Willet Martin Hays (19 October 1859 – 16 January 1928) was an American plant breeder and U. S. Assistant Secretary of Agriculture.
He graduated from Drake University in 1885 and obtained a master's degree in agriculture from the Iowa State College at Ames.
Among his successes were commercially important varieties of superior flax, wheat, corn, barley, and oat; he also discovered winter-resistant Grimm alfalfa.
[1] In 1904 Hays was appointed Assistant Secretary of Agriculture and served under James Wilson in the administration of Theodore Roosevelt.
He was responsible for setting up the project system for agricultural research that was later developed into the state experimental stations.