INTRODUCTION 291 



tenance of work already under way, Vilmorin undertook two projects 

 which yielded results of the greatest importance to the entire world. 

 One was the collection of wheats and other grains from many countries 

 in order to compare them and to select those of greatest value. In con- 

 nection with this work on grains he invented the pure-line method of 

 selection and progeny test which came to be known as the "Vilmorin 

 Method" and which has been used so successfully with wheat and other 

 self-fertilized plants. From our present knowledge of pure lines we 

 can understand why this method was effective. Vilmorin's other im- 

 portant project was the improvement of the sugar beet. Previous to 

 1850 the beets had been selected according to form only. This method 

 of selection began as early as 1787 on the seed farm of H. Mette in Qued- 

 linburg, Germany, according to Legier. Selection on the basis of specific 

 gravity was practised from 1850 to 1862, when the method of determining 

 sugar content by means of polarized light was introduced. His success 

 made beet-sugar production a commercial possibility and gave his name 

 an enduring place in history. 



More Recent Progress in Plant Breeding. The great world move- 

 ments of the 19th century following the improvement of transportation 

 facilities, the migration of peoples, industrial development and the growth 

 of international trade, together with the improvement of farm machinery, 

 resulted in the extension of agricultural industries and gave a greater 

 impetus to plant breeding. This activity was manifested first in Europe 

 and later, particularly in the United States Department of Agriculture 

 and the state experiment stations, in America. Naturally the efforts 

 at improvement were concentrated in the main on the crop plants pro- 

 ducing the raw materials of importance in the world's markets, such 

 as wheat and other small grains, sugar beets, corn, cotton, forage plants, 

 the apple and other fruits. The methods employed were those which 

 had been used in the past for the most part, but they were systematized 

 and combined for more effective utilization. These methods may be 

 classified under the following heads: 



1. Mass selection. 



2. Line selection and progeny test. 



3. Hybridization followed by direct utilization or selection and 

 fixation of new varieties. 



4. Clonal selection. 



Mass Selection. The method of mass selection consists simply in 

 picking out choice plants from the main crop and sowing the seed from 

 them en masse. It has long been used, especially in improving small 

 grains, but it has also been used with many other crops. With this 

 method it has usually been found necessary continually to repeat the 



