BSc- MSc Int.

The study entitled “Molecular characterization of ginger genotypes (Zingiber
officinale Rosc.)” was carried out at the Department of Plant Biotechnology and
Department of Plantation Crops and Spices, College of Agriculture, Vellayani during
2020 to 2021. The objective of the study was to assess the genetic diversity of ginger
genotypes using simple sequence repeats (SSR) and inter-simple sequence repeat
(ISSR) markers.
Leaf samples of twenty ginger genotypes maintained in the germplasm of
Department of Plantation Crops and Spices were collected and subjected for DNA
isolation using CTAB method. Quality and quantity of the isolated DNA samples
were determined using Agarose gel electrophoresis and spectrophotometric analysis.
Fifteen ISSR (ISSR 26, ISSR 14, ISSR 53, ISSR 54, ISSR 69, ISSR 79, ISSR 11, ISSR 12,
ISSR 72, ISSR 04, UBC 835, UBC 809, UBC 829, UBC 818 and UBC 828) and 15 SSR
(GES 440, GES 452, GES 454, GB-ZOM-033, GB-ZOM-040, GB-ZOM-055, GBZOM-064, GB-ZOM-103, GB-ZOM-107, GB-ZOM-111, GB-ZOM-140, RM 154,
RM 171, RM 135, and RM 125) markers were selected from previous studies for
molecular characterization of ginger genotypes. Out of these fifteen SSR primers four
were rice SSR primers (RM 154, RM 171, RM 135, and RM 125) with high
Polymorphic Information Content (PIC) value.
Isolated DNA samples showed good quality and their concentration ranged
from 132 to 3162 μg/ml. Average polymorphism of ginger genotypes using ISSR and
SSR primers were 56% and 67.6% respectively which revealed a moderate level of
polymorphism within the twenty ginger genotypes. ISSR markers UBC 829, ISSR 53,
ISSR 54, ISSR 72 and SSR markers GB-ZOM-055, GB-ZOM-103, GB-ZOM-064,
RM 154, RM 171, RM 135 showed 100 percentage of polymorphic loci. PIC value of
ISSR primers ranged from 0 (UBC 818, UBC 828, ISSR 69 and ISSR 12) to 0.49
(UBC 829) and SSR primers ranged from 0 (GES 452, GES 454, GES 440, GB-ZOM111, GB-ZOM-033, GB-ZOM-140) to 0.45 (RM 154). The Mantel’s statistic (r) value
based on Spearman's rank correlation obtained as 0.01652 with a significance value (p)
of 0.4457 indicated no significant correlation between SSR and ISSR marker
information.
In this study Jaccard’s similarity coefficients using ISSR and SSR marker data
ranged from 0.69 to 0.98 and 0.54 to 0.98. Dendrogram generated using ISSR and
SSR data separated twenty genotypes into three clusters and PCoA of twenty ginger
genotypes using ISSR and SSR data revealed 11 and 9 clusters respectively. A low to
moderate level of polymorphism between these twenty ginger genotypes were
observed using ISSR and SSR marker analysis. Divergent lines identified from the
Dendrogram of ISSR and SSR data are Mananthavady (T1), Murickassery (T14),
Thalavur (T20), Mannarkkad (T9), Plamoodu (T21), Kazhakoottam 1 (T11) and
Kazhakoottam 2 (T22). Compared to all other ginger genotypes Plamoodu (T21) and
Mannarkkad (T9) showed high variation in ISSR and SSR marker analysis. The
marker analysis revealed a higher similarity between ginger genotypes Kottarakkara
(T5) and Kothamangalam (T7).
The results of the study indicated the efficiency of SSR markers over ISSR
markers in evaluating the genetic diversity of ginger genotypes. Polymorphic bands
produced by the rice-SSR markers revealed that they are suitable for crossamplification studies in ginger. Among the twenty ginger genotypes characterized
using molecular markers, higher variation was noticed in Plamoodu (T21) and
Mannarkkad (T9) showing their suitability in future selection programs. The variation
detected at genetic level among these ginger genotypes from this study will be useful
for future genetic diversity studies.