THE METHOD OF EXPERIMENTAL BREEDING 



463 



was not revealed in the first filial generation, oi Fi generation, 

 arising from a cross between tall and dwarf parents, or Pi genera- 

 tion, emerges unchanged in the second filial, or F2 generation. 

 Dwarfness in such peas is as pure as was the dwarfness of their 



Ii 



Tall \ f TalA /Dwarf\ /Dwarf\ 

 Peas J V Peasy V Peasy V Peasy 



Fig. 243. — Diagram to illustrate mono-hybridization of peas that differ with 

 respect to length of the stem. Tall stem is dominant to dwarf stem. 



grandparents, and they give rise only to dwarf peas so long as they 

 are bred together. 



Breeding of the tall peas that constitute three-fourths of the F2 

 generation reveals the fact that, although these tall individuals 



