An efficient regeneration protocol through somatic embryogenesis and organogenesis for cassava (Manihot esculenta...

In the present study, an efficient regeneration protocol via somatic embryogenesis and organogenesis has been developed for cassava var. Vamas 1 utilizing leaf and node explants, respectively. Leaves were inoculated on Murashige and Skoog (MS) medium containing different concentrations (4, 8, and 12 mg l^-1) of Picloram or 2,4-dichlorophenoxyacetic acid (2,4-D) with 6 mg l^-1 1-naphthaleneacetic acid (NAA). The maximum callus formation (100%) was recorded in medium containing 4 mg l^-1 Picloram or 8 mg l^-1 2,4-D. However, the callus fresh weight (0.11 g) was higher in presence of 4 mg l^-1 Picloram with 2.72 scoring of callus proliferation after 3 weeks. After subculture, 12 mg l^-1 Picloram with 6 mg l^-1 NAA proved optimum medium that formed maximum 10.25±3.49 embryos (44.00±0.04% response) under dark conditions after 6 weeks. The green cotyledons were produced after 2 weeks of light incubation on 0.2 mg l^-1 6-benzyladenin (BA). which further formed shoots within 5 weeks. Simultaneously, nodal explants were placed in MS media augmented with BA (2, 4, 8, and 10 mg l^-1) individually and in combinations with 0.02 mg l^-1 NAA. Results revealed that maximum 4.13±0.56 shoots/explant were formed with 11.07±2.79 number of leaves and 3.61±0.17 cm shoot length at 2 mg l^-1 BA. These shoots induced 7.33±0.58 number of roots after 2 weeks in basal MS medium. At last, the plantlets derived via both the pathways were transferred to soil : rice husk (1 : 1 w/w), and they were successfuly acclimatized with 80% survival in greenhouse. Since the cassava plant regeneration is genotype-dependent, the developed protocol can be applied for mass-propagation of this recently released Indonesian superior variety Vamas 1. This will generate large number of plantlets for the farmers and also the protocol will be utilized for genetic improvement studies.