Abstract

The winter dormancy of buds on raspberry canes grown in Scotland does not always follow a time sequence in which dormancy is lost in response to the cumulative effect of cold. In 2 successive years (1984-85 and 1985-86), buds on some cultivars [details given] entered a period of secondary dormancy in midwinter. In one experiment, this was more intense for buds in the upper regions of the canes and is interpreted as a response to the stress factors to which they had been exposed. The percentage bud-burst was influenced by the nodal position of the buds on the cane. This relationship is attributed in part to interaction effects by the upper buds, but it was probably accentuated by differences in bud size, because buds experimentally isolated showed a linear relationship between nodal position and percentage bud-burst and also showed differences in rate of development associated with nodal position. For the fruiting canes of cultivars in earlier trials (in 1981 and 1982) in Scotland and British Columbia there was a linear relationship between nodal position and the percentage of buds that produced fruiting laterals, but there were small but significant deviations from this relationship in some cases.