Live Stock Breeders' Associatio7i. 89 



The cases cited are illustrations of what we call "Mendel's law 

 of dominance." We have many beautiful illustrations of this law. 

 For instance, if red tomatoes be crossed with yellow the fruit of 

 the hybrid is red. If white hogs be crossed with black or red the 

 hybrids are nearly always white. If the white faced Hereford 

 cattle be crossed with cattle having a colored face the crossbred 

 animals have white faces. If a red rose be crossed with a white 

 rose the hybrid is red. If a pink-eyed albino be crossed with an 

 individual having no albino blood, none of the progeny will be 

 albino. 



DOMINANCE NOT ALWAYS PERFECT. 



The dominance of one character over its opposite is seldom 

 absolute. In many cases there is some indication of the hybrid 

 character of the progeny. Even if there is no other indication the 

 hybrid is usually stronger growing and more vigorous than the 

 pure bred. But frequently the recessive character itself shows, at 

 least partially, in some individuals resulting from the cross. As 

 stated above, the cross between bearded and smooth wheat shows 

 a slight tendency to be bearded. The cross between polled and 

 horned cattle in a few individuals develops imperfect horns, or 

 scurs. Recessive characters are especially likely to show when 

 age comes on. 



In some cases, however, we have a very different result. There 

 is a certain red primrose which, when crossed with a certain white 

 primrose, instead of giving red progeny gives a beautiful purple 

 flower. This primrose has for years been sold on the market under 

 the name of "Imperial Primrose;" but it is a hybrid and does not 

 reproduce true to seed. We shall later see why this is the case. 



In some crosses, instead of having dominance of one character 

 over its opposite, the hyprid is intermediate between the two 

 parents. For instance, in my work with hybrid wheats some years 

 ago, I crossed several varieties of the ordinary types of wheat 

 with the extremely short headed club wheats grown on the Pacific 

 Coast. While the hybrids produced club shaped heads with the 

 characteristic dense growth of the club varieties, these heads were 

 nearly always longer than the original club heads, so there could 

 not be said to be complete dominance of the club character. Prof. 

 Castle, of Harvard, crossed long-eared rabbits with ordinary 

 rabbits, and the progeny had ears intermediate in length between 

 those of the two parents. On the other hand, when dwarf peas are 



