The domestication of American wildrice

Abstract

The expansion in wildrice (Zizania palustris) production and the associated research efforts represent the largest modern effort to domesticate a cereal grain. Wildrice growers brought the species under cultivation, but plant breeding and agronomic research have accelerated the domestication process. The domestication and commercialization of this diploid (2n = 30), protogynous, cross-pollinated, annual, aquatic cereal present an opportunity to examine crop evolution and domestication theory. Traits associated with the domesticated cereal grains are shattering resistance, tiller synchrony, and increased seed size. This syndrome of traits may result from automatic selection, the selective force applied by repeated cycles of planting of harvested seed. Positive responses from deliberate selection for these traits in wildrice populations indicate that a domestication ideotype is attainable through plant breeding and that founder effect in this diploid species may be negligible. Continued commercial production of wildrice in the Great Lakes region is not likely to further the domestication process, whereas automatic selection may be initiated in the emerging California wildrice industry.