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a Dep. of Soil and Crop Sciences, Texas A&M Univ., 370 Olsen Blvd., College Station, TX 77843
b Delta Research and Extension Center, 82 Stoneville Rd., P.O. Box 197, Stoneville, MS 38776
c International Textile Research Center, Texas Tech Univ., Lubbock, TX
d Cotton Incorporated, 6399 Weston Pkwy., Cary, NC 27513
* Corresponding author (cwsmith{at}tamu.edu).
ABSTRACT
Eight extra-long staple (ELS) upland cotton (Gossypium hirsutum L.) germplasm lines, TAM A106-15 ELS (Reg. No. GP-894, PI 654359), TAM A106-16 ELS (Reg. No. GP-895, PI 654360), TAM B147-21 ELS (Reg. No. GP-896, PI 654361), TAM B182-33 ELS (Reg. No. GP-897, PI 654362), TAM C66-16 ELS (Reg. No. GP-898, PI 654363), TAM C66-26 ELS (Reg. No. GP-899, PI 654364), TAM C147-42 ELS (Reg. No. GP-900, PI 654365), and TAM C155-22 ELS (Reg. No. GP-901, PI 654366), were developed by the Cotton Improvement Laboratory, Department of Soil and Crop Sciences, Texas AgriLife Research (Texas A&M University, College Station), and released in 2008 as part of an ongoing effort to create germplasm with combinations of improved fiber quality parameters, especially upper half mean (UHM) length and fiber bundle strength. All ELS lines exhibited high volume instrument (HVI) UHM fiber length greater than 32.0 mm, which is the minimum UHM to be classified as ELS upland according to Cotton Incorporated. Seven of the eight lines equaled or exceeded the minimum UHM length of 34.8 mm for pima (G. barbadense L.) in the USDA 2007 pima loan schedule in at least one performance trial. Fiber bundle strengths of the eight lines were equal to or higher than ‘Fibermax 832’.
Abbreviations: ELS, extra-long staple • HVI, high volume instrument • UHM, upper half mean • UI, uniformity index
Changes in cotton (Gossypium hirsutum L.) spinning technology and competition from man-made fiber have increased demand for improved cotton fiber quality. For example, the desired staple, or average fiber length, for U.S. cotton has been 26.7 mm, which is lower than the international base staple length of 27.8 mm (Braden and Smith, 2004). Along with increased international standards for staple length, processors desire greater strength, decreased short fiber content, and more uniform fiber length distributions. With increasing export of U.S. cotton and advances in spinning technology, improvement of fiber quality is essential for competitiveness of cotton produced in the United States.
Shifts in the needs of the textile industry over the past half-century and changes in fiber property measurement technology have effected generally a steady improvement in cotton fiber quality. Quality was determined subjectively before and during the early part of the 20th century, but by the 1980s, upper half mean (UHM) fiber length, fiber length uniformity index, fiber bundle strength, elongation of fibers at break, and micronaire, as an estimate of fiber fineness, were determined objectively for all cotton sold in the United States using high volume instrument (HVI) technology. Before objective measurement of fiber properties was mandated by the USDA, buyers bought cotton lint on its subjectively determined length, strength, and feel; thus, breeders were aware of and made selections based on the importance of fiber properties even before objective measurements were possible.
Many studies conducted to evaluate genetic gains reported little or no improvement of fiber length at their respective eras (Bridge and Meredith, 1983; Bridge et al., 1971; Culp and Green, 1992; Hoskinson and Stewart, 1977; Miller and Rawlings, 1967; Wells and Meredith, 1984), although a few experiments detected genetic improvement for this trait (Bayles et al., 2005; Turner et al., 1976). The USDA, Agricultural Marketing Service (2003) reported that fiber strength held steady from 1993 through 2003. Schwartz and Smith (2008) reported that UHM lengths generally improved with the release of new cultivars after and including ‘Deltapine 14’ (PI 528970), which was released in 1941. It is interesting to note that ‘Long Star’ (PI 528636), released in 1905, exhibited UHM length equal to or better than cultivars included by Schwartz and Smith that were released as late as 1974, including ‘Deltapine 55’ (PVP 7500103, PI 529282). ‘Stoneville 506’ (PVP 8100059, PI 529523) and ‘Deltapine 491’ (PVP 200100159, PI 618609), released in 1982 and 2002, respectively, exhibited longer UHM fiber lengths in that study.
Increases in fiber strength were reported by Bayles et al. (2005), Culp and Green (1992), and Turner et al. (1976), although a lack of progress was observed by Bridge and Meredith (1983), Bridge et al. (1971), Miller and Rawlings (1967), and Wells and Meredith (1984).
Schwartz and Smith (2008) reported that ‘Deltatype Webber’ (PI 528717), released in 1922, was equal to Deltapine 491 in HVI fiber bundle strength. These observations suggest that the lack of objective measurement technology and/or the lack of economic incentives impacted the development of longer and stronger upland cotton cultivars.
Methods
F2 populations were identified in 2001 that exhibited HVI UHM fiber length ranging from 31 to 32 mm and fiber bundle strength of 291 to 345 kN m kg–1. Individual F3 plants were selected the following year that exhibited UHM lengths of 33 to 36 mm and fiber bundle strength as high as 354 kN m kg–1. Individual plants were again selected within the resulting F3:4 progeny rows in 2003 that exhibited UHM lengths as high as 36 mm. Each of those plants formed the bases of an extra-long staple (ELS) strain and were reselected as progeny rows in 2004. Grab samples from machine harvested F4:5 progeny rows exhibited UHM lengths from 31 to 37 mm and fiber bundle strengths of 291 to 408 kN m kg–1. Selected upland ELS lines were performance tested in 2005 through 2007 with one or two lines from each parental combination selected for release as TAM ELS upland lines: TAM A106-15 ELS (Reg. No. GP-894, PI 654359), TAM A106-16 ELS (Reg. No. GP-895, PI 654360), TAM B147-21 ELS (Reg. No. GP-896, PI654361), TAM B182-33 ELS (Reg. No. GP-897, PI 654362), TAM C66-16 ELS (Reg. No. GP-898, PI 654363), TAM C66-26 ELS (Reg. No. GP-899, PI 654364), TAM C147-42 ELS (Reg. No. GP-900, PI 654365), and TAM C155-22 ELS (Reg. No. GP-901, PI 654366) (see Table 1 ).
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Seventy lines were selected from the F4:5 progeny rows in 2004. These 70 lines were divided nonselectively into two sets and performance tested at College Station, TX, in 2005. Yield performance was adequate for germplasm lines, with some lines yielding competitively with the two improved quality controls, Fibermax 832 and Deltapine 491 (Tables 2 and 3 ). Micronaire values, uniformity of fiber length, and elongation values were similar to the controls, whereas gin turnout was lower (p = 0.05) for all lines. Fiber length of all lines exceeded (p = 0.05) the improved quality checks, and all exceeded the minimum 32.0 mm to be classified as upland ELS (data not shown). Fiber UHM lengths of the ELS lines ranged from 34.0 to 35.3 mm, while Fibermax 832 and Deltapine 491 ranged from 29.7 to 31.5 mm. TAM B182-33 ELS, TAM C147-42 ELS, and TAM C155-22 ELS produced greater fiber bundle strength than the lowest control across the two trials.
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These TAM ELS upland lines are approximately 2 wk later maturing than current upland cotton cultivars recommended for production in central and south Texas. Otherwise, they have excellent shatter resistance, and six lines exhibit normal pubescence, while two lines have smooth leaf and stem. These germplasm lines combine extra-long staple fiber length with excellent fiber bundle strength in an upland phenotype. These ELS germplasm lines should provide private and public breeders with the parental material from which to develop ELS upland cultivars and/or upland cultivars that will produce UHM lengths under moderate to severe drought equivalent to that produced by currently available cultivars under irrigated culture.
Seed Availability
Inquires regarding availability of seed for research purposes should be directed to the corresponding author. Inquiries regarding commercial use should be directed to the Office of Technology Commercialization, 3369 TAMU, College Station, TX 77845 (979-847-8628).
Texas AgriLife Research (Texas A&M University, College Station) warrants that these germplasm lines were developed using traditional—that is, nontransgenic—breeding methods. Texas AgriLife Research warrants that no crosses were made intentionally with materials containing transgenes for herbicide tolerance, insect resistance, or any other known transgene. TAM ELS upland strains are experimental in nature, seeds and all plant parts are not proposed for human consumption, and seed is provided for additional research on an "as is" basis, without additional warranties or representation of any sort, expressed or implied.
Acknowledgments
Development of these extra-long staple upland germplasm lines was supported by the Texas Department of Agriculture's Food and Fiber Grant Program, Cotton Incorporated Core Program, and Cotton Incorporated Texas State Support Committee.
Footnotes
All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permission for printing and for reprinting the material contained herein has been obtained by the publisher.
Received for publication February 26, 2008.
References
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