Abstract
The effects of temperature on growth and development of floral organs and fruit in large fruited strawberry (Fragaria × ananassa Duch. cv. Ai-Berry) were investigated. Plants were grown in 1) growth cabinets held at constant temperatures of 15°, 20° and 25°C; 2) cabinet in which the day temperature was 25°C from 6:00 to 18:00 and 15°C from 18:00 to 6:00 and 3) an unheated greenhouse.
1. Before stamens differentiated, there was little difference in the rates at which flower development occurred in the treatments. However, after the onset of pistil differentiation, development of flower bud and pistil was hastened with higher temperatures.
2. Compared to plants grown in an unheated greenhouse, those grown at 15°C had more rows of pistils on the receptacle, differences in their developmental stages between the distal and proximal region of receptacle were larger, and they bloomed earlier. However, the difference in developmental stages of the proximal and distal pistils on a receptacle was small in greenhouse-grown flowers; they produced fewer malformed fruits than those grown at 15°C.
3. Fewer malformed fruits developed on plants kept at 20° or 25°/15°C than on those kept at the lower temperatures. However, the mean fruit weight on plants grown in the warmer cabinets was lighter than those from plants kept cooler.
We conclude from these results that if the average air temperature is kept higher than 15°C during the floral differentiation period, it may be more conductive to reducing malformed fruits.
