CONTENTS. 



Page. 



Object of the investigation ; 13 



Part I. — Historical: 



Some conditions affecting the composition and yield of wheat 17 



Composition as affected by time of cutting 17 



Influence of immature seed upon yield 20 



Influence of climate upon composition and yield 20 



Influence of soil upon composition and yield 23 



Influence of soil moisture upon composition and yield 29 



Influence of size or weight of the seed-wheat kernel upon the crop yield.. . 30 



Relation of size of kernel to nitrogen content 35 



Influence of the specific gravity of the seed kernel upon vield 37 



Relation of specific gravity of kernel to nitrogen content 39 



Conditions affecting the production of nitrogen in the grain 40 



Part II. — Experimental: 



Some properties of the wheat kernel 49 



Yield of nitrogen per acre 72 



Method for selection to increase the quantity of proteids in the kernel 76 



A basis for selection to increase the cjuantity of proteids in the endosperm of 



the kernel 84 



Improvement in the quality of the gluten 91 



Some results of breeding to increase the content of proteid nitrogen 95 



Yield of g ain as affected by susceptibility to cold 100 



Yield and nitrogen content of grain as affected by length of growing period. . 104 



Relation of size of head to yield, height, and tillering of plant Ill 



Summary and conclusions 118 



9 



