Genetic fidelity of long-term micropropagated Lavandula officinalis Chaix.: an important aromatic medicinal plant

A protocol for long-term in vitro conservation of multiple shoot cultures of Lavandula officinalis and regeneration of true-to-type plants from them is described here. Multiple shoots were developed from apical bud explants on a modified vitamin-enriched Murashige and Skoog’s basal medium supplemented with 2.5 mg/l Kinetin. The cultures were subsequently conserved in vitro for 6 years under slow growth conditions imposed by lowering the sucrose level from 3 to 2.0 % and increasing the agar concentration from 0.8 to 1.2 % in this medium. Complete plant regeneration from in vitro conserved shoots was achieved through axillary shoot proliferation on original 2.5 mg/l Kinetin containing medium followed by rooting of individual shoots in a hormone-free half strength MS basal medium. The genetic fidelity of the regenerated plants was tested by random amplified polymorphic DNA analysis. Twenty one arbitrary decamer primers produced a total of 64 scorable bands (1–6 bands/primer) in the size range of 100–5,148 bp. All DNA fingerprints with these primers displayed monomorphic band profiles indicating homogeneity among the regenerated progeny and their uniformity with the donor parent. Head-space gas chromatographic analysis of the leaf tissue excised from mother as well as regenerated plants also revealed a similar qualitative and quantitative profile of volatile terpenes. The utility of the developed protocol for long-term ex situ conservation and quality plant production for cultivation of this high value aromatic herb is discussed.