B 249 P42 opy 1 M i^!^l SB 249 A42 Copy 1 U. S. DEPARTMENT OF AGRICULTURE. BUREAU OF PLANT INDUSTRY— BULLETIN NO. Ill, PART IL ^K B. T. GALLOWAY, (hi)/ of Tiureau. THE FIBEIIS OF LONG-STAPLE UPLAND COTTONS. H. A.^ALLARD, Scientific Assistant, Cotton Breeding Investigations. Issued Septembeb 9, 1901 WASHINGTON: GOVERNMENT PllINTING OFFICE. 11M)7, »oi«r^ rJ stP 19 m? D. ofa o C N T H N T S Pace. rniforinity of cotton fibers 5 Ai>|>arent lack of uniformity and its occurrence 5 The true nature of the longer fibers 6 lU-u 3 ILLUSTRATIONS PLATES. Page. Plate I. Cotton seeds with fibers attached. A and B. — ■Cotton seeds with fibers combed out to show uniformity and nonuniformity in the length of the fibers. C. — Lock of Griffin cotton stretched so as to show points of origin of longer fibers 4 II. Seeds of cotton combed out to show the so-called longer fibers. A. — Columbia variety. B. — Grifiin variety 4 TEXT FIGURES. Fig. 1. Single cotton fiber? from the so-called longer group of fibers 6 2. A few extra-long cotton fibers, showing two fibers united 6 3. Cotton fibers tied together, very much magnified 7 lU-II 4 Bui. 1 1 I , Pt. II, Bureau of Plant Industry, U. S. Dept. of Agriculture. Plate I. Bui. 1 1 1, Pt, II, Bureau of Plant Industry, U. S. Dept. of Agriculture. Plate II. Seeds of Cotton Combed Out to Show the So-called Longer Fibers. yl.— Culuiubiii vHiioly. i;.— Giill'm variety. B. I'. I.— m"). THE FIBERS OF LONG-STAPLE UPLAND COTTONS. UNIFORMITY OF COTTON FIBERS. In investij^ations in cotton breeding where an improvement in cer- tain lint characters is desired several factors must be carefully consid- ered. Among these, some of the most important are tinoness of lint, the relative 3'ield of lint to the total yield of seed cotton, and the uni- formity of length of all the fibers when properly combed out and examined. The la-st character, uniformity of length, is a most impor- tant one and has much to do with subsequent waste and the produc- tion of good yarns in the process of manufacture. On Plate I are illustrations of cotton seeds with fibers combed out to show uniformity and nonuniforniity in the length of the fibers. The seeds to the left (A) show very poor uniformity and are of the "butterfly''' type, as they are commonly called. In marked contrast, the seeds to the right (B) show excellent uniformity as a result of several generations of careful selection. APPARENT LACK OF UNIFORMITY AND ITS OCCURRENCE. There is an apparent lack of uniformity which deserves consider- able attention from the standpoint of cotton growers and breeders. Plate II illustrates this character, although it is more striUdngly brought out in the operation of detaching the seed from the lock. From the illustration there would appear to be a great lack of uni- formity, due to a group of fibers about twice the length of th(^ geneml covering. This group ari.ses from the center of the main l)ody of fil)ers or, often, from those having a point of attachment near the larger end of tin' seed. This character is usually as.sociated with the liner, more crinkly types of long-staple cottons, such as the tin(>. long- linted Egyptian and Sea Island varieties and the long-staple Tpland varieties- Griftin, Allen, Cook, etc. It is a character which becomes more apparent as a variety is being rigidly selected generation after generation for finer, longer staple. This has l)een well illus- trated in the improvement of the lint characters of the Hussell variety and, to some extent, the .lones variety. The orginal condition ni-ii 6 THE FIBERS OF LONG-STAPLE UPLAND COTTONS. Fig. 1.— Single cotton fibers from the so-called longer group of fibers. of both of these varieties is remarkably free from this so-called longer group of fibers. In the case of the greatly improved Russell strain, which has become distinctive enough in good lint characters and yield to be designated as a new variety — the so-called Columbia cotton — these longer fibers are evident to a remarkable degree. THE TRUE NATURE OF THE LONGER FIBEl^S. It has been more or less the rule with cotton breeders and cotton growers acquainted with the requisites of desirable lint characters to regard these extra-long fibers as an unfavorable feature. In this light they meant a variation toward nonuniformity. In the work of selec- tion, to avoid as much as possible a perpetuation of this sort of varia- tion, plants showing this character most markedly were regarded with suspicion and later even discarded, although in other respects they were among the best in the field. A careful examination leads to the conclusion that these fibers should be regarded in a wholl}'^ different light. They are not longer Jihers aS they have heen generally considered^ hut are caused hy more or less curling and interweaving ^ which results in the pulling out of fibers from adjacent seeds. In the ordinary manner of stretching the locks to determine the drag, the fibers are slowly separated and drawn out, and at those points of greatest binding, as shown in Plate I, C, «, ^, and e, the groups of longer fibers appear to rise. If, now, a single seed is selected and detached from the rest and the entire group of fibers loosened from its attachment to the seed coat in the neighborhood of the longer groups, one can with fine forceps draw these fibers out carefully and com- pare their length with those of the rest of the seed. In many instances the sin- gle fibers now readily sepa- rate, since the tension of pulling has ceased. Several of these single fibers are shown in figure 1. In some instances fibers nearly twice the normal length are drawn out. Oftentimes with the naked eye the point of union or tying may be discerned by the tiny loose ends, as is shown in figure 2. In other cases, however, this i)oint of union is so intimate that only u iiigh microscopic power can make it evident. Figure 3 illustrates various Ul-II 2.— A few extra-long cotton fibers, showing two fibers united. TBK TRUE NATURE OF THE LONGER FIBERS. degrees of this tyiuj^ or ciaiiiio- together, as seen when grcatl}- mag- nified. In figures 1 and 2 single and united fibers, respeotivel}', of natural length arc shown, hut the diameters are of nccossitv much greater than normal, owing to tiic exceeding fineness of the fibers. The drag of cottons showing the longer fi})ers previously described gives a more extended, elastic tension than is manifest among the short-staplo varieties. It is probable that breeders may find this character a useful one in indicating a tendency toward increased length, fineness, and crinkliness of staple in the individuals in which it occurs most noticeal)ly — an indication of better spinnini;- riualit}'. It is important that l)reeders and grow- ers of 1 o n g - s t a p 1 e cottons should know that these apparently longer fibers are no indication of true lack of uniformity. The presence of these fibers in the long- staple Upland varie- ties has (juite univer- sally led to the erro- neous belief that such cottons arc rather inf(M-ior in uniformit\' as regards length of fibers. The Griffin cotton, in particular, recognized in other respects as the best long-staple Upland cotton grown, has always l)een descril)ed as decidedly unsatis- factory so far as uniformity in length of staple is concerned, since the drawing out of fibers from adjacent seed is a marked characteristic of this variety-. A knowledge of the true nature of these longer fibers will clear the reputation of some of the l)est long-staple Upland varieties of a seri- ous fault hitherto wrongly attributed to them by all breeders and irrowers. Fi<;. 3. — Cotton fibers tied together, very mueh niiigiiiMed. o LIBRARY OF CONGRESS «':iKC.f'«K 020 948 048 7 Wit :