Somatic Embryogenesis and Ploidy Stability in Cassava (Manihot esculenta Crantz) Cultivars Regenerated by in Vitro Culture of Young Leaves

抄録

The regeneration and cytogenetic analysis of 7 cassava (Manihot esculenta Crantz) cultivars obtained by organogenesis and somatic embryogenesis were investigated. In the first phase, callus formation was induced in young leaves using MS medium supplemented with 1.0, 5.0, 10.0, 15.0 and 20.0 mg/l of 2, 4-D or without a growth regulator (control). In the second phase (development), the calli obtained in the above treatments were transferred to MS medium supplemented with factorial combinations of GA₃ and BAP at 0, 0.5, 1.0, 1.5 and 2.0 mg/l. Results of the first phase showed that 2, 4-D induced the formation of both friable and compact calli. The compact calli displayed root and shoot formation, whilst somatic embryos were obtained only from friable calli in the medium with 1.0 mg/l GA₃. Plants obtained from somatic embryos were regenerated in MS medium supplemented with 0.04 mg/l BAP, 0.02 mg/l NAA and 0.05 mg/l GA₃. Cytogenetic analysis in 167 regenerated plants from somatic embryogenesis and 176 from organogenesis showed 2n=36 as a normal diploid chromosome number.