PRINCIPLES OF POULTRY BREEDING 85 



recessives will breed pure single combs and no amount of 

 selective breeding will make them purer. This is the dis- 

 covery of Mendel. Twenty-five per cent of the dominants, 

 rosecombs, will breed pure; that is, a third, but the only 

 way to pick out the third or determine which will breed 

 pure rose combs, is to test them by breeding. The way to 

 test them is to mate them to single comb fowls, and if the 

 progeny have rose combs, the rose comb parent is pure and 

 will always breed pure rose combs. This requires, of 

 course, individual mating. All this gives a new meaning 

 to prepotency. Prepotency is not altogether dependent 

 upon length of pedigree. 



Egg Color and Dominance. It has been discovered, how- 

 ever, that not all characters segregate in this way, and 

 herein comes some confusion. Some characters segregate, 

 others unite or blend. In place of resembling one parent, 

 the offspring resembled both in part. Again referring to 

 the experiment of Barred Plymouth Rocks and White Leg- 

 horns, the color of eggs laid by the female offspring of the 

 cross showed a blend. The color of the Leghorn egg is 

 white, while the egg of the Plymouth Rock is brown. The 

 eggs from the cross averaged medium, showing the influence 

 of both parents. This character, color of egg, did not act 

 like the character color of plumage. In the one case there 

 was a blend, in the other, segregation. In one, the offspring 

 took after both parents, in the other, after one parent, 



Pure-bred not Always Prepotent. In carrying this ex- 

 periment further, white cross-bred pullets from the mating 

 of Barred Plymouth Rocks and White Leghorns, were mated 

 to pure-bred Barred Plymouth Rock males, with the result 

 that the offspring had white plumage. They took after the 

 cross-bred parent, rather than the pure-bred parent. Other 

 white pullets of the same cross were mated to pure-bred 

 Brown Leghorn males, and out of over 150 chicks from this 



