Comparative Study of the Ability of Some Olive Genotypes to Root

This investigation was carried out during the growing seasons of 2022 and 2023 in the experimental farm of Horticulture Research Institute, Agriculture Research Center, Giza, on sub-terminal cuttings of eleven distinctive Olive genotypes resulting through the Olive Genetic improvement program in Egypt, to identify the ability of these genotypes to root formation under treatment with aqueous solution of Indole butyric acid (IBA) at 5000 ppm (that commonly used in Olive propagation), then it was planted under mist condition on planting dates (January, April, July and October). The results revealed a relationship between each of planting date, endogenous constituents, anatomical examination and cability of cuttings to root. The highest increment in root formation was attained by genotype (102) that may be due the increases in carbohydrates, nitrogen content, C/N ratio and total indoles. Moreover, the anatomical study, showed that, the sclerenchyma ring does not remain conjunctiva and disappear during the rooting period that leads to rapid forming adventitious root. Otherwise, the genotype (52) and (99) achieved the low formation of roots; it may be attributed to the decrease in total indoles, carbohydrates, nitrogen content and C/N ratio that important in root formation. Additionally, low rooting percentage might be due the existence of continuous chlorenchyma sheath that forming mechanical barrier to emerge newly roots that decreases the initiate adventurous root from coming out. The eleven genotypes categorized into three groups: genotypes (102 and 66) easy-to-root, moderate as (97, 91, 69, 32 and 138) and difficult-to-root as (92, 99, 48 and 52).