Résumé
The objective of this study is the production of friable embryogenic callus in citrus to having the necessary material for protoplast isolation to be integrated into rootstock improvment programm using the asexual pathway. Ovules, embryos and styles explants of Citrus five genotypes: Poncirus trifoliate, Citrus reshni Hort. ex Tan, Citrus amblicarpa, Citrus volkameriana and Citrus paradisi Macf., are cultured in MT medium supplemented with 4% sucrose, 0.05% of malt extract and 1% agar was used as basal medium. Hormones (kinetin (Kn), 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BAP) were added to this medium at different concentrations. The rate of callus of different explants was evaluated by determining the percentage of callus induction by explant. The conducted experiments show a significant effect of genotype, explant type and hormone combination chosen. Friable callus forms were on the 3 explants with variable frequencies. Embryo explants show is most favorable to the production of friable callus; the best callogenesis is obtained with the culture media containing auxin and cytokinin combined M2 (1mg/l 2,4D+ 0.5 mg/l BAP) and M3 (1mg/l2,4D + 0.5mg/l Kn), by against the style explants and ovule have induced embryogenic calli respectively on the M4 (0.5 mg/l BAP) and M5 (1mg/l Kn) medium.