Effects of some combined treatments on breaking the seed dormancy and enhancing the germination rate from different Morrocan varieties of date palm Phoenix dactylifera L

An accelerating worldwide trend toward planting elite cultivars is leading towards two types of date palm (Phoenix dactylifera L) propagation: offshoot propagation or a tissue culture propagation. However, the date palm diversity is nowadays facing crucial problems. The alternative for both these methods is seed propagation. Seed dormancy in date palm has continued to be challenging especially when cultivating through seeds. This study evaluated the efficiency of the operculum removal treatment combined with temperature on the seed dormancy for four different Moroccan cultivars (Najda, Boufegousse, Aziza, and Assian). A germination test was carried out using a completely randomized design. Seeds from the four cultivars were subjected to the pre-germination treatment and germination rate and speed index were measured. Results showed that the treatment significantly (p<0.05) affected the germination rate and percentage of all of the four cultivars of date palm. Germination rates were above 90% and below 20% in the treated and control seeds, respectively. Higher germination rates were found in Najda and Assian seedlings which also had the highest levels of the germination speed index. The study revealed that seed dormancy in date palm can best be overcome by a combined treatment of operculum removal and temperature.