Cotton Maturity Research Articles

Cottonscope fiber maturity, fineness, and ribbon width measurements with different sample sizes

The accurate and precise measurement of cotton maturity and fineness is often difficult, laborious, and/or expensive to perform. The Cottonscope® rapidly, accurately, and precisely measures fiber maturity and fineness with small quantities of sample (approximately 50 mg). Interest has been expressed in the use of different sample weights of fiber, especially lower sample weights by geneticists. A program was implemented to establish the capabilities of the Cottonscope to rapidly and accurately measure maturity (maturity ratio (MR), original polarized light microscopy maturity ratio (MRBF)), fineness, and ribbon width with different sample weights of fiber. The change in sample weight significantly impacted the Cottonscope results for MR, fineness, and ribbon width. Fineness was most impacted by varied sample weight. The impacts of sample weights on the cotton results were removed by re-calibrating the instrument at each sample weight. Decreasing the sample weight below 50 mg increased sample measurement times, especially at 10 mg sample weight. These results demonstrated that the Cottonscope can accurately and precisely measure the fiber’s maturity, fineness, and ribbon width with cotton fiber samples as small as 10 mg.

Assessing cotton maturity using distributional parameters of fiber cross-section measurements

Many previous studies on cotton maturity used a sole parameter to rank the maturity of a cotton sample containing a large number of fibers. In light of the complexity of maturity distributions, the sole-parameter approach does not appear to be reliable and rational for cotton maturity evaluation. More distributional parameters should be examined and included in the new classification methods. This paper (1) introduces important changes in the image-analysis algorithms for cotton cross-section measurements to enhance the consistency of fiber detections in order to reduce the bias on immature fibers, (2) investigates the characteristics and patterns of cotton maturity distributions, and (3) presents the experimental results on the cross-section images selected from seven cotton varieties that have a wide range of maturities. It is found that the skewness of a maturity distribution is an essential parameter for classifying the distribution pattern and that the dead fiber content and the mature fiber content are the important distributional parameters for assessing cotton maturity.

Giant Ragweed (Ambrosia trifida) Competition in Cotton

Glyphosate-resistant (GR) weeds, including giant ragweed, are among the most challenging weeds for growers to control in cotton. A field study was conducted in 2011 and 2012 to determine the competitiveness of giant ragweed with densities of 0, 0.1, 0.2, 0.4, 0.8, or 1.6 plants m−1of row. Early in the growing season, giant ragweed competition with densities of at least 0.8 plants m−1row reduced cotton height compared with the weed-free control. Based on node above white flower (NAWF) and node above cracked boll (NACB) data, a delay in cotton maturity was observed for treatments with giant ragweed present at a density of 1.6 m−1of cotton row for NAWF and 0.8 m−1or 1.6 m−1of row for NACB. Lint yield losses of 50% were estimated for cotton with rows growing along side of giant ragweed at a density of 0.26 plants m−1row. Cotton in rows located 140 cm away from giant ragweed required an estimated 1.85 plants m−1row to reduce yield by 50%. These data suggest that giant ragweed sphere of influence was at least 1 m wide. Cotton fiber quality was not affected by giant ragweed at any density. Giant ragweed is a highly competitive weed in cotton, even at low densities, and efforts should be implemented to control giant ragweed early in the season to prevent cotton yield loss.

Multiple Irrigation Levels Affect Boll Distribution, Yield, and Fiber Micronaire in Cotton

The boll distribution characteristics of upland cotton (Gossypium hirsutum L.) cultivars are related to cotton maturity and can interact with environment and management practices to determine yield and fiber quality. The boll distributions of six cotton cultivars under four irrigation levels were compared in 2011 and 2012 on the Texas High Plains. In 2011, a year of severe drought and heat, all cultivars had relatively compact fruiting patterns and increases in irrigation affected both boll accumulations up the plant and second‐position fruiting sites. In 2012, which was less hot and dry than 2011, all cultivars produced more fruit on higher sympodial branches; however many cultivars followed unique patterns of boll accumulation with increased irrigation. Later‐maturing cultivars significantly increased boll production at higher portions of the plant while early maturing cultivars retained more bolls at the bottom of the plant. One cultivar, DP1311, increased yield at the second position as irrigation increased. Micronaire was also compared among the cultivars and irrigation treatments. In 2011, micronaire increased with increasing irrigation, while in 2012, micronaire decreased with increasing irrigation. There was a strong irrigation by cultivar interaction for micronaire in both years, which may have been related to boll accumulation patterns for the cultivars. These findings suggest that the cultivars compensate for yield differently in response to increased irrigation, and the choice of a specific cultivar should also take into account fruiting habits and their potential effect on micronaire in respect to environmental and management factors, particularly water availability.

A rapid measurement for cotton breeders of maturity and fineness from developing and mature fibers

The Cottonscope simultaneously measures a cotton fiber’s maturity and fineness using a small amount of fiber sample. A program of testing was devised to establish the potential and capabilities of the Cottonscope to rapidly and accurately measure maturity and fineness of small quantities of near-isogenic cotton lines (NILs), and to examine the use of the Cottonscope maturity distributions for breeder applications. Cottonscope measurements were performed on mature and immature fibers of varying days post-anthesis (DPA) from two pairs of NILs (MD 52ne versus MD 90ne; TM-1 versus the low maturity im). The patterns of cotton maturity and fineness during cotton fiber development of each NIL measured by the Cottonscope were compared to those measured by more conventional methods (e.g. the Advanced Fiber Information System (AFIS), an older and currently more widely used method). The Cottonscope maturity and fineness results were much more responsive to increasing DPA than the AFIS results, and the patterns of Cottonscope maturity values were consistent with those of the Fibronaire micronaire. Comparisons of the Cottonscope maturity distributions among the NILs demonstrated that the maturity distribution for im was very different and exhibited much lower maturity values compared to the distributions of other lines. The results demonstrated that the Cottonscope is an efficient instrument for cotton breeders to monitor fiber maturity and fineness of developing and mature cotton fibers.

QTL analysis for early-maturing traits in cotton using two upland cotton (Gossypium hirsutum L.) crosses.

Making use of the markers linked closely to QTL for early-maturing traits for MAS (Marker-assisted selection) is an effective method for the simultaneous improvement of early maturity and other properties in cotton. In this study, two F2 populations and their F2:3 families were generated from the two upland cotton (Gossypium hirsutum L.) crosses, Baimian2 × TM-1 and Baimian2 × CIR12. QTL for early-maturing traits were analyzed using F2:3 families. A total of 54 QTL (31 suggestive and 23 significant) were detected. Fourteen significant QTL had the LOD scores not only > 3 but also exceeding permutation threshold. At least four common QTL, qBP-17 for bud period (BP), qGP-17a/qGP-17b (qGP-17) for growth period (GP), qYPBF-17a/qYPBF-17b (qYPBF-17) for yield percentage before frost (YPBF) and qHFFBN-17 for height of first fruiting branch node (HFFBN), were found in both populations. These common QTL should be reliable and could be used for MAS to facilitate early maturity. The common QTL, qBP-17, had a LOD score not only > 3 but also exceeding permutation threshold, explaining 12.6% of the phenotypic variation. This QTL should be considered preferentially in MAS. Early-maturing traits of cotton are primarily controlled by dominant and over-dominant effects.

Effect of Application of Plant Growth Regulators on Earias vittella (Fabricius), Infestation and Yield Components of Cotton

Studies were carried out on the effect of plant growth regulators on bollworm infestation and plant growth of cotton under field conditions. New cotton variety (CRIS-134) was sown in randomized block design with seven treatments including control (check) and was replicated three times on May 22, 2004. Mepiquate chloride, Acetyl salicylic acid and Naphthalene acetic acid (plant growth regulators) were applied on 10th, 25th August and 9thSeptember 2004.The results indicated that there was no significant effect of either removal of leaves and fruiting bodies of cotton plant and application of plant growth regulators on cotton plant height but significantly effect on volume of bolls and yield in comparison to control. Moreover, application of hormones significantly delayed the maturity of cotton. There was also significant effect of application of plant growth regulators on bollworm infestation compared with control treatments.

Yield, development and quality response of dual-toxin Bt-cotton to manual simulation of damage by Helicoverpa spp. in Australia

Larvae of Helicoverpa spp. can occasionally be found in Bollgard II® cotton (Gossypium hirsutum L.), raising concerns about the validity of current thresholds for their control. Experiments were conducted in two seasons to test these thresholds using artificial damage to different fruiting structures (squares or bolls or both) at three stages of cotton growth. At early flowering, Bollgard II® cotton plants tolerated 100% square removal from all plants without significant yield loss, indicating substantial compensation primarily through increased survival of subsequently produced fruit. This delay in the fruiting cycle, however, resulted in maturity delays of up to 6–13 d. At peak flowering, only 100% square removal or the combination of 30% boll damage and 100% square removal caused significant yield loss. Compensation in other treatments was primarily through increased boll weight. Square removal or square removal plus boll damage significantly delayed cotton maturity by about 5 d, but boll damage alone did not. At late flowering, the heaviest damage treatments (30% bolls damaged across 50% or all plants) significantly reduced yield, and there was a trend toward lower yield as damage increased, suggesting limited compensation. Boll damage had no effect on cotton maturation at late flowering. Damage distribution (all or half of the plants damaged) affected yield proportional to the amount of damage inflicted. Across all times and treatments, fiber quality was never affected to a degree that incurred price penalties commercially. In commercial fields, we rarely encountered damage levels equivalent to the heavier damage treatments, suggesting that current thresholds are adequate.

Development of Fourier transform infrared spectroscopy in direct, non-destructive, and rapid determination of cotton fiber maturity

Fourier transform infrared (FTIR) spectra of seed and lint cottons were collected to explore the potential for the discrimination of immature cottons from mature ones and also for the determination of actual cotton maturity. Spectral features of immature and mature cottons revealed large differences in the 900—1200 cm1 region, and such spectral distinctions formed the basis on which to develop a simple three-band ratio algorithm for classification analysis. Next, an additional formula was created to assess the degree of cotton fiber maturity by converting the three-band ratios into an appropriate FTIR maturity (MIR) index. Furthermore, the MIR index was compared with parameters derived from traditional image analysis (IA) and advanced fiber information system (AFIS) measurements. Results indicated strong correlations (R2 > 0.89) between MIR and M AFIS and between MIR and MIA among either International Cotton Calibration standards or selected cotton maturity references. On the other hand, low correlations between the pairs were observed among regular cotton fibers, which likely resulted from the heterogeneous distribution of structural, physical, and chemical characteristics in cotton fibers and subsequent different sampling specimens for individual and independent measurement.

Characterization of single cotton fibers using a laser diffraction system

The fineness and maturity of a cotton fiber is determined by its cross-sectional perimeter and area. However, measuring fiber cross-sectional perimeter and area is an extremely tedious and challenging task. This paper presents an alternative approach to measure fiber longitudinal width using Fraunhofer diffraction patterns, which can be used to estimate fiber fineness and maturity. We designed a laser diffraction system, developed a software program to denoise and process diffraction patterns, and tested the system on a uniform iron wire and individual cotton fibers from ten bales. The width of the iron wire measured by our system was 25.43 μm (0.1% different from the nominal value) with a 0.01 μm standard error of the mean. Cotton fiber width measured by the laser diffraction system could differentiate among ten cotton bales, which was in accordance with their relative differences in fineness. Linear regression analyses revealed that strong linear relationships exist between the fiber width and cross-sectional perimeter and area (r2 = 0.81 and 0.77, respectively), as well as between the fiber width and fineness and micronaire (r2 = 0.79 and 0.73, respectively) (n = 10, p = 0.01). This simple, replicable, and relatively inexpensive optical system could be used for single fiber longitudinal profile characterization and cotton fineness and maturity estimation.

Yield and Maturity of Ultra‐Narrow Row Cotton in High Input Production Systems

Ultra‐narrow row (UNR) cotton (Gossypium hirsutum L.), with rows spaced <40 cm apart, has the potential to reduce the time to maturity as UNR as fewer bolls per plant need to be produced to achieve comparable yields to 1 m spaced cotton crops. The objective of this study was to compare the maturity and yield of cotton grown under UNR spacing with conventionally spaced rows in high‐yielding, high‐input production systems (>1800 kg lint ha−1). Six field experiments comparing UNR and 1 m spaced systems were conducted across a range of environments in Australia where yield on average was increased by 14.4% (P < 0.05) in UNR but the magnitude of this difference varied among experiments (3.7–38.8%). There were no differences in crop maturity (60% bolls open) between the systems. As expected, plants under the UNR system were smaller and produced fewer and smaller bolls. The higher yield under UNR was associated with a greater number of bolls per unit area. Although plants in the UNR crop had fewer fruiting branches and bolls per plant, these bolls did not mature earlier than those in the conventionally spaced crop. Lower boll retention was measured in the UNR crop and may be a key reason for the UNR crops maturing at the same time. The use of UNR may offer opportunities for growers to improve yields, but not for shortening the time of maturity in high yield high input systems. The use of the mepiquat chloride did not affect outcomes in this study.

Fiber Longitudinal Measurements for Predicting White Speck Contents of Dyed Cotton Fabrics

Fiber Image Analysis System (FIAS)2 was developed to provide an automatic method for measuring cotton maturity from fiber snippets or cross-sections. An uncombed cotton bundle is chopped and sprayed on a microscopic slide. The snippets are imaged sequentially on a microscope and measured with customized image analysis software. Cotton maturity is assessed from fiber width variability (convolution) and intensity (translucency) of fiber ribbons. The highly translucent fibers are labeled by the system as ‘dead’ fiber. Dead fibers are the main source of nep formation, causing dye defects, known as white specks, in finished fabrics. This work compared the fiber longitudinal measurements with white speck data of 16 different cottons, and studied the possibility of establishing a predictive equation for white speck contents from bale fiber samples. The main advantages of using the longitudinal FIAS test are that it can more readily detect dead and immature fibers and takes much less time in preparing sample slides than the cross-sectional FIAS test.

High Volume Measurements of Cotton Maturity by a Customized Microscopic System

Information about cotton maturity is desirable to cotton breeders and growers for cotton enhancement and to textile manufacturers for quality control. This paper reports on the development of a dedicated system that facilitates direct, fast and high volume measurements of cotton maturity from longitudinal views, and the experimental results. The system examines cotton fibers in a projected 2-D image to measure the variations in fiber width, which reveal the severity of fiber convolutions, and the fiber translucence that reflects the thickness of the secondary wall. This paper describes the methodology for extracting these features and how they relate to cotton maturity.

Cotton Subsurface Drip and Overhead Irrigation Efficiency, Maturity, Yield, and Quality

Subsurface drip (SSD) is used as a water‐efficient alternative to overhead irrigation in many crops. This study compared soil water, water use, crop maturity, lint yield, and fiber quality of cotton (Gossypium hirsutum L.) grown with SSD to cotton grown with overhead irrigation. Three experiments were conducted at two Georgia locations in 2004 and 2005. Treatments consisted of overhead irrigated, nonirrigated, SSD matched to overhead irrigation rates (SSD Matched), and SSD based on soil water (SSD Fed). Cotton maturity was affected by irrigation treatment as nonirrigated cotton matured earliest, whereas overhead irrigated cotton matured latest. Subsurface drip irrigated cotton produced similar or higher lint yields than overhead irrigated cotton. Subsurface drip provided adequate soil water and irrigation amounts were 4.4, 8.2, and 0.5 cm less than overhead irrigation at the three locations. Water use efficiency (WUE) of cotton SSD irrigated was 23 and 15% higher than overhead‐irrigated cotton in two experiments. Irrigation method did not substantially affect fiber quality; however, micronaire was higher in cotton from the SSD Fed treatment than cotton in the Overhead treatment in two locations. We conclude that SSD irrigation provides the same positive effects as overhead irrigation in cotton production while reducing irrigation water use and may allow for improved irrigation efficiency.

Timing of Maturity in Ultra-Narrow and Conventional Row Cotton as Affected by Nitrogen Fertilizer Rate

Ultra-narrow row (UNR) systems and N fertilizer can influence cotton (Gossypium hirsutum L.) crop maturation. Study objectives were to measure impacts of UNR systems and N fertilizer rates on cotton maturation and to identify mechanisms by which these effects occurred. The location was Burleson County, Texas. In the split plot design, whole plots were N rates of 0, 50, 101, and 151 kg ha−1. Split plots were 19-, 38- (both UNR), and 76-cm (conventional row, CR) row spacings with 296,600, 195,400, and 136,300 plants ha−1, respectively. Thirty, 60, and 85% harvestable seedcotton each occurred 1.5 to 2.9 d earlier in UNR than CR spacings. First boll set occurred 1 d later in 19-cm than in wider row spacings. Boll set rate m−2 was greater in 19- than 76-cm row spacing during a 5-d flowering period shortly after first boll set, but did not differ by row spacing during three flowering periods thereafter. The percentage first position bolls was lower with wider row spacing, suggesting greater potential for concurrent boll set at multiple sites on individual plants. Eventual development of nonfirst position fruiting sites in 76-cm row spacing may have contributed to confinement of faster boll set in 19-cm row spacing to early bloom. Nitrogen rates did not affect the timing of 30, 60, or 85% harvest. Reductions in bolls plant−1 were counteracted by slower boll set rates with lower N. The limited observed interactions of N and row spacing do not suggest advantages from suboptimal N rates in UNR cotton.

Biased Experimental Fineness and Maturity Results

In an earlier paper, we developed models and performed computer simulations to understand the variability in coefficients of determination (R2) between fineness and maturity, micronaire and fineness, and micronaire and maturity of cotton. We subsequently concentrated on derivation and testing of several diagnostic models to enhance the R2 and provide information about the analytical quality (accuracy) of the results. We then introduced modeling of biased fineness and maturity results. Error functions were derived based on micronaire values, specifically, Lord's micronaire model. This paper demonstrates testing of a key diagnostic model on two different sample sets of 21 cottons. The results from one sample set — analyzed on the fineness and maturity tester — fit the model. Results from the other sample set — analyzed on both the advanced fiber information system (AFIS) A-2 and AFISPRO — demonstrate a lack of fit to the diagnostic model. This lack of fit is due to bias in the AFIS fineness and maturity measurements compared to the more traditional Lord's micronaire model. As a consequence of the bias, the dynamic range of the AFIS raw data for both fineness and maturity is very narrow. Results are confirmed by image analysis.

Modeling Biased Fineness and Maturity Results

In an earlier paper, our classical models study included simulations to explain the variability in coefficients of determination (R2) between fineness and maturity, micronaire and fineness, and micronaire and maturity of cotton. Subsequently, we emphasized the derivation and testing of three diagnostic models to enhance the R2 and provide information about the analytical quality (accuracy) of the results. In this paper, the theory of biased fineness and maturity measures is introduced and effects on the relationships with micronaire are simulated. Error functions based on Lord's micronaire model are derived to express biased results relative to the unbiased values. The simulations include three case studies in order of increasing complexity: bias varies linearly with micronaire, bias is nonlinear with micronaire, and random error is added to the bias. Classical and diagnostic model plots of the simulated unbiased and biased data are presented in detail to readily determine differences in the relationships.

Phenological and Morphological Components of Cotton Crop Maturity

Full season cotton (Gossypium hirsutumL.) cultivars may be better adapted to the lower southeastern USA because early maturing cultivars may not recover from the many episodic drought events that annually plague the region. The objective of this investigation was to determine if cotton maturity may be defined on the basis of flowering interval, boll maturation period, or whole plant yield distribution. Studies were conducted at the University of Georgia Coastal Plain Experiment Station in 2001, 2002, and 2003. Nine commercially available cotton cultivars were over seeded and hand thinned to 10.8 plants m−2Areas within each plot were reserved for daily white flower and open boll tagging and hand harvest. Mean vertical flowering intervals were 2.1 (2001), 2.7 (2002), and 2.6 (2003) d. Mean vertical flowering intervals increased from main stem node 5 to about main stem node 11 and then began to decline. Mean horizontal flowering intervals were 3.2 (2001), 4.4 (2002), and 3.8 (2003) d and were shorter than those in previous reports. In all years, the earlier maturity cultivars possessed the shortest boll maturation periods while the later maturity cultivars possessed the longest. The earlier maturity cultivars also produced a greater percentage of their total lint yields at lower main stem nodes. of the many possible pathways to early crop maturity, the ones investigated in this study that appear to have been most useful in breeding programs are shortening of the horizontal flowering interval and boll maturation period and lengthening of sympodial branches at lower main stem nodes.

Response of nonglyphosate-resistant cotton to reduced rates of glyphosate

Field research was conducted in 1999 and 2000 to determine the effect of reduced glyphosate rates on growth and yield of nonglyphosate-resistant cotton. Rates of 9, 18, 35, 70, 140, and 280 g ha−1, representing 0.008, 0.016, 0.031 0.063, 0.125, and 0.25, respectively, of the maximum use rate per application (1,120 g ha−1), were applied to cotton at the two-, five-, or nine-node growth stage. On the basis of visual injury estimates, cotton was more tolerant to glyphosate at the nine-node than at earlier growth stages. Plant dry weight was reduced with 70 g ha−1of glyphosate or higher, when applied at the two- and five-node growth stages in two of three experiments. Dry weight was not affected by glyphosate at the nine-node stage. Plant height also was unaffected by glyphosate rates below 70 g ha−1, but height reduction was noted for all growth stages by experiment combinations, with the exception of the nine-node application for both experiments in 2000, with herbicide rates of 70 g ha−1or higher. Cotton maturity delay, as noted by an increase in node above white flower number, was observed only at the highest glyphosate rate applied to two- and five-node cotton in one of three experiments. Percent open boll data analysis indicated a decreased opportunity of observing an open boll with increasing glyphosate rate, and this effect was greater at the five-node compared with the two- and nine-node stages in two of three experiments. Seedcotton yield after all glyphosate applications was equivalent to that for the nontreated control.

How to Succeed by Doing Nothing

Clarifying the amount of pest damage that can be tolerated without justifying insecticidal control will be useful in reducing insecticide use and in development of integrated pest management (IPM) systems. This study investigated the ability of irrigated, high‐yielding cotton (Gossypium hirsutum L.) to recover from artificially applied damage simulating that of early season insect pests. Six experiments were done across five cotton‐growing seasons. Damage included defoliation, terminal damage, and flower bud removal in a range of timings, combinations, and intensities. Crop yield was unaffected by defoliation applied before first flower buds appeared, even when 100% of true leaves were removed on three occasions (Nodes 2, 4, and 6). Crop maturity was affected by sustained high levels of leaf loss with a peak delay of 10 d after 100% defoliation three times. Up to three light tip damage events or one heavy damage event had no effect on yield and only a slight effect on crop maturity (<5‐d delay to harvest). Heavy early fruit loss (100% fruit removal from the first four fruiting branches) did not affect yield but caused a delay in maturity of ≈7 d. Equations describing the relationship between damage type, intensity, and repetition and the yield and maturity of cotton were developed and used in sensitivity analysis to define tentative damage thresholds for IPM systems in cotton.