it has been known for a long time that bud variation occurs in vegetatively propa- 

 gated plants, the study of this phenomenon has been somewhat neglected for 

 several reasons. It has been quite generally believed that when an asexually 

 propagated variety has become established no further selection is necessary. The 

 reasons for, and the necessity of, selection of plants grown from seed have become 

 matters of common knowledge. On the other hand, the causes of bud variations 

 are not fully understood as yet, the extent and frequency of this phenomenon 

 have not been determined except in the case of a few plants, and the facts con- 

 cerning the importance of bud variation and bud selection in the amelioration of 

 plants are not widely understood. Furthermore, the scientific study of seeds 

 produced under controlled conditions and of the behavior of the plants grown 

 from them provides particularly convenient and fascinating material for investi- 

 gation and demonstration. The results of such study have often been extremely 

 spectacular and have attracted a deservedly vital interest in the minds of the 

 general public. These and other related conditions have naturally led to a con- 

 centration of interest, both from the scientific and commercial standpoints, in 

 this phase of plant improvement and to a lack of interest in similar work with 

 vegetatively propagated plants. The purpose of this paper is to present evidence 

 to show that bud variations are of frequent occurrence in many plants and to 

 suggest the importance of bud selection in the economic improvement of those 

 plants. This discussion will be largely confined to the practical application of 

 bud selection work in the improvement of certain agricultural crop plants which 

 are of commercial value and importance and which are propagated without refer- 

 ence to sexual reproduction. 



DEFINITION OF THE TERMS BUD VARIATION AND BUD SELECTION. 



The term bud variation, as we understand it, applies to any variations that 

 take place in the soma of the plant as distinguished from the variations appar- 

 ently caused by sexual reproduction and shown by the behavior of seedlings. 

 Webber states (77) in this connection * * * "from our present knowledge 

 of the cytology of heredity we would assume that hereditary changes such as 

 those manifested by bud variation, as well as seedling variations, are due to re- 

 arrangements of the hereditary units or anlagen which occur during cell division. 

 In the case of seedling variation we assume that this rearrangement takes place 

 primarily during the progress of the reduction division that precedes the forma- 

 tion of sexual cells. So far as microscopic investigations go we have no evi- 

 dence that would strengthen the idea of such a redistribution of characters ever 

 taking place in somatic cells. However, we have the strongest of all possible 

 proofs that it does occur in the fact that in bud variation we get segregations of 

 character analogous to the segregations of seedlings." 



Bud variations may be divided into two general classes: (1) those which are 

 not inherited and (2) those which are inherited. The non-heritable variations 

 include that type of variation which is the result of environmental influence and is 

 exhibited in the response of all kinds of plants in the same definite way to the 

 stimulation of environmental factors. 



