20 



ELEMENTS OF AGRICULTURE 



getting desirable blends or new combinations of charac- 

 ters. But this is done with the knowledge that the great 

 majority will have to be discarded. The large number of 

 poor ones is the price paid for a possible one or two su- 

 perior ones. The farmer who is not a breeder does well to 

 decide on what breed he wants, and then stick to it. 



Half-breeds are often good in the first generation; but 

 this is what we should expect, because only the dominant 

 characters are apparent. Mendel found that by crossing 

 peas with stems one foot in length with those six feet in 

 length he got hybrids six to seven and one-half feet in 

 length larger than either parent; but, in the next gen- 

 eration, short forms reappeared. The succeeding genera- 



70. 



.9. 



.100 



FIQ. 8. Yield in grams of 100 plants of Fife and Blue-stem wheat and of a 



hybrid between the two. (Adapted from Hays.) 

 Yield of Blue-stem. Yield of Fife, x-x-x Yield of hybrid. 



tions are the ones that are likely to bring disappointment. 

 If the half-breeds are to be sold to the butcher, crossing 

 may be desirable. This agrees with common experience, 

 that it is not wise to use half-breed animals as sires even if 

 they do appear to be good. 



Fig. 8 shows the yield of one hundred plants of fife and 

 blue-stem wheat and of a hybrid between the two. The 



