Toward a taxonomic definition of perennial wheat: a new species ×Tritipyrum aaseae described

Nearly a century has passed since the first crosses were made between wheat (Triticum L.) and perennial Triticeae relatives with the goal of developing a perennial grain and forage crop. Numerous crosses of different species and genera have been attempted, and many have yielded fertile hybrids. Despite these successes, a definitive taxonomic treatment of stable hybrids has never been established. “Perennial wheat” is the term commonly used to refer to these hybrids when the traits of interest are the perennial growth habit and grain yield, regardless of parentage. In order to establish a consistent system in which researchers can effectively communicate and collaborate, it is important to characterize unique combinations. In this paper we briefly outline the history of perennial wheat breeding, suggest a naming convention based on the International Code for Nomenclature and describe one combination within the new nothogenus ×Tritipyrum. The development of perennial grains has the potential to allow for new agricultural systems that take advantage of the persistent nature of the crop. The taxonomic definition of this new crop type will help focus research and breeding efforts as well as organize the literature and facilitate collaboration.