CHAPTER XIV 

 PLANT IMPROVEMENT 



Meaning of plant improvement. Plant improvement refers 

 to the practice of securing high-yielding plants and keeping 

 them at a high level of production. Agricultural plants vary 

 greatly in their capacity for production. Attention has been 

 called to the importance of selecting plants which are best 

 adapted to the soil and climate of the particular region where 

 they are to be grown. But this is not the only selection 

 necessary to secure a high yield. Among plants of the same 

 kind there are differences that must be considered in order 

 that maximum production may be reached. For example, 

 the yield of a single variety of corn, such as Reid's yellow 

 dent, will vary in the same locality, although the fertility of 

 the soil, preparation of the seed bed, cultivation, and other 

 factors influencing the growth of the plant are similar. Other 

 things being equal, the greatest yield will occur when the 

 most careful attention is paid to the selection of seed. It 

 requires but little more labor and expense to produce a crop 

 from high-yielding plants than is necessary to produce one 

 from low-yielding plants. 



How high-yielding and otherwise desirable plants are 

 secured. Considering only those qualities possessed by 

 plants themselves, and not those resulting from fertility of 

 the soil or from other agencies influencing plant growth, 

 highly productive plants, or plants having exceptional quali- 

 ties, are secured in four ways: by introducing plants from 



147 



