The effect of direction of shoot growth on fruitfulness and yield of sultana vines

Abstract

Experiments are described in which the effect of training sultana shoots vertically or horizontally was tested. Horizontal training of shoots caused reduction in fruitfulness in all cases, with the exception of one experiment with very vigorous young vines.

Vertical growth tended to improve vigour, in which case fruitfulness was greater, but this effect decreased with increasing numbers of vertical canes per vine. Increased yield was obtained in one year out of three in a field trial where the shoots to be used as pruning wood were encouraged to grow vertically.

It is concluded that increased fruitfulness will result from measures which improve the vigour of shoots, such as vertical training, preservation of the shoot tip, or prevention of early trailing of the shoot; and that shoots which have grown horizontally should be avoided as pruning canes.