Abstract

Annual removal of first-flush canes to reduce cane vigour increased the yield of fruit by an average of 38% over a 5-year period. Varying the height at which first-flush canes were removed had no effect on cumulative yield, but the later the date of annual treatment the more rapid and severe was the decline in the height and number of second-flush canes. This was more than offset by greater productivity per cane except in the fifth year. Resting plots in alternate years gave a cumulative yield 31% greater than that of untreated plots, but maintained cane production at a higher level than on annually-treated plots, thereby prolonging the potential productive life of the plantation. Increased yield of fruit by second-flush canes in comparison with first-flush canes was associated with a lower incidence of cane death probably due to raspberry cane midge (Resseliella theobaldi), but also involved were increases in the number of cropping nodes per cane and the production of more and bigger berries per cropping node. The results are discussed in relation to maximizing the beneficial effects of the cane vigour control technique on plantations of cv. Glen Clova and exploiting fully the potential yield of this cv. under Scottish conditions.