The Effect of Abscisic Acid and Sucrose on Post-Thaw Embryogenic Competence and Subsequent Plant Recovery from Embryogenic Calli of Cassava

摘要

The effect of sucrose with or without abscisic acid (ABA) in cryoprotective medium on postthaw embryogenic competence and subsequent plant recovery of embryogenic callus clumps of cassava was investigated. Post-thaw viability depended on duration of cryoprotection on the 0.3M sucrose cryoprotective medium. The presence of only ABA in the cryoprotective medium resulted in callus proliferation but loss of post-thaw viability. However, the inclusion of sucrose with low concentrations of ABA (5-10 mg/l) in the cryoprotective medium decreased callus proliferation but subsequent cryopreservation resulted in post-thaw viability and/or embryogenic competence, except at the higher concentration of ABA (20mg/l) where there was complete loss of post-thaw viability. Also, callus clumps pre-treated with low concentrations of ABA with sucrose prior to cryopreservation resulted in significantly higher plant recovery than only sucrose pre-treated callus clumps. Plants recovered from cryopreserved callus clumps were phenotypically similar to non-cryopreserved callus clumps. These results indicates that cryopreservation of embryogenic calli of cassava is a feasible option for long-term conservation of the crops’ genetic resources.