Responses of the Buds of Three South African Sweet Potato (Ipomoea Batatas) Accessions to Different Cryoprotectants

BACKGROUND: Plant Vitrification Solution 2 (PVS2) was reported to be a successful cryoprotectant solution in regenerating plantlets from sweet potato shoot tips after cryostorage. However, this was not the case for the South African sweet potato accessions. OBJECTIVE: This study assessed the responses of buds of sweet potato to different concentrations of the components of PVS2 both individually and in combination. MATERIALS AND METHODS: The percentage material that regenerated into plantlets was recorded against the total that was evaluated. RESULTS: Regeneration of buds after treatment with 5% dimethyl sulphoxide was significantly better (p<0.001) than 10-15% dimethyl sulphoxide while exposure to ethylene glycol concentrations of 5-10% were better than 15% for all but one accession. Significant difference (p<0.001) was observed in treatment with 30-40% glycerol. Combination of the components at 5% (PVS5%) was better than 10-15% dimethyl sulphoxide and ethylene glycol and 20% glycerol. CONCLUSION: It is recommended that PVS5% be used for further development of the cryopreservation protocol for the South African accessions.