Influence of Explants Type, Nodal Positions and Two Cytokinins on Cassava (Manihot esculenta, Crantz) In vitro Organogenesis

Abstract

Cassava In vitro regeneration is essentially influenced by exogen factors as well as explants nature.  This work aimed to evaluate explants type and positions influence, phytohormone on cassava plantlets regeneration in modified MS media. The apex and nodes of the position 3, 5, and 7 were initiated on Murashige and Skoog (MS) based media supplemented with Gamborg B5 vitamins and growth regulators such as naphthalene acetic acid (NAA), 6-benzylaminopurine (BAP) and zeatin (ZEAT) in different concentrations. The results indicated a significant difference (p=0.0001) among explants sprouted regarding the nodes position and the cultivar genotype during the time of culture. The highest rate of regenerated plantlets was found with nodes of position 5 (95.33%) followed respectively by nodes of the position 7 (93.33%), nodes of the position 3 (89.33%), and the apex (76%). Regarding the growth regulators, NAA (0.5 mg/l) + BAP (0.5 mg/l) combination was favorable for height growth (26.2cm), and leaves development (7.84 cm) in most of cultivars, whereas NAA (0.5 mg/l) + ZEAT (0.5 mg/l) combination was more favorable to rhizogenesis in overall cultivars. Among the cultivars, the best performance in stem height (26.2 cm), in leaf length (7.84 cm), and roots number (4.64) were observed with INA 1er cultivar. The cultivars RB89509, BEN 86052, and DOKU were less grown on MS supplemented with 0.5 mg/l of BAP or ZEAT. These findings could contribute of using nodes of the positions 5, 7 as potential explants and Zeatin for cassava plantlets rhizogenesis.