UNITED STATES DEPARTMENT OF AGRICULTURE 



BULLETIN No. 644 



Contribution from the Bureau of Plant Industry 

 WM. A. TAYLOR, Chief 



Washington, D. C. 



PROFESSIONAL PAPER 





January 18, 1918 



LINT PERCENTAGE AND LINT INDEX OF COT 

 TON AND METHODS OF DETERMINATION. 



By G. S. Meloy, Assistant, Crop Acclimatisation and Cotton Breeding. 



CONTENTS. 



Pace. 



Relation of lintpercentagesto lintindexes 1 



Lint percentages 2 



Lint indexes 2 



Illustrations of the relation between lint per- 

 centage and lint index 3 



Lint index determines the number cf bells to 



the pound of fiber 5 



Relation of the lint index to the cost cf pick- 

 ing 5 



Increasing the lint percentage dees net alter 

 the cost of production if the lint index re- 

 mains constant 8 



Page. 



Improved methods for obtaining lint per- 

 centages s 



Advantages of using samples cf standard 

 wei~ht 10 



Methods of calculating lint indexes and seed 

 weights 10 



Number of seeds in a standard sample an in- 

 dication of their sice 10 



Planters can estimate the lint index 11 



Summary 11 



RELATION OF LINT PERCENTAGES TO LINT INDEXES. 



The danger of reducing the vitality and earliness of cotton vari- 

 eties and of breeding varieties with undesirable characters by over- 

 emphasizing the percentage of lint as a measure of their compara- 

 tive values was pointed out in 1908 by Mr. O. F. Cook. 1 It was sug- 

 gested that the weight of the lint or fiber ginned from 100 seeds, in- 

 stead of the lint percentage alone, be used as an additional standard 

 for judging varieties. This standard of comparison was called the- 

 lint index. Subsequent experience has not only demonstrated the 

 desirability of using this standard, but has led to the development 

 of improved methods and devices for determining both the lint index 

 and the lint percentage in experimental samples of seed cotton with 

 which breeders have to work. 



x Cook, O. F. Danger in judging cotton varieties by lint percentages. 

 Bur. Plant Indus. Cir. 11, 16 p. 1908. 

 21683°— 18— Bull. 644 



U. S. Dept. Agr.„ 



