3.1.3. Cluster analysis based on phenotypic traits
A cluster dendrogram of 112 accessions was created from 20 phenotypic
traits obtained from PC analysis (Fig. 2). The 112 accessions were
divided into seven major groups. The G1 group only contained two
accessions of CY-256 and CY-257 from Hainan Province, characterized by
no flower, no bulbil, and no stem wing but spiny and turning left. The
leaves were nearly round, and the tubers were small and nearly round.
The G2 group consisted of 29 accessions, and the main features were stem
wings, purple-green stems, purple tuber flesh color or purple inner
epidermis color, no flowers nor bulbils, and purple-green petiole. The
G3 group included 13 accessions and was very similar to the G2 group.
The biggest difference was that the tuber endodermis color was mostly
beige, while the tuber flesh color was mostly white.
The G4 group contained nine
accessions. CY-206 and CY-209 belonged to D. fordii , while the
rest of the accessions belonged to D. opposita . The G5 group was
composed of 40 accessions. The typical characteristics were flowers,
bulbils, dark-green leaf color, yellow-green vein, columnar-white tuber
flesh color, and a variation of length-to -width leaf ratio ranging from
1.2 to 1.5. The G6 group contained 19 accessions characterized by no
flowers, no bulbils, oval leaves, purple petioles, yellow-green veins,
and brown tuber skin.