Spatially structured morphological and molecular diversity amongDioscorea cayenensisandD. rotundatayam accessions

Abstract

Yams (Dioscorea spp.) are one of the main root and tuber crops in the world, especially within the species complex Dioscorea cayenensis/D. rotundata. Few studies have been conducted in Brazil with these species, including genetic diversity. The objective of this study was to characterize the genetic diversity of local varieties of D. cayenensis and D. rotundata using morphological and molecular markers, and provide information on the management and use of the crop by family farmers from different regions in Brazil. Thus, yam tubers were sampled from several municipalities in the South, Southeast and Northeast regions. Eighteen morphological traits and ten microsatellite loci were used to analyse 47 yam accessions (23 D. cayenensis and 24 D. rotundata). Species identification was carried out after field morphological evaluation. Spatial genetic analysis indicated significant structure among the local varieties, mostly between regions and species. Both cluster and Bayesian analyses showed a separation of the accessions into two distinct groups: group I with accessions originated from the Southeast region and group II with accessions originated from the Northeast region, while accessions from the South region were intermediate or included in either group. The results showed a separation between D. cayenensis and D. rotundata accessions in Brazil, and that D. cayenensis occurs predominantly in the Southeast region, while D. rotundata occurs in the Northeast region. Further studies with larger sampling would be welcome in order to confirm these findings. Also, this study highlights the importance of family farmers in the genetic diversity conservation of these species in Brazil.

Uncovering the genetic diversity of yams (Dioscorea spp.) in China by combining phenotypic trait and molecular marker analyses

“…SSR and SRAP markers have a high degree of polymorphism, which is useful for the identification of germplasm resources, and the application of these two markers has effectively produced a large amount of reliable genetic data (Dong et al, 2019;György et al, 2016). The methods described above have been widely used in the identification of genetic diversity and genetic relationships of yam germplasm resources (Anokye et al, 2014;Mignouna, Dansi, et al, 2002;Mignouna, Mank, et al, 2002;Silva et al, 2017). At present, there are some reports on the genetic diversity of D. alata in China (Wu et al, 2009(Wu et al, , 2019.…”

Multi-Trait Selection Index for Superior Agronomic and Tuber Quality Traits in Bush Yam (Dioscorea praehensilis Benth.)

“…Many authors [10][11][12][13] have reported the effectiveness of morphological markers in assessing genetic diversity in D. alata. In Guinea yams (D. rotundata and D. cayenensis), morphological traits have been successfully employed in evaluating genetic variability [14,15]. The application of morphological descriptors has also been used in D. bulbifera [16].…”

Uncovering the genetic diversity of yams (Dioscorea spp.) in China by combining phenotypic trait and molecular marker analyses

“…rotundata complex) from Cameroon by using morphology and isozyme, and the clustering results of the two were relatively consistent. Silva et al (2016) used 12 microsatellites and four morphological markers to analyze the genetic diversity and structure of 89 yam (D . alata ) in Brazil; a high diversity is found in Brazilian yam, but it is not related to geographical location.…”