Evaluation of foreign varieties of Gleditsia triacanthos L. in two sites of Central Macedonia, Greece

Gleditsia triacanthos L. is a leguminous tree, endemic to North America, resistant to drought and with good growth in alkaline and saline soils. Although it has many uses, its most important is the high feeding value of its fruits (pods) to domestic and wild animals which resulted in the development of several varieties. ln this research, 9 varieties-clones selected in southem France and the American ‘Millwood” were evaluated in two sites with semidry Mediterranean climate in the prefecture of Thessaloniki, northern Greece. In each site, 50 barerooted saplings, grafted a year ago on two years old wild rootstock, were planted (5 from each variety). Mortality and height measurements were taken at the end of growing season for 4 and 3 years respectively in the two sites. In the first site (Loutra Thermis) the mortality did not exceed 10% during the experimental period and the establishment was satisfactory. In the second site (Scholari), on the contrary, saplings started to get dry on the tops and mortality exceeded 26% apparently due to its sandy soils which could not support the plants especially during the first two very dry years. Height was significantly different among varieties in Loutra Thermis in the first 3 years but not in Scholari. In both sites, however, almost the same varieties ranked tallest all along thus suggesting their higher adaptation potential to the study areas. The first pods appeared in two varieties at the fourth year since grafting but in the following year the majority of them fruited. lt is concluded that Gleditsia has a great potential as a fodder tree but more selection work is needed so that the best varieties are developed for the semi-dry environments of northern Greece.