Plant Breeding. 273 



variety (21)* as this word is used with reference to cul- 

 tivated plants. There are two possible ways of fixing a 

 desirable variation : 



a—By propagating the plant by division (345). This 

 enables us to maintain a given variation through many 

 generations with comparatively little deviation from the 

 form with which we started (341). Our varieties of 

 fruits, potatoes, geraniums and many flowering plants, 

 and of many of our finest ornamental trees and shrubs 

 are fixed in this manner. It is well known that varie- 

 ties propagated in this way rarely "come true" from 

 ^eed, i. e., their seed does not usually produce plants of 

 the same variety as the parent. But it is not practi- 

 cable to propagate all plants by division. 



With plants more conveniently propagated from seed, 

 such as the cereals, Indian corn and most garden vege- 

 tables, we may fix varieties to a certain limit. 



h—By persistent selection toward an ideal type. For 

 example, if we discover a single pea plant in a row of 

 peas that produces earlier pods than any other plant 

 and we desire to fix this variation, we should save all 

 the peas from this plant and sow them the next spring. 

 Most of the plants from this seed will probably be later 

 than the parent, but two or three of them may equal 

 it in earliness. We should save the ^ seeds from the 

 earliest plant again, and continue this selection through 

 several seasons. It would be well to note the incidental 

 characters of the earliest plants, i. e., whether the pods 

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



* Varieties that produce thSlr more important characters when 

 grown from seed, are often called races. 



