Strategies, Advances, and Challenges in Breeding Perennial Grain Crops

The development of new perennial crop species is gaining momentum as a promising approach to change the fundamental nature of ecosystem processes in agriculture. The ecological argument for perennial crops grown in polycultures is strong, but until recently, perennial herbaceous grain crops have been absent from agricultural landscape. This is not because perennial herbaceous species do not exist in nature-there are thousands of perennial grasses, legumes, and other broad leaf plants. Rather, for a variety of reasons, early farmers focused on cultivating and domesticating annuals, and the perennial herbs were largely ignored. Today, we have a tremendous opportunity to explore another agricultural path. Building on contemporary knowledge of plant biology and genetics that early farmers lacked, and using a rapidly expanding toolbox that includes sophisticated genomic and analytical approaches, we can develop viable perennial grain crops. These crops can then be used to assemble diverse agroecosystems that regenerate soils and capture other important ecosystem functions.