BULLETIN OF THE 
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 differ in 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 
