5O Breeding of Plants and Animals. 



finally to the individual wheat plant as the unit. Just 

 as in animals, so in plants we must record and compare 

 the breeding powers of the individuals. The group of 

 several culms from the single parent seed, each bearing 

 a spike of wheat, constitute the plant. The spike or 

 ear of wheat, generally called head, is no more the 

 plant unit than is one of the several ears on a branching 

 stalk of popcorn. In breeding plants we deal with blood 

 lines just as we do in breeding animals. Since in the 

 thickly-sown wheat field at harvest time we cannot dis- 

 cern the culms arising from one seed which are inter- 

 woven with the culms from another seed, wheat must 

 be grown in hills, one seed in a hill, that one plant 

 may be compared with another. It has been found by 

 both formal and extensive practical experimentation 

 that 4x4 inches is a suitable distance to gro-. -Ting 

 wheat, and 5x5 inches winter wfieat, where the iirli virt- 

 ual plants are to be compared. Wheats thus planted in 

 plots and the entire plants compared are bred on a far 

 different basis than wheat bred by selecting out the best 

 heads in the field or by selecting out the best kernels by 

 means of the fanning mill. Those methods are wcrth 

 while and should be carefully followed in general farm 

 practice and by all wheat seed growers and particularly 

 in case of new varieties which have had the abnormal 

 quality of high yielding made still more abnormal either 

 by selection or by hybridizing aided by selection. But 

 nursery breeding as described in future pages is very 

 much more important as a method for wheat improve- 

 ment. 



In 1893 Henry Vilmorin, the great Paris seedsman 

 and plant scientist, said that "wheat flowers are nearly 

 always self-pollinated, not one in ten thousand being 

 fertilized by pollen from another plant." Formal ex- 

 perimentation shows that his statement is substantially 

 true. This fact makes wheat breeding a very unique 

 problem, although many other plants are also commonly 

 self-fertilized. Talk about inbreeding-, here is the most 

 incestuous of inbreeding! Self-breeding is the almost 



