PRACTICAL AND SCIENTIFIC BREEDING 
The Centgenitor System—Prof. Hays in breeding wheat at 
Minnesota, first used in this country a system of breeding 
which is essentially as follows: A large variety of individual 
seeds are selected. These are planted separately and the 
amount and character of the yield observed. The offspring 
of one seed is kept separate for several generations, or until 
the character of the tribe is thoroughly established. The 
advantage of this plan of breeding is in that the selection is 
not made by comparing individuals, but by comparing the 
offspring of individuals. Thus, we necessarily select the only 
trait really worth while; that is prepotency or the ability to 
beget desirable qualities. 
The application of this centgenitor system necessitates in- 
breeding; it also necessitates large operations. Of the former, 
breeders have generally been afraid; of the latter they have 
lacked opportunity. But the centgenitor system, combined 
with Burbank’s principle of large opportunity of selection, is, 
in the writer’s belief, the method by which the 200-egg hen 
will be ultimately established in America. 
Much of the recent stimulus to the study of the Science of 
Breeding was occasioned by the discovery of Mendal’s Law. 
Briefly, the law states that when two pure traits or characters 
are crossed, one dominates in the first generation of offspring 
—the other remaining hidden or recessive. Of the second 
generation, one-half the individuals are still mixed, bearing 
the dominant characteristic externally and the other hidden; 
one-fourth are pure dominants and one-fourth are pure reces- 
sives. In future generations the mixed or hybrid individuals 
again give birth to mixed and pure types apportioned as 
before, thus continuing until all offspring become ultimately 
pure. For illustration: If rose and single comb chickens are 
crossed, rose combs are dominant. The first generation will 
all have rose combs. The second generation will have one- 
fourth single combs that will breed true, one-fourth rose 
combs that will breed rose combs only, and one-half that again 
will give all three types. 
Mendal’s Law works all right in cases where pure unit char- 
acteristics are to be found. For the great practical problems 
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