Growing of Black Locust (Robinia pseudoacacia L.) Candidate Cultivars on Arid Sandy Site

In the late 1990s, Hungarian Forest Research Institute researchers produced 15 micropropogated black locust (Robinia pseudoacacia L.) clones as part of a program to select clones that could be successfully grown on arid sites. Five of these clones (R.p. ‘Vacsi’, R.p. ‘Szálas’, R.p. ‘Oszlopos’, R.p. ‘Homoki’ and R.p. ‘Bácska’) have been categorized as cultivar candidates. The current study presents information concerning the ‘Bácska’, ‘Vacsi’ and ‘Homoki’ candidate cultivars. Based on research results obtained thus far, the three aforementioned candidate cultivars seem the most promising. The cultivars, aged 6-15 years, were tested in a variety comparison trial under arid, sandy soil conditions in the Danube–Tisza Interfluve near the town of Helvécia. Significant differences (p<0.05) were observed during results evaluation of full inventories and during the comparison of candidate cultivars partly with common black locust and partly with ‘Jászkiséri’ cultivars. The 15-yearold ‘Homoki’ outperformed common black locust in diameter and mean tree volume; ‘Vacsi’ outperformed in stem quality. The 14-year-old ‘Bácska’ candidate cultivar was compared with the ‘Jászkiséri’ cultivar and the ‘Oszlopos’ cultivar candidate. ‘Bácska’ proved to be significantly better in diameter and mean tree volume than Jászkiséri’, but weaker in trunk quality. The South Korean National Institute of Forest Science has supported this research for several years. The growing technology of the mentioned candidate cultivars are also examined in Korea, taking local ecological conditions into account.