COMPARISON AMONG DIFFERENT APRICOT TRAINING SYSTEMS IN GREENHOUSE AND IN OPEN FIELD CONDITIONS

The experimental plot includes:

• meadow orchard 2.25 x 0.1–1.0 m (4444–8888 trees/ha)
• central leader 4.50 x 1.5 m (1441 trees/ha)
• Y shaped 4.50 x 1.5 (1441 trees/ha)

For each of these planting and training systems, an equal number of trees have been used both in greenhouse and in open field conditions.

The greenhouses were covered in 1987 and 1988 with E.V.A. plastic film (thickness 0.10 mm).

After the 1986 harvest, half of the trees in the "meadow orchard" was cut back to 25 cm of height, while the remaining trees were trained as "central axis".

Pruning of "central leader" and "Y shaped" trees has been carried out mainly in summer.

The yields obtained in 1987 and 1988 were higher under plastic and the ripening time was 15–20 days earlier than in open field.

The meadow orchard (8888 trees/ha) had the highest yield per hectare, but the lowest tree crop.

The cut back leads to a severely reduced production in the following year.

The "Y shaped" training system, requiring heavy pruning, yielded less than the "central leader" both per hectare and per tree.

The fruit weight in "meadow orchard" was lower than the two other training systems.