Growth Habit Varieties with erect growth habits lend themselves to systems with lower renewal zones such as mid-wire cordon or pendlebogen. Varieties with procumbent habits should have a high renewal zone. Fruiting Habit Crop control is easier with varieties with fruitful base buds when there are fewer sites for base bud retention. Cordons have many sites where base buds are retained, and these greatly increase the number of clusters produced at a given pruning level. Another factor to consider is cluster weight.
Traditional spur pruning generally retains fewer nodes per vine than cane pruning.
Thus spur pruning is useful for varieties with high crop weight production per retained node, and cane pruning is used for shy bearing varieties with small cluster weight. Disease susceptibility Fruit and the buds in the renewal zone tend to be produced in the same place. Shaded renewal zones also tend affect the micro-climate of the fruit zone. Dense canopies restrict air flow, increase drying time and interfere with spray penetration. For varieties which are sensitive to bunch rot, such conditions can spell disaster.