Understanding physiological and biochemical mechanisms associated with post-harvest storage of Yam tuber (Dioscorea sp.)

Abstract

Yam (Dioscorea sp.) is an economically important staple root tuber crop of tropical and subtropical regions. Tubers are nutritious and contain carbohydrates, proteins, micronutrients, vitamins, and several other beneficial compounds. Yam species differ in their biochemical constituents, dormancy period, and storability. Tubers are dormant after harvest and the duration of the dormancy period in yams varies from 50 to 210 d depending on species, genotype, cultural practices, growing, and storage conditions. Depending on the final usage, tubers can either be stored for short- or long-term periods under proper ventilation with 15−17 °C/70%−80% relative humidity. Post-harvest storage losses are one of the major constraints in yam production that limits its usage for human consumption and industrial purposes. Long-term storage causes tuber sprouting, transpiration, respiration, rotting, pathogen infestation, and other physiological losses. Both dormancy and storage can be manipulated using the application of synthetic chemical fungicides, bio-pesticides, and plant growth hormones such as gibberellic acid along with the proper storage practices. As both dormancy and storage of yams result in physiological, biochemical, and molecular changes, understanding key metabolites, genes, and regulatory pathways associated with these processes is necessary. This can be achieved by measuring rotting losses, weight loss, starch, and sugar content along with the associated enzymes and expression of key genes involved in starch-to-sugar conversion. The present review summarizes insights into post-harvest storage losses, dormancy, metabolomic, and transcriptomic approaches associated with yam tubers.

Keywords

• dioscorea
• dormancy
• metabolomic
• nutritional
• physiological
• storage