Interactive Effects of Water Stress, CO2 and Ozone on Upland Cotton III. Fiber Quality Characteristics

Mohamed I. Zakaria, Charles L. Mulchi, Eugene L. Vigil and Devron P. Thibodeaux


In a field study, cultivars Deltapines 50 and 90 (G. hirsutum, L.) grown in open-top chambers were exposed to two levels each of soil moisture, CO2, and O3. Fiber samples collected at first and second pickings were evaluated for lint length, maturity, and fineness. The two-way interaction of O3*CO2 and CO2*CV showed significant impacts on lint length. Higher CO2 level appeared to compensate for the reductions in O3. Plants grown under CF air and treated with 500 µmol CO2 mol-1 had higher values than those treated with ambient CO2 for length at both pickings and for upper quartile length (UQL) by number at second picking. Varietal differences were significant for length under ambient CO2 and for UQL under both CO2 levels. DP50 responded to high CO2 treatment and had higher UQL values than DP90. Fiber maturity [circularity and immature fiber fraction (IFF)], and fineness [cross section area (A), and micronafis] responses to the interactive effects for O3*CV and CO2*CV were significant at first picking only. Varietal differences were significant under CF air and 350 µmol CO2 mol-1, with DP50 having lower circularity and higher IFF. Also, varietal differences were significant under both O3 levels for A and under CF air for micronafis. The three-way interaction analysis showed that the M*CO2*CV interactive effects was significant for maturity and fineness parameters. The results suggest that the availability of carbon improved fiber length and consequently reduced the percentage of short fiber contents for plants grown under well-watered+NF air and limited-water+CF air conditions.

Reprinted from Proceedings of the 1994 Beltwide Cotton Conferences pp. 1455 - 1458
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998