Physiological Response to Nitrogen Deficit in Potato Under Greenhouse Conditions

Potatoes have low nitrogen (N) use efficiency due to their shallow root systems, which results in nitrate loss and reduced yield. The objective of this study was to determine physiological parameters, yield, and quality components in three potato varieties subjected to N deficiency in a greenhouse, as there are few previous studies on the relationship between N deficiency and physiological parameters. The control plants were fertilized twice with 27% calcium ammonium nitrate, while the stressed plants were not fertilized. Chlorophyll content (SPAD), biomass, N, and leaf area showed highly significant differences (<i>p</i> value < 0.05) between the control and stressed plants, the latter showing higher photosynthetic activity. Agria cv. obtained the highest SPAD value (T0: 47.93, T1: 44.45; T2: 40.18) under stress. In tubers, the concentrations of N, amino acids, vitamin C, and phenols were higher in the control plants, and Agria exhibited the greatest reduction under stress conditions. Production was reduced the most in Kennebec, with 29.22%, compared to Agria with 15.73% and Monalisa with 26.58%. The Agria variety under N deficiency showed the lowest values of nutritional compounds such as vitamin C. Physiological parameters such as photosynthetic activity showed significant correlations with tuber quality parameters such as vitamin C, amino acids, and macro- and microelements. These parameters may be useful for stress identification, as well as for the selection of more N-deficiency-tolerant parents in potato breeding programs. Upcoming studies and investigations will seek to validate the parameters assessed in field trials.