In Vitro Growth Response of Different Varieties of Greater Yam (Dioscorea alata L.)

Abstract

A simple, reproducible and efficient micropropagation protocol was developed for three different varieties of greater yam (  Dioscorea alata L.) viz., Sree Roopa, Sree Keerthi and Sree Shilpa using nodal segments for axillary shoot proliferation at Central Tuber Crops Research Institute, Thiruvananthapuram, India. The effect of different explants, surface sterilants and different combinations and concentrations of Benzyl Adenine (BA) and Napthalene Acetic Acid (NAA) on different parameters  viz., number of shoots, shoot length, number of roots, root length, number of leaves and number of nodal meristems were evaluated. The use of nodes from young, vigorously growing vines of sprouted tubers as well as 4 - 8 nodes from the tip of field grown plants proved to be the best explant source which gave a quick response. Minimal risk of contamination was observed with 0.08% mercuric chloride (HgCl2), which was found to be an effective surface sterilant. For  in vitro regeneration, MS media with 0.5 mg l-1 NAA and 0.75 mg l  -1 BA with 0.1% activated charcoal was found to be the best. A high percentage of shoots were seen rooted in the same medium containing 0.1% activated charcoal (92%). Regenerated plants were successfully hardened and transplanted. About 90% of plantlets survived under net house conditions.