The effect of temperature on the vegetative growth and reproductive development of the primocane fruiting raspberry 'Autumn Bliss'

An experiment was carried out under semi-controlled environmental condition s to determine the effect of temperature on the rate of vegetative and repr oductive development in the primocane fruiting raspberry 'Autumn Bliss'. pl ants were grown in 5 glasshouse compartments with heating set point tempera tures of 10, 14, 18, 22, 26 degrees C and venting set points 4 degrees C hi gher under a 16 hour daylength. Vegetative and reproductive development wer e recorded weekly. The rate of node production was highly temperature depen dent increasing to an optimum temperature of 22 degrees C and declining the reafter. The rate of progress to first pick increased with temperature to a n optimum temperature of 22.4 degrees C and also declined at temperatures a bove this. Further analysis indicated that first pick occurred after the ac cumulation of 2300 Ced (effective day degree) above a base temperature of 1 .7 degrees C. The use of these data to develop a predictive model for the t ime of fruiting of 'Autumn Bliss' is discussed.