In Experiment 1, mean daily air temperature ranged from 8.3 to 30.8 °C, averaging 20.7 °C during the growing season (Fig. 1). Daily maximum air temperature ranged from 14.1 to 40.4 °C and minimum air temperature from 0.3 to 25.9 °C. From May 17th to harvest (53 days), 44 days had a maximum temperature above 30 °C; which would inhibit tuber growth according to Kar and Kumar (2007). Air temperature in Experiment 2 varied similarly. In Experiment 3, mean daily air temperature ranged from −0.6 to 28.5 °C, averaging 19.7 °C during the growing season (Fig. 1). Daily maximum air temperature ranged from 4.6 to 36.6 °C and minimum air temperature from −4.8 to 22.1 °C. There were 51 days with maximum temperature above 30 °C during the growing season,
mainly concentrated
in the June–August period.