INTRODUCTORY STATEMENT. 



Wliile the art of plant breeding has been practiced for nearty a 

 century, the last decade has witnessed a marvelous awakening of 

 interest in the subject, both from a scientific and practical stand- 

 point. The keen competition in crop production and the resulting 

 cheaper prices, the great and varying demands of modern trade con- 

 ditions, etc., render it necessary that the modern plant breeder have 

 the most thorough knowledge possible of the plant which he is striv- 

 ing to improve. Not only must we secure varieties and races differ- 

 ing in external characters and yielding more heavily under a certam 

 set of conditions, but we must also examine the chemical constit- 

 uents of the product and strive to change and improve them in order 

 that they may better fit our purpose. 



The great achievements of plant breeding in the past have been 

 mainly in physical characters, requu'ing only superficial knowledge 

 and gross examination for recognition. Many of the improvements 

 now demanded, however, require the most careful chemical exami- 

 nation of the product and the devising of careful means and methods 

 of selection based on the knowledge thus obtained. 



The first and still the most noteworthy achievement of this nature 

 is the increase of the sugar content in the sugar beet. When the 

 work on this subject was first started by Louis Vilmorin, the mother 

 beets, which were supposed to contain the most sugar, were separated 

 by their greater density, this being determined by throwing the beets 

 into a solution of brine of such density that the greater number of them 

 would float. The few heavier ones which were found to sink were 

 retained as mothers and planted to raise seed. Later the methods 

 were improved, and finally the percentage of sugar content in the 

 different individual beets was determined by actual chemical analy- 

 sis. This careful method of selection has been in operation for more 

 than forty j^ears, and has resulted in greatly increasing the sugar 

 content in the beets, and has rendered their cultivation profitable 

 w^here otherwise the industry would have failed. 



The second most noteworthy case of increasing certain chemical 

 constituents in a plant b}- careful breeding is that furnished by the 

 investigations of the Illinois Agricultural Experiment Station in 

 increasing the nitrogen, oil, and starch content in corn. These note- 

 worthy experiments carried out by Doctor Hopkins and his assist- 

 ants have greatly stimulated breeding work of this nature, and have 

 paved the way for further research of a similar kind. 



In wheat it is particularly necessary that a thorough knowledge 

 be obtained of the variations in the chemical constituents and their 

 relation to the other characters of the plant, such as yield, size of 



