202 MAKING BETTER PLANTS 



tage, especially of extreme variations, or " sports," if their 

 character is promising, because here Nature has done 

 more of his work for him. (3) He experiments with 

 new crosses to secure types that Nature of herself has not 

 produced or which at least she has not preserved. 



151. The Perpetuation of a New Variety. We have just 

 mentioned three distinct ways in which the breeder secures 

 new kinds of plants. In all three, he works with the 

 natural tendency to variation. But in all three, too, in fixing 

 and perpetuating the new variety he relies upon the force 

 of heredity to aid him. 



To use this force, however, the breeder must know a 

 little more about it. At first any one of his new varieties 

 consists of very few plants, perhaps of only one chosen 

 plant. Now, in all forms of life, the offspring inherits its 

 character not merely from its immediate parents, but also, 

 through them, from more distant ancestors. Accordingly, 

 there is a strong tendency in the offspring of the first plants 

 of a new variety to return (" revert ") to the average char- 

 acter of the older variety from which the new one was 

 developed. This tendency is strengthened still farther, 

 in a wild state, by crosses between the new variety and 

 the old one. The offspring of such crosses, as a rule, are 

 more like the old variety than the new one, because the 

 character of the old has been fixed longer and more firmly. 



If the grape " sport " that appeared in Mr. Bull's Concord 

 garden had appeared instead in the forest, it would itself 

 have produced " Concord " grapes ; but most of the plants 

 from the seeds of those grapes would probably have " re- 

 verted " to the character of ordinary wild grapes, and, in 

 time, at best there would have been merely a few vines in 

 the neighborhood with slightly better fruit than the aver- 

 age fox grape. Mr. Bull saved the new variety by propa- 

 gating it, not by seeds, but by slips. In this kind of 



