MONO-HYBRID CROSSES 173 



crossed with white. Thus, if the hybrid plants are bred 

 together or self-fertilized, the resulting cobs will exhibit 

 a proportion of three smooth grains to one wrinkled 

 grain. In an actual example there were obtained 5,310 

 smooth grains and 1,765 wrinkled, or 75-06 per cent, 

 of the former and 24-94 P er cent, of the latter. 



In a further generation the wrinkled grains breed 

 true. One out of every three smooth grains does the 

 like. The remaining two smooth grains are of hybrid 

 nature, and on self-fertilization yield again the same 

 proportion of three smooth to one wrinkled. Such 

 hybrid grains and the plants into which they develop 

 are spoken of as heterozygotes. 



Thus, if we write B for smooth and b for wrinkled, 

 the following scheme will express the result of crossing 

 together plants which bear these characters, and after- 

 wards self-fertilizing the offspring obtained : 



P (dominant character) B x b (recessive character) 



F! Bb 



(heterozygote looking like B} 

 on self-fertilization yields 



