Studies on dormancy in strawberry plants
II. Vegetative and flowering response of Donner variety transfered from the open to a greenhouse at different dates in autumn and winter
1970 Volume 39 Issue 3 Pages 232-238
Details
1970 Volume 39 Issue 3 Pages 232-238
Twenty potted plants each of Donner variety were transfered from the open to a greenhouse, in which minimum temperature was maintained higher than 10°C, at two weeks intervals from September 28 to February 2. One half of each group was kept under natural day length, while another half was exposed to longday (16 hours), and their subsequent vegetative and flowering behaviors were recorded.
Petiole length and leaf area of new leaves and flower cluster length were reduced as the transfer was delayed until November 23, and thereafter, they were increased as it was delayed. This result showed that dormancy in Donner variety was deepest in late November, and was broken gradually by chilling temperature during winter in this experimental condition.
Vegetative growth of the plants exposed to long day was better than that of the corresponding plants grown under natural day length (short day). The promoting effect of long day was least in the plants transfered in late November, and was significant in the plants in non-dormant condition.
Runner was not formed in the plants transfered earlier than January 18 under natural day length, and earlier than January 4 under long day condition. It seemed that the plants could not form runners until their dormancy was nearly broken.
A flowering period of about 60 days was followed by a second flowering period with a short interval of few flowerings in the plants under natural day length. Under long day condition, the second flowering period was observed in the plants exclusively transfered from October 26 to January 4 while it was not found in the plants transfered earlier or later than the above mentioned period. This result suggested that the plants in deep dormancy could form flower buds even under the long day condition which was known to be unfavorable to the flower bud formation.
Proper time of covering plants with plastic film was discussed in relation to the forcing of Donner variety.
