In Vitro Propagation of the Important Tasar Oak (Quercus serrata Thunb.) by Casein Hydrolysate Promoted High Frequency Shoot Proliferation

Abstract

An efficient micropropagation protocol has been developed for tasar oak. Nodal segments from in vitro grown seedling were used for shoot multiplication. Best shoot multiplication response, in terms of number of shoots per explant as well as shoot length, was obtained in woody plant (WP) medium supplemented with 6-benzyladenine and indole-3-acetic acid (8.88 μM BA + 1.43 μM IAA); but the establishment of cultures was difficult due to basal callus formation and necrosis in due course of time. Out of the two used growth adjuvants, casein hydrolysate (CH, 500 mg L−1) promoted shoot multiplication rate significantly in comparison to silver nitrate and also eliminated the basal callus formation problem and necrosis faced during the later stage of shoot proliferation. In vitro rooting on WP medium supplemented with 100 μM indole-3-butyric acid (IBA) when applied for 48 hr gave the best results in comparison to prolonged exposure. Well-acclimatized plantlets were transferred to the field with 80% survival rate. This protocol could be useful not only to propagate and conserve this oak but can also uplift the socioeconomic status of the Himalayan people as its leaves are used to feed the tasar silk worm during rearing period. This method will also be helpful for propagation of high value trees for a reforestation program.