Short days and temperature effects on growth and flowering in strawberry (Fragaria x ananassa Duch.)

'Korona', 'Elsanta', 'Bounty' and 'Senga Sengana' strawberry (Fragaria x ananassa Duch.) plants, were placed at constant temperatures of 9, 15 or 21 degrees C and daylengths of 8 h (short day) or 24 h (long day). The plants were given different numbers of short-day (SD) cycles, and flowering and growth were studied. 'Korona' and 'Elsanta' were responsive to both short-day treatment and temperature, with optimum flowering at 15 degrees C and 24 SD. 'Bounty' was more responsive to temperature, inducing flowers independently of the number of SD cycles at 9 degrees C and 15 degrees C. In 'Senga Sengana' flowering was induced independently of temperature and the number of SD cycles, indicating that it had a stronger dependence on other environmental effects. The effect of the number of short-day cycles and the temperature on vegetative growth variates such as the number of stolons and daughter plants, the length of flower trusses and petiole length were also studied.