406 ANNUAL REPOBTS OF DEPARTMENT OF AGRICULTURE. 



makes it possible to secure a better understanding of many matters of 

 agricultural importance, such as the diversity and instability of ex- 

 pression that are induced in a select stock by crossing with other 

 varieties or with degenerate mutations. Another result of these in- 

 vestigations of general problems has been to develop more simple and 

 effective methods of breeding and selection. 



Extension of cotton culture. — One of the inevitable results of 

 the boll-weevil invasion is the extension of cotton culture into the 

 drier regions of Texas and other Southwestern States where the 

 climatic conditions afford protection against the weevils and other 

 adverse conditions encountered in the more humid Eastern States. 

 The fact that cotton is a dry-land crop that can be brought to ma- 

 turity with a very small amount of water is only beginning to be 

 appreciated and is likely to lead eventually to a complete change in 

 the agricultural prospects of much of the southwestern country. In 

 districts where water for irrigation purposes becomes available, long- 

 staple cotton is likely to become the principal crop, for, with a prop- 

 erly controlled supply of water, fiber of good quality can be produced 

 if the soil conditions are at all favorable; but special methods of 

 culture, thinning, roguing, and picking have to be used in the pro- 

 duction of superior filjer, and these methods require the establishment 

 of communities of intelligent and efficient farmers. 



The extension of cotton culture into the Southwest is responsible 

 for the settlement of a new farming population under conditions 

 quite different from those of other agricultural regions of the United 

 States. The production of the cotton crop in particular calls for 

 farming activity during the summer months when human endurance 

 is often carried to its extreme limits. The lack of any adequate pro- 

 tection from the midday heat, such as the inhabitants of other arid 

 countries have learned to provide by thick-walled adobe or stone 

 houses, which make it possible to rest in the middle of the day, is a 

 cause of much unnecessary suffering and loss of agricultural effi- 

 ciency. It is proposed to consider the human factors as well as the 

 plant adaptations in future studies. 



Relative merits of Egyfitan and Upland cottons. — There are 

 many reasons for expecting that long-staple cotton, either of the 

 Egyptian or of the Upland type, will become the chief commercial 

 crop of most of the irrigated lands that are now being reclaimed in 

 the Southwestern States. After several years of acclimatization and 

 breeding, improved varieties and cultural methods have been devel- 

 oped which make it possible to produce good crops of high-grade 

 Egyptian cotton in Arizona and southern California, thus opening 

 the way to the establishment of a new industry. Though experiments 

 had shown the Egyptian cotton to be distinctly superior to any of 

 the long-staple varieties previously known, the introduction of the 

 Durango cotton has brought another factor into the problem. Fur- 

 ther experiments have become necessary to determine whether the 

 Egyptian or the Durango cotton is best suited to the various irrigated 

 districts. 



Elimination of vegetative branches in cotton. — The increased 

 need of earliness or prompt development of the crop to avoid weevil 

 injury is making it desirable to have methods of controlling the de- 



