Role of season, source of explant, media concentration and sterilants in obtaining aseptic cultures for initiating in vitro tuberization in sweet potato

In vitro tuberization in sweet potato is a potential means for germplasm exchange in sweet potatoes, though not exploited due to the lack of a reliable protocol. The initiation of in vitro cultures and in vitro tuberization in sweet potato is limited due to fungal contamination and poor response of cultures. In order to obtain aseptic cultures, the effect of season was studied in khariff, rabi and summer seasons, and effect of source of explants studied using explants from storage root sprouts vs. field grown plants. Two sterilants, sodium dichloroisocyanurate and mercuric chloride, were compared on explants from storage root sprouts. The effect of media concentration on plant growth parameters was studied using full and half-strength MS medium. Significant difference was obtained in the results. Summer season was found to be best for the collection of field explants, storage root sprouts were better to field explants and sodium dichloroisocyanurate was assessed as an effective sterilant in terms of low contamination and better survival percentage. A single-node culture gave rise to shoots with 23 nodes after 20 weeks on full-strength MS media, which could be used as source of aseptic explants for initiating in vitro tuberization without using sterilants, thus improving in vitro response.