G. Ledyard Stebbins
He worked on the genetics of grass grown for grazing, looking at polyploidy and the evolution of the Poaceae (grass family). He produced an artificial autotetraploid grass from the diploid species Ehrharta erecta by treatment with the chromosome doubling agent colchicine. He was able to establish the plant in the field, and after 39 years of field trials found that the tetraploid was not as successful as its diploid parent in an unchanging environment.