Physiological growth responses by nutrient interruption in aeroponically grown potatoes

This study was conducted to retard potato (Solanum tuberosum L. cvs Superior, Atlantic, and Jasim) shoot growth by nutrient interruption and thereby induce tuber formation in an aeroponic cultivation system. In the period between 25 and 55 days after transplanting (DAT), a 10-day nutrient interruption was carried out on the potato plants. The interruption of nutrient supply significantly increased root activity and stolon anthocyanins, but it decreased photosynthesis and transpiration rates, and nutrient uptake in leaves. These changes in physiological growth responses induced tuber formation along the short, thin and purple-pigmented stolons. Nutrient interruptions decreased shoot growth by 50 -60% and thereby decreased tuber growth 5 -36%, when compared with the control plants. Tuber numbers increased 18% in cv Superior and did not different with the control plants in cvs Atlantic and Jasim by nutrient interruptions. The results also suggest that for minimizing a reduction of tuber production, nutrient interruptions should be conducted after sufficient haulm development (35 and 45 DAT treatment). This technique may be used to induce significant tuberization, particularly in late-season cultivars such as Jasim under hydroponic conditions.