Abstract

1. Certain varieties of red raspberry generally bear two distinct buds (here termed primary and secondary) at each cane node. In the scale axils of these are smaller buds (termed tertiary). Inflorescence primordia may be found from late September onwards in buds of all three types, the largest and earliest-formed being on the main axes of primary buds.
2. All types of bud can produce fruiting laterals; but field surveys in two seasons of fairly average climatic conditions (1953 and 1954) showed that, whilst most of the laterals in ten varieties were formed from primary buds, there were marked varietal differences in the extent to which secondary and tertiary buds produced laterals.
3. An experiment involving the shortening of primary laterals in spring showed varietal differences in the amount of replacement growth formed from secondary and tertiary buds and in the effects of the treatments on fruit yield.
4. Canes of the variety Malling Promise in 1955 suffered severe damage ('die- back') considered to have been caused by the weather of the preceding autumn - winter period. Where complete cane death did not occur there was more injury to individual buds in this variety than in others. The problem of winter injury is discussed.