10 The Bulletin. 



He also found "where samples of the same variety have been accurately 

 measured the lint varied greatly in length owing to differences in soil." 

 Mr. Tracy found further that "some varieties gave enormous yields 

 when all conditions were favorable, but failed miserably when planted 

 on unfavorable soils." After a long series of carerul investigations in 

 citrus fruit-growing in the Gulf States, Prof. P. H. Rolfe concludes: 

 "In the production of oranges it is absolutely necessary to choose the 

 particular variety which is adapted to any peculiar soil." 



Relative to the production of wheat in Tennessee, Director A. M. 

 Soule, of the Tennessee Experiment Station, after testing a number of 

 varieties, concludes : "The selection at random of varieties of wheat has 

 led the farmers to conclude that the soil and climatic conditions prevail- 

 ing in Tennessee are antagonistic to the production of a superior grade 

 of wheat, but careful research has revealed the fact that when the varie- 

 ties are found specially adapted to the soils in this State, the results are 

 quite as satisfactory as those secured in other part of the United States." 



During our study of the adaptation of varieties of plants to soil types 

 we have found in every case investigated that each variety has been 

 developed in a quite distinct type of soil, and our study of the later 

 history of these varieties goes to show that they give best results only 

 when grown on soils similar to those on which they have been developed. 

 Indeed, it appears to us higlily improbable that a good and distinct 

 variety of any of our staple crops can be developed in a field where there 

 is a medley of soil types. Uniformity of soil is essential to the produc- 

 tion of a uniform variety of plant. The Toole variety of cotton wa* 

 developed on the Norfolk sand, and may be expected to give better results 

 on this and closely allied types of soil than any other variety of cotton. 



It is hardly too much to say that the farmers of this country lose 

 millions of dollars yearly by not knowing the particular varieties of 

 corn, wheat, cotton, etc., best suited to the different soil types found on 

 their farms. 



SEED SELECTION. 



There is, perhaps, no more potent factor in the adaptation of varie- 

 ties of plants to soil types or soil environments than that of careful seed 

 selection. As we said above, when a plant is forced to grow in a new 

 environment it at once begins to adjust itself to the new conditions of 

 life. In case of the cotton plant, for example, we will see here and 

 there in the field, during the first or second generations, a few plants 

 making a better growth and setting fruit more liberally than the general 

 run of the field. The grower will mark these plants and select seed 

 from them for planting the following year, etc., and in a little while 

 will have his whole field set with plants that are rapidly adjusting 

 themselves to the new soil conditions. This practice of selecting seed 

 from the best plants and planting these selected seed again on the same 

 type of soil is the best — the only — means by which to force the plant to 

 its highest point of productiveness. Indeed, seed selection is beneficial 

 mainly in that it accelerates the complete adaptation of the plant to the 

 particular soil environment. 



