THE PLANT 73 



PLANT IMPROVEMENT 



Origin of Cultivated Plants. Our cultivated plants, as you 

 probably know, originated from wild ones. These kindred of our 

 field crops exist still in many parts of the world, and it is interesting 

 to compare the two. In appearance and in habits of growth, the 

 wild and the cultivated plants differ as much as do savage and 

 civilized races of men. For instance, the ancestor of most of our 

 apple trees is a European crab. It is small and poorly flavored, 

 very unlike the large and luscious fruits familiar to us. Hundreds 

 of varieties differing in habit of growth, and in the size, color, flavor, 

 and ripening season .of their fruit have been developed from that 

 insignificant-looking, ill-flavored crab. 



How have these wonderful changes been made ? It has been 

 done by years and centuries of care and cultivation, raising plants 

 from the best specimens under the most favorable conditions. 



The Law of Heredity. Changes in varieties are made by taking 

 advantage of certain laws which govern all living things, both plants 

 and animals. The first is the law of heredity, that ' like begets 

 like.' Corn produces seed which brings forth corn, never by any 

 chance wheat or rye. The product shares the general, and, to a 

 great extent, the special characteristics of the parent plant. If that 

 ripened early, so will this ; if that was sugar corn, this will be sweet. 



The Law of Variation. You will notice that we say that a 

 plant inherits ' to a great extent ' the special characteristics of its 

 parents. It is just here that another laws comes in, a law which 

 makes progress possible. This is the law of variation, the tendency 

 of offspring to be unlike the parents. If the plant were in all 

 respects exactly like its parents, no improvement would be possible. 

 Usually variations are not great, for the law of heredity is very 

 strong. 



