ISHS Acta Horticulturae 903: IX International Symposium on Integrating Canopy, Rootstock and Environmental Physiology in Orchard Systems
APPLE CROP AND FRUIT QUALITY INFLUENCED BY LOW AND HIGH PLANTING DENSITIES ON M.9 AND M.27 ROOTSTOCKS IN NORTHERN GERMANY |
| Author: | R. Stehr |
| Keywords: | Malus × domestica, yield, fruit colour, fruit size |
| DOI: | 10.17660/ActaHortic.2011.903.93 |
| Abstract:
Apple cultivars ‘Elstar’ (Elshof) and ‘Jonagold’ (Rubinstar) were planted on rootstocks M.9 and M.27 in autumn 1994 at the Fruit Research Station Jork in Northern Germany at densities of 1500, 2000, 2500, 3000, 4000, 5000, 6000 and 8000 trees/ha. Orchard data of yield per tree and per hectare as well as fruit size and fruit colouration were recorded for 13 years. During the first years yields per tree were similar in the different planting densities. Later on the yield per tree remained static in the high-density plot while the lower-density plots showed continued yield increases. High yields per hectare were quickly obtained with high densities, while lower densities took much longer to reach full production capacity. Highest cumulative yields per ha were obtained with 5000 trees/ha on rootstock M.9, and these were not surpassed even with very high densities on rootstock M.27 (5000, 6000 or 8000 trees/ha). With increasing planting densities and higher fruit yields, the average fruit size at harvest decreased slightly by about 1 mm diameter. In a similar manner, average fruit colour was inferior at higher densities, decreasing between 5-10%. The semi-coloured ‘Elstar Elshof’ was more strongly affected by decreasing fruit colour at higher tree densities than the nearly full and dark red coloured ‘Jonagold Rubinstar’. The economic success of different planting densities depends not only on yield and fruit quality but also the cost of trees and cost of labour, and it is very much influenced by the price per kg fruit. We have not yet calculated the most successful tree density from the economic point of view, but our recorded data during a long orchard life-time provides should provide a strong database for such calculations. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
