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Grass to Grain: Sustainable food by design.
L. R. DEHAAN (1), X. Zhang (2), J. Anderson (2). (1) The Land Institute, Salina, KS, U.S.A.; (2) University of Minnesota, Saint Paul, MN, U.S.A.

Kernza wheatgrass (<i>Thinopyrum intermedium</i>) is a perennial grain crop currently being developed. A perennial grain crop would have substantially improved sustainability compared to currently grown grain crops.
Four cycles of have been performed over the past nine years. The population resulting from two cycles of selection has been evaluated in multiple years and locations. Under irrigation, yields had been increased by 77%.
The highest grain yield obtained from clones selected for yield and grown in small plots under irrigation in Kansas has been 1130 kg ha-1. In contrast, clones selected for seed mass in Kansas have produced 2000 kg ha-1 in Minnesota without irrigation. Due to consistently higher seed yields in northern climates, high temperatures during grain filling is the working hypothesis for limited grain yield in southern locations.
Maximum biomass yield in small plots grown in Kansas (with irrigation) and Minnesota has been 18 to 20 Mg ha-1, but average yields have been 10-13 Mg ha-1. Harvest index in these plots was 6 to 9%. High biomass production coupled with comparably low seed yield highlights the importance of increasing harvest index as a breeding objective. High biomass yields reveal potential for use as a sustainable dual biofuel and grain crop.
Seed mass of kernza is currently small, only about 15% of wheat. Therefore, seed size is a major limitation to use of the crop and a primary breeding objective. Seed mass has been less responsive to selection than yield, increasing by only 23% in response to two cycles of selection. Individual clones have had seed mass 90% greater than the starting population.
Kernza have reached the point where it may be successfully grown as a specialty crop. Several decades of work, including utilization research and breeding for quality, remain before it can become a widely grown commodity crop.

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