BUREAU OF PLANT INDUSTRY. 437 



and varieties grown in the semiarid regions have been compared 

 under carefully controlled conditions, in order to ascertain their 

 relative water "^requirements. The results prove that, other things 

 being equal, the plants which have the lowest water requirement are 

 best adapted to crop production in regions of deficient rainfall. 



The methods developed in the physiological investigations of 

 drought resistance are being applied in studying the related subject 

 of alkali resistance. Preliminary results indicate that the presence 

 of an excess of alkali salts has no effect upon the wilting coefficient 

 of a given soil. On the other hand, the results indicate that the 

 water requirement of the plants is increased by the presence of 

 alkali. The methods developed by these physiological investigations 

 are being practically applied in studying the effects of alkali and of 

 a deficiency of soil moisture upon the growth of orchard trees in 

 irrigated sections of Colorado and California. 



Indicator value of natr-e vegetation. — A cooperative investiga- 

 tion has been conducted in a limited area in central Utah to estab- 

 lish definite correlations between the moisture capacity, normal 

 moisture content, and salt content of the land, on the one hand, and 

 the composition and character of the native growth on the other. 

 The results warrant the belief that the native plants can be used 

 with considerable precision, in this portion of the Great Basin region 

 at least, in determining what areas are best adapted to dry farming 

 and also what areas are characterized by the presence of alkali in 

 sufficient quantity to injure crop plants. 



Egyptian cotton breeding. — Seed of the Yuma variety, an im- 

 proved type of EgA'ptian cotton developed in the course of this work 

 and adapted to growing under irrigation, has been distributed to 

 farmers in Arizona and California, with the result that a good stand 

 has been produced upon an acreage su^cient to insure a thorough 

 practical test of this variety. Another very promising variety, the 

 Sacaton, is also being tested on a commercial scale. 



Plans for future work. — It is planned to continue the work dur- 

 ing the fiscal years 1913 and 1914. 



INVESTIGATIONS IN ECONOMIC AND SYSTEMATIC BOTANY. 



The investigations in economic and systematic botany and range 

 work have been continued under the direction of Mr. F. V. Coville. 



The experiments looking toward the domestication of the blue- 

 berry, the first results of which have already been published, have 

 been continued along the lines thought to be essential to a proper 

 foundation for a blueberry-growing industry. It has been found 

 that seedlings grown from very lai-ge-lx>rried bushes produce small 

 berries oftener than large ones and that budded and grafted plants 

 continually send up new and objectionable shoots from the stock. 

 The desirability of devising some method of propagation by cuttings 

 is therefore obvious. The problem proved so diflicult that an elabo- 

 rate study was necessary before the various causes of failure could 

 be understood and eliminated. Three successful methods of repro- 

 ducing blueberry plants have now been devised. Berries exceeding 

 eleven-sixteenths of an inch in diameter have been grown in the 

 greenhouse. The search for other and still better wild stocks con- 



