George Harrison Shull, American botanist and geneticist (d. 1954)
George Harrison Shull (April 15, 1874 – September 28, 1954) was an eminent American plant geneticist and the younger brother of botanical illustrator and plant breeder J. Marion Shull. He was born on a farm in Clark County, Ohio, graduated from Antioch College in 1901 and from the University of Chicago (Ph.D.) in 1904, served as botanical expert to the Bureau of Plant Industry in 1903-04, and thenceforth was a botanical investigator of the Carnegie Institution at the Station for Experimental Evolution, Cold Spring Harbor, N. Y., giving special attention to the results of Luther Burbank's work.

Shull played an important role in the development of hybrid maize (in the USA, popularly 'corn') which had great impact upon global agriculture. As a geneticist, Shull worked with maize plants. He was interested in pure breeds not for their economic value but for his experiments in genetics. He produced maize breeds that bred true and then crossed these strains. The hybrid offspring of the sickly pure breeds were vigorous and predictable. In short, an ideal economic maize resulted from a project motivated purely to advance science. For his work on maize, Shull was awarded the Public Welfare Medal from the National Academy of Sciences in 1948.He also described heterosis in maize in 1908 (the term heterosis was coined by Shull in 1914) and made a number of other key discoveries in the emerging field of genetics. Shull was the founder of the scientific journal Genetics.

He was called George in distinction from his son Harrison Shull (1923–2003), also a distinguished scientist, specializing in the quantum mechanics of small-molecule electronic spectra.