24 THE FAMILY AND THE NATION 



factor for horns is dominant in rams and recessive in 

 ewes ; it has difficulty in manifesting itself in presence of 

 the factor which makes a sheep a female. 



The practical application of this new-won knowledge 

 to the arts of the breeder of new varieties of domestic 

 plants and animals has only now begun. 



Perhaps the most striking success already obtained 

 is the production of new varieties of wheat by R. H. 

 Biffen. English wheat bears large crops, but is deficient 

 in a certain baking property known as "strength," 

 which yields the kind of puffy white bread now in 

 fashion. Canadian wheats are " strong," but those of 

 them which maintain their " strength " in English soils 

 yield small crops. Biffen found that " strength " and 

 its absence were definite Mendelian properties in wheat, 

 " strength " being the dominant. By crossing a 

 " strong " Canadian wheat with a " weak," high- 

 cropping English variety, he got a first generation of 

 hybrids, all of which were " strong." In the second 

 generation the proportion of " strong " to " weak " was 

 three to one, and of the "strong" some bred true in future 

 generations, and contained also, as a fixed character, the 

 high-cropping qualities of the other original progenitor. 



Another pair of qualities in wheat shows Mendelian 

 phenomena : liability to the attacks of the fungoid 

 disease known as rust, and immunity from those 

 attacks, Biffen has used the new methods of experi- 

 ment to obtain varieties in which immunity to rust is 

 combined with other desirable properties. 



The experiments we have described make it clear 



