UNITED STATES DEPARTMENT OF AGRICULTURE 



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1 BULLETIN No. 288 



Contribution from the Bureau of Plant Industry 

 WM. A. TAYLOR, Chief 





Washington, D. C. 



¥ 



September 7, 1915 



CUSTOM GINNING AS A FACTOR IN COTTON- 

 SEED DETERIORATION. 



By D. A. Saunders, Plant Breeder, and P. V. Cardon, Assistant Agronomist, Office 



of Crop Acclimatization. 



INTRODUCTION. 



The admixture of cotton seed is largely responsible for the rapid 

 deterioration of cotton varieties which is so apparent throughout the 

 cotton belt, and which, to a large extent, is directly traceable to the 

 planting of seed which has been mixed at the custom gins. When 

 plants of different varieties of cotton grow in close proximity, cross- 

 fertilization takes place through the aid of insects and other pollen- 

 bearing agencies, with the result that varieties become interbred and 

 deterioration follows. Hitherto, however, nothing has been pub- 

 lished which fully emphasizes the extent of the mixing which occurs 

 during the ginning process, and consequently the seriousness of the 

 evil is not generally appreciated. 



The lack of definite information on this point is due, no doubt, 

 to the difficulty in making accurate determinations of the actual 

 amounts of seed of different varieties present in the admixture under 

 observation. This difficulty arises from the fact that the seeds of 

 most of the more common varieties are so similar in appearance 

 that it is almost impossible to distinguish between them. To 

 overcome this difficulty and to measure the degree of mixture with 

 reasonable accuracy a method was devised by one of the writers, 

 Mr. Saunders, at Greenville, Tex., in 1914. The results obtained 

 from an application of this method show that mixing occurs to a far 

 greater extent than is commonly supposed, and emphasize the ne- 

 cessity of materially modifying common ginning methods if supplies 

 of pure seed are to be maintained. Full appreciation of these facts 



Note. — This bulletin should be of service to all who are interested in the production and maintenance 

 of pure cotton seed. 

 2781°— 15 



