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THE AMERICAN NATURALIST [Vol. XLIV 



were di-hybrids, but only Ear 5 was grown another 

 generation. The kernels classed as white proved to be 

 pure ; the open field crop from the yellow kernels gave 14 

 pure yellow ears and 14 hybrid yellow. Theoretically 

 the ratio should be 7 pure yellows (that is, pure for 

 either one or both yellows) and 8 hybrid yellows (4 giv- 

 ing 15 yellows to 1 white and 4 giving 3 yellows to 1 

 white). Five hand-pollinated selfed ears were obtained. 

 Three of these gave mono-hybrid ratios, with a total of 

 607 yellows to 185 white kernels. One ear was a pure 

 dark yellow (probably r^r^). The other ear was 

 poorly filled, but had 27 dark yellows (probably Y t Y 2 ) 

 and 7 light yellow kernels (Y 1 or Y 2 ). Unfortunately no 

 15 : 1 ratio was obtained in this generation, but this is quite 

 likely to happen when only five selfed ears are counted. 

 The gradation of colors and the general appearance of 

 the open field crop, however, lead me to believe that we 

 were again dealing with a di-hybrid. 



Two yellows appeared in still another case, that of white 

 sweet No. 40$ X yellow dent No. 3J\ Only one selfed 

 ear was obtained in the F 2 generation giving 599 yellow 

 to 43 white kernels. Of these kernels 486 were starchy 

 and 156 sweet, which complicated matters in the F.^ gen- 

 eration because it was very difficult to separate the light 

 yellow sweet from the white sweet kernels. Among the 

 selfed ears were three pure to the starchy character, and 

 in these ears the dark yellows, the light yellows and whites 

 stood out very distinctly. Ear 12 had 156 dark yellow; 

 47 light yellow; 14 white kernels. Ear 13 had 347 dark 

 yellow; 93 light yellow; 25 white kernels. The third 

 starchy ear, No. 6, had 320 light yellow ; 97 white kernels. 

 Two ears, therefore, were di-hybrids, and one ear a mono- 

 hybrid. 



The ears which were heterozygous for starch and no 

 starch and those homozygous for no starch, could not all 

 be classified accurately, but it is certain that some pure 

 dark yellows, some pure light yellows, some showing seg- 

 regation of yellows and whites at the ratio 15 : 1, and some 



