Field responses of potato to increased temperature during tuber bulking: Projection for climate change scenarios, at high-yield environments of Southern Chile

Potato is considered a key crop for food security, mainly in developing countries. Increased temperature in future climate scenarios could be a significant constraint for potato productivity in tropical regions, while favorable for temperate regions. Global warming in the range of moderately high temperatures (15-32 °C) is projected for temperate areas of southern Chile, which is a high potential environment for potato. The present study assessed the impact of moderately high temperatures on yield and physiological traits, during tuber bulking (TB) of two native Chilean varieties and three commercial varieties. Experiments were carried out under field conditions during two growing seasons. Three thermal regimes were applied: (i) ambient temperature (T0), and increased temperature (2.3-5.3 °C) for 20 days (ii) from the beginning to middle of TB (T1) and (iii) from the middle of TB until the beginning of leaf yellowing (T2). Effect of temperature on yield and physiological performance of genotypes were dependent on the timing of heat treatments. T1 increased tuber yield by 11-59%, but T2 did not modify tuber yield. Yield sensitivity was highly dependent on genotype. Harvest index was the most sensitive trait to increase temperature at T1, decreasing in the range of temperatures evaluated without reduction for tuber yield. Increased tuber yield at T1 was associated with higher intercepted radiation between flowering and 50% of leaf brownship, explained in part by elongation of this period and stomatal conductance of leaves.