3.2.2. Cluster analysis based on SSR and SRAP markers
On the basis of SSR-SRAP molecular marker data, 112 accessions of yam were divided into six groups (Fig. 3-A). The G1 group included CY-256 and CY-257 from Hainan Province, and they belonged to D. esculenta . A total of 51 accessions were assigned to the G2 group, with CY-40 belonging to D. opposita . The G3 group contained 14 accessions, with CY-179 and CY-251 belonging to D. persimili s, and the similarity coefficient between CY-244 and CY-247 reached 0.98, suggesting that they may be of same variety. Seven accessions were categorized into the G4 group, and the accession of CY-117 belonged to D. opposita , while the remaining belonged to D. alata . The G5 group was a collection ofD. fordii and D. alata , in which 29 accessions wereD. alata , and the remaining (CY-193, CY-201, CY-206, and CY-209) were D. fordii . In the G6 group, CY-227 and CY-23 were from D. opposita , and the remaining accessions were from D. alata .
The results of PCoA was basically consistent with those of molecular marker cluster analysis (Fig. 3-B). The 112 accessions could be divided into three groups (G1, G2, and G3). The G1 group composed of D. persimilis , the G2 group was D. opposita , and the G3 group consisted of D. alata and D. fordii .