In vitro Pollen Germination of r our Olive Cultivars (Olea europaea L.): Effect of Boric Acid and Storage

摘要

This work aimed to optimize the pollen germination of four olive cultivars Koroneiki, Frantoio, Manzanille and Nabali, in order to use pollen resource in cross pollination assays. Pollen samples were subjected to 2 experiments to assess the effect ofboric acid and storage treatments on the germination fertility (viability, germination and tube growth). First, pollen of each cultivar was exposed to boric acid at 0 and 100 ppm added to an agarized medium. For storage, pollen grains were conserved in freezer (-20°C), in refrigerator (+10°C) and at room temperature (25°C; control) during 0, 1, 6 and 12 months. The results showed that the addition of 100 ppm boric acid to the culture medium not only increased the pollen germination by 12-24.9% according to the cultivars but also resulted in an increased tube length after 5 h instead of 9 h in control (without boric acid). Pollen of all cultivars showed greater tolerance for low temperature storage -20 and 10°C and not for high temperature (25°C).Increasing storage period of pollen grains from 1 to 12 months, resulted in a decrease in those parameters in all cultivars tested, these reductions were evident after one month of storage. Pollen death occurred rapidly after 1 month when held at room temperature (25°C) while for temperatures storage of -20 and +10°C, pollen death occurred after 6 months. These pollen characters indicate a potential for using these pollen grains as pollinator for self-incompatible olive cultivars found in Al-Jouf conditions.