124 INBREEDING AND OUTBREEDING 



plants obtained from seed of a commercial variety grown 

 in Illinois known as Learning Dent. This variety was 

 given the number 1, and four plants which were self- 

 pollinated and selected for continuation of the inbreeding 

 experiment were numbered 1-6, 1-7, 1-9, and 1-12. These 

 four lines were perpetuated each year by self-pollination 

 and will be referred to hereafter as the Learning strains. 

 In the second inbred generation two self -pollinated plants 

 in the 1-7 line were saved for seed and from them two 

 inbred lines were split off which consequently came origi- 

 nally from one line inbred two generations. These were 

 numbered 1-7-1-1 and 1-7-1-2. Many other inbred strains 

 coming from different material have been started from 

 time to time and several of them are still being continued. 

 There is no need to mention them specifically, except as 

 they bring out special features. 



TABLE III 

 THE EFFECT OF INBREEDING ON THE YIELD AND HEIGHT OF MAIZE 



