CHAPTER V. 

 PLANT BREEDING. 



432. Plants Have Improved Under Culture. From 

 our point of view, our cultivated varieties of plants are 

 superior to their wild prototypes. The strawberries of 

 our gardens are larger, more productive and firmer 

 than those of the fields; the cultivated lettuces are 

 more vigorous, more tender and milder in flavor than 

 wild lettuces; and the cultivated cabbages and cauli- 

 flower are greatly superior, in the food products they 

 furnish, to their progenitors. The superior qualities of 

 long cultivated plants, as compared with their wild 

 parents, are conspicuous wherever the wild forms are 

 known. 



433. Whence this Improvement? It probably results 

 from two causes, a — In culture, the natural hindrances 

 to development are largely removed. Cultivated plants 

 are less crowded by too-near neighbors than wild plants, 

 and they commonly receive more abundant food and 

 moisture. They are, therefore, able to reach higher 

 stages of development than are possible in nature, where 

 plants are constantly restricted by environment. 



b—The principle of selection has doubtless been more 

 or less operative since the beginning of culture (19). 

 All of our cultivated plants must have existed origi- 

 nally in the wild state. The most satisfactory plants 

 of any desirable species have been most carefully 



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