Molecular characterisation of east Indian Lemongrass (Cymbopogon flexuosus stapf} Germplasm Accessions
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Date
2013
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Centre for Plant Biotechnology and Molecular Biology, College of Horticulture, Vellanikkara
Abstract
East Indian lemongrass (Cymbopogon flexuosus Stapf.) is commonly
known as Malabar or Cochin grass. It is an aromatic crop cultivated for its
commercial essential oil and oil exported from India is known as “Cochin oil” in
the world trade. The major component of this oil is citral which is widely used in
pharmaceutical and perfumery industry. The Aromatic Medicinal plants Research
Station, Odakkali has maintained around 400 accessions of East Indian
lemongrass. Among them twenty five elite accessions good in oil and citral
content were selected for the molecular characterization. The study elucidated
genetic variation among the selected accessions.
The present investigations on “Molecular characterization of East Indian
lemongrass (Cymbopogon flexuosus Stapf.) germplasm accessions” were carried
out at the Centre for Plant Biotechnology and Molecular Biology, College of
Horticulture, Kerala Agricultural University during the period 2011-2013. The
objective of the investigation was to characterize twenty five accessions of East
Indian lemongrass using molecular markers, Random Amplified Polymorphic
DNA (RAPD) and Inter Simple Sequence Repeats (ISSR).
For molecular characterization, good quality genomic DNA was isolated
from East Indian lemongrass accessions using CTAB method (Rogers and
Benedich, 1994). Thirty five RAPD and thirty one ISSR primers were screened
for amplification of genomic DNA and ten RAPD and ten ISSR primers were
selected for further analysis based on the amplification pattern. RAPD analysis
using selected primers produced 101 amplicons, 58 were polymorphic with an
average of 5.8 polymorphic bands/primer and polymorphism percentage was 57.
In ISSR, selected primers produced 117 amplicons, 48 were polymorphic with
average of 4.8 polymorphic bands/primer and a polymorphism percentage was
41.
The RAPD markers found to be more effective to bring out variability
among the accessions. The RAPD primer OPC 2 gave maximum polymorphism i.e. 77 per cent. In ISSR, the primer ISSR 5 gave maximum polymorphism i.e. 58
per cent. The polymorphic information content and resolving power of ISSR
primers was higher than RAPD primers.
The dendrogram generated based on RAPD and ISSR profiles grouped
twenty five accessions of East Indian lemongrass into 3 main clusters. The first
cluster grouped 21 accessions of lemongrass together. This cluster includes the
accessions OD-11, OD-2, OD-28, OD-320, OD-9, OD-10, OD-4, OD-39, OD-24,
OD-15, OD-40, OD-16, OD-21, OD-18, OD-8, OD-14, OD-20, OD-12, OD-29,
OD-25 and OD-29. In this cluster, the accessions OD-4 and OD-39 were
genetically similar which yielded 86.40 to 83.70 per cent citral content and these
accessions were collected form Kollam district of Kerala state. This indicates that
accessions of same geographic origin are genetically and biochemically similar.
These 2 accessions were similar in terms of same leaf sheath colour. This first
cluster formed one subcluster with accession OD-13 showed only 5 per cent
variation with first cluster. The second cluster involved 2 accessions i.e. OD-7
and OD-17 showed 75 per cent similarity with each other with 84.40 and 83.20
percent citral content. The third cluster involved only one accession i.e. OD-23
with high citral content i.e. 88.50 percent was collected from Dehradun. The
information generated will be useful in designing future breeding programmes
involving the selected accessions.
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