BULLETIN 250. 



STUDIES ON OAT BREEDING. IV. PURE LINE 

 VARIETIES. 1 



By 

 Frank M. Surface and Jacob Zinn. 



The agricultural importance of the oat crop in Maine led the 

 Experiment Station to undertake some definite breeding work 

 with this cereal at Highmoor Farm in 1910. The general outline 

 of this work has been given in a previous paper. 2 One of the 

 lines of work attempted, has been to develop new varieties 

 which would be better adapted to our conditions than any of 

 those now grown. In attempting to do this several methods 

 have been employed. One of these has been the isolation of 

 "pure lines" out of certain standard commercial varieties. This 

 work has now reached such a point that a discussion of the 

 results may be undertaken. 



Before proceeding to the discussion of these "pure lines" it is 

 important to have a clear understanding of what is meant by 

 this term. This term was first used by the Danish botanist, 

 Johannsen. According to Johannsen's 3 definition a "pure line" 

 is the offspring of a single, self-fertilized, homozygous individ- 

 ual. The exact meaning of this can perhaps best be made clear 

 by referring to the work of Johannsen himself. 



Johannsen, in his work on beans, brought out very clearly 

 three things which in themselves and in their implications are of 

 fundamental importance to all practical breeders of animals or 

 plants, as well as to students of breeding. These three things 

 are: 



J Papers from the Biological Laboratory of the Maine Agricultural 

 Experiment Station No. 96. 



"Surface, F. M. and Barber, C. W. Studies on Oat Breeding. I. 

 Variety Tests 1910-1913. Maine Agricultural Experiment Station, Ann. 

 Rept. 1914, pp. 137-192. (Bulletin No. 229). 



"Johannsen, W. Elemente der exakten Erblichkeitslehre. Jena, 1913, 

 pp. XI + 723. 



