Since the recent Deepwater Horizon Gulf of Mexico oil spill, the need for environmentally friendly oil sorbents has intensified. This study deals with the sorption of crude oil by raw cotton, a biodegradable sorbent. To our best knowledge, the data related to crude oil sorption by unprocessed raw cotton and correlation with cotton characteristics such as micronaire, fineness, and maturity are unavailable. More importantly, our work quantifies the oil sorption (g/g) of low micronaire (immature) cotton. Results showed at the minimum level, low micronaire raw cotton has 30.5 g/g crude oil sorption capacity. Furthermore, the crude oil sorption capacity of low micronaire cotton was significantly higher than the sorption capacity of high micronaire cotton. Brunauer−Emmett−Teller (BET) surface area and environmental scanning electron microscopy analyses support the correlation between the quality characteristics of raw cotton and its oil sorption capacity. In contrast to synthetic sorbents, raw cotton with its high crude oil sorption capacity and positive environmental footprint make it an ecologically friendly sorbent for oil spill cleanups.

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A novel sorbent was developed using the aligning of raw unprocessed cotton fibers leading to low-density, hydrophobic, oleophilic, and sustainable cotton batt. Cotton batting developed using immature cotton exhibited oil sorption capacity of 50.27 g/g, which is significantly higher than the oil sorption capacity of many commercial sorbents reported in the literature. Fundamental mechanisms such as adsorption, absorption, and capillary action govern the oil sorption phenomenon, which were verified using environmental scanning electron micrographs. In addition, optical microscopy was used to understand the difference in the longitudinal cross section of the mature (base range) and immature (low micronaire) cotton, which was determined quantitatively using Brunauer–Emmett–Teller surface area analysis. Effect of cotton characteristics such as fineness and maturity on the oil sorption capacity was also investigated. Nonwoven cotton batts consisting of immature and finer cotton fibers showed oil sorption capacity that was 7% higher than that of cotton batts developed using mature and coarser fibers.

Fruiting of cotton (Gossypium hirsutum L.) was evaluated by main stem node and branch position in 11 experiments over a 4-yr period to determine if mepiquat chloride (MC) (1,1-dimethylpiperidinium chloride) altered fruiting position development or retention. Fruiting events were monitored for main stem nodes 7 to 20 for first fruiting position on sympodial branches (SB1), secondary fruiting positions on sympodial branches (SB> 1), and fruiting positions on monopodia) branches (MD). Ten consecutive plants were plant mapped from each of four replications in each experiment and combined as a 40-plant total for analysis of treatment and node effects using experiments as replications. Mepiquat chloride was applied at 49 g ha-1 when average plant height was 0.57 m and plants averaged 0.9 white blooms m-'. Summed across nodes, plant zones SB1, SB>1, and MD accounted for 60, 26, and 13% of all harvestable bolls, produced 37, 46, and 17% of all fruiting positions, and set 45, 16, and 23% of all fruiting positions as harvestable bolls, respectively. Application of MC did not increase total number of bolls. The interaction of MC treatment and nodes was significant for SB1 and SB> 1, with MC treated plants setting more bolls at lower nodes but fewer at upper nodes. The maximum cumulative benefit occurred at node 12 where MC treated plants had 15% more bolls matured than control plants (58.3 and 50.6 bolls m-', respectively). This advantage from MC treatment was not maintained as upper nodes matured fewer bolls than control plants. Plants treated with MC produced 3.1% fewer (P = 0.07) fruiting positions than control plants (288 and 279m-2 , respectively). Treatment by node interactions were significant for SB1 and SB> 1, with MC increasing fruiting positions up to node 15 at SB1 and up to node 9 for SB> 1, but having fewer at the remaining nodes. Early boll load was stimulated by MC. Late season boll load was decreased, apparently not by limited initiation of fruiting positions, but rather by increased abortion of fruiting forms. Use of MC according to the rate and timing of these tests would be of benefit when length of the season is a primary constraint to yield potential. In full-season, non-rank cotton, however, the early benefit in boll load is lost.

Fusarium wilt, caused by the soil‐borne fungus Fusarium oxysporum f. sp. vasinfectum (FOV) race 4 (FOV4), is one of the most destructive diseases in cotton (Gossypium spp.) in the southwestern and western Cotton Belt. However, the virulence of FOV4 is currently unknown. In this study, 17 FOV isolates collected in the Fabens, TX, area were determined to be FOV4 based on FOV4‐specific polymerase chain reaction (PCR) and sequence analysis of three genes encoding for translation elongation factor, β‐tubulin, and phosphate permease. A further multiplex PCR analysis determined that they all belonged to the Tfo1/MULE MT genotype. Based on disease severity ratings (DSR) on two upland and two pima cotton lines in the greenhouse, virulence of the 17 FOV4 isolates differed but was overall congruent on the four lines, and differences among cotton genotypes accounted for 82% of the total variance. Variance in virulence due to FOV4 isolates and FOV4 isolate × cotton genotype interaction each accounted for only 8–11% of the total variance. A virulent MT FOV4 isolate was used to inoculate 104 entries representing 92 cultivars and elite lines in two tests at 21–23 °C. The combined ANOVA detected a significant genotypic variation in DSR with moderate broad‐sense heritability estimates (.62–.69). About 90–91% of the genotypes were susceptible to FOV4, including 100% mortality in 59–91% of the genotypes. Pima PHY 805 RF and three upland cultivars including FM 2334GLT, Acala 1517‐08, and Acala Daytona RF had similar resistance responses to the resistant check pima PHY 841 RF. This study demonstrated that cotton genotypes played a predominant role in determining FOV4 virulence, reinforcing the validity of using a representative isolate to screen cotton for FOV4 resistance.