CHAPTER V 
PLANT BREEDING 
432, Plants Have Improved Under Culture. From 
our point of view, our cultivated varieties of plants are su- 
perior 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 cul- 
tivated cabbages and cauliflower are greatly superior, in the 
food products they furnish, to their progenitor. The super- 
ior qualities of cultivated plants, as compared with their 
wild parents, is conspicuous whenever the wild form is known. 
433. Whence this Improvement? It probably re- 
sults from two causes. (1) In culture, the hindrances to 
development are largely removed. Cultivated plants are 
less crowded by too-near neighbors than wild plants, while 
food and moisture are often directly supplied to them. 
They are, therefore, able to reach higher stages of develop- 
ment than is possible in nature, where plants are constantly 
restricted by environment. 
(2) The principle of selection (19) has doubtless been 
more or less operative since the beginnings of culture. All 
of our cultivated plants must have existed originally in the 
wild state. The most satisfactory plants of any desirable 
species have been most carefully guarded, and when the art 
of propagation became known, these plants were most multi- 
plied. In each successive generation, the most desirable 
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