Yam (Dioscorea spp.) is a major staple food whose production is hampered by viral diseases. However, the prevalence, diversity, transmission, and impact of yam-infecting
viruses remain poorly documented. This study reports on the symptomatology, prevalence, and molecular diversity of eight viruses in 38 D. rotundata accessions from a
germplasm collection and 206 F1 hybrid progenies maintained in Ct̥e d'Ivoire. Mean
severity scores as assessed from leaf symptoms ranged from 2 to 4 in the germplasm
collection and from 1 to 3 in F
1 hybrids, respectively. Dioscorea mosaic-associated
virus (DMaV), potexviruses, and yam mosaic virus (YMV) were detected by PCR-based
diagnosis tools in single and mixed infections in both the D. rotundata collection and F1
progenies, whereas badnaviruses were detected only in the germplasm collection. In
contrast, cucumber mosaic virus (CMV), yam macluraviruses, yam asymptomatic virus
1 (YaV1), and yam mild mosaic virus (YMMV) could not be detected. No correlation
could be established between severity scores and indexing results. Phylogenetic analysis performed on partial viral sequences amplified from infected samples unveiled
the presence of two putative novel viral species belonging to genera Badnavirus and
Potexvirus and provided evidence for plant-to-plant transmission of YMV, DMaV, and
yam potexviruses.