Abstract:
Dioscorea, commonly known as yam, is one of the most important staple crops in the
tropics, crucial for economic stability and food security. The Plant Genetic Resource
Centre (PGRC) in Sri Lanka has conserved 215 Dioscorea accessions as of 2024,
which have not been fully characterized yet. The main objective of this study was the
morphological characterization of selected Dioscorea accessions conserved in the
PGRC germplasm. All accessions were cultivated under standard homogeneous
conditions for characterization during the period from June 2024 to November 2024.
International standardized descriptors for yams were used to characterize 84
morphological characters from 25 accessions during the vegetative phase of
Dioscorea, each grown in duplicate. The cluster analysis, cluster variations and
descriptive statistics were obtained using SAS JMP Pro 18. No duplications of
conserved germplasm at PGRC were observed, thus each accession was unique under
morphological characters. Three distinct clusters were identified, while cluster 1
consisted of three accessions: BTD - 6, BTD - 67, and BTD – 243, all belonging to
Dioscorea bulbifera. Cluster 2 contained six accessions belonging to Dioscorea
esculenta, while cluster 3, Dioscorea alata was represented by 16 accessions and the
cluster analysis explained 73.2% of variation using qualitative characters and 69.6%
using quantitative characters. When both qualitative and quantitative characters were
for clustering 72.6% of variation in the collection was explained without altering the
clustering pattern. Clustering was largely based on young stem color, young stem
wing color and hairiness on the mature stem as qualitative and young stem length,
leaf measurements and number of branching (above ground) as quantitative
characters. The finding of this study is useful for systematic germplasm conservation
and the utilizing of prominent traits in yam varietal improvement programs. Future
studies should aim to include reproductive and storage characteristics to broaden the
application of these results.
