Abstract
The effects of day and night temperatures after flowering on the seed growth of quinoa were examined using two varieties, Amarilla de Marangani (valley type) and NL-6 (sea-level type), cultivated in growth cabinets. From sowing to flowering time, both varieties were grown at a day temperature of 25°C and night temperature of 10°C under a 13-hour day length condition. After flowering, the plants were divided into 6 plots, and kept under an 11-hour day length condition with a day temperature of 30°C, 25°C or 20°C with a night temperature of 17°C (30/17, 25/17, 20/17°C), or night temperature of 10°C, 15°C or 20°C with a day temperature of 25°C (25/10, 25/15, 25/20°C). The increase of night temperature from 10 to 20°C did not change the seed thickness. However, the decrease of day temperature from 30 to 20°C promoted seed growth, and the 1000 seed weight was the largest at 20°C although the seed thickness was not changed. The change in day temperature to 20°C increased both 1000 seed weight and seed number in Amarilla de Marangani, and the seed weight was the heaviest at a day temperature of 20°C. On the other hand, in NL-6, the seed number decreased with the decrease in day temperature, and seed weight was the heaviest at a day temperature of 30°C. Thus, there were differences in the effects of day temperature on seed growth and formation between the valley type and sea-level type quinoa.
