PLANT BKEEDING AND EVOLUTION 



205 



In this manner improved races of cereals and forage crops, 

 adapted to the varying soil and climatic conditions of the 

 country, have been obtained in Sweden at the Svalof station. 



This method of selecting seeds from one plant and growing 

 them in isolated culture plots (Fig. 114), so that the progeny of 

 single individuals can be observed and recorded, is called pedi- 

 gree culture. Pedigree culture has been practiced for many years 

 in the breeding of animals, but its application to plant breeding 



FIG. 114. Centgener plots of flax and beans alternating 



One hundred seeds are planted in each centgener plot. Photograph furnished by 

 the United States Department of Agriculture 



has been greatly stimulated in the experiment stations of this 

 country by the experiences of the Swedish station mentioned 

 above. Pedigree culture is thus very different from the older 

 mass-culture method, by which seed is collected from a consider- 

 able number of the best plants in a field and then sowed en 

 masse, without any attempt to trace or record the progeny of 

 one particular plant. The mass-culture method is often used 

 for selecting the better varieties from a general field, and is then 

 followed by pedigree culture applied to a few best individuals 

 selected from the mass-culture plots. 



