Sweetpotato: Germplasm Evaluation For Wound Healing Efficiency

The short shelf-life of sweetpotato storage roots under tropical marketing conditions is a major limitation in many developing countries. The shelf-life under sub-optimal environments typical of marketing conditions, is related to the ability of roots to heal their wounds. A rapid method was developed to assess the wound healing efficiency by staining for lignin, which forms an important barrier above the new wound periderm, that grows underneath a wound. A wide range of cultivars (44), sourced from various regions of the world, were screened and tested for their wound healing efficiency, dry matter content, sugar content, and the rate of water loss after wounding. Wound healing efficiency was related to the origin of cultivars and African cultivars; were poor wound healers. Dry matter and sugar content were also found to be related to wound healing efficiency, although other factors are clearly more important. The actual rate of wound-healing under optimal conditions was not related to the ability to wound heal under sub-optimal market conditions. Blocks of tissue show wound-healing capacity and will be used for further investigations. Desiccation of tissue blocks inhibits wound-healing in a cultivar specific manner, although no differences in rates of water loss among cultivars could be found. Studies on the water activity within the tissue, changes with water loss and the relationship to activity of key enzymes during lignification are underway.