316 POMOLOGY 



The terms "mass selection" and "line selection" cannot 

 properly be applied to the methods employed in obtaining 

 new fruits. They refer to securing an improved variety in 

 plants that are propagated sexually (i. e., by seed), where 

 an effort is made in each generation to obtain individuals 

 that will be superior to the original form, 



279. Mass-selection refers to the choice of several 

 superior individuals from which seed would be sown en masse, 

 no effort being made to keep the progeny from any single 

 plant separate; and from the new individuals which arise, 

 the superior ones would again be selected, until a strain or 

 race is secured which is superior to the original stock. Such 

 a process has never been undertaken with fruit-trees, since 

 it is not necessary for a variety to be homozygous in order 

 to propagate it asexually or for it to have superior fruit 

 characteristics. 



The term mass-selection may be applied in a broad way 

 to the method used by Van Mons and to that of Burbank. 

 Seeds selected from one or more trees (themselves heterozy- 

 gous) are planted in order to secure a large number of new 

 individuals. From these new forms the superior ones are 

 selected, usually after they come into fruiting, and are prop- 

 agated as new varieties with no further selection. 



280. Line-selection has no special application to fruits 

 because, as yet, no one has tried to secure a race or variety 

 which will come true from seed, as is necessary with the 

 common farm and garden crops. With the latter plants, the 

 term refers to a line of progeny derived originally from one 

 individual. 



281. Clonal-selection. — The term " clonal-selection " ap- 

 plies only to plants which are propagated asexually, hence 

 to fruit-trees. Clones have been defined as "groups of culti- 

 vated plants the different individuals of which are simply 

 transplanted parts of the same individual, the reproduction 



