A PROMISING AND COST EFFECTIVE SURFACE STERILIZING METHOD FOR SWEET POTATO (IPOMOEA BATATASL.) CULTIVATED IN OPEN ENVIRONMENT

摘要

Sweet potato is an important staple food and industrial material crop in the world. The crop is favored by resource poor farmers due to its good performance under adverse farming conditions, peak productivity in small farming areas and high carbohydrate and vitamin contents. The advances in genetic engineering technologies have helped the researchers to modify sweet potato to encode insect, herbicide and virus resistant traits. The efficient surface sterilization method is pre requisite for successful genetic improvement in sweet potato. We report an efficient, cost effective surface sterilization procedure of sweet potato seedlings collected from green house as well as field conditions for the initiation of in vitro culture. The seedlings from six sweet potato breeding lines were used to serve the purpose. Earlier, common bleach (NaOCl) was used to sterile sweet potato terminal buds to study their effectiveness in preventing microbial growth. Fungi and bacteria were most common microbial contaminants observed in cultures. Later on, the use of H2O2 in combination with ethanol resulted in relatively less contamination. The treatment of sweet potato explants with 70% ethanol for 5 min, 0.5% Mancozeb (Dithiocarbamate) for 5 min, followed by 5% hydrogen peroxide 5 mins resulted in suppressing microbial contaminations. This is the first report of the use of Mancozeb in combination with H2O2 for successful in vitro culture studies of sweet potato using explants from open environment. These findings will help to alleviate much burden associated with initiation of sweet potato cultures especially grown in field conditions.