Limited research has been done to relate cotton plant growth parameters such as height, height-to-node ratio and internode length to remotely sensed imagery. Earnest and Varco (2005) found that the Green Normalized Difference Vegetation Index (GNDVI) was related to cotton plant height. Using a tractor mounted spectrometer, reflectance values were related to plant heights taken from scouting data. It was found that relationships between GNDVI and height were weak in the early season and peak during the late bloom stage. Teague et al., (2005) conducted intensive scouting of cotton growth parameters based on the COTMAN Crop Monitoring System. Although several aerial images were taken throughout the growing season, only cotton height was reported to be correlated with the imagery. In an extensive study of image-based, variable-rate PGR, Bethel et al., (2003) compared cotton plant parameters such as plant height, total main stem nodes, and internode length to aerial multispectral imagery. Variable rate PGR prescription maps were created based upon correlations between the imagery and plant parameters. Although no specific relationships were reported, it was found that the variable-rate prescriptions were based on a positive relationship between cotton growth and the aerial imagery. In a comparison between image- based PGR applications and standard recommendations based on crop scouting, Kirkpatrick et al., (2005) indicated that the image-based recommendations correlated well with PGR applications derived from standard scouting methods. It was also noted that NDVI was significantly correlated both with cotton plant height and top five node elongation. Although no quantitative analysis was done, Thurman and Heiniger (1998) noted that a visual
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Keiser, numerous attempts were made to mechanically prepare a 97 cm raised bed with the crown rolled flat to a width of 61 cm, which was required for seeding cotton in the multiple planting patterns specified for this research. However, formation of a raised bed that allowed proper seed placement and depth was not accomplished, which caused the observed plant densi- ties to be approximately 25-50% less than the desired plant densities shown in Table 1. At Marianna in 2007, heavy rainfall (10 cm) following planting caused soil crusting, which hampered cotton emergence thus reducing observed plant densities 15-30% 30 d after emergence. This variation in plant stand necessitated the need to exclude all Keiser and 2007 Marianna data from analysis because their inclusion would not allow proper evaluation of the effect that planting pattern and plant density may have had on cotton plant struc- ture and boll distribution. Therefore, only data from Marianna in 2008 and 2009 were utilized for analysis. Table 1 shows the actual plant densities at Marianna in 2008 and 2009, which differed among plant density treatments as desired, but not among planting patterns. Plant density data indicates that the desired survival of approximately 80% was achieved (Table 1).
In 2012, only 2.7% of North Carolina’s cotton (Gossypium hirsutum L.) was irrigated compared to the national average of 39%. The small size and nonuniform shape of most North Carolina fields are not conducive for a center pivot system. However, benefits to yield due to irrigation in North Carolina have been reported, specifically in years receiving below average or sporadic rainfall. The objective of this research was to investigate the impact of subsurface drip irrigation (SDI) on growth and yield of early- and late-maturing cot- ton cultivars at varying planting dates in eastern North Carolina. In 2014, the site received more than 750 mm of rainfall and no differences were observed for any parameters between irrigated and non-irrigated plots. Total rainfall in 2015 and 2016 was lower with several extended periods with- out rain events. There was a greater plant height increase and dry weight accumulation throughout the growing season in response to SDI. Cotton yields were increased by SDI in 2015 and 2016. Cultivar only influenced lint yield in 2016 with the earlier-maturing ‘PHY 333 WRF’ having greater lint yield than ‘PHY 499 WRF’. Planting date did not influence yield under irrigated conditions, and the timing of rainfall played a role similar to previ- ous reports in North Carolina. Irrigation applied via SDI will increase cotton plant stature, fruit retention, and yield in response to deficit moisture conditions, independent of planting date or cultivar.
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High Volume Instrument (HVI) Measure- ments. Fiber samples from each subplot were sent to the Cotton Fiber Testing Laboratory at the LSU AgCenter (Baton Rouge, LA) for testing. Fiber samples were evaluated using an Uster 900 SA HVI (Uster Technologies, Inc., Knoxville, TN). This instrument tests each sample four times to generate a mean value for each of the properties analyzed except for micronaire, which is deter- mined only twice. Parameters measured were: upper half fiber length (mm), which is the mean length of the longer half of the fibers in the sample, UHL; fiber length uniformity index, which is the ratio between the mean length and the upper half mean length in percent; short fiber index, which is the percentage of short fibers (fibers less than 12.7 mm long), SFI; strength required to break a fiber bundle (g/tex); elongation, or distance that the fiber bundle extends before it breaks during strength determination (%); maturity, which is the maturity ratio as determined based on measure- ments made by this instrument; and micronaire, which is a measurement of fiber fineness based on resistance to airflow (Stetina et al. 2014).
Cotton emergence was lower in this study compared to cotton grown in a mono-crop situa- tion. Reduced cotton emergence compared to cot- ton not planted following wheat production may be attributed to allelopathy from decomposing wheat stubble as suggested by Hicks et al., (1989) and Wu et al., (2001). In addition, less than opti- mal soil conditions at planting including cloddy soil where re-bedding occurred as well as heavy residue in the no-till treatments resulted in poor seed to soil contact in some instances. In addition, soil moisture was lacking where land was double disked and re-bedded prior to planting cotton seed. Although row cleaner attachments were utilized in this study, instances where poor seed to soil con- tact occurred due to the presence of heavy wheat stubble and straw. This made optimizing seed to soil contact difficult. Hicks et al., (1989), sug- gests that cotton tolerance to allelopathic effects are variety dependent. The cultivar utilized could have reduced tolerance to allelopathic chemicals produced by wheat residue and roots. In instances where wheat straw and wheat stubble were burned the level of trash was greatly decreased however, the burning of residue also caused the soil to become increasingly hard. In 2013 furrow irriga- tion was implemented one week after planting in an attempt to aid cotton emergence. Previous research indicates up to a 21% reduction in cotton emergence may occur when cotton was planted following wheat production (Hicks et al., 1989). Furthermore, with increasing cotton seeding rates, a reduction in cotton emergence may be due to increased plant competition, less than optimum planting conditions, and environmental conditions (L.T. Barber, Personal Communication).
Growth retardant spray (pix and cycocel @ 50 and 100 ppm) on two cotton genotypes reduced the vegetative growth i.e. leaf area (20-25%) and plant height (9-17%) whereas it increased the reproductive growth i.e. boll weight (5-16%), harvest index (8-12%) and seed-cotton yield (4-9%). The net returns of cotton-wheat system increased by 6%. Two sprays at 90 and 120 DAS in cotton reduced the vegetative growth, yield attributes and seed-cotton yield resulting in less net returns (12% reduction) as compared to one spray. Seed-cotton yield, boll weight and harvest index of LHH 144 were significantly higher (4.5%, 15.8% and 17%, respectively) as compared to F 1861. Growth retardants increased the specific leaf weight (70-80%) resulting in higher leaf chlorophyll content (29-69%). This led to higher photosynthesis (20-22%), photosynthetic radiation use efficiency (22%) and photosynthetic water use efficiency (15-32%). It is revealed that application of pix (50 ppm) in cotton at 90 DAS is useful in controlling excessive vegetative growth and enhancing the yield of cotton under irrigated conditions. Key words: Leaf area index, net returns, photosynthesis, seed-cotton yield, wheat yield equivalent
tribution of summation of DSFW during the ‘most active’ planting and harvesting dates, respectively, for the remaining 12 cotton producing states are presented in Figure 3 and 4. Figure 3 and Figure 4 indicate how the number of DSFW for planting and harvesting, respectively, varied across the cotton belt. Figure 3 presents DSFW for the remaining 12 cotton producing states for their respective ‘most active’ planting periods. New Mexico had the least variability in the total number of DSFW while Mis- souri had the most variability (Figure 3). Figure 4 presents the range of DSFW for the ‘most active’ harvest period for 12 cotton producing states. Un - like planting periods, New Mexico has considerable harvest time variability, similar to the other states. Of the 21 years of data collection, only 12 and 15 years of observed data were collected for Oklahoma and Kansas, respectively, for the entire most active harvest date (Figure 4). Other states had additional years but typically less than possible 21 years of data. Only North Carolina had all possible 21 years of data on DSFW during harvest.
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Cotton aphid (Aphis gossypii G.) populations in the ﬁeld have ﬂuctuated over the past years, yet it is unknown whether infestation by these insects alters cotton (Gossypium hirsutum L.) physiology. Although it is important to determine if aphids con- tribute to plant stress, there is only limited informa- tion on plant stress responses after aphid herbivory. In an attempt to quantify plant stress, the activity of cotton foliar antioxidant enzymes after aphid feeding was examined. Cotton aphids were col- lected from cotton ﬁelds at Lonoke, AR, and reared in the laboratory. Fifty aphids were transferred to cotton (G. hirsutum ‘Stoneville 474’) leaves of the same age and size, and were allowed to increase in numbers without restriction. Leaf samples were collected for protein extraction and antioxidant enzyme assays after 6 d and 9 d of aphid exposure. Enzyme activities of catalase (CAT), peroxidase (POX), ascorbate peroxidase (APX), and gluta- thione reductase (GR) were measured. The initial population of 50 aphids increased to 137 aphids per leaf after 6 d. Of the antioxidant enzymes tested, only GR activity increased in aphid-infested leaves. After day 9 of infestation, there were 255 aphids per leaf, but the activity of foliar antioxidant enzymes was not different from control plants. In general, antioxidant enzyme activity in cotton plants was not altered by the levels of infestation and feeding duration used in this study.
Currently, the most widely used promoter for expression of foreign gene constructs (transgenes) in dicot plants is the cauliflower mosaic virus (CaMV) 35S promoter (Ow et al., 1986). The CaMV 35S promoter provides strong constitutive expression in most dicot plants, including cotton. However, to develop transgenic cottons with specialized agronomic traits such as fiber quality and seed nutrition components, a larger arsenal of constitutive and tissue-specific promoters will be required. The characteristic expression patterns provided by these promoters must be analyzed to determine whether they can be used to express beneficial genes in specific target tissues or developmental stages at maximum levels. Although such promoter tests can be conducted with transient expression assays or in model plant systems such as transgenic tobacco and Arabidopsis, gene expression analysis in stable transgenic cotton plants provides confirmation that these promoters can be used for development of transgenic cotton for commercial production. Although several fiber-specific promoters have been tested in transgenic cotton plants (Dang et al., 1995; John and Crow, 1992; Rinehart et al., 1996), the isolation of constitutive and tissue-specific promoters (Song and Allen, 1997; Song et al., 1998) is also of interest. Here we report the expression patterns of two promoters from cotton that direct seed-specific and leaf-specific expression in transgenic cotton plants. We anticipate that these promoters can be used to direct expression of transgenes in cotton and other plants.
A field study was conducted at the Lon Mann Cotton Research Station in Marianna Arkansas (34˚5'N, 90˚5'W) in 2005 and 2006. The cultivars used were DP444BR, ST5599BR, and FM960BR. The soil was a Captina silt loam (typical fragiudult). The experimental plot size was four rows by 15m and the plant population 10 plants per m 2 . The study was furrow-irrigated based on an irrigation scheduler program  (University of Arkansas Coo- perative Extension Database Service 2007). The fertiliza- tion program was determined by preseason soil tests and recommended values for cotton. Weed and insect control were conducted according to Arkansas extension recom- mendations. At first flower BM86 (Goëmar Laboratories, Saint-Malo, France) was applied to the right 2 rows of each plot at 2.34 mL/ha (recommended rate from Goë- mar Laboratories) with a backpack CO 2 sprayer cali-
Application of MC significantly increased the number of open bolls per plant over the untreated control in both years. These results agree with those previously reported by Mekki (1999), Biles and Cothren (2001), and Ram et al. (2001). Increases in bolls per plant may be due to increased photosyn- thetic activity of leaves following MC application (Wu et al., 1985). Increased photosynthesis increases flowering and boll retention (Kler et al., 1989). Khan (1996) stated that plant growth regulators could be used for maintaining internal hormonal balance and an efficient sink source relationship that enhances crop productivity. Others, however, have not found an increase in boll numbers associated with MC ap- plication (Lamas and Staut, 1999).
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The cotton fleahopper, Pseudatomoscelis seriatus Reuter, is a widespread and important insect pest of cotton in Texas and Oklahoma. This plant bug feeds on small floral buds, which results in bud abscission, delayed fruiting, and subsequent crop loss. In central and southeast- ern Texas, two to four insecticide applications are typically applied for cotton fleahopper management. Primitive race stocks of cotton have been identified as an important source of resistance to a wide range of insect pests, but they have not been evaluated for resistance to cotton fleahopper. The objective of this study was to evaluate selected groups of primitive race stocks of Gossypium hirsutum L. for resistance to cotton fleahopper. Resistance was identified by caging cotton fleahoppers on cotton plants in a no-choice feeding trial and comparing the mean number of damaged squares per plant to a standard susceptible genotype. Four primi- tive race stocks, TX706, TX188, TX1530, and TX1156, were identified as resistant to cotton fleahopper in a collection of 65 primitive race stocks representing 18 genetic groups and col- lected throughout Mexico and Central America. No resistance was found in a collection of 11 accessions previously identified as resistant to Lygus spp. and no resistance was identified in a collection of 78 primitive accessions converted to day-neutrality. The possibility that some ge- netic resistance in these race stocks to the cotton fleahopper might have been lost as a result of the conversion to day-neutrality is discussed.
A field experiment was carried out to study efficacy of different selected chemicals against bacterial blight of cotton with ten treatments in Randomized Complete Block Design (RCBD) single factor with three replications in variety CB- 9. Seeds were treated with Cupravit 50 WP (0.4%), Indofil M-45 (0.4%) and Streptomycin Sulphate (0.015% and 0.15%) either alone or in combination (Table 1). Treatment combinations were T 1 = Seed treatment with Cupravit 50 WP at
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An important management variable that producers can directly control is tillage. Preplant soil preparation, in- season weed control and postharvest stalk management are tillage-related operations in cotton production that can account for 25% or more of overall cotton-production costs (Carter 1996). These tillage operations represent not only high energy, equipment and labor costs, but they also reduce soil organic matter (Reicosky and Lindstrom 1995), and contribute air pollutants such as oxides of nitrogen and fine particulate dust (Baker et al. 2002). The adoption of conservation tillage (CT), or reduced- tillage practices similar to those used successfully elsewhere in the Cotton Belt, may be a viable means for increas- ing profitability and improving the soil in San Joaquin Valley cotton fields.
At the end of the experiment (13 days later), the plants were transferred back to Tifton, GA. Leaf area was determined using a LiCor LI-3100 area meter. Leaf and shoot dry mass was also determined after drying the plant material to uniformity at 60°C. Data were analyzed using the General Linear Model procedure (SAS Institute, 1997).The experimental design was a randomized complete block with two replications (one replication per growth chamber) and a group of 15 plants as the experimental unit.
Since there were no differences in plant density, height, and total leaves per plant prior to treatment, differences observed after the treatments were at- tributable to the treatments. Leaf kill exceeded 80% following the application of chemical defoliant 5 d later than the thermal treatment at both locations. In the thermal plots, >80% of desiccation was ob- served within 24 h. Hot air at 149 ° C for 8 sec has been reported to result in 89% desiccation and 60% defoliation after 2 wk (Funk et al., 2003), but this study demonstrates the rapidity of desiccation. De- foliation was >75% in the chemical treatment after 6 d, but further defoliation was negligible. Although leaves in the thermal treatment were killed quickly, they tended to stay attached to the plant longer, and defoliation did not exceed 65% after 13 d. It is possible that the sudden exposure to heat disrupted the physiological or chemical processes essential to leaf abscission.
Cotton (Gossypium hirsutum L.) and mustard (Brassica compestris L.) cake used to suppress pathogenic fungi and ultimately enhanced the growth of tomato (Lycopersicon esculentum) plant. During field experiment tomato plant was treated alone and combine use of mustard and cotton cake with different concentration viz, 1, 3 and 5% W/V. Fusarium solani, Botrytis cinerea and Fusarium samitactum was completely controlled by the combine effect of mustered and cotton cake at 1%MC+5%CC, similarly Rhizoctonia solani was completely controlled at 1%MC+1%CC, while 5%MC, 5%CC, 1%CC+5%MC also showed the significant (P< 0.05) result by reducing the percent infection of F. solani, R. solani at 11.11 each. Plant height enhanced significantly (P< 0.05) by all treatments alone and combine, while maximum plant height and weight was produced by combine effect of mustard and cotton cake at 1%MC+5%CC was 14cm and 23.41g respectively.
increasing plant populations that would tend to promote excessive vegetative growth led to a greater response in lint yield to mepiquat chloride (york, 1983b). Much of the yield increase was attributed to the earlier maturity of the plants treated with mepiquat chloride rather than to control of vegetative growth. None of the previous mepiquat chloride or plant density studies were conducted under the very early-planted conditions used with the cotton early planting production system (Pettigrew, 2002). Be- cause of this, there is uncertainty about the response of early-planted cotton to mepiquat chloride-type compounds and different seeding rates. in addition, the optimal seeding rate for early-planted cotton, which will allow the producer to minimize technol- ogy fee, remains uncertain. The objectives of this study were to determine how early-planted cotton responds to different levels of mepiquat compounds and to different seeding rates.
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Conservation tillage production systems are recommended for cotton production on highly erosive soils. The residues and/or winter covers normally used for erosion control affect the soil environment by restricting water evaporation and reducing soil temperatures - conditions that tend to reduce seed germination, plant vigor, and root growth and possibly increase pathogen activity. Two commercial products reported to improve root growth-PGR-IV and Asset RTU-were evaluated for cotton produced in disk- and no-tillage systems.
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Abstract: Studies were conducted at three locations in North Carolina in 2004 to evaluate density-dependent effects of glyphosate-resistant (GR) corn on GR cotton growth and lint yield. GR corn was taller than GR cotton as early as 25 d after planting, depending on location. A GR corn density of 5.25 plant/m of crop row reduced late-season cotton height by 49, 24, and 28% at Clayton, Lewiston-Woodville, and Rocky Mount, respectively, compared to weed- free cotton height. At Clayton, GR corn dry biomass per m crop row and GR corn seed biomass per m of crop row decreased linearly. The relationship between GR corn and GR cotton yield loss was described by the rectangular hyperbola model with the asymptote (a) constrained to 100% maximum yield loss. The estimated coefficient i (yield loss per unit density as density approaches zero) was 9, 5, and 5 at Clayton, Lewiston-Woodville, and Rocky Mount, respectively. The examined GR corn densities had a significant effect on cotton yield, but not as significant as many other problematic grass and broadleaf weeds.
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