|Pyrus communis, high density planting, rootstocks, cultivar, fertigation, salinity
The main trend in European pear orchard design is to increase planting density.
High density plantings (HDP) in pear are expanding due to the widespread use of quince rootstocks to reduce tree size and induce early bearing.
However, since HDP entails high investments, the break-even point occurs 5 to 8 years after planting.
Planting density in many districts is increasing to achieve high yields, i.e. over 40-50 t/ha.
Nevertheless, planting density still ranges from less than 1,000 to 13,000 trees/ha.
Increasing pear yields beyond a certain limit can reduce fruit quality if orchard efficiency is not maintained.
Research must advance to upgrade tree efficiency via the use of dwarfing or semi-dwarfing quince or pear clonal rootstocks.
At the moment the most suitable rootstock for HDP is quince C. The planting density with quince C can range from 4,000 to 13,000 trees/ha but the level of management practices and inputs must be high to avoid a loss of tree efficiency.
For densities ranging from 2,000 and 3,000 trees/ha, the main quince stocks are BA29, which is declining in popularity, and the new Sydo which is gaining in popularity.
New quince stocks with vigour similar to quince C are the East Malling selection QR193-16, marketed as MH, and Adams.
The most important stocks for LDPs are seedlings.
The clonal seedlings from the OH×F series include some especially interesting genotypes like OH×F40 (Farold® 40). Many training systems are suitable to increase planting density, especially the V and vertical axis systems.
New ideas regarding tree shape include plants with 2 or 4 axes so as to divide the vigour over more branches.
Nurseries can provide pre-formed trees with two axes (Bibaum®) ready to be planted or, alternatively, knip the trees for spindle.
In pear a very intensive pruning can enhance fruit set of such cultivars as ‘Abbé Fétel’, ‘Doyenné du Comice’ and ‘Passe Crassane’.
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