Morphological variations and isoenzyme polymorphism of date palm clones from in vitro culture acclimatized and established on soil in South Morocco

Five clones of date palm (Phoenix dactylifera L.) corresponding to three reputed Moroccan cultivars (BFG, JHL and BSK) and two selected seedling genotypes (S16 and S35). derived from in vitro culture, were acclimatized and planted in Errachidia soil (South Morocco) in 1989. After 10 years of culture, clones were evaluated on the presence/absence of the two principal morphological characters (offshoots, inflorescences). Then. their leaf extracts were subjected to electrophoresis on polyacrylamide gels in order to determine their isoenzyme polymorphism. Inflorescence formation is relatively more frequent in the clones S 16 and S35 than in clones JHL and BSK. Clone BFG showed an intermediate situation. High isoenzyme variations were found for the oxidoreductases (peroxidases (POX) and polyphenoloxidases (PPO)), the transferase (glutamate oxaloacetate transaminase (GOT)) and the hydrolases (esterases (EST) and endopeptidases (ENP)) enzymes. The factorial component analysis exhibited a negative correlation between the two principal morphological characters (presence of inflorescences and offshoots formation). Date pal in clones typified respectively by high inflorescences and high offshoots formed two separated groups showing each one some isoenzyme characteristics. All morphological and enzyme variations were discussed in respect to the genotype effect on the micropropagation process.