Micropropagation of some Sewa Oasis Date Palm (Phoenix dactylifera L.) Cultivars Grown in Egypt

Abstract

Shoot tip and leaf primordial explants of Phoenix dactylifera L. cvs. (Sewi and Oshkingbeel) were cultured in modified MS medium supplemented with various combinations between different growth regulators cytokinins (2iP or BA) and Auxins (2, 4-D or NAA). Friable callus was produced from shoot tip and leaf primordial explants. The highest percentage of callus initiation was achieved on modified MS medium supplemented with 100 mg/L 2,4-D and 3 mg/L 2iP for shoot tip and leaf primordial explants. The highest percentage of embryogenic callus was achieved on modified MS medium supplemented with 10 mg/L 2,4-D, 5 mg/L NAA, 3 mg/L 2iP and 3.0 g/L activated charcoal which gave 87.5% and 75% for Sewi and Oshkingbeel cvs., respectively. Somatic embryos formation were obvious on modified MS medium plus 0.1 mg/L NAA which gave the highest average number (5.16, 4.94) for Sewi and Oshkingbeel, respectively after three subcultures. Greatest embryonic elongation resulted at 0.5 mg/L 2iP + 0.5 mg/L kinetin + 40 g/L sucrose in solid full strength MS medium. Also, the highest value of leaves number was shown on the same medium. The complete plantlets developed from individual embryos (5-10 cm) were transferred to rooting MS medium supplemented with 1 mg/L NAA with good growth in solid and liquid media. Rooted date palm plantlets from both cultivars were transferred to plastic pots (5cm diameter) containing peat-moss, sand and vermiculite at equal volume. Acclimatization percentage decreased gradually during four months in the first acclimatization stage. Date palm plantlets produced from the first acclimatization stage were transferred to plastic pots (20 cm diameter) containing peatmoss, washed sand and vermiculite at equal volume for more growth and development to be ready to cultivate in the field. Although survival percentage was low during the first acclimatization stage, it was very high in the second acclimatization stage and date palm survival percentage became constant after another six months with good growth.