ISHS Acta Horticulturae 514: XXV International Horticultural Congress, Part 4: Culture Techniques with Special Emphasis on Environmental Implications
A FAR-RED-INTERCEPTING FILM PREVENTS BULB FORMATION IN ALLIUM WAKEGI ARAKI CULTIVATED IN SUMMER |
| Authors: | H. Yamazaki, Y. Yamato, M. Hamano, H. Miura, R. Oi |
| Keywords: | Allium wakegi, bulb formation, far-red light, long day, R/FR ratio |
| Abstract:
The effects of the partial interception of far-red (FR) light on bulb development and growth of A. wakegi were investigated in the field. The bulbs were planted on Aug.6, 13, 20, 27, and Sep.3. After planting, the plants were covered with a film which had low transmittance in the FR region (FR-intercepting film), a clear film combined with a piece of white cheesecloth, or no film. The red/far-red (660±5/730±5nm) photon flux density ratios under the FR-intercepting film, clear film, and no film in natural daylight were 1.55, 1.18, and 1.10, respectively. In the plants planted on Aug.6 and 13, the bulbing ratio, the ratio of the maximum diameter to the neck diameter of a bulb, was the highest in the plants under no film, and the lowest under the FR-intercepting film. Most of plants planted on Aug.6 and some planted on Aug.13 under the clear and no films formed scaly leaves, but none of them formed scaly leaves under the FR-intercepting film. In the plants planted on Aug.6, there were no differences in shoot fresh weight under the three light regimes. When the bulbs were planted later than Aug.20, the plants did not develop bulbs under any light regimes examined, and shoot fresh weight under the FR-intercepting film tended to be inferior to that under other light regimes. These results suggest that A. wakegi plants develop bulbs when planted earlier than Aug.13, and that the covering with the FR-intercepting film prevents bulb development under such conditions. | |
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