ISHS Acta Horticulturae 65: Symposium on High Density Planting
COMPARISON OF FLAT FORMS WITH ROUND FORMS OF APPLE TREES IN THE CLIMATIC CONDITION OF CENTRAL EUROPE |
| Author: | A. Mika |
| Abstract:
Two climatic factors limit modern apple production in Central Europe: extremely low temperatures in winter restrict the use of dwarfing rootstocks, while relatively low radiation in summer requires large planting distances to assure good illumination of large and vigorous trees. In experiments started in 1964-1966 the apple cultivars Bancroft, Jonathan, McIntosh, Starking Delicious and Wealthy grafted on vigorous rootstocks (A.2, M.ll, MM.lll, Antonovka sd.) and a semi-dwarfing rootstock (MM.106) have been trained as flat forms (hedgerows) and round forms (bushes). Trees grown as hedgerows were planted at a distance of 4 - 5 m between the rows and 3 - 4 m in the rows. Trees grown as bushes were planted at 6 - 7 m between the rows and 4 - 5 m in the rows. In both the systems the trees were trained by shoot bending, tying and light pruning. There were no significant differences in yield per tree between the two systems in the early years. Gradually round bush trees became larger and produced more fruit than the flat hedgerow trees. In spite of this the yield estimated per ha during the 12 years of the experiment was much higher from flat forms than from round forms. The higher crop per ha was due to the larger number of flat trees per unit area. Flat trees reached their maximum dimensions in 8 - 10 years after planting and yields leveled off at 40 tons per ha. Round trees of the same age had still space for further growth and the yield per ha was about 20% lower. Hedgerows kept within the dimensions 3 m in height and 2 m in width with a 2 - 3 m alleyway were better illuminated than bush trees of the same age which were 3.5 m in height and 4 m in diameter. Unless the hedgerows were well illuminated the fruit colour was poorer than on bush trees. Stiff and permanently fixed branches in hedgerow system caused apples to develop red colour only on one side, while bush tree apples developed red colour on all sides because branches changed their position during summer. The hedgerows required 3 times more labour for training than the bush forms. There were no significant differences in pruning and fruit picking efficiency. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
