X 



X 



10 



(Ax 10) F, 



Fig. 2.7 — One of the first four-zcay or double crosses ever grown from selfed strains of maize. 

 The single crosses for this double cross were made in 1909, the cross between the Fi's was 

 made in 1910, and the double-cross ear at bottom (G35.62) was grown in 1911 and grains 



from it were used for i)lanting in 1912. 



