274 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



by the Egyptian system of sorting the crop by hand to remove the 

 inferior Hindi fiber, which is pure white in color. A study of hered- 

 ity in cotton has revealed the fact that brown color and length of 

 fiber are incompatible characters, not readily secured or maintained 

 in combination. Longer and stronger fiber is obtained from very 

 pale or white varieties. Such fiber has been raised in Arizona and 

 southern California and has brought higher prices than imported 

 Egyptian fiber. 



Adaptation or Egyptian methods of cotton culture to Ameri- 

 can CONDITIONS. — Though it is not practicable to establish the Egyp- 

 tian system of cotton culture in the United States, owing to the much 

 greater cost of the hand labor required, some of the Egyptian methods 

 can be adapted to machine cultivation. The most important ad- 

 vantage of the system is that it enables the development of vegetative • 

 branches to be controlled through closer planting and the restriction 

 of the supply of water in the early stages of growth. Excessive 

 vegetative growth that delays the maturit}' of the crop and increases 

 the expense of picking is the most serious obstacle to the development 

 of an Egyptian cotton industry in the irrigated districts of southern 

 California and Arizona, the production of high-grade fiber having 

 been demonstrated in numerous plantings. 



Factors of heredity in cotton. — In conducting experiments in 

 the acclimatization and breeding of cotton it has been necessary to 

 take account of the different principles or factors of heredity that 

 influence the behavior of the plants. As these experiments cover a 

 wide range of species and varieties of cotton brought from many 

 different regions and grown under many different conditions in the 

 United States, they afford an unusually broad basis for determining 

 the relations that call forth or prevent the development of the differ- 

 ent characters. The results of these investigations are contributing 

 to the solution of general problems of heredity and the development 

 of improved methods of breeding. 



First-generation hybrids in sweet corn. — Sweet corn has been 

 found to be no exception to the rule that hybrids yield more than 

 their parents, while quality and uniformity do not suffer if well- 

 selected strains are used. Since most of the sweet-corn varieties 

 sucker abundantly and produce a succession of tassels, the propor- 

 tion of self-pollinated seed is larger than in most of the varieties of 

 field com. Unless precautions are taken to insure cross-pollination 

 the yield and vigor of the stock are greatly reduced. 



Importance of eliminating self-pollination in corn. — While the 

 deleterious effect of self-pollination has long been appreciated, the 

 extent to which seed is self-pollinated under ordinary field conditions 

 seems never to have been fully realized. The reduced yields due to 

 planting self-pollinated seed can be eliminated by removing the tas- 

 sels from the plants of alternate rows and using the seed from de- 

 tasseled plants. In western Kansas, where the prevailing high winds 

 might be expected to reduce self-pollination to a minimum, seed 

 selected from detasseled plants outyielded selections from the general 

 field by 40 per cent. While the extent of self-pollination indicated 

 by this experiment may be exceptional, there can be little doubt that 

 the yields of corn can'be materially increased by the elimination of 

 self-pollinated seed. 



