4 BULLETIN 644, U. S. DEPARTMENT OF AGRICULTURE. 
The lint index given for a seed weight of 13 + 25 per cent is practi- 
cally identical with that given for a seed weight of 6 + 42 per cent. 
In each case practically the same quantity of fiber is obtainable from 
a given number of seeds, although one variety has a lint percentage 
of 25 and the other 42. Thus it is seen that the larger percentage of 
lint is due entirely to a decrease in the weight of the seeds without 
change in the amount of fiber per seed, a striking illustration of the 
fallacy of basing an opinion as to the value of a variety of cotton on 
the percentage of lint alone. 
A high percentage of lint, therefore, does not necessarily mean an 
abundance cf fiber. The fiber is actually less abundant when there is 
42 per cent of lint in a variety the seeds of which weigh 8 grams per 
hundred than when there is 30 per cent of lint in a variety the seeds 
of which weigh 14 grams per hundred. 
That the percentage of lint will steadily increase as the size of the 
seed decreases without altering materially the actual amount of fiber 
obtainable may be seen if the lint index under a seed weight of 
13 + 25 per cent be taken as a base. Approximately the same lint 
index may be traced diagonally across the table to the lint index 
under a seed weight of 6 + 42 per cent. It can readily be appreciated 
that this trend represents the possible results of selection based on 
lint percentages alone. 
Conversely, an increase in the weight of the seed may reduce the 
percentage of lint without reducing the actual amount of lint: but 
unless the reduction in the percentage of lint is proportionate with 
the increase in the size of the seed the abundance of the lint is also 
increased, notwithstanding the reduction of the lint percentage. 
This is in accord with the results obtained by Mr. T. H. Kearney 
in his work in the acclimatization of Egyptian cotton, 1 in which he 
noted that the lint percentages of his best selections were steadily 
decreasing from year to year below that of the original imported 
strain, but on ascertaining the lint indexes of the selections and 
imported stock he found that there was no actual diminution in the 
quantity of fiber produced. The decrease in the lint percentage was 
due entirely to an increase in the weight of the seeds. Mr. Kearney 
concludes : 
The negative correlation between the characters lint percentage and weight 
of seeds is sufficiently pronounced to indicate that a high percentage of lint 
is in large measure associated with low weight of seeds. * * * It might 
be inferred from these facts that lint percentage can be used with greater 
safety as an index of productiveness in comparing individual plants of a fairly 
uniform variety than in comparing different varieties. 
That the percentage of lint of a selection or variety of cotton 
should be considered onlv in the light of the lint index is well illus- 
1 Kearney. T. II. Lint index and lint percentage in cotton breeding. In Ann. Bpt, 
Amer. Breeders' Assn., v. 7/8. p. 25-29. 1912. 
