Äppelträd på egen rot

Tutkimustuotos: OpinnäyteKandidaatintutkielma


I cite literature for the use and characteristics of own-
rooted apples. The own-rooted trees have been reported for many good qualities: life vigour, disease resistance, fruit setting, fruit quality and re-growth true to the variety after damage to the trunk. In absence of growth control through dwarfing rootstocks, the growth management of own-rooted trees has to be done by cultural methods such as: careful use of nitrogen and irrigation, right and timely pruning (summer), bending down young branches and use of crowded planting.

A problem with own-rooted trees remains in propagation, as it is difficult to root cuttings from apple varieties. A great deal of research on the methodology of rooting apple cuttings has been done in England, at research station in Long Ashton, East Malling and Brogdale. There is however still insufficient knowledge about feasible techniques of propagating own-rooted trees from cuttings. No work has been done so far with the varieties cultivated in Finland.

I concentrate my paper on describing the methods of rooting apple cuttings. These involve the use of IBA-hormone (indolyl butyric acid), wounding of the cutting base, bottom heat in the rooting bins and withholding budburst by low air temperatures. Micro propagation has today become an important means of propagating large numbers of plants with certified variety, origin and free from disease. Rooting apple micro cuttings confronts similar problems as rooting normal cuttings and is by no means a straight forward process. Research in rooting micro cuttings has been done at different research stations round the word. In Finland MTT Agrifood Research Finland, Laukaa Research Station micro propagates today 10 own-rooted apple varieties (6 fruit trees). I further consider the propagation of own-rooted apple from root cuttings and from coppice shoots. In these cases you need to have an own-rooted tree to begin with. The nurse root method, however, involves the use of grafting onto a week rootstock (‘M27’) that cannot meet the requirements of the scion. This promotes the development of adventitious roots on the scion itself.

I made a rooting experiment with hardwood cuttings of 8 Finnish apple varieties and the rootstock ‘A2’ following methods mentioned above. This experiment failed most probably because it was done too late in the season; air temperatures could not be controlled, which in turn led to rapid budburst before rooting. The only surviving cuttings were those of the rootstock ‘A2’, which is very easily rooted. From the 30 ‘A2’ cuttings 50 % rooted. These were more often the larger ones and those treated with IBA or “willow water” (a legendary natural rooting agent), but the difference does not reach significance on account of the low frequencies. A small experiment with softwood cuttings showed clear difference between callus growths on different apple varieties. Liquid solutions of IBA, willow water and water control seemed also to have different effects.

I discuss the possibility of using own-rooted apples and hence the need of finding out effective methods of propagation. The own-rooted trees have special values for home gardens, but there may be additional usage in the commercial production at the edge of the fruit cultivation area (Finland) and in ecologic farming. The rooting of apple cuttings should be tested for the Finnish apple varieties. I very much hope to be able to continue with such experiments myself.

I want to express my special gratitude to Hilma Kinnanen from MTT, Piikkiö, who helped me so willingly with the practicalities of the experiment work and to Hugh Ermen, the father of the own root fruit tree project in England, who gave me valuable hints for literature and information on personal experiences by e-mail. I also thank Ursula Twomey from East Malling and Marjatta Mikkonen from the Finnish Museum of Natural History for help with literature, Antero Järvinen and Risto A. Väisänen (FMNH) for advice on statistic analysing, the supervisors of my work and other staff at the gardening school Överby trädgårdsskola, the staff at MTT research stations in Piikkiö and Laukaa, and student Curt Lönnberg and my brother Pentti Hildén for showing interest at my work.
Julkaisun otsikon käännösApple trees growing on their own roots
TilaJulkaistu - 9 jouluk. 2007
Julkaistu ulkoisestiKyllä
OKM-julkaisutyyppiG1 Ammattikorkeakoulututkinnon opinnäytetyö, kandidaatintyö

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