NUCLEAR DNA CONTENT ANALYSIS OF FOUR CULTIVATED SPECIES OF YAMS (DIOSCOREA SPP.) FROM CAMEROON

Yam ( Dioscorea spp.) is an important food source in Africa, but diseases and storage pests hinder the African farmers to achieve high yields during the harvest. One important limitation to the genetic breeding of yam is the relatively unknown ploidy level variation within and among species.  The objective of this study was to determine the nuclear DNA content of 59 accessions representing four cultivated Dioscorea species collected from three regions of Cameroon (Adamawa, Centre and Southwest) using flow cytometry with propidium iodide staining. Our findings suggested the variation of the genome size both within and among the yams species. Nuclear DNA content (mean 2C-value) in studied yam collection ranging from 0.72 ± 0.013 pg in D. dumetorum to 2.801 ± 0.068 pg in D. cayenensis. The accessions could be divided into four different categories according to their, nuclear DNA content suggestive of four different ploidy levels. Ploidy variation was observed within all species with the exception of D. dumetorum that is likely diploid. This study contributes to a better understanding of the genome characteristics of yam species from Cameroon and may help to the genetic improvement of this important crop in the future.