164 BREEDING CROP PLANTS 



"4. When a sufficient number of F 2 individuals are available, the 

 grandpa rental types should be recovered. 



"5. In certain cases individuals should be produced in F% that show a 

 more extreme deviation than is found in the frequency distribution of 

 either grandparent. 



"6. Individuals from various points on the frequency curve of an F z 

 population should give Fz populations differing markedly in their modes 

 and means. 



FIG. 36. A, N. data (jrandiflora; B, Fi of N. langsdorfii X N. alata grandi- 

 f.ora; C, N. langsdorfii (1911); D and E, extremes of the F 2 generation (1912) X 

 H. (After East.) 



"7. Individuals either from the same or from different points on the 

 frequency curve of an F% population should give Fz populations of diverse 

 variabilities extending from that of the original parents to that of the 

 Ft generation. 



"8. In generations succeeding the F*, the variability of any family 

 may be less but never greater than the variability of the population 

 from which it came." 



All of the above eight conditions have been obtained in experi- 

 ments and no fact directly opposed to them has been discovered. 



The quantitative characters in tobacco which have been 

 studied are, therefore, typically Mendelian in their inheritance. 



