Effect of Culture Media and Plant Growth Regulators on Shoot Proliferation and Rooting of Internode Explants from Moroccan Native Almond (Prunus dulcis Mill.) Genotypes

In this study, several methods have been used to facilitate shoot formation from nodal explants of local almond ecotypes known as “Beldi” grown in Eastern Morocco. Nodal segments of divers old local genotypes were cultured on various concentrations of auxin (indole-3-butyric acid (IBA)) and cytokinins (6-benzyl-aminopurine (BAP), thidiazuron (TDZ), and kinetin (KIN)) added to two different media (Murashige and Skoog (MS) and Heller medium). The results showed that TDZ was more effective than the other tested hormones for in vitro proliferation of the “Beldi” ecotype. TDZ at the concentration of 1 mg/L significantly improved the nodal shoot proliferation rate, with the highest percentage (63.6% ± 0.63) and number of regenerated shoots (13 ± 0.54) recorded for S1 genotype inoculated on MS medium, while the most significant rooting rate (60.41% ± 0.81) of proliferated shoots and number of roots per shoot (7.3 ± 1.36) were achieved for S2 genotype on 1 mg/L of IBA incorporated to a half-strength MS medium. With 80% of plantlets survival, the rooted shoots were successfully adapted to the in vivo conditions and were grown vigorously in the greenhouse without any morphological abnormalities.