6o 



The Journal of Heredity 



A TYPICAL BERKSHIRE BOAR 



In addition to the wild hog, the Berkshire, Duroc-Jersey and Tannvorth breeds were used. A 

 photograph of the registered Berkshire boar used is not now available, but the above illustration 

 shows a typical boar of this breed. Its ears are erect like those of the Tamworth and wild breeds. 

 Photograph from U. S. Dept. of Agriculture. (Fig. 8.) 



not give the numbers for an F2 genera- 

 tion and none of the Fi individuals in 

 this experiment reproduced, hence 

 there is not even an indication of the 

 number of factors responsible for the 

 face differences in these three breeds. 

 However the data clearly indicate this 

 much: Tamworth long straight face is 

 dominant o\er Berkshire short dished 

 face; Yorkshire dished face forms an 

 intennediate Fi with Tamworth long 

 straight face; therefore Berkshire short 

 dished face and Yorkshire dished face 

 must be similar phenotypes produced 

 by somewhat different factor com- 

 plexes. 



The face shape of the Duroc- 

 Jersey is intermediate to that of the 

 breeds just di.scussed in that it is mod- 

 erate in length and in dish, while the 

 forehead and the hair which grows 

 upon it usually slope smoothly upward 

 and backward. In the Fi generation 

 of the Berkshire X Duroc-Jersey cross, 



the forehead in every case approached 

 closely that of the Berkshire type and 

 the face was strongly dished but not 

 quite to the degree of the Berkshire 

 ideal. There was some variation in dish 

 and in length of face among the Fis 

 but they were all pronounced enough 

 to be more Berkshire than Duroc- 

 Jersey in type. In the Fo generation 

 very much wider variation was ob- 

 served. Since no practicable means 

 of measuring these three elements of 

 face shape was discovered, they were 

 simply classified according to their 

 resemblance to one or the other of the 

 grandi:)arental t\j)es. Table I shows 

 the result: 



Table I 



