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UNITED STATES DEPARTMENT OF AGRICULTURE 
wwmm BULLETIN No. 288 «,, 
"^aMa/Vgy Contribution from the Bureau of Plant Industry %JMy, 
JfUR^Wl* WM. A. TAYLOR, Chief «JTW<^W6. 
Washington, D. C. V 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 
