124 



INBEEEDING AND OUTBEEEDING 



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 Leaming 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 



Year 

 grown 



1916 

 1905 

 1906 

 1908 

 1909 

 1910 

 1911 

 1912 

 1913 

 1914 

 1915 

 1916 

 1917 



No. of 

 genera- 

 tions 

 selfed 



Four inbred strains derived from a variety of Leaming dent corn 





 



1 



2 

 3 

 4 

 5 

 6 

 7 

 8 

 9 

 10 

 11 



1-6-1-3-etc. 



Yield 



bu. per 



acre 



74.7 

 88.0 

 59.1 

 95.2 

 57.9 

 80.0 

 27.7 



41.8 

 78.8 

 25.5 

 32.8 

 46.2 



Height 

 inches 



117.3 



l-7-l-l-etc. 



Yield 

 bu. per 



acre 



86.7 



96.0 



" 97.7 

 103.7 



74.7 

 88.0 

 60.9 



1908460 



63.2 

 25.4 



Height 

 inches 



1-7-1-2-etc. 



1-9-1-2-etc. 



117.3 



39.4 

 47.2 

 24.8 

 32.7 

 42.3 



81.1 



83.5 



84.9 

 78.6 



Yield 



bu. per 



acre 



74.7 

 88.0 



60.9 

 190759.3 



1908597 



68.1 

 41.3 



Height 

 inches 



117.3 



90.5 



58.5 



19.2 

 37.6 



88.0 



86.9 

 83.8 



