ON THE SMALL GRAINS 



Breeding a wheat with beardless ears and white 

 grain, for example, with a wheat having bearded 

 ears and red grain, all the progeny will be beard- 

 less and red-grained; but bearded ears and white 

 grain will reappear, in various combinations, in 

 one fourth of the progeny of the second generation. 



It is never safe for the plant developer to draw 

 exact inferences as to the hereditary tendencies of 

 one plant from observation of a quite different 

 plant. Nevertheless it is of interest to observe cer- 

 tain analogies between the wheat grains as studied 

 by Professor Biff en and certain of our plant devel- 

 opments already cited. 



In particular we may note that red grain is 

 dominant to white grain, suggesting what we have 

 said as to the dominance of black blackberries 

 over white blackberries. 



Again, the rough leaf surface and bristly stem 

 of the wheat proved dominant to the smooth leaf 

 and smooth stem, suggesting the case of our thorny 

 stemmed briars in which the thorns proved 

 dominant to smoothness of stem. 



But doubtless the most important revelation 

 made by Professor Biffen's investigation was the 

 fact that susceptibility to rust was dominant to 

 immunity to rust. 



This means that when a susceptible type of 

 wheat is crossed with an immune one, all the off- 



[61] 



