i 4 2 PLANT-BREEDING 



justify a discussion of this principle from a scientific point 

 of view and a few suggestions upon the great superiority of 

 the row system of testing. The main point is to support 

 the view that the detasseling of the barren stalks themselves 

 is only a very imperfect method, but that the same treatment 

 of the whole rows is what is absolutely necessary, the pollen 

 of the normal plants of such rows being as dangerous as 

 that of the barren stalks themselves. My suggestions are 

 based partly on my own experience with a special kind of 

 barren stalks, which produced neither ears nor tassels, and 

 partly on my experiments with other kinds of monstrosities 

 in other plants. For barrenness is to be considered as a 

 monstrosity, which, like all other monstrosities, is inherent 

 in a race, but is developed only in a certain percentage of 

 its individuals. The same monstrosity may occur in some 

 races only in a small per cent, being found in other strains 

 of the same variety in as much as 30 to 40, or even 50 and 

 more per cent. Evidently this holds good for barrenness in 

 corn, too, and the families with 30 to 50 per cent are those 

 which must be eliminated by selection, while only those with 

 a small per cent may be multiplied until the time that 

 strains will be discovered without any propensity to this 

 deviation. Ordinary monstrosities can be propagated, in 

 scientific experiments, as easily from the self-fertilized seeds 

 of the completely normal individuals as from the seeds of 

 the monstrous plants. There is no difference in the quan- 

 tity of the deviating specimens of the progeny between these 

 two sources of seed, the normal plants being as liable to 

 give a monstrous progeny as the monsters themselves. 



Some instances may be adduced. Torsions are of quite 

 common occurrence among teasels. I isolated a family 

 which produced yearly, during a long series of its biennial 

 generations, from 30 to 45 per cent of twisted stems. In 

 1900, 1 protected the twisted specimens from the pollen of the 



