Influence of Multiple Foliar Sprays of BA or Alternate-Year Root Pruning on Growth and Fruit Size of 'Melrose' Apples

Abstract

Melrose'/M.26 apple trees that previously had been root pruned for four years or unpruned controls were either unsprayed or received five sprays of 50 ppm BA and in a second study trees were root pruned annually or in alternate years from 1987 through 1990. Multiple sprays of BA had no influence on shoot length, but root pruning reduced shoot length by 20%. Root pruning had no significant influence on yield, but reduced the amount of fruit classed as culls. Multiple sprays of BA had minimal influence on fruit size, except in 1989 when yield and fruit number/tree were reduced severely. There was little difference in the effects of annual or alternate-year root pruning on growth, yield, or fruit size. It was concluded that multiple sprays of BA cannot compensate for the reduction in fruit size caused by root pruning.