88 



Heredity and Eugenics 



character; while the last term, resulting from the fusion of 

 two non-starchy gametes, is a zygote that breeds true to 

 non-starchiness. Since the zygotes having the gametic 

 constitution shown b\' the first three terms are alike in 

 looks, the second hybrid generation (F_, generation) gives 

 approximately three starchy zygotes to one non-starchy 

 zygote. But the three starchy zygotes, though alike in 

 looks, are different in their breeding capacity. One out of 

 three breeds true to starchiness; two out of three are hy- 

 brid and again segregate into starchy and non-starchy in 

 the next generation. Diagrammatically the process may be 

 illustrated thus: 



Starchy gamete Non-starcKy gamete 



S S 



S s 



Hybrid zygote 



S S 



Hybrid 

 starchy 

 zygotes 



Pure 



non-starchy 



zygote 



