Study of genetic diversity among the gurmar (Gymnema sylvestre R.Br.) accessions
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Date
2012
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Publisher
CCSHAU
Abstract
Gurmar (Gymnema sylvestre R.Br.) is a medicinal herb, found mainly in central andsouthern
India. It has anti-diabetic properties due to gymnemic acid content in its leaves. This study was
undertaken with the objective to standardize the protocol of DNA isolation from 12
accessions of gurmar and to study the genetic diversity among these accessions. DNA
extracted from young leaves of 12 gurmar accessionswas amplified by using 50 ISSR and 10 RAPD
primers. Out of these primers, 28 ISSR and 6 RAPD primers were showing amplification and were
selected for present investigation. For ISSR and RAPD assays, data was analyzed to calculate various
parameters such as the number of total bands, number of polymorphic bands, percent polymorphism,
bands per primer, polymorphic bands per primer, similarity matrices and dendrogram. Both ISSR and
RAPD generated a high level of average percentage of polymorphism i.e. 89.64% and 89.16%
respectively. The ISSR primers yielded average 2.53bands per primer while RAPD primers amplified
average 4.16 bands per primer. The average number of polymorphic bands was higher in case of
RAPDs (3.66) as compared to that in ISSRs (2.17). Overall, size of PCR amplified products ranged
between 200bp and 1800bp for ISSR primers and between 600bp and 4000bp for RAPD primers.
Based on ISSR similarity matrix data, the value of similarity coefficient ranged from 0.130 to 0.680
with an average genetic similarity of 0.405. RAPD similarity matrices between different accessions
ranged from 0.105 to 0.778 with average similarity coefficient of 0.441. Dendrograms generated using
ISSR and RAPD markers separated accessions into twomajor clusters, which were further divided into
sub clusters. Dendrogram based on RAPD markers was not in accord with dendrogram based on ISSR
markers. However, dendrogram obtained, with combined marker system resulted in better grouping of
various accessions of gurmar.A high percentage polymorphism (approx. 89%) was observed among
different accessions. The average similarity across all the accessions was found out to be 0.405,
indicating a high level of genetic dissimilarity among the accessions. Accessions having lowest
similarity coefficient are most diverse and can be used in breeding and crop improvement programmes.
Description
Keywords
Rapd, Genetics, dna, Polymorphism, Planting, pcr, Concentrates, Crops, Genotypes, Genomes