Abstract:
Ginger is a medicinal plant and a valuable spice. The present study was conducted to assess the
consumer preference, antibacterial activity and genetic diversity of local ginger in comparison to
the Chinese and Rangoon ginger cultivars grown in Sri Lanka. The ginger samples were collected
from fi ve districts. The preferred colour, aroma and degree of pungency of rhizomes were recorded
by employing a taste panel and the data were subjected to association analysis. The antibacterial
activity of the ginger samples were tested against two model pathogens Escherichia coli (JM
109) and Staphylococcus aureus (NCTC 4838) using methanol extract of rhizomes using the
paper disc method and measured as diameter of zone of inhibition (DZBI). The DNA extracts of
the three cultivars were subjected to PCR, using DNA barcoding primers trnH-psbA, followed
by DNA sequencing, alignment and cluster analyses. Two trnH-psbA sequences of Zingiber
offi cinale and Curcuma longa (as out-group) available in GenBank were used for comparison.
There were signifi cant associations among ginger cultivars in colour, pungency and aroma. The
highest preferred colour was observed in Chinese ginger and the highest degree of pungency
and highest preferred aroma were observed in Local and Rangoon gingers. All ginger samples
collected exhibited at least 6 mm of DZBI. E. coli was less aff ected by methanol extract compared
to S. aureus. A clear PCR amplicon was obtained for all three gingers. Another second amplicon
of lesser intensity was also observed for Chinese and Rangoon gingers. DNA sequencing helped
to generate a clear sequence for local ginger but no sequences were obtained for Chinese and
Rangoon gingers. This could be due to the presence of second amplicon that would have inhibited
DNA sequencing. The DNA sequence based clustering revealed that local ginger is 0.8 % diff erent
from the two Z. offi cinale sequences available in GenBank implying that local ginger in Sri Lanka
is genetically diff erent.
