Domestic Cotton Research Articles

Properties of TiAl/TiAlN/TiAlCN Films Deposited by Arc Ion Plating on GCr15 Rings

Ring is one of the major textile spinning machine consumable part, it has an important influence on yarn quality and cost. Ring of domestic cotton spinning enterprises generally has poor hardness, bad accuracy, not durable and difficult to guarantee the quality of the yarn, foreign ring has excellent performance, but it is too expensive, so it is difficult to widely used in China[1]. Vacuum arc ion plating technology has a wide range of applications in the aerospace, automobile, mold, tool, electronics and other fields [2-3]. TiN film which is prepared by arc ion plating technology has been widely used because of the TiN film has poor oxidation resistance and wear resistance at high temperatures, so the ternary films are developed on TiN film, such as TiAlN [4], TiCN etc. Traveller circle in the ring on the slide to produce large amounts of heat, it makes the ring surface temperature reach 400°C. When higher than 400°C, the TiCN film failure, therefore, ring should not be plated on the TiCN films. While TiAlN film oxidation temperature reaches 800°C. In HSS twist drill, depositing of TiAlN film can improve the service life more than four times [5]. Studies [6-8] have found that using pulsed laser deposition and chemical vapor deposition technique to prepare TiAlCN film, its wear resistance, high temperature stability is better. Pulsed laser deposition is mainly used in laboratory research. It is difficult to deposit a large area uniform film. Chemical vapor deposition of deposition rate is less than the arc ion plating, and produces lots of waste gas, leading to the environment is polluted. Arc ion plating technology can deposit the uniform films of large area with high deposition rate and deposition with no environmental pollution, therefore, this study, by means of vacuum arc ion plating technology to prepare high-precision, long-life and low-cost domestic cotton spinning ring. In order to obtain the best film process parameters, the performance of film is investigated at different bias and arc current.

Comparative Evolutionary and Developmental Dynamics of the Cotton (Gossypium hirsutum) Fiber Transcriptome

The single-celled cotton (Gossypium hirsutum) fiber provides an excellent model to investigate how human selection affects phenotypic evolution. To gain insight into the evolutionary genomics of cotton domestication, we conducted comparative transcriptome profiling of developing cotton fibers using RNA-Seq. Analysis of single-celled fiber transcriptomes from four wild and five domesticated accessions from two developmental time points revealed that at least one-third and likely one-half of the genes in the genome are expressed at any one stage during cotton fiber development. Among these, ∼5,000 genes are differentially expressed during primary and secondary cell wall synthesis between wild and domesticated cottons, with a biased distribution among chromosomes. Transcriptome data implicate a number of biological processes affected by human selection, and suggest that the domestication process has prolonged the duration of fiber elongation in modern cultivated forms. Functional analysis suggested that wild cottons allocate greater resources to stress response pathways, while domestication led to reprogrammed resource allocation toward increased fiber growth, possibly through modulating stress-response networks. This first global transcriptomic analysis using multiple accessions of wild and domesticated cottons is an important step toward a more comprehensive systems perspective on cotton fiber evolution. The understanding that human selection over the past 5,000+ years has dramatically re-wired the cotton fiber transcriptome sets the stage for a deeper understanding of the genetic architecture underlying cotton fiber synthesis and phenotypic evolution.

中国棉花期货市场价格发现功能的实证研究

本文用相关性分析、单位根检验、协整检等分析方法，实证分析中国棉花期货市场的价格发现功能。结果显示，我国棉花期货市场成立近10年来，期货市场价格发现功能已经初步具备，但由于我国棉花期货市场成立时间较短，国内涉棉企业参与较少等原因，在价格形成方面有待于进一步完善。Based on correlation analysis, unit root test and co-integration test, this paper empirically analyzes the price discovery function of China’s Cotton Futures Market. The result shows that the cotton futures market initially has the price discovery function with the market having been established nearly 10 years. However, the price forming needs to be further improved because of the short developing history and little participation of domestic cotton related enterprises.

The feasibility of replacing the sliding scale duty with cotton subsidies in China

PurposeThis paper aims to determine whether domestic cotton support permitted by the current or potential World Trade Organization (WTO) rules would be sufficient to compensate the cost to China's cotton farmers if the sliding scale duty (SSD) on cotton imports is removed.Design/methodology/approachThe simulation was conducted using a static spatial equilibrium model (SEM) of the world cotton market. First, a base model was specified to provide a good representation of the world cotton market's conditions. Second, simulations were conducted to evaluate the effects of replacing the SSD and subsidizing cotton producers pursuant to the current or potential WTO rules on domestic cotton support.FindingsThe results of the simulations suggest that China's cotton farmers are bound to incur losses. In either case, cotton subsidies permitted by the current or potential WTO rules are not sufficient to compensate for the cost to China's cotton producers if the SSD is eliminated.Research limitations/implicationsIt should be pointed out that these findings could suffer from a bias, primarily because the authors assumed that the WTO's blue box subsidies have no incentives for farmers to produce, and no substitution between cotton and alternative products. Thus, additional work is needed to reflect a more realistic situation in future studies.Originality/valueThe simulation estimation contributes to a better understanding of the issue of whether China should replace the current SSD with cotton subsidies to protect cotton producers.

Repeated polyploidization of Gossypium genomes and the evolution of spinnable cotton fibres

Polyploidy often confers emergent properties, such as the higher fibre productivity and quality of tetraploid cottons than diploid cottons bred for the same environments. Here we show that an abrupt five- to sixfold ploidy increase approximately 60 million years (Myr) ago, and allopolyploidy reuniting divergent Gossypium genomes approximately 1-2 Myr ago, conferred about 30-36-fold duplication of ancestral angiosperm (flowering plant) genes in elite cottons (Gossypium hirsutum and Gossypium barbadense), genetic complexity equalled only by Brassica among sequenced angiosperms. Nascent fibre evolution, before allopolyploidy, is elucidated by comparison of spinnable-fibred Gossypium herbaceum A and non-spinnable Gossypium longicalyx F genomes to one another and the outgroup D genome of non-spinnable Gossypium raimondii. The sequence of a G. hirsutum A(t)D(t) (in which 't' indicates tetraploid) cultivar reveals many non-reciprocal DNA exchanges between subgenomes that may have contributed to phenotypic innovation and/or other emergent properties such as ecological adaptation by polyploids. Most DNA-level novelty in G. hirsutum recombines alleles from the D-genome progenitor native to its New World habitat and the Old World A-genome progenitor in which spinnable fibre evolved. Coordinated expression changes in proximal groups of functionally distinct genes, including a nuclear mitochondrial DNA block, may account for clusters of cotton-fibre quantitative trait loci affecting diverse traits. Opportunities abound for dissecting emergent properties of other polyploids, particularly angiosperms, by comparison to diploid progenitors and outgroups.

Homoeolog expression bias and expression level dominance in allopolyploid cotton

Allopolyploidy is an evolutionary and mechanistically intriguing process, in that it entails the reconciliation of two or more sets of diverged genomes and regulatory interactions. In this study, we explored gene expression patterns in interspecific hybrid F(1), and synthetic and natural allopolyploid cotton using RNA-Seq reads from leaf transcriptomes. We determined how the extent and direction of expression level dominance (total level of expression for both homoeologs) and homoeolog expression bias (relative contribution of homoeologs to the transcriptome) changed from hybridization through evolution at the polyploid level and following cotton domestication. Genome-wide expression level dominance was biased toward the A-genome in the diploid hybrid and natural allopolyploids, whereas the direction was reversed in the synthetic allopolyploid. This biased expression level dominance was mainly caused by up- or downregulation of the homoeolog from the 'non-dominant' parent. Extensive alterations in homoeolog expression bias and expression level dominance accompany the initial merger of two diverged diploid genomes, suggesting a combination of regulatory (cis or trans) and epigenetic interactions that may arise and propagate through the transcriptome network. The extent of homoeolog expression bias and expression level dominance increases over time, from genome merger through evolution at the polyploid level. Higher rates of transgressive and novel gene expression patterns as well as homoeolog silencing were observed in natural allopolyploids than in F(1) hybrid and synthetic allopolyploid cottons. These observations suggest that natural selection reconciles the regulatory mismatches caused by initial genomic merger, while new gene expression conditions are generated for evaluation by selection.

Population Structure and Genetic Diversity of the Boll Weevil (Coleoptera: Curculionidae) onGossypiumin North America

AbstractAlthough the boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), is a devastating pest in the United States and Mexico, its population structure and genetic diversity in Mexico on wild and cultivated cotton hosts (genus Gossypium) is poorly understood. Past studies using morphology, host use, and distribution records suggest that A.grandis grandis comprises three forms with host-associated characteristics: the southeastern form (from domesticated Gossypium hirsutum L., southeastern United States and northeastern Mexico), the thurberia form (from Gossypium thurberi Todaro, Arizona and northwestern Mexico), and the Mexican form (from multiple Gossypium species and other malvaceous plant genera in the remainder of Mexico and Central America). However, the phylogenetic relationships, host preferences, and distributions of these forms are not completely understood. An alternative hypothesis of an eastern and western form of the boll weevil is suggested by the suspected phylogeographic range expansion from an ancestral distribution in the tropics northward along both Mexican coasts, culminating in the maximally contrasting phenotypes observed in the northeastern and northwestern arms of the current distribution. In this study, we sequenced one mitochondrial and four nuclear genes to gain insight into the evolutionary relationships among the putative forms and their distributions on wild and domesticated cotton hosts. Using models of evolution, we compared the three-form to the two-form classification and to two alternative classifications that incorporate geography and host use traits. The genetic data at most loci provide stronger support for the two-form than the three-form hypothesis, with an eastern and western group separated by the Sierra Madre Occidental mountain range. They do not support separate taxonomic status for boll weevils developing on G.thurberi.

Geminivirus-Mediated Delivery of Florigen Promotes Determinate Growth in Aerial Organs and Uncouples Flowering from Photoperiod in Cotton

BackgroundPlant architecture and the timing and distribution of reproductive structures are fundamental agronomic traits shaped by patterns of determinate and indeterminate growth. Florigen, encoded by FLOWERING LOCUS T (FT) in Arabidopsis and SINGLE FLOWER TRUSS (SFT) in tomato, acts as a general growth hormone, advancing determinate growth. Domestication of upland cotton (Gossypium hirsutum) converted it from a lanky photoperiodic perennial to a highly inbred, compact day-neutral plant that is managed as an annual row-crop. This dramatic change in plant architecture provides a unique opportunity to analyze the transition from perennial to annual growth.Methodology/Principal FindingsTo explore these architectural changes, we addressed the role of day-length upon flowering in an ancestral, perennial accession and in a domesticated variety of cotton. Using a disarmed Cotton leaf crumple virus (CLCrV) as a transient expression system, we delivered FT to both cotton accessions. Ectopic expression of FT in ancestral cotton mimicked the effects of day-length, promoting photoperiod-independent flowering, precocious determinate architecture, and lanceolate leaf shape. Domesticated cotton infected with FT demonstrated more synchronized fruiting and enhanced “annualization”. Transient expression of FT also facilitated simple crosses between wild photoperiodic and domesticated day-neutral accessions, effectively demonstrating a mechanism to increase genetic diversity among cultivated lines of cotton. Virus was not detected in the F1 progeny, indicating that crosses made by this approach do not harbor recombinant DNA molecules.ConclusionsThese findings extend our understanding of FT as a general growth hormone that regulates shoot architecture by advancing organ-specific and age-related determinate growth. Judicious manipulation of FT could benefit cotton architecture to improve crop management.

Microsatellite loci for Gossypium davidsonii (Malvaceae) and other D‐genome, Sonoran Desert endemic cotton species

Microsatellite primers previously developed for domesticated cotton (Gossypium hirsutum; tetraploid) were screened for their utility in investigating genetic structure and gene flow within G. davidsonii and five other wild, Mexican, D-genome cotton species (all diploid). We screened 50 microsatellite primer pairs from the Cotton Marker Database, identifying 10 loci as polymorphic within G. davidsonii. In genotyping approximately 200 individuals from four populations, we found that the number of alleles per locus ranged from seven to 17, and mean observed and expected heterozygosity ranged from 0.145 to 0.492 and from 0.436 to 0.734, respectively. We genotyped six to 20 individuals from each of the remaining species, finding these 10 loci to cross-amplify in all cases and in most cases to be polymorphic. These markers may be useful for further investigation of population genetics of G. davidsonii and other wild D-genome cotton species.

Molecular evolution and phylogenetic analysis of genes related to cotton fibers development from wild and domesticated cotton species in Gossypium

The domestication of both diploid and tetraploid cotton species was carried out for fiber utilization. To understand the origin and domestication of fibers, 18 genes related to fiber development were individually cloned and sequenced from 22 different cotton species. Their structures, phylogenetic relationship and molecular evolution were further studied. In the orthologous and homeologous loci of the 18 genes, the sequence and structure of 72.22% were conserved and 27.78% were diverse. Tree topologies constructed based on the combined sequences showed that all 13 D-genome species were congruent with Fryxell’s subsection taxonomy, the A- and D-subgenomes independently evolved in the allopolyploid after polyploid formation, and Gossypium raimondii had the closest relationship with all allotetraploids of D-subgenomes. The molecular evolutionary rates revealed approximately equivalent rates among different D-genome species, and purifying selection acted on all genes in the wild D-genome species. Among orthologs and homeologs, the D-subgenomes had higher evolutionary rates than the A-subgenomes in tetraploid cotton species, and the cultivars had higher evolutionary rates than either the semi-domesticated or wild species. Our study revealed that human domestication altered the molecular evolutionary pattern of genes related to fiber development, and Gossypium hirsutum endured greater selective pressures than Gossypium barbadense during the domestication process.

Parallel up-regulation of the profilin gene family following independent domestication of diploid and allopolyploid cotton ( Gossypium )

Cotton is remarkable among our major crops in that four species were independently domesticated, two allopolyploids and two diploids. In each case thousands of years of human selection transformed sparsely flowering, perennial shrubs into highly productive crops with seeds bearing the vastly elongated and abundant single-celled hairs that comprise modern cotton fiber. The genetic underpinnings of these transformations are largely unknown, but comparative gene expression profiling experiments have demonstrated up-regulation of profilin accompanying domestication in all three species for which wild forms are known. Profilins are actin monomer binding proteins that are important in cytoskeletal dynamics and in cotton fiber elongation. We show that Gossypium diploids contain six profilin genes (GPRF1-GPRF6), located on four different chromosomes (eight chromosomes in the allopolyploid). All but one profilin (GPRF6) are expressed during cotton fiber development, and both homeologs of GPRF1-GPRF5 are expressed in fibers of the allopolyploids. Remarkably, quantitative RT-PCR and RNAseq data demonstrate that GPRF1-GPRF5 are all up-regulated, in parallel, in the three independently domesticated cottons in comparison with their wild counterparts. This result was additionally supported by iTRAQ proteomic data. In the allopolyploids, there This usage of novel should be fine, since it refers to a novel evolutionary process, not a novel discovery has been novel recruitment of the sixth profilin gene (GPRF6) as a result of domestication. This parallel up-regulation of an entire gene family in multiple species in response to strong directional selection is without precedent and suggests unwitting selection on one or more upstream transcription factors or other proteins that coordinately exercise control over profilin expression.

Gene expression in developing fibres of Upland cotton (Gossypium hirsutum L.) was massively altered by domestication

BackgroundUnderstanding the evolutionary genetics of modern crop phenotypes has a dual relevance to evolutionary biology and crop improvement. Modern upland cotton (Gossypium hirsutum L.) was developed following thousands of years of artificial selection from a wild form, G. hirsutum var. yucatanense, which bears a shorter, sparser, layer of single-celled, ovular trichomes ('fibre'). In order to gain an insight into the nature of the developmental genetic transformations that accompanied domestication and crop improvement, we studied the transcriptomes of cotton fibres from wild and domesticated accessions over a developmental time course.ResultsFibre cells were harvested between 2 and 25 days post-anthesis and encompassed the primary and secondary wall synthesis stages. Using amplified messenger RNA and a custom microarray platform designed to interrogate expression for 40,430 genes, we determined global patterns of expression during fibre development. The fibre transcriptome of domesticated cotton is far more dynamic than that of wild cotton, with over twice as many genes being differentially expressed during development (12,626 versus 5273). Remarkably, a total of 9465 genes were diagnosed as differentially expressed between wild and domesticated fibres when summed across five key developmental time points. Human selection during the initial domestication and subsequent crop improvement has resulted in a biased upregulation of components of the transcriptional network that are important for agronomically advanced fibre, especially in the early stages of development. About 15% of the differentially expressed genes in wild versus domesticated cotton fibre have no homology to the genes in databases.ConclusionsWe show that artificial selection during crop domestication can radically alter the transcriptional developmental network of even a single-celled structure, affecting nearly a quarter of the genes in the genome. Gene expression during fibre development within accessions and expression alteration arising from evolutionary change appears to be 'modular' - complex genic networks have been simultaneously and similarly transformed, in a coordinated fashion, as a consequence of human-mediated selection. These results highlight the complex alteration of the global gene expression machinery that resulted from human selection for a longer, stronger and finer fibre, as well as other aspects of fibre physiology that were not consciously selected. We illustrate how the data can be mined for genes that were unwittingly targeted by aboriginal and/or modern domesticators during crop improvement and/or which potentially control the improved qualities of domesticated cotton fibre.See Commentary: http://www.biomedcentral.com/1741-7007/8/137

Cotton domestication: dramatic changes in a single cell

Investigations on the nature of genetic changes underpinning plant domestication have begun to shed light on the evolutionary history of crops and can guide improvements to modern cultivars. A recent study focused on cotton fiber cells tracks the dramatic genome-wide changes in gene expression during development that have accompanied selection for increased fiber yield and quality.See Research article: http://www.biomedcentral.com/1741-7007/8/139

Current state of the cotton and textile industry in Kazakhstan

The textile industry of Kazakhstan is presented basically by enterprises created in period of centrally planned economy and as consequence. Low labor productivity, lacking equipment base and technologies, poor marketing are problems of the current state of industry. But, there are also advantages as a vicinity of potential cotton manufacturers - Uzbekistan, Tajikistan, Turkmenistan. A free economic zone (FEZ) “Ontustik” has been established and a program of “Ontustik” FEZ development has been adopted for developing the cotton and textile cluster in Kazakhstan. The law “About development of the cotton branch” has been adopted in Kazakhstan to provide the textile enterprises with necessary raw material and to develop the domestic cotton growing.

Parallel expression evolution of oxidative stress-related genes in fiber from wild and domesticated diploid and polyploid cotton (Gossypium)

BackgroundReactive oxygen species (ROS) play a prominent role in signal transduction and cellular homeostasis in plants. However, imbalances between generation and elimination of ROS can give rise to oxidative stress in growing cells. Because ROS are important to cell growth, ROS modulation could be responsive to natural or human-mediated selection pressure in plants. To study the evolution of oxidative stress related genes in a single plant cell, we conducted comparative expression profiling analyses of the elongated seed trichomes ("fibers") of cotton (Gossypium), using a phylogenetic approach.ResultsWe measured expression changes during diploid progenitor species divergence, allopolyploid formation and parallel domestication of diploid and allopolyploid species, using a microarray platform that interrogates 42,429 unigenes. The distribution of differentially expressed genes in progenitor diploid species revealed significant up-regulation of ROS scavenging and potential signaling processes in domesticated G. arboreum. Similarly, in two independently domesticated allopolyploid species (G. barbadense and G. hirsutum) antioxidant genes were substantially up-regulated in comparison to antecedent wild forms. In contrast, analyses of three wild allopolyploid species indicate that genomic merger and ancient allopolyploid formation had no significant influences on regulation of ROS related genes. Remarkably, many of the ROS-related processes diagnosed as possible targets of selection were shared among diploid and allopolyploid cultigens, but involved different sets of antioxidant genes.ConclusionOur data suggests that parallel human selection for enhanced fiber growth in several geographically widely dispersed species of domesticated cotton resulted in similar and overlapping metabolic transformations of the manner in which cellular redox levels have become modulated.

Global analysis of gene expression in cotton fibers from wild and domesticated Gossypium barbadense

Gossypium barbadense is widely cultivated because of its extra-long staple cotton with superior luster, silkiness and high yield. These economically important traits were selected during initial domestication of an agronomically inferior wild ancestor, followed by millennia of human-mediated selection. To reveal the effects of this history on the cotton fiber transcriptome, we conducted comparative expression profiling on mechanically isolated fiber cells at three different stages encompassing early, mid, and late fiber elongation in wild (K101) and domesticated (Pima S-7) accessions, using a microarray platform that interrogates 42,429 unigenes. The distribution of differentially expressed genes across developmental stages was different in the two accessions, with a shift toward greater change earlier in cultivated than in wild G. barbadense. Approximately 4200 genes were differentially expressed between wild and domesticated accessions at one or more of the stages studied. Domestication appears to have led to enhanced modulation of cellular redox levels and the avoidance or delay of stress-like processes. Prolonged fiber growth in cultivated relative to wild G. barbadense is associated with upregulation of signal transduction and hormone signaling genes and down-regulation of cell wall maturation genes. Clues are provided into the processes and genes that may unwittingly have been selected by humans during domestication and development of modern elite lines. Several of the transcriptomic differences between wild and domesticated G. barbadense described here appear to have parallels in a second domesticated cotton species, Gossypium hirsutum, suggesting that replicated domestication of two different species has resulted in overlapping, parallel, metabolic transformations.

The effects of MFA quota elimination on Indian fibre markets

This article examines the effects of multi-fibre arrangement (MFA) quota elimination on Indian fibre market. The partial equilibrium Indian fibre model was developed using a theoretically consistent framework and incorporated regional supply response, substitutability between cotton and man-made fibres, and appropriate linkage between cotton and textile sectors. Baseline projections were developed for supply, demand and prices of cotton, man-made fibres and textiles under a set of exogenous assumptions. The effects of MFA textile quota eliminations were introduced into the model by conducting three scenarios, i.e. increasing textile exports by 10, 20 and 30% from the baseline level. The results suggest that on an average, cotton imports rise by 4–8% annually, while the man-made fibre exports from India decline with the opening of textile markets in the developed countries. The higher domestic cotton prices encourage acreage expansion in cotton in all the three regions in India, but not enough to meet rising mill demand under the scenarios of higher textile exports. The rise in cotton imports from India has little effect on world cotton prices.

The Evolution of Spinnable Cotton Fiber Entailed Prolonged Development and a Novel Metabolism

A central question in evolutionary biology concerns the developmental processes by which new phenotypes arise. An exceptional example of evolutionary innovation is the single-celled seed trichome in Gossypium (“cotton fiber”). We have used fiber development in Gossypium as a system to understand how morphology can rapidly evolve. Fiber has undergone considerable morphological changes between the short, tightly adherent fibers of G. longicalyx and the derived long, spinnable fibers of its closest relative, G. herbaceum, which facilitated cotton domestication. We conducted comparative gene expression profiling across a developmental time-course of fibers from G. longicalyx and G. herbaceum using microarrays with ∼22,000 genes. Expression changes between stages were temporally protracted in G. herbaceum relative to G. longicalyx, reflecting a prolongation of the ancestral developmental program. Gene expression and GO analyses showed that many genes involved with stress responses were upregulated early in G. longicalyx fiber development. Several candidate genes upregulated in G. herbaceum have been implicated in regulating redox levels and cell elongation processes. Three genes previously shown to modulate hydrogen peroxide levels were consistently expressed in domesticated and wild cotton species with long fibers, but expression was not detected by quantitative real time-PCR in wild species with short fibers. Hydrogen peroxide is important for cell elongation, but at high concentrations it becomes toxic, activating stress processes that may lead to early onset of secondary cell wall synthesis and the end of cell elongation. These observations suggest that the evolution of long spinnable fibers in cotton was accompanied by novel expression of genes assisting in the regulation of reactive oxygen species levels. Our data suggest a model for the evolutionary origin of a novel morphology through differential gene regulation causing prolongation of an ancestral developmental program.

EFFECTS OF CHINESE CURRENCY REVALUATION ON WORLD FIBER MARKETS

A partial equilibrium model is used to analyze effects of Chinese currency revaluation on world fiber markets. Unique characteristics of this model include incorporation of a regional supply response of cotton, substitutability between cotton and manmade fibers, and linkage between raw fiber and textile sectors. Simulation results show renminbi revaluation is likely to increase China’s fiber imports and lower domestic cotton prices. Internationally, the world cotton price, polyester price, and cotton trade are expected to increase. A scenario modeling currency devaluation in China is run to test the stability of the model and ascertain its accordance with economic theory. (JEL F17, F42, F47, O2) With a view to establish and improve the socialist market economic system in China, enable the market to fully play its role in resource allocation as well as to put in place and further strengthen the managed floating exchange rate regime based on market supply and demand, the People’s Bank of China, with authorization of the State Council, is hereby making the following announcements regarding reforming the RMB exchange rate regime: Starting from July 21, 2005, China will reform theexchangerateregimebymovingintoamanaged floating exchange rate regime based on market supply and demand with reference to a basket of currencies. RMB will no longer be pegged to the U.S. dollar and the RMB exchange rate regime will be improved with greater flexibility.

Fusarium Wilt of Cotton: Population Diversity and Implications for Management.

Fusarium wilt of cotton, caused by the fungus Fusarium oxysporum Schlechtend. f. sp. vasinfectum (Atk.) Snyd. & Hans, was first identified in 1892 in cotton growing in sandy acid soils in Alabama (8). Although the disease was soon discovered in other major cotton-producing areas, it did not become global until the end of the next century. After its original discovery, Fusarium wilt of cotton was reported in Egypt (1902) (30), India (1908) (60), Tanzania (1954) (110), California (1959) (33), Sudan (1960) (44), Israel (1970) (27), Brazil (1978) (5), China (1981) (17), and Australia (1993) (56). In addition to a worldwide distribution, Fusarium wilt occurs in all four of the domesticated cottons, Gossypium arboretum L., G. barbadense L., G. herbaceum L., and G. hirsutum L. (4,30). Disease losses in cotton are highly variable within a country or region. In severely infested fields planted with susceptible cultivars, yield losses can be high. In California, complete crop losses in individual fields have been observed (R. M. Davis, unpublished). Disease loss estimates prepared by the National Cotton Disease Council indicate losses of over 109,000 bales (227 kg or 500 lb) in the United States in 2004 (12).