38 CIRCULAR NO. 110, BUREAU OF PLANT INDUSTRY. 



COMPARISON OF THE DIFFERENT PICKINGS. 

 LENGTH OF STAPLE. 



In 33 out of the total number of 60 individual selections made at 

 Sacaton, careful measurement and comparison of the length of staple 

 in the first and in the second picking, respectively, were made. 1 The 

 fiber from the second picking of these 33 plants averaged one-sixteenth 

 of an inch longer than that from the first picking. The uniformity 

 of length was also greater hi the second picking. In 42 selections 

 in which the variation in length was recorded, it averaged three- 

 sixteenths of an inch hi the first picking and two-sixteenths of an inch 

 in the second picking. In 30 of these plants the variation was greater 

 in the first picking, hi 6 plants it was greater in the second picking, 

 and in the remaining plants it was the same in both pickings. 



STRENGTH OF FIBER, 



In 44 individual selections hi which the first and second pickings 

 were compared in respect to strength, 27 showed a greater strength 

 of fiber in the second picking than hi the first, 13 showed no marked 

 difference between the two pickings, and only 4 showed stronger fiber 

 in the first picking. 



LINT INDEX. 



The fiber was decidedly more abundant in the second picking than 

 in the first, the average lint index (weight in grams of fiber per 100 

 seeds) in the 60 individual selections having been 4.90 for the first 

 picking and 5.17 for the second picking. 



FINENESS OF FIBER. 



It has been observed every year during which breeding work with 

 Egyptian cotton has been carried on in the Southwest that the fiber 

 from the bolls which open first is often coarser and harsher to the 

 touch than the fiber produced in bolls higher on the plant, which 

 ripen later under the influence of more equable temperatures. 



WEIGHT OF SEEDS. 



The average weight of 100 seeds in the 44 individual selections in 

 which the two pickings were compared in this respect was 12.9 grams 

 for the first picking and 13.4 grams for the second picking, indicating 

 that the seeds produced in the bolls which ripen earliest are decidedly 

 lighter than those hi later ripening bolls borne higher on the plant. 



1 The measurement of length in each of the two pickings was made as follows: From the sample of seed 

 cotton representing each picking from a given individual plant, 10 seeds were drawn at random from different 

 portions of the mass. A cluster of fibers from near the middle of each seed was pulled out and the average 

 length of these fibers was estimated. The mean of the average lengths of the fiber from the 10 different 

 seeds was taken as representing the length of staple for the picking in question. 



[Cir. 110] 



