Progress Breeding Kernza® Perennial Grain.

Thinopyrum intermedium (Host) Barkworth & D.R. Dewey (intermediate wheatgrass) is a perennial grain crop currently being developed. Limited commercial production of this new crop is just beginning, and in products it will be marketed as Kernza® perennial grain. Kernza has been registered as a trademark by The Land Institute to provide a unique name that will be easily recognized by consumers. Farmers producing and selling Kernza perennial grain will do so through an identity preservation system that will ensure the purity of Kernza perennial grain in the marketplace.

Since 2003, five cycles of selection primarily based on seed yield per head, free threshing ability, and seed mass have been performed. Selection has been performed in either the first or second year. We tested the hypothesis that selection on yield per head and seed size in young widely spaced plants will improve yield and seed size in aging solid-seeded plots. We planted seed from the starting population, first, second, and third selection cycles in replicated plots at two locations in central Kansas. One location was irrigated and the other rainfed.

Selection consistently increased grain yield and seed size in both locations. Considering fourth year data, where young plant selection is expected to have the worst performance, grain yield had increased on average 26.5% per breeding cycle. Mass per seed had a weaker response to selection, increasing on average only 13.9% per cycle, even though selection was stronger for seed mass than for grain yield. Mass per seed is substantially reduced in dense stands compared to widely spaced plantings. In conclusion, selecting for high yield per head in young widely spaced plants effectively increases yield of intermediate wheatgrass, even as the stand ages, but new selection approaches may be necessary to rapidly increase seed size in aging dense stands.