22 THE APPLES OF NEW YORK. 



reproducing itself by seed. Thus dwarf lima beans have originated from 

 pole lima beans, and dwarf sweet peas from tall-growing varieties. Vari- 

 ous other instances of this kind might be cited. If it should seem desir- 

 able to perpetuate such a sport by seed it is quite probable that it would 

 be necessary to fix the type before introducing it as a new variety. 



Bud Sports. Bud sports are well known. They correspond to seed 

 sports in that they appear suddenly. They usually show permanent char- 

 acters when propagated, entitling the sport to be called a new variety. 

 Moreover, these characters may be transmitted, to a greater or less 

 extent, through the seed produced by such a sport. Numerous instances 

 in which varieties have originated as bud sports are found among orna- 

 mental plants and they are not unknown among orchard fruits. 



SELECTED STRAINS. 



In the case of a sport a variation from the ordinary type arises sud- 

 denly. In other cases as great variations have been developed gradually 

 by selecting individuals for breeding purposes which showed a tendency 

 to vary in some particular way which it was desirable to perpetuate and 

 intensify. Selected strains may be developed either sexually or asexually. 

 Many well-known strains of garden vegetables have been originated by 

 gradual selection under propagation by seed. So also under asexual 

 propagation distinct strains have in some cases originated through a 

 gradual process of selection of the propagating wood, or whatever other 

 material is used in propagating the variety. This latter process corre- 

 sponds to the development of strains by seed selection. By it varieties 

 of the pear which in the original seedling tree were armed with sharp 

 thorny spurs have been changed so that it may be truly said that the 

 thorns have been bred away. In a like manner thorns have been bred 

 away from certain cultivated varieties of the orange. Galloway, 1 who 

 has given much attention to the growing of violets, states that " left to 

 itself the tendency of the violet is to retrograde. By proper selection and 

 right cultural methods the yield may be raised from fifty flowers to one 

 hundred flowers per season in three years." 



From all that has been said it appears that new varieties may be pro- 

 duced sexually in seed hybrids, asexually in graft hybrids; sexually in 

 seed sports, asexually in bud sports; sexually in selected seed strains, and 

 asexually in selected bud strains. 



VARIATIONS DUE TO ENVIRONMENT. 



It is important to discriminate between those variations that are in- 

 herent in the plant and capable of being propagated, as in those cases 

 which have been just considered, and variations which are due to the 

 peculiar influences of local environment and which are not transmitted 

 under propagation. 



Many of the differences that different orchard trees show in habits of 

 growth and productiveness; in the size, color and quality of the fruit 

 produced; in resistance to disease, and in other ways, may be satisfac- 

 torily accounted for on the ground of differences of environment. For 



1 Violet Culture: 109-116. 



