BUREAU OF PLANT INDUSTRY. 291 



ACCLIMATIZATION AND ADAPTATION OF COTTON, CORN, AND 



OTHER CROPS. 



The investigations directed toward the acclimatization and adapta- 

 tion of varieties of cotton, corn, and other crop plants that have 

 originated in tropical countries have been continued under the gen- 

 eral supervision of Mr. O. F. Cook. Bionomist, assisted by Mr. G. N. 

 Collins. Botanist. Different branches of the field investigations are 

 conducted by Messrs. S. M. Bain. E. B. Boykin, J. H. Kinsler. F. L. 

 Lewton, A. 'McLachlan, H. Pittier. and D. A. Saunders. Particular 

 attention is being given to the adaptive characters, environmental 

 reactions, and methods of breeding and local adjustment of varieties 

 of cultivated plants, in order to determine the best methods (1) of 

 improving the crops. (2) of developing increased resistance to unfa- 

 vorable conditions, diseases, and insect enemies, and (3) of extending 

 the range of cultivation in the United States. 



Increased yields fro:m crossing varieties of corn. — Further tests 

 in crossing varieties indicate a very wide application of this method 

 of increasing the yields of corn. The- results of experiments with 

 more than twenty different crosses grown in seven States have been 

 brought toirether. In nearlv all crosses the vields were materiallv 

 increased over th.e average of the parent varieties, the mcrease rang- 

 ing as high as 50 per cent. These experiments have shown further 

 that the crossed strains possess in a very marked degree the ability to 

 withstand drought, a fact of obvious importance in the extension of 

 corn culture in the United States. A krge series of crosses have been 

 made between the different t3'pes and varieties of corn to determine 

 which combinations are the most advantageous for different condi- 

 tions of climate and soil. 



Adaptive characters in corn. — Experiments in southern Texas 

 have demonstrated the importance of growing only varieties of corn 

 that have the ears well protected by long, tightly closed husks. The 

 lack of this character is one of the chief reasons why carefully 

 selected northern varieties are usually a disappointment in this sec- 

 tion. Hybrids with the small Chinese type of corn have proved to be 

 prolific and specially adapted to withstand high winds, and have also 

 shown a decided increase in drought resistance, though the silks are 

 not as well protected by the bases of the leaves as in the Chinese 

 parent variety. 



Acclimatization of w^eevil- resisting types of cotton. — Experi- 

 ments have been continued with Central American types of Upland 

 cotton introduced because of their weevil-resisting characters. The 

 most effective weevil-resistant character of the Kekchi cotton in the 

 dry climate of southern Texas is the tendency to produce longer 

 branches and more numerous bolls close to the ground. Select strains 

 with large bolls and good fiber have been developed and have shown 

 themselves more productive than any of our United States Upland 

 varieties in several experiments. Field tests are to be made as soon 

 as sufficient seed can be grown. 



Characters changed during accli:matization. — In addition to the 

 excessive growth and abnormal sterility of cottons newly introduced 

 from Central America, other very definite changes of characters take 



