Alteration of media enables efficient in vitro cloning of mature Elaeocarpus serratus L. (Ceylon olive): a commercially important fruit tree.

Abstract

Elaeocarpus serratus is a fruit tree able to propagate through conventional vegetative means to a limited extent restricts its wide cultivation by the farmers. In the present report, we have developed an efficient in vitro propagation protocol using mature nodal explants from a 17-year-old tree for the first time with 6.6 shoots/culture. Explants cultured on agar (0.8%) gelled standard Murashige and Skoog (MS) medium, ½ MS, ¾ MS, White's, Gamborg's B5 or woody plant medium (WPM) supplemented with 2.5µM benzyl adenine (BA) and 0.1µM α-naphthalene acetic acid (NAA) showed the superiority of ½ MS medium in terms of explant response and number shoots (6.6). Further optimization of ½ MS medium by altering nutrient elements (macros, micros, vitamins and Fe EDTA) were undertaken, and MS medium composed of half-strength major salts, original strength of minor salts and vitamins were supplemented with BA (2.5µM) and NAA (0.1µM), produced enhanced axillary bud proliferation (8.88/explant) and shoot elongation (3.83cm). Reculturing of original explant on this medium after IV passages produced more than 16 healthy shoots per culture which attained a length of 4.13cm. Microshoots raised through this way were rooted (86.11%) ex vitro by pulse treatment with 2mM indole-3-butyric acid (IBA) for 5min followed by planting in nursery pots containing a 1:1:1 (v/v/v) mix of sand, soil, and farmyard manure. The hardened plants were successfully planted in the fruit tree garden of the Department. Genetic fidelity of micropropagated and mother plants were tested using random amplified polymorphic DNA (RAPD) and inter simple sequence repeat (ISSR) markers which showed a high degree of monomorphism thus supported morphological uniformity of micropropagated plants.