72 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



On several of these projects most of the settlers are unfamiliar 

 with irrigation, and instruction and demonstration of methods of 

 applying water is proving to be an important part of the work. 



ALKALI AND DROUGHT RESISTANT PLANT-BREEDING INVESTIGATIONS. 



The Department is engaged in extensive tests of crop varieties in 

 order to ascertain which ones are most resistant to drought, and is 

 seeking to secure increased resistance by plant-breeding methods. 



Some of the problems which are being studied are: (1) Ability to 

 adjust growth to available moisture, as varieties of grain crops, for 

 example, that make a limited stem and leaf growth withdraw less 

 moisture from the soil early in the season and have a better chance 

 to ripen seed than do ranker gro^ving, freely stooling varieties; (2) 

 character of the root systems, whether extensive and shallow, per- 

 mitting the fullest possible utilization of light rains, or deeply pene- 

 trating, thus tapping supplies of moisture at greater depths in the 

 soil; (3) conservation of water by reducing transpiration or, in other 

 words, increased economy in the use of water; and (4) avoidance of 

 drought by maturing early before extremely dry weather begins or 

 tolerance of drought through ability to arrest growth during dry 

 periods, resuming development whenever a rainfall brings sufficient 

 moisture. 



In the arid and semiarid regions thousands of acres of hitherto 

 untilled land are being taken up by farmers. As a rule the newcomer 

 is unable to estimate closely the capabilities of the land until it has 

 been put into crops. During the past three years correlations 

 between the different types of native plant covers and the conditions 

 influencing crop production have been worked out in portions of the 

 Great Plains area, and these have made it possible to judge from the 

 character of the natural vegetation the adaptability of the land for 

 different crops. 



The plant-breeding work with Egyptian cotton in the Southwest 

 has resulted in the development of two new and distinct varieties 

 quite different in the characters of the plants and fiber from the Mit 

 Afifi stock with which the work was begun. The new types are 

 distinguished by the large size of the bolls and the fineness and great 

 strength of the lint, which averages in both varieties about If inches 

 long. One of them has already been tested on a field scale at several 

 locahties in Arizona and southern California, and has proved very 

 satisfactory in yield and in the uniformity of the product. Strains 

 have also been secured by selection which possess the characteristics 

 of the Mit Afifi variety, but are greatly superior to the average of that 

 variety as grown from imported seed in productiveness, size of bolls, 

 and quality of fiber. The different types of fiber produced by these 

 varieties are well adapted to most of the uses to which the $12,000,000 



