A New Origin of Sugarcane: the Undiscovered Species

The Saccharum sensu stricto (s.s) genus consists of three recognised species: S. spontaneum, S. officinarum and S. robustum, and three subspecies: S. sinense, S. barberi and S. edule. Currently, limited knowledge is available about the precise descent of these species from one another. Modern sugarcane arose through the ‘Nobilization’ process, and it is believed that S. officinarum and S. spontaneum were involved in an interspecific cross with subsequent backcrossing to S. officinarum. Molecular phylogenetic studies reveal the need to partition Saccharum s.s into four species: S. narenga; S. spontaneum; S. officinarum and the lineage of modern hybrid cultivars which are derived from a cryptic founder species that the authors formally name Saccharum cultum sp. nov. Lloyd Evans and Joshi, 2016. This necessitates the re-evaluation of the origins of sugarcane cultivation. This study integrates genome science, history, archaeology, geophysics, ethnobotany and ethnolinguistics to reveal a new history of sugarcane from its wild origins to modern cultivars. These findings overturn the current models of sugarcane taxonomy and sugarcane origins and reveal that South African Miscanthidium is the most closely related genus to Saccharum. Moreover, this study reveals a new, integrated, model of sugarcane origins that will pave the way towards more effective introgression breeding by accurately determining the effective window for hybridization outside the Saccharum genus. In light of these findings, the origins of sugarcane cultivars is re-evaluated and the claim that New Guinea is the site of sugarcane’s origin is refuted.