636 EXPERIMENT STATION RECORD. 



' ' The individual plant produced from a seed is the important unit in plant breed- 

 ing. The 'bud unit,' though of much consequence in case of marked bud variation, 

 is usually of minor importance. 



"Heredity, centripetal-like, enables us to produce from certain choice plants 

 many descendants which, on the average, quite resemble their parents. 



"Variation, centrifugal-like, causes the production among the descendants, along 

 with very many average plants, of a few very good individuals and a few very poor 

 ones. 



"By selecting those best plants which upon trial produce superior progeny, the 

 whole variety may be slightly or considerably improved. 



"Since the plants of each succeeding generation also vary, by repeatedly choosing 

 the best, the variety or race is further improved. 



"In many cases crossing increases the average vigor of the progeny, but in other 

 cases it decreases the average vigor, size, or other desirable characteristics. 



"In all cases crossing increases variation, as a rule, both to ward. better j^lants and 

 toward poorer ones, thus giving opportunity for selecting from among the best plants 

 individuals which are superior, as progenitors of varieties, to any individuals which 

 could have been secured without crossing. 



"New varieties can best be founded upon one to a dozen superior selected or cross- 

 bred seedling plants used as parents. 



"Very large numbers of individuals must be used from which to select or breed in 

 order that mother plants may certainly be discovered from which superior varieties 

 will spring. 



"In addition to growing large numbers, the breeder of plants should grow all the 

 plants of a given stock under uniform conditions, that they may be accurately 

 comj)ared. 



"The testing of the finished variety must include adaptability to the soil and 

 climatic conditions, the quality and value of the resulting crop, and the relative 

 cheapness and practicability of its production. ' ' 



Under methods of i^lant breeding the author considers breeding by selection and 

 by hybridization and selection. Discussions on breeding wheat, corn, timothy, pota- 

 toes, apples, black walnuts, and flax are presented to illustrate many of the general 

 methods. Views of prominent horticulturists on the subject of hybridizing apples 

 are quoted, and complete descriptions of wheat flowers and the operations of hybrid- 

 izing are given. The "centgener plats," to which reference is made in the bul- 

 letin, are described as follows: "One hundred, more or less, of the seeds, from 

 each of [the selected] . . . plants are jjlanted in separate nursery plats in the 

 wheat-breeding nursery the second season in a manner similar to that under which 

 the seed was grown the first season. These collections of plants are called 'cent- 

 geners,' this word having been originated to mean a hundred plants, more or less, 

 springing from the seeds of a single mother plant — that is, a larger number of one 

 generation." 



The results so far obtained in breeding wheat at the INIinnesota Agricultural 

 Experiment Station are briefly summarized. These results show that the heavy- 

 yielding spikes, as well as the heavy-yielding plants, should be selected. The 

 centgener plan of experimenting has been found expedient in the selection of plants 

 for greater ability to stand erect. "The tendency in the blood of a mother plant 

 to beget a race with stiff straw can not well l)e judged with the single plant, but 

 it can with the small plat of a hundred or more of the progeny. . . . Recent 

 results from incrosses and outcrosses lead to the belief that hybridizing is of para- 

 mount importance to supply the best stocks for the more laborious work of selec- 

 tion. . . . Hybrid wheats vary as to the length of time variation continues under 

 rigid nursery selection, but generally they are reduced to a type in a few generations, 

 this being accomplished with little special effort while selecting for superior yield 



