VARIATION AND CORRELATION OF OATS (A VENA SATIVA) 



PART II. EFFECT OF DIFFERENCES IN ENVIRONMENT, VARIETIES, 

 AND METHODS ON BIOMETRICAL CONSTANTS ^ 



Clyde E. Leighty ^ 



(Received for publication April 9, 1914) 



INTRODUCTION 



Biometrical methods have recently come into considerable use in 

 studies of genetics. An increasing number of papers discussing the 

 subject are appearing each year, and work of this kind promises to be an 

 important addition to the literature bearing on variation, correlation, 

 and inheritance. The use of the exact methods of measurement required, 

 and the possession of formulae by means of which a mass of data may 

 be concisely and accurately expressed, mark distinct advances in the 

 science of genetics. It is difficult, for example, for the mind to grasp 

 the data concerned in the relation of height and yield for a thousand 

 plants, but if such data are expressed as a correlation coefficient in a single 

 number the difficulty disappears. 



With increasing use of these biometrical methods, a determination of 

 their exact status in studies of variation, correlation, inheritance, and 

 the like, is of importance. It is important to know the conditions that 

 must exist to make comparable the results obtained, to know the effect 

 of environment and hereditary differences on the constants determined. 

 It is also of importance to know, and to have expressed in a statistical 

 way, the variation and correlation that exist in and between the various 

 important characters of many plants. This is especially true of plants 

 of economic importance on which breeding work is being done. 



The studies herein reported are on oats (Avena saliva), with which 

 considerable breeding work is being done and which stand in need of a 



1 Paper No. 50, Department of Plant-Breeding, Cornell University, Ithaca, New York. 



Also presented to the Faculty of the Graduate School of Cornell tfniversity, as a major thesis in partial 

 fulfillment of the requirements for the degree of Doctor of Philosophy. 



- Formerly assistant in the Department of Plant-Breeding at Cornell University, now Agronomist in 

 Charge of Eastern Wheat Investigations, Bureau of Plant Industry, Washington, D. C. 



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