POSSIBILITIES AND DIFFICULTIES OF CULTIVAR INTRODUCTION INTO HUNGARIAN PLUM GROWING

The program of the Fruit Research Institute, Cegléd, comprises the introduction and testing of 5 Prunus sp. and 32 cultivars grafted on ‘Myrobalan C.679’ (P. cerasifera provar. myrobalan) seedling rootstocks. In addition, two cultivars (‘Laroda’ and ‘Santa Rosa’) have been investigated on three different seedling rootstocks: ‘Myrobalan C.174’ (P. cerasifera), ‘Bitter almond C.449’ (P. amygdalus var. amara) and ‘Sweet almond C.471’ (P. amygdalus var. dulcis). The authors explain the three possible causes of low yields experienced in non-European plums as 1: unfavorable environmental conditions; 2: lack of irrigation; and 3: insufficient information concerning the cultivar, rootstock and inadequate traditions as well as growing practices. A rather tight correlation has been found between blooming dates and the main ripening period. However, early blooming time alone cannot be considered as the cause of low productivity, without considering the possibility of a pathogen infection. The decay of plum trees is attributed to special ecological requirements and phytosanitary problems of the foreign plum cultivars. Relations involving several other characteristics were found, facilitating the appropriate selection of parents for mutual crossing in the breeding program.