The effects of lifting date, chilling duration and forcing temperature on vegetative growth and fruit production in the Junebearing strawberry cultivar Elsanta

Summary

The effects of different durations of cold storage (0, 2, 4, 6, 8, 10 and 12 weeks at –2°C and +3°C) on strawberry plants cv. Elsanta from two different lifting dates (6 November and 6 December) were investigated, to determine the chilling required for optimum growth and development. With greater durations of chilling, the petiole length, leaf weight and runner production of plants were increased. The chilling requirement for optimum vegetative growth was saturated after 6–8 weeks. For chilling durations up to six weeks there was no difference between the two cold storage temperatures, but with larger durations subsequent vegetative growth of the plants stored at –2°C was reduced compared with plants stored at +3°C. The vegetative growth after cold storage of plants lifted on 6 December was greater than that of plants lifted on 6 November. Cold storage temperature did not affect the number of flowers produced per plant, fruit number or fruit weight. However fruit number and fruit weight were both greater in plants lifted on 6 November than in those lifted on 6 December. In a second experiment, the effects of chilling duration on growth and fruiting at three forcing temperatures were studied. There was no significant interaction between chilling duration and temperature during forcing, and while eight weeks chilling was optimum for vegetative growth, in terms of fruit production four weeks chilling was optimum. Overall, these results indicate that there may be an important interaction between fruit set and vegetative vigour and that field chilling is more effective than cold store chilling in promoting vegetative growth. The results also show that the optimum chilling requirements for vegetative vigour and fruit production are different, and that chilling becomes more important when the temperature during forcing is low.