EFFECT OF VARIETY ON SUCCESSFUL GRAFTING AND DEVELOPMENT OF NURSERY TREES OF WALNUT (JUGLANS REGIA L.)

In order to improve the production of walnut nursery trees, the study was conducted on the effect of genetic characteristics of walnut varieties on callusing and development of nursery trees in the field. Leading walnut varieties and selections in the Yugoslav assortment were used: Elit, Ovcar, Champion, Ceinovo, G-139, G-251 and G-286. Graftings were taken immediately before grafting (early March, 1992, 1993). Grafting was done manually, using the method of whip grafting. Nursery trees were grown for two years in the field.

The lowest percentage of grafting realization was recorded with Champion (54.7%) and G-251 (75.1%) and highest with Ceinovo (92.9%). The above-mentioned walnut varieties with poor realization of graftings also had lower percentage of graftings survived (Champion, 76.8%; G-251, 84.9%), whereas with G-139, G-286 and Ceinovo 92% of graftings survived. One-year growth ranged from 11.2 cm (Elit) to 24.1 cm (Ovcar). Two-year growth varied between 152 cm and 187 cm for some varieties. The width of shoots averaged from 6.1 mm (G-251) to 8.3 mm (G-139). Two-year shoot width was between 15.2 mm (G-251) and 19.3 mm (Champion).

The varieties which showed more vigorous growth in the first year proved to result in better-quality nursery trees in the second year. It was observed that varieties with poor realization and survival percentage showed poor growth of nursery trees. It was concluded that walnut varieties highly influenced the development of nursery trees.