TRAINING AND PRUNING OF PEAR TREES IN COUNTRIES CHARACTERIZED BY LONG HOT SUMMERS AND WHERE DWARFING ROOTSTOCKS CANNOT BE USED, OR ARE NOT AVAILABLE.

ISHS Acta Horticulturae 367: VI International Symposium on Pear Growing

TRAINING AND PRUNING OF PEAR TREES IN COUNTRIES CHARACTERIZED BY LONG HOT SUMMERS AND WHERE DWARFING ROOTSTOCKS CANNOT BE USED, OR ARE NOT AVAILABLE.

Author:

D.K. Strydom

Abstract:
This paper deals with the pruning and training of pear trees in areas characterized by long hot summers i.e. South Africa, Chile and Argentina and also in regions where the traditional dwarfing rootstocks used for pear trees like Quince A and Quince Adams are not available. In Chile and Argentina, pear trees are only available on seedling rootstock (normally Winter Nelis). In South Africa the position is more favourable in that two locally developed clonal rootstocks i.e. BP1 and BP3 are now freely available. The climate in the abovementioned countries is also such that the switch from spring to summer is often very abrupt, resulting in unsatisfactory growth of newly planted trees during the first year. In the case of South Africa, there is also the added problem of insufficient winter chilling which necessitates the use of artificial rest breaking agents. In all the countries mentioned, sunburn of fruit is a real potential problem and any training system which is proposed should take this aspect into consideration.

In the case of pears, as with apples and other deciduous fruits there has, in recent years, been a movement to plant trees at higher densities. Initially the model developed for apples was also followed for pears, but in the recent past there has been an awareness that the growth and fruiting habits of pears are different to that of apples and that these differences should be considered when establishing, training and pruning new pear orchards. In the countries which I referred to, the starting point in most cases is a two year old "whip" or a "whip" with a few unbalanced feathers. Planting a one-year-old whip is not recommended.

The differences in the growth and fruiting habits between apples and pears can be listed as follows:

Pear trees show more transplant "shock" than apple trees. Balancing root:shoot ratio at planting time is therefore important.
Most of the pear varieties are not as strongly basitonic as apples i.e. they tend to always have a very strong central leader and a weak set of first side-scaffolds. In fact, the central leader is often too strong.
Pear trees in general suffer more from shoot:fruit competition than apples which often results in poor fruit set despite sufficient blossom. Fruit:shoot competition is especially evident when seedling rootstocks are used.
Pears in general are more easily negatively affected by poor light distribution within the trees than apples. Poor light

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