Influence of planting density and tree form on yield and fruit quality of 'Golden Delicious' and 'Royal Gala' apples.

摘要

A trial with different planting densities and tree training systems for the apple cultivars Royal Gala and Golden Delicious was planted in the autumn of 1992 at the experimental farm Guttingen of the Swiss Federal Research Station Wadenswil, Switzerland. The V-system with planting densities of 3000, 4000, 5000 and 6000 trees/ha, single row systems (2400, 3000 and 5000 trees/ha), the drilling system (2000 trees/ha) and the mikado system (1500 trees/ha) were compared. With increasing planting density, growth and yield per tree decreased. Thus, yield per hectare did not increase proportionally with the number of trees per hectare. The doubling of the density from 3000 to 6000 spindle trees per hectare generated 30-40% higher yields per hectare up tothe seventh year. However, this is not sufficient in offsetting the additional investment costs. Planting density of 6000 trees per hectare resulted in slight reduction of fruit size. The internal fruit quality (firmness, soluble solids and titratable acidity) was more affected by annual conditions than tree density. The orchard yields of the drilling system (3 branch elements per tree) and the mikado system (4 branch elements per tree) with 6000 elements per hectare were lower in the first years, but after that yields per hectare were equal to those of spindles with higher planting densities. The open tree form of the drilling and mikado allows optimum light interception and generates good fruit quality.