EFFECT OF TEMPERATURE ON DEVELOPMENT OF PRIMARY AXILLARY FLOWER BUNCH IN STRAWBERRY BENCH CULTURE

Flower bud differentiation of strawberry at fall term is delayed in recent years by global warming. Especially, because the differentiation of the primary axillary flower bunch is delayed, the expansion of a harvest recess period is feared in the super-forcing culture shipped in November. As for high-bench culture, the temperature of the medium is influenced easily by the air temperature around the benches, and it is surmised that the possibility of promoting the harvest recess is higher than the normal ground culture. We had executed the strawberry high-bench culture from 2007 to 2009 by the same material and method to grasp correctly the influence of the emergence timing of the primary axillary flower bunch by high temperature.
The average air temperature in September in 2007 was about 2 to 3°C higher than other two years among 3 years from 2007 to 2009. The medium temperature of the high-bench culture also showed a similar tendency. When the plants in which the terminal flower bunch was differentiated was transplanted in the end of August, and the day of the emergence of the first axillary flower bunch was investigated, it was about 7 days later in Fragaria × ananassa ‘Benihoppe’ in 2007 compared with other two years. In addition, the emergence of the primary axillary flower bunch in ‘Sachinoka’ was 12 days slower in 2007 than in 2009. As a result, it was clarified for the high temperature in September to delay the differentiation of the primary axillary flower bunch, and to expand a recess of the harvest.