Genome analyses reveal the hybrid origin of the staple food crop white Guinea yam

Abstract

White Guinea yam (Dioscorea rotundata) is an important staple tuber crop of West Africa. However, its origin remains unclear. In this study, we re-sequenced 336 accessions of white Guinea yam and compared them with the sequences of the wild Dioscorea species using an improved reference genome sequence of D. rotundata. Our results suggest a hybrid origin of white Guinea yam from crosses between the rainforest wild species D. praehensilis and the savannah-adapted D. abyssinica. We identified a higher genomic contribution from D. abyssinica in the sex chromosome of Guinea yam and an extensive introgression around the SWEETIE gene. Our findings point to a complex domestication scenario for Guinea yam and highlight the importance of wild species as gene donors for improvement of this crop through molecular breeding.