A. Yamasaki et al., Effects of day and night temperatures on flower-bud formation and bolting of Japanese bunching onion (Allium fistulosum L.), J JPN S HOR, 69(1), 2000, pp. 40-46
Citations number
15
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Plant Sciences
Journal title
JOURNAL OF THE JAPANESE SOCIETY FOR HORTICULTURAL SCIENCE
Effects of day and night temperatures on flower-bud formation and bolting o
f Japanese bunching onion (Allium fistulosum L.) were investigated by using
mid - season flowering 'Kincho' and 'Asagi-kujo', and late-season flowerin
g 'Cho-etsu'.
Exp.1. Plants were grown at 3, 7, 11, and 15 degrees C at night and 20 degr
ees C during the day for 20 to 60 days. Flower- bud formation was promoted
at 3 degrees C: and, especially, at 7 degrees C in all cultivars. More than
50% of 'Kincho' and 'Asagi-kujo' plants formed flower buds at 15 degrees C
when grown for 60 days; only 10% of 'Cho-etsu' bolted.
Exp.2. Plants were grown at 7.0, 13.5, 20.0 or 26.5 degrees C during the da
y and 7.0 degrees C at night. Bolting of 'Kincho' and 'Asagi-kujo' plants a
t 7.0 degrees C and 26.5 degrees C was slightly retarded, compared to plant
s exposed to 13.5 degrees C and 20.0 degrees C. The bolting rate of 'Cho-et
su' was lower in all day temperatures than were those of 'Kincho' and 'Asag
i-kujo', irrespective of the duration of treatments. Over 60% of 'Cho-etsu'
bolted when grown at 7.0 degrees C and 13.5 degrees C for 75 days, whereas
only 33.3% bolted at 20.0 degrees C; no plants bolted at 26.5 degrees C. T
hus,'Cho-etsu' plants were devernalized at day temperature 20.0 degrees C a
nd 26.5 degrees C.
Based on these results, the optimum night temperature for flower bud format
ion of Japanese bunching onion is 7 degrees C at 20 degrees C during the da
y. Devernalization occurs in 'Cho-etsu' at and above 20 degrees C; it rarel
y occurs in 'Kincho' and 'Asagi-kujo' below 26.5 degrees C.