BSc - MSc (int.)

Root and tuber crops are a rich source of carbohydrates. Globally, they are the most
cultivated energy source especially in the tropical regions of the world. The edible
starch is stored in the subterranean stems, roots, rhizomes, corms and tubers which are
well known for their medicinal, antioxidant and antimicrobial properties. Besides their
wide range of industrial applications, a multitude of appetizing and healthy cuisine
can be prepared from these crops. Solenostemon rotundifolius (Poir.) J. K. Morton
(Chinese potato) with chromosome number 2n=64 belongs to the family Lamiaceae is
one among these tubers which are commonly consumed mainly by Keralites, known
as "Koorkka" in their native language. Morphological characterization using standard
descriptors will help to identify different accessions with diverse phenotypic features
for selection by the breeders. Molecular marker studies are very effective that can be
used as reliable tools for the analysis of genome architectures and gene polymorphism
in crop germplasm. In the present study assessment of genetic variability among 27
accessions of Chinese potato germplasm maintained in the ICAR-CTCRI field
genebank using morphological and molecular markers was carried out. Morphological
characterization was based on the standard minimal descriptors published by ICARNBPGR (2006) and RHS colour chart (1966). Seven qualitative and sixteen
quantitative characters were recorded. The morphological data was subjected to
cluster analysis, Pearson Correlation Coefficient analysis and Principal Component
Analysis using XLSTST 2021.2 statistical package. On UPGMA cluster analysis, the
27 accessions were grouped into 3 major clusters. PCC analysis showed that
maximum genetic variability was between Sree Dhara and TCR-136 and the least
between TCR-136 and TCR-110. The principal component analysis gave 5 PCA
components and the first 3 principal components have high eigenvalues, accounting
for 96.70 % of the variability among the traits studied. Quality DNA ranged from
106.9 (ASA-8) to 450.7 (ASA-5) was isolated from 27 accessions of Chinese potato
using a combined DNA isolation method. Ten polymorphic ISSR and eight SSR
markers were screened and optimized, which generated an average of 13.8 and 1.4
scorable bands per marker and revealed high overall percent polymorphism of 97.82
and 72.72 respectively. Cluster analysis showed maximum genetic variability between
TCR-120 and ASA-10 and the least between SAASV-20 and TCR-111. The SSR
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markers gave single bands that are polymorphic and the analysis showed less
genotypic variability. The present study revealed that the morphological characters
and molecular markers used were effective in germplasm characterization and genetic
diversity studies in Chinese potato.