EVALUATION OF SOME WALNUT CULTIVARS WITH DIFFERENT BEARING HABITS IN THE ECOLOGICAL CONDITIONS OF OLTENIA – ROMANIA

Romania is one of the European countries with temperate climate which has significant walnut production. The Oltenia region is situated in the SW of Romania and has 15% of the walnut trees. Over 90% of the walnuts are natural hybrids on their own roots which lead to non-uniform walnut fruit production. In the last 2 decades, modern orchards with Romanian cultivars have been established. Evaluation of more then 28 cultivars (17 introduced from abroad) emphasized differences between terminal, mixed or lateral bearing cultivars regarding growth and yields in the conditions of Romania. On alluvial soils with good drainage and fertility the growth of trees in the first 12 years after planting was good for the terminal and lateral bearing cultivars. Important differences were observed regarding the response to bacterial blight attack (Xanthomonas campestris pv. juglandis). Autochthonous cultivars have less fruits affected than the introduced cultivars. Most of the lateral bearing cultivars proved to be protandrous; the cultivars with terminal bearing are almost equally divided into protandrous and protogynous. For most of the autochthonous cultivars blooming time occurs during the middle and end of April, rarely the beginning of May. The lateral bearing cultivars bloom from the end of April till the middle of May. In the 12th leaf the yields varied between 1.5 to 2.6 t/ha in the case of terminal bearing cultivars and from 1.7 to 4.1 t/ha for the lateral bearing ones. The best cultivars in the ecological conditions of Oltenia proved to be: ‘Valcor’ and ‘Jupânesti’ (terminal bearing), Hartley (intermediate) and Vina and Ferjean (lateral bearing).