Abstract:
Sorghum (Sorghum bicolor (L.)) ranks fifth among cereals in terms of production and area
planted worldwide. It is well adapted to the range of environmental conditions. This study was
performed to evaluate the morphological diversity of some sorghum germplasm accessions based
on qualitative traits. Twenty six sorghum germplasm accessions including sixteen local and ten
foreign accessions (Italian and French) conserved at the seed gene bank of Plant Genetic
Resource Center, Gannoruwa, Sri Lanka were characterized using morphological descriptors
developed by the International Plant Genetic Resources Institute (IPGRI). The evaluation of
these germplasm accessions was based on 4 binary and 10 multicategorical traits. Cluster
analysis was performed using SAS software by following Ward minimum variance clustering
method with the dissimilarity measure of Gower and Legendre. According to the psedo-F and
psedo-t
2
criteria obtained from the cluster analysis based on qualitative data, the optimal number
of clusters required to represent the genetic diversity among the studied sorghum germplasm
accessions was seven. ‘Cluster I’ comprised of two foreign accessions with unknown origins.
Three Italian and two French accessions were clustered in ‘Cluster III’ while the remaining three
Italian accessions were grouped into ‘Cluster IV’. Sri Lankan accessions were observed in
‘Cluster II’, ‘Cluster V’, ‘Cluster VI’ and ‘Cluster VII’. Clustering pattern based on the
qualitative traits depicts the geographical origin of the studied accessions. This can be explained
by the fact that qualitative traits are less influenced by the environment. In principle, qualitative
data are expected to provide additional information on hierarchical units. Observation of a
considerably high number of clusters consolidates that principle. This study reveals sufficient
genetic relatedness of studied sorghum germplasm accessions which will in the conservation and
breeding programs of the crops.
