An efficient mass propagation system for cassava (Manihot esculenta Crantz) based on nodal explants and axillary bud-derived meristems

Nodes from 3- to 5-week-old in vitro plants of different cassava cultivars were cultured for 2-3 days on solid Murashige and Skoog basal medium supplemented with cytokinin to induce the enlargement of axillary buds. Subculture of theses buds on the same medium resulted in multiple shoot formation within 4-6 weeks. Of the four cytokinins tested (6-benzylaminopurine (BAP), thidiazuron (TDZ), zeatin, and kinetin), BAP induced shoot development most efficiently. The best results were obtained with cultivar TMS 30555, in which 63% of the explants each produced at least 25 shoots on medium with 10 mg/l BAP. In cultivars that did not produce shoots, the addition of the surfactant Pluronic F-68 (2% wt/vol) raised the percentage of explants forming at least 5 shoots from 0 to 20-60%. Axillary buds were also used to dissect meristems and test their ability to regenerate into shoots. Shoot formation from meristems of six different cultivars was observed after preculture on medium with 5 mg/l BAP followed by transfer to 10 mg/l BAP. (Résumé d'auteur