Olive seedlings are used in breeding programs as well as rootstocks for grafting of hard–to–root cultivars. However, olive seed germination is not easy, low and slow germination rate are some of the persisted problems. In vitro germination of isolated embryos could be a useful method for increasing the efficiency of germination. One of the main following objectives in embryo culture is the isolation of embryo from the endosperm that contains inhibitory germination substances. This results to shortening of reproductive cycle and the necessary time for obtaining seedlings. In this study, the embryo germination potential of three olive cultivars including \\\\\\\\\\\\\\\'Manzanilla\\\\\\\\\\\\\\\' and two Iranian cultivars i.e. \\\\\\\\\\\\\\\'Dezful\\\\\\\\\\\\\\\' and \\\\\\\\\\\\\\\'Zard\\\\\\\\\\\\\\\' was evaluated. Also the effect of three harvesting times (middle of August, September and October) on growth and development of embryos was studied. Aseptically isolated embryos were cultured in MS medium with one third of macro elements and placed in growth chamber at 25°C day, 21°C night with 16-h photoperiod. According to results, some differences were revealed between germination percent of embryos and the following growth of them. The highest germination percent and seedling formation was obtained at the first culture time with means of 86 and 73 percent, respectively. \\\\\\\\\\\\\\\'Dezful\\\\\\\\\\\\\\\' cultivar with 90% germination and 79% seedling formation showed the highest values.

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