Impact of cultivation on growth rate and agar content of Gelidiella acerosa (Gelidiales, Rhodophyta)

Tissue cultured progenies of callus regenerated Gelidiella acerosa were successfully transferred from the laboratory, then were cultivated in the exposed sea. Four plantlets (approx. 0.04 ± 0.01 g fresh wt. and 2-3 cm length) cultured initially in closed net bags in the lagoon waters were multiplied to produce 73 plantlets each with an average biomass of 70 ± 20 g fresh wt.plant− 1. These plantlets were then shifted to exposed sea and cultivated using the suspended stone method along with wild harvested plantlets. The biomass, Daily Growth Rate, agar yield and quality of the wild and tissue cultured farm plants grown under identical conditions were compared. Biomass of the tissue cultured farm plants ranged from 1.86 ± 1.0 to 2.97 ± 0.7 kg fresh wt.m− 2, while wild farm plants ranged from 0.44 ± 0.12 to 0.62 ± 0.31 kg fresh wt.m− 2. Similarly, DGR of the tissue cultured farm plants ranged from 1.81 ± 0.70% to 2.00 ± 0.50% whereas wild farm plants ranged from 1.0 ± 0.40% to 1.2 ± 0.30%. The gel strength of agar extracted from tissue cultured farm plants was higher (2400 ± 250 g cm−2 than wild farm plants (1900 ± 135 g cm−2). Agar extracted from tissue cultured G. acerosa was found to be suitable for microbial culture and DNA electrophoretic applications. The increased growth and gel strength of the agar recorded in tissue cultured progenies suggested their possible use as improved seed stock for the large scale cultivation of G. acerosa.