In-situ preliminary assessment of centennial olive trees in Lebanon indicates a high potential for selection

Abstract

Olive has a long and majestic history in Lebanon, and centennial trees are still growing in the country as an integral part of the agricultural system. No information is yet available on the fruit and oil traits of these trees. In this study, we characterized a set of 28 olive centennials growing in five locations in the south (Hasbaya, Quawqaba, Deir Mimas), the north (Bcheale) and Mount Lebanon (Kfar Matta) between 300 and 1200 m a.s.l. Thirty-one traits related to foot and trunk dimensions, fruit and endocarp descriptors, oil content by Abencor system and fatty acids of the extracted oil by gas chromatography-flame ionization detector (GC-FID) were assessed. We noted a large variability among the centennials for most of the traits studied. The largest trees in terms of foot, trunk and cavity dimensions were those from Bcheale, followed by those from Hasbaya and Kawkaba. Small to medium-sized fruits were found in most of the centennials studied, varying between 1.11 and 3.38 g fruit-1. Endocarp morphological traits varied slightly among the centennial trees, while oil traits presented significant variability. Oil content was the highest in Kawkaba centennials, with values up to 25-28%. As to the fatty acid composition, Bcheale centennials were distinguished by their highest content of oleic acid (C18:1 up to 77.64%) and Hasbaya centennials by their highest content of both linoleic (C18:2 up to 15.2%) and palmitic (C16:0 up to 17.33%) acids. Our results indicate the technological potential of the monumental olive trees of Lebanon that should be further investigated in order to understand their performance and to evaluate them in selection programs.