2002 Volume 71 Issue 6 Pages 829-831
The interception of far-red (FR) light obviously inhibits the bulb formation of Allium × wakegi Araki plants grown in summer, but only slightly in those planted in autumn and grown until the following spring. The exposure to low temperature during winter is presumed to impair the effect of the FR-deficient light. To verify this hypothesis, bulbs of A. × wakegi 'Kiharabansei No.1', exposed to 5 or 25°C for 70 days, were grown under FR-deficient (-FR) and natural daylight (NDL). After exposure to 25°C, the plants grown under NDL formed bulbs, whereas those under -FR did not. Exposure to 5°C promoted the bulb formation in the plants grown under both light conditions. The inhibition of the bulb formation by -FR was incomplete after exposure to 5°C. The difference in the extent of the bulb formation between the plants grown under -FR and NDL was less remarkable after exposure to 5°C than to 25°C. Thus, A. × wakegi plants, exposed to 5°C, reversed the inhibitory effect of FR-deficient light on the bulb formation.