CORRELATIONS BETWEEN VARIOUS CHARACTERS OF 
WHEAT AND FLOUR AS DETERMINED FROM PUB¬ 
LISHED DATA FROM CHEMICAL, MILLING, AND BAK¬ 
ING TESTS OF A NUMBER OF AMERICAN WHEATS 1 
By Jacob Zinn 2 
Formerly 3 Associate Biologist, Maine Agricultural Experiment Station 
INTRODUCTION 
From a plant breeder’s point of view it would be very desirable to 
establish an index by means of which the baking quality or strength of 
wheat flour could be determined at an early stage of the breeding work 
so that the weak wheat strains could then be discarded, instead of 
carrying them through all the stages of propagation and the processes 
in the bakehouse. The solution of this problem calls for the establish¬ 
ment of a definite relation between a wheat character, determinable 
early in the selection or breeding work, and the strength of the flour as 
measured by the loaf volume. 
A study of the literature on the chemistry of wheat (j #) 4 reveals a 
marked divergence of views as to the significance of the various chemical 
characteristics of wheat in relation to the bread-making quality of the 
flour. Almost without exception, the work on the relationship of the 
chemical characters to bread-making value is characterized by the lack 
of statistical methods. The writer is aware of no publication in which 
this relationship and its degree are expressed in terms which will allow 
of comparison. 
In the present paper a large number of published data on the chemistry 
of wheat are compiled and the coefficients of correlation for the important 
chemical characters computed. In submitting the results of this study 
attention must be called to the limitations of the material. In order to 
exclude possible errors due to differences in the nature of the material 
and in technic, it was thought advisable to an alyze the data into groups 
by States and according to the kind of wheat rather than to lump them 
together into larger classes including several States or wheat districts. 
This, of course, resulted in a reduction of the data in the individual 
groups, which in some correlation tables reaches a point where con¬ 
clusions can not always safely be drawn. 
A further limitation of the material considered in this study lies in 
the relatively small amount of data on the chemistry of wheats and flours 
derived from pure strains. The data on pure lines are limited both in 
regard to localities and number of samples analyzed. The writer believes 
that the proper approach to the solution of the question of correlations 
1 Accepted for publication Nov. 14, 1921. . . . 
Wheat Investigations II. Papers from the Biological Laboratory of the Maine Agricultural Experiment 
Station, No 147. . . . 
* In the preparation of this paper the writer received helpful suggestions from Dr. John W. Gowen, of 
the Maine Agricultural Experiment Station, and assistance from Mr. H. C. McPhee and Mr. E. R. Ring, 
also of the Maine station, in the tabulation and computation of the data. 
* Dr. Jacob Zinn died in October, 1921. 
♦Reference is made by number (italic) to “Literature cited,” p. 548. 
Journal of Agricultural Research, Vol. XXIII, No. 7 
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Washington, D. C. 
ach 
26550—23-4 
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