Browsing by Subject "cotton"
Now showing 1 - 20 of 35
Results Per Page
Sort Options
Item A Phenotypic Evaluation of 61 Mutated Lines of TAM 94L-25(2011-02-22) Brown, Ismael NinoAmong the available methods of creating selectable variation, induced mutagenesis has been historically under-utilized in cotton improvement. Dick Auld showed that chemical mutagenesis could be used to enhance fiber length of a medium staple cotton cultivar without sacrificing yield. The goal of this project was to determine if mutagenesis could be used to improve the fiber quality of a germplasm line already considered to be at the upper-limits of fiber length. Seed of TAM 94 L-25 were treated with EMS in 2001 and the M2 generation was produced at Lubbock, Texas in 2002. More than 1200 M3 plants were grown at College Station, Texas in 2004, harvested individually, and HVI fiber properties determined. The top and bottom 1 percent for UHML, strength, and elongation were selected and the seeds of these individuals planted as an M4 progeny row nursery in 2005. Approximately ten individual plants per progeny row were harvested for re-evaluation of fiber parameters. From the approximately 1600 individual TAM 94L-25 M4 plants harvested in 2005, 61 were selected and subsequently treated as pure lines. Agronomic performance trials were conducted on 61 of those TAM 94L-25 M lines along with the M0 check and two commercial cultivar checks, Fiber Max 832 and Phytogen 355, in 2008 and 2009 in College Station and Weslaco, Texas. Within-boll yield components were examined for 13 representative mutant lines and the three checks. TAM 94L-25 averaged 751 kg lint ha^-1, 31.1 mm UHML, 303 kN m kg^-1 fiber bundle strength, and 6.0 percent elongation. The 61 mutant lines yielded from 366 to 932 kg lint ha^-1, exhibited UHML from 24.3 to 34.9 mm, fiber bundle strengths of 261 to 333 kN m kg^-1, and elongations from 5.4 to 8.1 percent. Seed surface area of the TAM 94L-25 M-lines was between 99 and 124 mm^2, and fibers per unit seed surface area from 123 to 168 fibers mm^-2. The M0 parent, TAM 94L-25 averaged 125 mm^2 seed-1, and 128 fibers mm^-2. The data presented herein demonstrate that EMS-induced mutagenesis was successful in creating TAM 94L-25 M-lines with superior fiber and yield traits to that of the non-mutated, high fiber quality parent, TAM 94L-25.Item A study of programmed cell death in cotton (gosypium hirsutum) fiber(2009-05-15) Roche, Meghan C.Cotton fiber has been postulated to undergo a process of programmed cell death (PCD) during the maturation phase of development. A parallel may exist between cotton fibers and xylem tracheary elements, which have periods of elongation, secondary cell wall deposition and death. Secondary wall formation and PCD are purported to be coupled events in tracheary elements. In this study, an attempt was made to observe the occurrence and timing of PCD in cotton fibers by TUNEL staining to detect DNA strand breaks, and also to monitor DNA content by PI staining. The staining patterns produced by PI and TUNEL left room for interpretation. TUNEL-positive and PI-stained areas were observed, but failure to observe nuclei of conventional appearance in my cytological preparations at any time-point, along with possible nonspecific staining or autofluorescence of cell wall and intracellular components, made it difficult to draw firm conclusions of significance. Thus, additional analyses will be needed to prove or disprove current PCD theories. Nevertheless, the differences in TUNEL and PI signals across fiber development stages indicate that the observed fluorescence patterns are marking discrete developmental phases. The PI signal is dispersed throughout the cell during the elongation phase (5-15 DPA) and appears to condense during secondary cell wall synthesis (25- 40 DPA). TUNEL-positive signal may be observed as early as 25 DPA, but the signal is not widespread until 45 DPA. At 50 DPA and beyond, PI staining is reduced. Visually detectable DNA can be extracted from cotton fiber nuclei between 5 and 40 DPA, although a laddering pattern was not visible at any time-point. The results, although inconclusive, point to the possibility that PCD may be a process leading to maturation in the cotton fiber, succeeding completion of secondary cell wall synthesis.Item Advanced Analysis of the Responses of Cotton Genotypes Growing Under Water Stress(2012-11-12) Maeda, Murilo Minekawa 1985-The ever-growing world population raises the concern and necessity of rational use and distribution of limited water resources. Water deficit is the single most dominant abiotic factor limiting cotton (Gossypium hirsutum L.) yield in drought-prone Texas croplands. Characterizing plant traits conferring drought tolerance to cotton genotypes and then transferring this information back to breeders and geneticists have the potential of significantly increasing and stabilizing production statewide. Although a plethora of physiological studies have been conducted and have demonstrated that drought tolerance in plants is likely to be conferred by a combination of plant traits rather than a single trait, this knowledge has not translated into improved breeding lines. Experiments were conducted in 2010 and 2011 in the Drought Tolerance Laboratory (Texas AgriLife Research and Extension Center in Corpus Christi, TX) to analyze the responses of cotton genotypes to different levels of water stress. This facility is equipped with computerized systems capable of continuously monitoring whole-plant water use as well as several environmental parameters. Sixteen cotton genotypes were provided by Monsanto Co. and the Texas AgriLife Cotton Improvement Programs at College Station and Lubbock. Seeds were pre-germinated in wet paper towels and then hand planted in large pots previously filled with fritted clay. A total of 3 and 8 (2010 and 2011, respectively) pots containing plants of each genotype were permanently placed on micro-lysimeters for continuous measurement of water use. Water regimes were imposed in 2010 (well-watered and water-stressed), and 2011 (water-stressed) when plants reached the early-flowering stage and were carried until plants reached maturity (100% open bolls). Data collected showed that genotypes have very distinct water use patterns. The water stress treatment imposed on the test plants negatively affected plant growth that was indicated by a lower plant height, total number of leaves, and main-stem nodes of stressed plants when contrasted to their well-watered counterparts. Stomatal density was remarkably different among genotypes and a higher density was found on the abaxial (lower) leaf surface for all genotypes studied. Root dry mass production had different responses depending upon the severity of the water stress. Highest root dry mass was observed when plants were exposed to a mild stress and lowest when a more severe water restriction was imposed.Item An empirical simulation analysis on cotton marketing strategies in west Texas(2009-05-15) Elrod, Christopher PatrickThe three marketing strategies, buying a put option, cash sale at harvest, and cash sale in June after December harvest, are simulated for six representative irrigated and dryland cotton farms in West Texas. Each marketing strategy is ranked using the net cash income probability distribution for the representative farms using stochastic efficiency with respect to a function (SERF). SERF rankings were consistent across dryland and irrigated farms. The buying of a put option was found to be the marketing strategy that produced the highest certainty equivalent (CE) for normal risk averse decision makers. Cash sale at harvest followed by cash sale in June marketing strategies were ranked second and third, respectively. A sensitivity analysis increased the national baseline price used in the model by 45 percent. Cash sale at harvest then consistently became the highest ranked marketing strategy followed by buying a put option and then cash sale in June. The research found that if a strike price and premium that covered the production costs of the representative farm was available during the pre-harvest period, the decision maker may have the ability to increase utility by hedging with the put option.Item COMPARISON OF PICKER AND STRIPPER HARVESTERS ON IRRIGATED COTTON ON THE HIGH PLAINS OF TEXAS(2010-01-16) Faulkner, William B.Over a fourth of the cotton produced in the US since 2002 has been produced in Texas, with most coming from the High Plains. In recent years, Texas has accounted for almost half of all US cotton production (USDA-NASS, 2008b). Most cotton on the High Plains is of more storm-proof varieties that have traditionally been harvested using stripper harvesters. However, improvements in irrigation technology and shifting markets for US cotton have increased interest in picker harvesters in the region. A holistic comparison of picker and stripper harvesters in irrigated cotton on the High Plains of Texas was conducted focusing on differences in system efficiencies, the costs of ginning, fiber and yarn quality, and potential economic returns under comparable crop yields and conditions. Harvester performance was evaluated based on harvest efficiency, time-inmotion, and fuel consumption. Stripper harvesters left less cotton in the field, but most of the cotton left by the picker was of low quality. While the time spent in each operation of harvest was highly dependent on the operator and support equipment available, in general, picker harvesters were able to harvest a unit area of high-yielding cotton more quickly than stripper harvesters. The cost of ginning picked and stripped cotton was evaluated considering current fee schedules from gins on the High Plains. On average, it cost a producer $4.76 more per bale to gin stripped-and-field-cleaned cotton than picked cotton. Fiber quality parameters were compared between harvest treatments based on results from High Volume Instrument (HVI) and Advanced Fiber Information System (AFIS) tests. Samples were ring-spun into carded and carded-and-combed yarns. Differences in fiber quality between harvest treatments were more pronounced when growing conditions were less favorable. Few differences were detected in carded yarn quality between harvest treatments, while more pronounced differences favoring picked cotton were seen in carded-and-combed yarns. A cost-benefit analysis was conducted to determine the production scenarios in which picker and stripper harvesters were most appropriate. Results indicate that, if a producer has sufficient yields coupled with sufficient area to harvest per machine, picker harvesting is a more profitable alternative to producers of on the High Plains.Item Cotton Leaf Grade as Influenced by Harvest Aid Regimes and Cultivar Characteristics(2013-08-09) Eder, Zachary PhillipCotton, Gossypium hirsutum L., leaf grade values can significantly increase with remnants of leaf and bract materials, and can result in increased ginning costs and discounts to the producer. Cotton classed through the USDA-AMS Classing Office in Corpus Christi, Texas has reported increases in leaf grade values beginning in 2000 (USDA, 2012). The impacts of the interaction of agronomic characteristics of cotton cultivars with those of various harvest aid regimes were studied over three growing seasons, and data were used to narrow possible contributors to the observed increased leaf grade values. Multiple trials were conducted throughout the Coastal Bend and Blackland Prairie of Texas, in addition to Tifton, Georgia. Cotton was harvested, lint samples were ginned in a microgin, and lint quality was quantified with HVI. Harvest aid regimes selected provided a broad range of defoliation and desiccation, from a multiple herbicidal and hormonal modes-of-action. Defoliation levels ranged from 0 to 96% and desiccation levels ranged from 0 to 90%. Harvest aid treatments had no impact (P?0.05) on leaf grade values for either of the years of the trials. Multiple trials were conducted in five counties in Texas, including the Lower and Upper Coastal Bend and the Blackland Prairie, and were defoliated with a uniform harvest aid treatment to identify leaf and bract morphological differences, and to determine their role in leaf grade. Multi-acre module trials were conducted with a smooth leaf cultivar and a hairy leaf cultivar to obtain leaf grade values following commercial ginning. Leaf and bract pubescence, and leaf and bract area were collected to analyze the resulting impact on cotton leaf grade values. Visual quantification of leaf and bract trichome density was quantified on 10 youngest fully-expanded leaves and 10 mid-canopy full sized bolls, respectively, when cotton was at physiological cut-out. Trichome density quantification indicated substantial variation in cultivars and discrepancies from company based rating systems. Leaf grades values generally increased with increasing trichomes densities, although not always statistically significant. In the split plot cultivar and harvest aid trial, harvest aid efficacy was similar for each of the cultivars, but cultivar trichome density was positively influence the cotton leaf grade value.Item Cotton Response to 1-Methylcyclopropene Under Different Light Regimes and Growth Stages: Lint Yield and Yield Components(2010-10-12) Carden, Charles WarrenLow photosynthetic photon flux density (PPFD) during certain growth periods of cotton (Gossypium hirsutum L.) has been shown to impact yield, ethylene synthesis, and fiber quality. Previous research with shading has shown that lint yield can be significantly reduced in the latter stages of growth. This two-year field study was conducted at the Texas A&M AgriLife Research Farm in Burleson County, Texas, in 2008 and 2009. The study evaluated the impact of an 8-day period of shade (63 percent reduction of PPFD) on cotton yield parameters, fiber quality, and the impact of 1-methylcyclopropene (1-MCP), an ethylene inhibitor, to alter detrimental cotton responses when applied as a foliar spray under shaded and non-shaded conditions. Shade and 1-MCP were imposed at four developmental stages of growth: pinhead square (PHS), first flower (FF), peak flower (PF), and boll development (BD). Data pooled over both years indicated that there were no significant differences in yield for 1-MCP treatments; however, numerical differences existed. Shade applied during the BD stage of development showed significantly lower yield than the untreated control. These results showed a decline in seed cotton and ginned seed cotton by 522 and 207 kg ha-1, respectively. To further analyze further yield components, box-mapping was conducted during both years. However, this data failed to explain consistent patterns of the observed yield responses. Data was also collected to determine the amount of fibers per seed and seed weights. Cotton fiber data did not show consistent correlations with the numerical increases and significant decreases in yield. Electrolyte leakage and stomatal conductance data also were collected. Electrolyte leakage showed no statistical differences when compared to the untreated control. Stomatal conductance measurements showed no consistency for treatments during both years.Item Development of a screening method for drought tolerance in cotton seedlings(Texas A&M University, 2007-04-25) Longenberger, Polly SuzanneThe key to an efficient screening method is the ability to screen large amounts of plant material in the shortest time possible. Unfortunately, due to the complexity of drought tolerance, a quick and effective screen for this trait has yet to be established. The research reported herein was designed to evaluate a screening method for drought tolerance in cotton (Gossypium hirsutum L.) seedlings. Twenty-one converted race stocks (CRS) and two cultivars were evaluated for seedling drought tolerance on an individual plant basis. CRS are day-sensitive primitive lines derived from various wild race stocks that were converted to day neutrality for use in temperate region plant improvement programs (McCarty et al., 1993). Genotypes were evaluated October - November 2004 and February - March 2005 under greenhouse conditions at the Norman E. Borlaug Center for Southern Crop Improvement, College Station, TX. Seedlings were subjected to three sequential cycles of drought at 15 days after planting (DAP). Drought cycles consisted of withholding water until the moisture content of "indicator" cone-tainers, containing Deltapine 491 (DP 491), had an average volumetric water content of 0.07. Plants were then watered to field capacity and percent survival was recorded after 48 hours. Genotypes differed in their percent survival following three consecutive drought cycles. Drought cycles 2 and 3 did not contribute to the separation of genotypes. DP 491 was the most tolerant genotype evaluated. None of the CRS were more or less tolerant than Acala 1517-99. CRS M-9044-0165 was the most stable genotype across the two experiments.Item Diallel analysis of within-boll seed yield components and fiber properties in upland cotton (Gossypium hirsutum L.) and breeding potential for heat tolerance(Texas A&M University, 2004-09-30) Ragsdale, Paul IrwinA diallel analysis of eight upland cotton (Gossypium hirsutum L.) genotypes was conducted in the field over two years to determine the potential for improvement in within-boll seed yield components and fiber quality parameters. Four exotic germplasm lines from the converted race stock (CRS) collection and four commercial types representing Texas, mid-South, and Eastern production regions were crossed and evaluated in a diallel with parents but without reciprocals according to Griffing's Model I, Method 2. Significant variation for genotypic, general combining ability (GCA) effects, and specific combining ability (SCA) effects (P 0.05) were identified for all traits studied indicating potential for improvements through selection. Significant interactions of these parameters with years were also observed, suggesting that selection should be based on multiple years and or locations. In addition to effects on yield, individual seed number traits were found to respond to heat stress under controlled growth chamber conditions, suggesting their potential for use in screening genotypes for heat tolerance. These traits were not found to interact with temperature, which indicates that selection for improvements in these traits could be conducted in any environment. Improvements in seed yield components and, putatively, in heat tolerance could be achieved using CRS M-9044-0162. As expected, CRS accessions reduced fiber quality parameters in addition to other agronomic traits, suggesting that improvements for within-boll seed yield components and heat tolerance should be made utilizing a backcross approach. Also observed in this population was a superior hybrid for fiber length and fiber strength from the cross of TAM 94L-25 with PD 6186. This combination could lead to improved fiber length and strength potential in upland cotton.Item Effect of an upper temperature threshold on heat unit calculations, defoliation timing, lint yield, and fiber quality in cotton(2009-05-15) Fromme, Daniel D.Crop managers need to determine the most profitable time to defoliate cotton (Gossypium hirsutum L.) in a high rainfall environment such as the coastal region of Texas. In cotton production, delaying defoliation exposes open bolls to a higher probability of rainfall, and thus, reduces lint yield and fiber quality. Premature defoliation, however, has detrimental affects on lint yield and fiber quality. A more recent method to determine defoliation is based on heat-unit (HU or DD15) accumulation after physiological cutout or five nodes above white flower (NAWF=5). Results have been inconsistent across a wide range of field environments when utilizing HU accumulation past cutout; therefore, adoption of this method has been limited. Many regions of the Cotton Belt have maximum day time temperatures during the growing season that are above optimum for maximum growth. Field studies were conducted for three consecutive growing seasons in the Brazos River Valley and Upper Gulf Coast regions of Texas. The purpose of this research was to identify an upper temperature threshold (UTT) for calculating degree days for defoliation timing. The experimental design consisted of a split-plot design with four replications. The main plots consisted of three upper temperature thresholds (32?C, 35?C, and no upper limit) and the subplots were five HU timings (361, 417, 472, 528, and 583) accumulated from date of cutout. Utilizing an UTT to calculate daily HU failed to explain differences in the optimum time to defoliate based on accumulated HU from cutout for the upper thresholds investigated. Accumulated HU had a significant impact, however, on defoliation timing. Comparison of the two locations showed that maximum lint yield was obtained at 472 HU and 52% open boll at Wharton County versus a maximum of 528 HU and 62% open boll for the Burleson County location. Employing the NACB=4 method to time defoliation at both locations would have resulted in premature application of harvest aids and reduced lint yields. No differences were observed in adjusted gross income values at Wharton County among the 417, 472, 528, and 583 HU treatments. For Burleson County, adjusted gross income peaked in value at 528 HU.Item Effects of Exogenously Applied Indole-3-Acetic Acid (IAA) to Cotton(2011-08-08) Clement, Jenny D.There is a need in the cotton industry for cultivars with enhanced lint yield potential and high-quality fiber properties. Indole-3-acetic acid (IAA) is a phytohormone that is predominantly responsible for cell elongation and required for primary elongation in cotton fiber development. An increase in IAA at specific fiber developmental stages may promote increased lint percent and longer fibers. Objectives of this research project were to determine how exogenous applications in a field environment affect fiber traits and lint yield potential in diverse genotypes. The first study examined application methods to ascertain the optimal placement and timing of IAA. The second study focused on genotype reactions to elevated levels of IAA. Results indicate exogenously applied IAA provided a potential yield increase but did not improve fiber length. Further research needs to be conducted to effectively understand IAA?s role in fiber development and establishing protocols for maximizing IAA potential in a field environment.Item Efficacy of abamectin as a seed treatment for control of Meloidogyne incognita and Rotylenchulus reniformis on cotton(2009-06-02) Faske, Travis RyanAbamectin is a blend of B1a and B1b avermectins that is being used as a seed treatment to control plant-parasitic nematodes on cotton. Data on the toxicity of abamectin and its effectiveness as a seed treatment to control Meloidogyne incognita or Rotylenchulus reniformis on cotton are lacking. The toxicity of abamectin was based on an assay of nematode mobility, LD50 values of 1.56 ?g/ml and 32.9 ?g/ml were calculated based on 2 hr exposure for M. incognita and R. reniformis, respectively. There was no recovery of either nematode after exposure for 1 hr to its LD50 concentration. Sublethal concentrations greater than 0.39 ?g/ml for M. incognita and 8.2 ?g/ml for R. reniformis reduced (P = 0.05) infectivity on tomato. In field trials, suppression (P = 0.05) of M. incognita was observed 32 DAP by abamectin seed treatment whereas no suppression of R. reniformis was observed. No suppression of M. incognita was perceived by abamectin seed treatment in microplots. Suppression of M. incognita was observed in microplots by harpinEA and harping?? as a seed treatment and foliar spray, respectively. Seed cotton yields were variable for abamectin-treated seed, but numerically positive for harpin-treated cotton. Initial gall formation on developing taproots was suppressed (P = 0.001), and penetration of 5-cm long taproots by M. incognita and R. reniformis was numerically suppressed by abamectin-treated compared to non-treated seed, but infection increased with root development. Using an assay of nematode mobility, the proportion of dead second-stage juveniles (J2) was higher (P = 0.05) following exposure to an excised radicle from abamectin-treated seed than non-treated seed, but lower (P = 0.05) than J2 exposed to the abamectin-treated seed coat. Thus a higher concentration of abamectin remained on the seed coat than emerging radicle. The concentration of abamectin transferred from the seed coat to the developing roots was limited, which contributed to the variability in suppression of plant-parasitic nematodes on cotton.Item Evaluation of chlorophyll fluorescence as a tool for the identification of drought tolerance in upland cotton(2009-05-15) Longenberger, Polly SuzanneA novel bioassay for the evaluation of plant water status was developed by Burke (2007). The research reported herein was designed to evaluate this new protocol as a tool for use in cotton breeding programs for the identification of drought tolerant genotypes. Twenty genotypes were selected to represent diverse germplasm pools for a two-year field evaluation. Replicated tests were performed in Lubbock, TX and College Station, TX in 2005, 2006, and 2007. Dryland and irrigated treatments were administered in a split plot arrangement of a randomized complete block design. Fluorescence measurements were taken at mid-bloom and late bloom growth stages of growth. Source leaf tissue was harvested at predawn and subjected to high temperature incubation with fluorescence measurements subsequently taken hourly for five hours. Drought stressed plants had not mobilized their carbohydrate reserves from their source leaves overnight and thus maintained cell viability and therefore higher chlorophyll fluorescence values throughout the incubation with the opposite being true for nonstressed plants. Fiber lint yield and fiber properties were measured at the conclusion of the 2005 season in College Station and the 2006 season in College Station and Lubbock for comparison with the fluorescence data. Five genotypes, ?Acala 1517-99?, ?Deltapine 491? (PVP no. 200100159), ?Tamcot CAMD-E?, ?Tamcot 22? and TAM 89E-51, an unreleased breeding line, were selected based on field evaluation results in a preliminary study in 2005 to be included in a diallel analysis to determine the heritability of fluorescence measurements. Genotype x treatment effects complicated the classification of genotypic responses to drought. Few and inconsistent correlations were found among fluorescence values and lint yield or fiber properties. The diallel analysis did not identify general combining ability or specific combining ability effects for chlorophyll fluorescence measurements. Thus this procedure provides little potential in selecting plants for drought tolerance when plants are grown under field culture. Selection among Tamcot 22 and TAM 89E-51 plants for high and low genotypes according to fluorescence values did not yield progeny different from unselected Tamcot 22 and TAM 89E-51.Item Evaluation of organophosphate insecticides on performance of transgenic and conventional cotton(Texas A&M University, 2005-08-29) Hundley, Christopher AlanGenetically modified cotton (Gossypium hirsutum L.) acreage has increased dramatically over the last six years. Reports of variable results in fiber quality and yield have arisen in these cultivars. Some changes in production practices have occurred coincident with the introduction of transgenic technology, such as reduced use of broad-spectrum insecticides, including organophosphates (OP) that could potentially influence the growth and yield of cotton. One factor that might affect these parameters is the difference in the amount of foliarly-applied phosphorus (P) between an OP and non-phosphate (NP) insecticide regime. Therefore, a study was conducted to investigate selected growth characteristics, yield, and fiber quality of genetically modified and conventional cotton as influenced by OP and foliar phosphorus (FP) applications. A four replication strip-plot experimental design was utilized with cultivar serving as the whole plot and insecticide regime as the sub-plot. Three cultivars of the same recurrent parent (ST4892BR, ST4793R, and ST474) were planted in 2001 and 2002 under irrigated conditions in Burleson County, TX on a Weswood silty clay loam (fine-silty, mixed, thermic Fluventic Ustochrept). The insecticide regime consisted of NP, NP+FP, and OP treatments. The FP was applied at P2O5 weight equivalent to the P component in the concurrent OP application. ST4892BR had greater lint yield than ST4793R and ST474. The yield increase can be explained through plant mapping analysis which showed ST4892BR producing larger bolls and greater boll numbers. In addition, evaluation of fruiting distribution showed ST4892BR contained more lint on sympodial branches 6 through 10. The insecticide regime effect on lint yield resulted in higher yield (P=0.08) for the NP+FP regime. Examination of yield components revealed NP+FP increased second position bolls, predominantly at sympodial branches 6 through 10. Leaf tissue analysis revealed increased levels of P for the OP and NP+FP over that of the NP insecticide regime, which indicates a potential for plants to acquire P from OP insecticides. Furthermore, the considerable yield response to small amounts of FP is not clearly understood. While conclusive evidence exists regarding cultivar yield differences, this study does not provide sufficient evidence to conclude that OP insecticides influence growth, yield, or fiber quality characteristics of these cotton cultivars.Item Evaluation of Testing Locations in Central and South Texas(2014-08-06) Al-Azzawi, RashaPerformance yield trials are some of the most expensive processes in a cotton breeding program. Cotton plots require a great deal of land, agronomic inputs, and plot-sample processing. Much of the equipment is expensive and specialized such as the harvesters, gins, and fiber measurement devices. Therefore it is important to only test strains and cultivars in the most distinguishing environments. Traditionally the best testing environment has been in the Mississippi Delta near Greenville, MS. More recently it has been thought that growing environments in Australia are allowing breeders there to distinguish high-yielding, broadly adapted genotypes. The program of the Cotton Improvement Lab at Texas A&M University in College Station, TX, regularly conducts performance trials throughout Central and South Texas. Several stability tests such as the ?cultivar superiority measure?, ?ecovalence? and ?stability variance? were used in AgroBase? to determine stability. Biplot analysis was also used to characterize testing locations. Based on data collected from 2008 to 2012 from the commercial cultivar tests, it was concluded that the high-yielding locations at Weslaco and College Station are the best locations at identifying cultivars with the highest yield potential, but many of the dryland locations are better locations for determining stable and repeatable fiber qualities. Cultivars such as Tamcot 73 and PHY 375 WRF that have been tested extensively in the region showed more stability in comparison to other cultivars in this study.Item Factors determining the adoption or non-adoption of precision agriculture by producers across the cotton belt(Texas A&M University, 2006-04-12) Lavergne, Christopher BernardThe purpose of this study was to determine factors influencing cotton producer adoption of Precision Agriculture in the cotton belt according to members of the American Cotton Producers of the National Cotton Council. The National Research Council??s Board on Agriculture defines Precision Agriculture (PA) as ??a management strategy that uses information technologies to bring data from multiple sources to bear on decisions associated with crop production.?? For the purpose of this study, Precision Agriculture technologies included yield monitors, global positioning units, variable rate applicators, and similar components. Many studies have found that adoption of Precision Agriculture can be profitable for agricultural producers. However, the fact that Precision Agriculture is relatively new and unproven hinders rapid adoption by agricultural producers. According to the National Research Council Board of Agriculture widespread adoption relies on economic gains outweighing the costs of the technology. This study attempted to find the factors associated with adoption of these technologies in the cotton belt. The sample population consisted of cotton producer representatives from the leading cotton-producing states. A Delphi approach was utilized to establish a consensus of cotton producer perceptions of the advantages of adopting Precision Agriculture technologies. Advantages included more accurate farming (i.e., row spacing, reduced overlap, and cultivation). Barriers to adoption were also documented, questioning employee capability to operate equipment, learning curve, technology complexity, and uncertain return on investment.Item Genetic Improvement of Upper Half Mean Length and Short Fiber Content in Upland Cotton, Gosspium hirsutum(2012-10-19) Beyer, BenjaminDesired base upper half mean length (UHML) of upland cotton (G. hirsutum) in the U.S. has been set a 27.0 mm and is shorter than the standard set by the international community. Upland cotton genotypes from China, South Africa, West Africa, and the U.S. were test crossed to an extra long staple upland (ELSU) and a short staple upland (SSU) and selected genotypes that included both ELSU and MSU phenotypes were crossed in a half-diallel mating scheme to estimate general combing ability (GCA) effects and specific combining ability (SCA) effects. A recombinant inbred line (RIL) population was established to determine the narrow sense heritability (h^2) of AFIS short fiber content by weight (SFCw) and lower half mean length (LHML) and to estimate SFCw using HVI fiber properties. Obsolete cultivars from China are not likely sources for UHML improvement, cultivars from Africa and the U.S. could harbor alleles not being used in current elite short staple cultivars or modern ELSU cultivars. Two ELSU lines used in this study derived through interspecific hybridization with G. barbadense could contain alleles for UHML improvement in modern ELSU cultivars developed without any apparent G. barbadense introgression. A third line D&PL 45-867, might contain alleles for UHML improvement in long staple upland cotton genotypes. Narrow sense heritability estimates indicated a much higher heritability of LHML than AFIS SFCw. Correlation between AFIS SFCw and LHML did not agree with previous studies when using an ELSU X MSU cross. Further study is needed to understand this complex relationship.Item Impact of Cotton Harvesting and Storage Methods on Seed and Fiber Quality(2012-02-14) Hamann, Mark ThomasThere are currently two main types of machinery used for harvesting cotton in the United States, cotton pickers and cotton strippers with or without field cleaners. These different machine types package seed cotton with varying amounts of burrs, sticks, and leaves. Harvested cotton is placed in modules for storage prior to ginning. Recent developments in the industry include on-board module builders that package seed cotton as they harvest. This leads to three methods of storage: 1) traditional seed cotton modules, 2) half-modules, and 3) round modules utilized by harvesters with on-board module builders; all of these have different levels of packaging density. Cotton is harvested under widely varying conditions throughout the country and the moisture content of seed cotton at the point of containerization can be an important factor in the final quality of the crop. Seed cotton is being stored for increasing periods of time before being processed by cotton gins. The number of cotton gins in the U.S. has decreased while the production of cotton has increased. All cotton is harvested as it matures and the harvesting rate greatly exceeds the ginning rate. As a consequence of fewer gins, increased harvesting rates and increased quantities of cotton, the storage time of seed cotton prior to ginning has increased. It is hypothesized that the impact of varying densities, varying trash contents, and increased storage times prior to ginning is impacting the quality of the cotton lint and seed. The goal of this research is to quantify the impacts of these factors. The purpose of this research is to evaluate the effects of packaging seed cotton from any of the three different harvesting methods into varying types of storage as a function of differing moisture content and increased storage time. Results are indicated in terms of quality of both the fiber and the seed of ginned samples, as well as how the quality changes affect the value of the processed cotton. Samples of seed cotton are sealed in plastic containers for up to three months at varying levels of moisture, density, and trash content. Temperature and oxygen levels are monitored during storage. Samples are ginned and cottonseed and fiber are analyzed. The results of this research indicate that density does not affect the final quality of the lint and seed harvested. Increased moisture contents have a negative effect on both the quality and the value of the seed cotton, and this effect becomes more pronounced as the length of storage increases.Item Improvement of Cotton Fiber Maturity and Assessment of Intra-Plant Fiber Variability(2012-10-19) Kothari, NehaThe temporal system of fruiting on the cotton plant lends itself to bolls at different fruiting sites developing under different environmental conditions and with varied source-sink relationships. To investigate this, intra-plant fiber quality was assessed in four upland cultivars at College Station, Texas for three years and at Lubbock, Texas for two years. It was concluded that fiber quality steadily declines from the bottom sympodial branches towards the upper branches. 'FiberMax 832' had the best fiber quality among all cultivars but it also had the highest degree of variability within the plants. 'Half and Half' and 'Acala 1517-99' appear to have the least amount of intra-plant variability of fiber quality. Bolls from the bottom region of the plant have higher trash content compared to the upper region. To test the impact of fiber quality variability on boll sampling techniques employed, ten sampling protocols were compared against each other for three years in College Station, Texas, for two upland cultivars. Results suggest that randomized boll samples containing 50 bolls worked well to estimate inherent fiber quality for most fiber traits while estimation of trash and lint percent was not predictable based on boll samples. One of the problems associated with intra-plant fiber variability was the presence of immature fibers. In order to determine the potential for improvement of fiber maturity and standard fineness, five upland cotton (Gossypium hirsutum L.) genotypes were subjected to a diallel analysis at College Station, Texas, in 2011. Four cultivars that tend to produce fine and mature fibers and one cultivar that tends to produce coarse fibers were intermated in all combinations, without reciprocals. Estimates of general (GCA) and specific combining ability (SCA) for fiber maturity ratio and standard fineness based on Griffing's diallel Model I, Method 4 were calculated for AFIS and fiber micronaire, length and strength measurements for High Volume Instrument (HVI). Four parents had significant GCA effects and Acala 1517-99 was found to be the best parent for improving standard fineness followed by FiberMax 832 and 'Tamcot HQ-95'. Tamcot HQ-95 was the best parent to improve fiber maturity ratio while 'Deltapine 90' was the best parent to reduce fiber maturity ratio. The specific cross between Acala 1517-99 and Tamcot HQ-95 had the best performance. Diallel analysis indicated that fiber maturity ratio was influenced by non-additive gene effects more than additive gene effects while fiber standard fineness was highly influenced by additive gene effects. Developing cultivars with optimal fiber standard fineness and maturity should be prioritized to address problems associated with neps and short fiber content and improve spinning performance of US cotton.Item Inheritance of cotton fiber length and distribution(Texas A&M University, 2006-10-30) Braden, Chris AlanFiber quality data from five upland cotton (Gossypium hirsutum L.) genotypes, which were grown at College Station, TX during 2001 and 2002, were subjected to diallel and generation means analyses to determine the potential for improvement of fiber length and to determine the inheritance of length distribution data. Four near-long staple (NLS) upland cotton genotypes and one short-staple genotype were crossed in all combinations, excluding reciprocals. Estimates of general (GCA) and specific combining ability (SCA) for fiber length based on Griffing??????s diallel Model I, Method 4 were calculated for high volume instrumentation (HVI) upper-half mean (UHM) fiber length and advance fiber information system (AFIS) mean fiber length by weight (FLw), mean fiber length by number (FLn), upper quartile length by weight (Uqlw), fiber length distribution cross entropy (using 3 different standard or check distributions - CEA, CEB, and CEC), fiber length distribution kurtosis (FLwKurt), and fiber length distribution skewness (FLwSkew) for FLw. Across environments, GCA effects were significant for fiber length measurements of UHM, FLw, FLn, Uqlw, and SFCw and distribution measurements of CEA, CEB, FLwKurt, and FLwSkew. On the basis of GCA effects, TAM 94L-25 was the best parent to be used in a cross to improve upland fiber length, while Acala 1517-99 was the parent of choice to improve distribution among the 4 parents tested. The inheritance of AFIS fiber length measurements and distribution data was estimated using parents, F1, F2, and backcross generations. The magnitude and significance of the estimates for non-allelic effects in the parental combinations suggest that epistatic gene effects are present and important in the basic mechanism of AFIS fiber length and length distribution inheritance for the populations studied. Gene effects and variances for all AFIS fiber length and distribution data measurements were inherited differently in different environments and specific parental combination, suggesting environmentally specific mechanisms. Developing genotypes with enhanced fiber length and an optimal fiber length distribution should be a priority to improve spinning performance and product quality of U.S. upland cotton.