UNITED STATES DEPARTMENT OF AGRICULTURE 

 BULLETIN No. 869 



Contribution from the Bureau of Plant Industry 

 WM. A. TAYLOR, Chief 



Washington, D. C. 



PROFESSIONAL PAPER 



September 30, 1920 



THE INHERITANCE OF THE LENGTH 



OF INTERNODE IN THE RACHIS 



OF THE BARLEY SPIKE 



By 



H. K. HAYES, Head of Section of Plant Breeding, Division cf 

 Agronomy and Farm Management, College of Agriculture, Uni- 

 versity of Minnesota, and HARRY V. HARLAN, Agronomist in 

 Charge of Barley Investigations, Office of Cereal Investigations 



CONTENTS 



Scope of the Experiments 



Historical Review 



Pure-Line Varieties Used in These 



Studies 



Reliability of Experimental Methods . . 

 Effects of Environment and Varying 



Sources of Seed on Density .... 



Page 



Purity pf Parental Forms 5 



Inheritance of Length of Internodes in 



Crosses between Pure Lines .... 9 



Summary of Results 20 



Discussion of Results 21 



Conclusions 24 



Literature Cited 25 



WASHINGTON 

 GOVERNMENT PRINTING OFFICE 



1920 



