ISHS Acta Horticulturae 284: I International Symposium on Walnut Production
SELECTION OF SPANISH WALNUTS (JUGLANS REGIA L.) |
| Author: | D. Frutos Tomás |
| DOI: | 10.17660/ActaHortic.1990.284.14 |
| Abstract:
The Spanish population of walnuts (Juglans regia L.) represents an important genetic resource consisting in more than half a million of old seedlings; these resources have been evaluated for several years- 1977 and 78 and from 1980 to 85- through prospective trips which included most of the places where walnuts are located. During these trips samples of fruits were collected and parameters such as bark type, tree shape and size, edafic and climatic features and accompanying flora were noted down. The Spanish walnuts can grow on soils of calcareous, granitic or metamorfic origin, most often with low fertility. Also its presence has been observed on stony sandy and clayey soils, and sometimes on waterlogged areas, but they have never been found on saline soils. The old productive walnut seedlings are also found in areas ranging from a few metres over the sea level to over 1,600 metres high. Due to these diverse conditions, a big variability has been observed in the accompanying flora. According to the bark type of the trees, five walnut groups have been distinguished. The shape of walnuts can be mainly erect or round. Several new cultivars have been selected from the most prominent old seedlings widespread in Spain. To do that, a new walnut hot callusing device has been used. This device allows using weak scion for winter grafting. | |
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