268 PRINCIPLES OF PLANT CULTURE 



acters of the earliest plants, i.e., whether the pods are 

 borne singly or in pairs, if they are straight or crooked, 

 and whether the plants are tall or dwarf. Having de- 

 cided on the characters that seem to accompany the 

 extreme earliness, we should save seeds only from plants 

 that show all of these characters. After following this 

 kind of selection eight or ten years, we may be able to 

 introduce a new variety of pea. 



It is impossible so to fix variations in plants grown 

 from seed that they will continue to come true without 

 a certain amount of selection, hence varieties propa- 

 gated by seed continually tend to " run out," i.e., to 

 lose their distinctive characters. Seed growers find it 

 necessary to use the utmost care in maintaining their 

 varieties, and the more distinct a variety propagated by 

 seed, the more difficult it is to maintain. 



437. Seed selection is of great importance. From 

 what has been said, it is clear that the cultivator can- 

 not afford to be indifferent as to the quality of the seed 

 he sows. It is not enough that the seed is fresh and 

 plump; it should be of carefully-bred varieties. In 

 the cabbage and cauliflower, success or failure in the 

 crop will depend largely upon the quality of seed sown, 

 and the same is more or less true in all crops grown from 

 seed. 



438. Inducing variation. — We can induce variation, 

 in some cases, by special treatment of the parent plants, 

 or by the use of a particular selection of seed. 



By culture. — It is generally conceded that culture 

 tends to promote variations that would not have ap- 

 peared in the wild state, in consequence of the changed 

 growth conditions. In improving wild plants, there- 

 fore, we probably have a better chance of securing vari- 



