436 EXPERIMENTS WITH PLANTS 



the end; the weight and color of the grain and of 

 the cob; the number, size and shape of the kernels, 

 and many other points must be considered. 



It is not sufficient to select the best ears: we 

 must know which of the selected ears can transmit 

 its good qualities in ' the highest degree ; in other 

 words, we must determine what is known as the 

 hereditary percentage 1 (i. e., the percentage of off- 

 spring which inherit the desirable characters). For 

 this purpose the kernels from each ear are sown by 

 themselves in a separate row, so that the offspring 

 of the different ears can be readily compared. 



The poor, or barren stalks, and the suckers are 

 removed before the tassel appears. Since the pollen 

 is carried by the wind for about a mile, it is an 

 obvious advantage to have the field well separated 

 from other fields likely to contaminate it. In the 

 fall the seed for next year's crop is selected from 

 the rows which, all things considered, give the best 

 results. 



The results of this work may be illustrated by the 

 experience of a farmer in southern Illinois who was 

 induced to plant three hundred acres with improved 

 Corn seed. These three hundred acres yielded thirty 

 bushels per acre more than the fields planted with 

 unimproved seed, or, in other words, gave about 



lr The hereditary percentage is one of the most important matters in 

 selection and is only too commonly lost sight of by breeders. 



