INFLUENCE OF NITROGEN NUTRITION ON THE FRUIT QUALITY OF VIRUS-FREE AND VIRUS-INFECTED APPLE TREES
Fruits were harvested in September 1978 and analysed for components such as carbohydrates, malic acid and mineral elements. The rest of the fruits were stored at low temperature for investigations of bitter pit. The analyses showed the following results: fruits taken from apple mosaic virus-infected trees showed higher contents of glucose and fructose independent of their nitrogen nutrition.
Virus-infected trees had the highest sucrose content. The starch content was lowest in trees infected with apple mosaic virus. There appeared to be an inverse relationship between the contents of sugars and starch, i.e. a low glucose and fructose content corresponded to a high starch content and vice versa.
No differences were observed in the malic acid content. In spite of this, due to differing sugar contents, differing sugar/acid ratios were obtained for fruits of virus-free and virus-infected trees.
Changes in mineral content were found both with the nature of viral infection and the level of applied nitrogen.
DOI: 10.17660/ActaHortic.1980.92.41
https://doi.org/10.17660/ActaHortic.1980.92.41