Yield and physiological responses of potato crop under future climate scenarios of temperature increase in southern Chile

Abstract

Moderate high temperatures (15–32°C) and a decrease in rainfall are projected due to climate change for temperate areas of southern Chile, which is a high potential environment for potato. Current temperatures in these regions are in the optimum range for potato, therefore moderate temperature increases could negatively affect yields, especially in the case of a water deficit. These environmental conditions would be especially severe during the summer months when tubers bulking occurs. The objective of the present thesis was to evaluate the effect of moderately high temperatures on potato crops in order to quantify the effect of the future climate conditions expected in southern Chile, applied at different times during tuber bulking and under different water availability scenarios. Two experiments were carried out under field conditions in Valdivia, southern Chile. First, two short periods (i.e. 20 days) of exposure to moderately high temperatures were evaluated during tuber bulking under irrigation conditions. Subsequently, another experiment was carried out where a long exposure period (i.e. 40 days) to moderately high temperatures was evaluated during tuber bulking under contrasting conditions of water availability. This thesis demonstrated that an increase temperature as well as projections for climate change expected in southern Chile during tuber bulking will not adversely affect potato crop yield. Conversely, positives effects on yield could be reached in a short period of moderate high temperatures at the beginning of tuber bulking without water restriction. The advantage acquired under a short heating period, expressed as prolongation of crop cycle and increment of tuber yield, could be suppressed over a longer period under moderate high temperature. Unlike expected, the moderate high temperature under rainfed conditions would not imply a scenario more severe than each climate conditions per separate. However, temperature increase apparently will reduce the potential yield (i.e. under irrigation) of crop estimated for this region. Although Desiree exhibited a high tuber-yield stability under different ambient conditions, the results provided clear evidence that Chilean native potato Chona Negra displays a contrasting behaviour to the commercial genotypes, which would mean an advantage to future climate conditions