BULLETIN OF THE 



WiffiNlOFAfflOJIl 



No. 137 



Contribution from the Bureau of Plant Industry, Wm. A. Taylor, Chief 

 October 16, 1914. 



(PROFESSIONAL PAPER.) 



SOME DISTINCTIONS IN OUR CULTIVATED BARLEYS 



WITH REFERENCE TO THEIR USE IN 



PLANT BREEDING. 



By Harry V. Harlan, 

 Agronomist in Charge of Barley Investigations, Office of Cereal Investigations. 



INTRODUCTION. 



When the writer began active operations in barley breeding in 

 1909, the intelligent selection of mother plants was found to be very 

 difficult because of the lack of sufficient information to enable minor 

 variations to be recognized and interpreted. European breeders 

 had subjected the taxonomic details to a most exacting scrutiny, but 

 their results were not immediately useful. It was necessary to confirm 

 the European findings, for a character found stable there could not be 

 considered stable under the widely varying climatic conditions of 

 America until it had been so proved. Again, the European authorities 

 were far from united. There was not even a broad taxonomic char- 

 acter whose stability had not been questioned at one time or another, 

 and often by the highest authorities in barley classification. More- 

 over, even if the groundwork could have been adopted entire, the 

 more or less established taxonomic characters are only the beginning 

 of the problem. Breeding must take" note of characters that are 

 trivial in taxonomy. The intangible must be analyzed and made 

 to serve, as well as the tangible. 



Even the very plausible idea of adopting European methods and 

 importing improved European stocks was only partially successful. 

 Conditions in America dinWin one vital particular from conditions 

 in Europe. On the Continent and in Great Britain barley has been 

 cultivated for centuries, and it is therefore practically indigenous. 

 Each geographical locality has, through long periods of time, been 

 provided by natural selection and acclimatization with superior 

 native races. Breeding, under such conditions, is largely concerned 

 with the improvement of these existing stocks, with small likelihood 

 of any importation proving to be a serious competitor. 



Note. — A large part of the data herein presented was obtained in cooperation with the 

 Minnesota Agricultural Experiment Station, and the article itself was submitted as a 

 thesis as required for the degree of doctor of science in the University of Minnesota. The 

 subject is of interest to "plant breeders and agronomists. 



52783°— Bull. 137—14 1 



