7 2 



Plant Genetics 



the result. In this way the results of germinal consti- 

 tution may be somewhat obscured by the varying 

 external conditions of growth. 



FIG. 18. Graphic illustration of situation represented in fig. 17. In 

 both diagrams it is evident that two plants appearing in same quanti- 

 tative class must have same number of doses; this should always occur 

 if environmental influences did not obscure the result. 



FIG. 19. Diagram illustrating how environmental influences may 

 obscure phenotype classes of F*. Overlapping of phenotype classes 

 makes possible that two apparently identical plants might actually have 

 a different number of doses; diagram also shows that while breeder 

 could not recognize whether a plant had two or three doses, he could 

 distinguish between plants of two and four doses, etc.; thus intelligent 

 selection could be effective. 



