynamic deficit irrigation is lacking. This study aimed to evaluate, over two growing seasons and using two potato cultivars (Arinda and Timate), the effects of five irrigation regimes on mean tuber weight and nutritional profile (starch, dry matter, protein, reducing sugars, and ash content) during tuber growth and at final harvest. The irrigation treatments included I0 (dry control), I100 (100% ETm from tuber initiation to the end of tuber growth), I100-0 (100% ETm until 50% of tuber growth, then no irrigation), I100-50 (100% ETm until 50% of tuber growth, then 50% ETm), and I100-75 (100% ETm until 50% of tuber growth, then 75% ETm). Regardless of cultivars and seasons, I100-50 led to higher starch content and comparable mean tuber weight, dry matter, protein, reducing sugars, and ash contents compared to I100, with a saving of irrigation water of about 800 m3 ha−1 per season. Moreover, I100-0 did not substantially modify mean tuber weight compared to I100 but improved tubers’ nutritional profile by higher starch and dry matter contents and comparable values of reducing sugars and ash, providing a water saving of about 1500 m3 ha−1 per season. The studied cultivars behaved similarly with respect to the irrigation regimes. In conclusion, it was possible to effectively apply dynamic deficit irrigation to save irrigation water without compromising tuber weight and nutritional traits.