The recent development and current status of research on the cotton weed in China were summarized, including the weed occurrence, distribution rule, population dynamics, weed damage and control techniques. Although the research on basic theory and chemical management technologies of cotton weed in China has got a faster development, problems of frequent herbicide injury, dominant weed population changes, lag in control techniques and deficiencies of transgenic resistant herbicide cotton still exit. Therefore, the study on basic theory should be strengthened. On the basis of chemical control, we should speed up the creation of novel chemical herbicide, strengthen the monitoring and management of herbicide resistant weeds, and carry out further research on biological weed control and herbicide resistant cotton.

Field experiment about cotton chemical and manual detopping was conducted in Akesu (41°17′N, 86°26′E), Xinjiang, with cultivar CCRI 49 as material, from 2008 to 2010. The chemical detopping agent contained slow-released mepiquat chloride and additives, and was applied at the same time as the manual detopping in cotton. The results indicated that the plants detopped by chemical agent were taller and narrower than those detopped by hands, which resulted in more light transmittance in middle and lower layer of cotton canopy. Additionally, chemical detopping did not alter the boll weight, but reduced the lint percent slightly. The boll number per plant and yield for chemical detopping were greater than those for manual detopping in 2010, but the same as the latter in 2009. There were no significant difference in comprehensive fiber quality between chemical detopping and manual detopping. It was concluded that the chemical detopping is a potential practice to replace the manual detopping in cotton in Xinjiang.

There are three phases of DNA fingerprint technology based on molecular marker：the first is RFLP based on Southern blot，the second are several markers based on PCR and the third is SNP（single nucleotide polymorphism）.Research and application of variety identification technology was discussed，four main molecular marker technologies applied in cotton variety identification were introduced in detail as follow:RFLP,RAPD,AFLP and SSR.Technology principle,research and application status,advantage and disadvantage about each molecular marker applied in cotton variety identification were expatiated.As compared，the viewpoint was put forward:SSR marker was the most appropriate molecular marker in cotton variety identification,and the necessity of construction of Chinese cotton DNA fingerprint database based on SSR marker technology was analyzed.

The dynamics of the activities of protective enzymes and MDA content in two kinds of genetically modified (GM) cotton varieties and their non-GM parents after being piercing-sucked by Lygus lucorum were studied. The results showed that: before and after the vaccination of Lygus lucorum, there were no significant difference on the activities of protective enzymes and MDA content between two kinds of GM cotton varieties and their non-GM parents, so it has no effect on physiological indices when exogenous genes were introduced into cotton. Throughout the period of Lygus lucorum's attacking, there was very significant difference in the activities of protective enzymes and MDA content to the same cotton variety; the three indicators, SOD, MDA and PAL activities or content, showed significant or very significant differences in the interaction effect between variety and bug accepting time, and the rest of the interaction was not significant.

Effects of nitrogen application rates and mepiquat chloride （DPC） sparing doses on content of chlorophyll and SPAD value in leaf of earliermiddle spring cotton variety Yuza 35 and shortseason one Yinshan 1 were studied.The results showed that content of chlorophyll and SPAD value in leaf of two cotton varieties increased with enhancing nitrogen application rates or DPC sparing doses.There were significantly positive correlations between SPAD value and content of chlorophyll in leaf in most growth stages.But content of chlorophyll in leaf decreased more quickly than SPAD value in later growth stage,i.e.,the content of chlorophyll in leaf in boll opening stage decreased significantly than that in full bolling stage, and the SPAD value in boll opening stage decrease slightly than that in full bolling stage.Therefore,SPAD value is still efficient to conduct leaf color threshold when DPC is applied to cotton,but attention should be paid to the different tendency of content of chlorophyll and SPAD value in later growth stage of cotton.

Based on the cotton pot experiment involving four varieties (three were upland cotton and one was sea island cotton) and two N treatments and field experiment with different N treatments,the spatial differences of N and Chlorophyll contents (SPAD value) in the four upper fully expanded leaves and their relationships with whole leaf and plant N concentration were investigated. The results showed that leaf N contents and SPAD values at different leaf positions differed obviously,leaf N contents and SPAD values increased and differences among different position leaves decreased at high N rates. The sensitivity of the fourth leaf from the top to N was the highest,and next was that of the second leaf from the top was the lowest,while that of the first and the third leaves varied within the varieties. The SPAD value of the fourth leaf from the top was most correlated with whole leaf and plant N concentration among the top four leaves through the bud stage,initialflowering stage. The CV of SPAD value of the fourth leaf from the top was the smallest under optimal N level. It was suggested that the fourth leaf from the top was the most ideal indicator when using SPAD value or leaf color difference to diagnose N status in cotton.

To investigated the effects of nitrogen rates on dry matter accumulation and distribution of bolls and fiber quality characteristics,field experiments were conducted in Nanjing (middle lower reaches of Yangtze River Valley) and Xuzhou (Yellow River Valley).The three N rates is 0,240 and 480 kg·hm^-2,standing for low,optimum and high nitrogen application level, respectively.The results showed that the effect degree of nitrogen rates on fiber was higher than that on seed or fiber.The decrease in seed/fiber ratio came from an allometric growth between seed and fiber,which could be expressed by the following equation: y=a+bx(x is the natural logarithm of cottonseed and y is the natural logarithm of fiber dry weight per boll,a is intercept and b is regression coefficient for the linear equation)."b" of the cotton bolls bloomed on Jul 25 was significantly declined under low-nitrogen or high-nitrogen treatment,fiber strength also decreased correspondingly. "b" of the cotton bolls bloomed on Sep 10 has a little difference between high-nitrogen treatment and medium-nitrogen treatment,but significantly higher than low-nitrogen treatment,and the indices of fiber length,strength and uniformity showed similar trends too.All the results indicated that the larger "b" is,the more favorable to form high fiber quality.

Cotton Verticillium wilt caused by Verticillium dahliae Kleb. has become one of the main impediments to cotton sustainable production in China in recent years．This disease is a soil-borne and seed-borne vascular disease and difficult to control. The host range of V. dahliae is unusually wide as a plant pathogen．This paper summarized the latest research progresses of the pathogenicity differentiation, genome sequence, pathogenesis mechanism, microsclerotial development and germination mechanism of V. dahliae, molecular mechanism of disease resistance in cotton as well as the control methods of cotton Verticillium wilt．

The experiment was conducted to evaluate the effects of transgenic Bt cotton on soil microbial community in 2006 under the field based on phospholipid fatty acid (PFLA) method.Three transgenic Bt cotton lines ( JM26,JM44 and CCRI41) and one non-Bt cotton line were used.The results showed transgenic Bt cotton increased amount of PFLA for soil microbe.Bt-cotton soils were characterized by the predominance of actinomycetes,fungi and eukaryotes in comparison with non-Bt cotton soil.In contrast,the microbial community was characterized by the predominance of Gram-positive bacteria in non-Bt cotton soil.Soil microbial community were characterized by the predominance of protoza and Gram-negative bacteria for Bt-cotton soils in square growth stage,and for non-Bt cotton soil in the open boll stage.PFLA anlysis was accepted as indicator for risk evaluation of transgenic Bt cotton on soil microbial community.

Cotton is one of the most economically important crops in China, and the improvement of cotton production technology and equipment has played a major role in cotton production. In a systematic manner this paper discusses developments in cotton production, considers how cultivation can be improved and analyzes favorable conditions from three perspectives: (1) national policy and capital supports; (2) present laws and regulations; and (3) the related public service system. We propose effective measures to improve cotton cultivation, and these will provide guidance for the sustainable development of China's cotton industry.

Core SSR primers were used for constructing DNA fingerprint database of cotton DUS testing standard varieties based on fluorescence detection system and multiplex PCR (polymerase chain reaction) technology, and the genetic diversity was analyzed. Ten sets of 4 multiplex PCR combinations were established according to fundamental principle of multiplex PCR and characteristic of fluorescent system. DNA genetic analyzer was used for construction of fingerprinting database. Among the 30 varieties, 40 primer pairs had 146 allelic variations, and 3.65 allelic variations were detected by each SSR primer pair on an average with the range from 2 to7. The number of homozygous loci and heterozygous loci is almost the same. Clustering analysis indicated that sea island cotton (Hai7124) and upland cotton varieties were obviously divided into two categories. Xinluzao1 from Xinjiang cotton region differed from other upland cotton varieties. Multiplex fluorescence detection system has many advantages such as high-precision, high-throughput, high degree of automation compared to conventional silver staining system, especially for construction of large-scale fingerprint database. A primary idea about the application of molecular marker technology in cotton DUS testing by the construction of fingerprinting database of known varieties was proposed.

In Xinjiang, the mechanical harvest cotton cropping model mainly applies 6 cotton rows with 2 dripping pipes under a plastic film mulching plantation pattern (plantation spacing 10 cm + 66 cm + 10 cm + 66 cm + 10 cm). To explore optimal irrigation scheduling of this cropping model, a field experiment was designed using different irrigation frequencies (F5 and F8) and water amounts (I80, I60 and I40). Cotton plant growth, yield, fiber quality and water use efficiency (WUE) were observed. The results showed that applying high-frequency and full or medium irrigation water amounts effectively controlled crop plant height, increased leaf area index and improved boll ratio in shoot biomass. With the same frequency, application of high or low water amounts was not beneficial to boll weight and yield improvement. When using the same water amount, however, high irrigation frequency increased seed cotton yield by 0.59 to 1.56 percent. Irrigation scheduling in this experiment had no significant effects on cotton fiber quality. Crop evapotranspiration (ET_c) and WUE were significantly affected by applied water amount, but they had no obvious connection with irrigation frequency. Applying high irrigation frequency(F5) and medium water amount (I60) was regarded as optimal irrigation scheduling under this cotton mechanical harvest cropping model in southern Xinjiang regions. This scheduling was 12 irrigations and about 300 mm water applied over the entire growth stage.

Ignoring the influence of soil, cultivation, and boll position, a preliminary model of cotton fiber quality was constructed based on important meteorological factors using multiple stepwise regression analysis of fiber quality data and meteorological factors between July and September 2006-2011, collected from 27 sites in major cotton-producing regions of China. The results showed that in all cotton-growing regions, fiber length was significantly affected by daily mean temperature, effective accumulated temperature above 12 ℃, and number of rain days; fiber strength was affected by daily mean minimum temperature; and fiber micronaire was affected by daily mean minimum temperature, number of rain days, and average relative humidity. In the Yellow River region, fiber length was significantly affected by daily mean temperature, average relative humidity, and precipitation, while fiber strength was affected by the number of rain days. In the Yangtze River region, fiber length was significantly affected by precipitation; fiber micronaire was affected by effective accumulated temperature above 12 ℃, and precipitation; and fiber grade was affected by daily minimum temperature and effective accumulated temperature above 12 ℃. In the Northwest region, fiber length was significantly affected by the number of sunshine hours and precipitation; fiber strength was affected by effective accumulated temperature above 12 ℃; and fiber micronaire was affected by the numbers of both sunshine hours and rain days. We conclude that meteorological factors greatly affect cotton fiber quality and thus quantification of their relationships would be important for climatic regionalization and optimization of cotton-producing areas.

Field experiments were conducted in three sites to study the effects of plant pruning mode (with or without vegetative branches) and plant density (2.7×10⁴, 3.3×10⁴, 3.9×10⁴, 4.5×10⁴ plants·hm^-2) on yield and fiber quality of cotton in a garlic-cotton intercropping system in southwestern Shandong province. The results showed that pruning mode, planting density or their interaction had no significant effect on cotton fiber quality, but there existed a significant interaction effect of pruning mode and planting density on cotton yield. Three combinations, 3.3×10⁴ plants·hm-2 with vegetative branches(VB), 2.7×10⁴ plants·hm^-2 with VB, and 3.3×10⁴ plants·hm^-2 without VB, improved lint yield by 20.4%, 9.2% and 10%, respectively, compared with the traditional cultivation method(2.7×10⁴ plants·hm^-2 without VB). They were also significantly higher than other treatment combinations in lint yield. Increased plant density, maitaining VB or their combination significantly increased biomass, but decreased the harvest index. Compared with traditional cultivation method, 3.3×10⁴ plants·hm^-2 with VB,  2.7×10⁴ plants·hm^-2 with VB and 3.3×10⁴ plants·hm^-2 without VB increased biomass by 13.7%, 27.8% and 11.6%, decreased harvest index by 5.3%, 11.5% and 4.5%, respectively. Significant improvement on lint yield by the three combinations was attributed to the increased biomass and total number of bolls per unit area on the basis of maintaining relatively higher harvest index and boll weight. It is concluded that appropriate increase in plant density combined with maintaining VB is an important practice to improve cotton yield and benefit in the garlic-cotton intercropping system.

This paper reviewed cotton fiber quality and its evaluation method in china. We discussed research progress of cotton color feature index e.g. fiber light reflection ratio (Rd) and fiber yellowness (+b), and compared with traditional fiber classification such as visual grade, fiber length, strength and fineness. We also analyzed the effects of ecological climatic factors on the cotton fiber quality, and the correlation between cotton fiber quality index and cotton color feature index. The results indicated the importance of application of cotton color feature in demand of standard cotton quality test. We proposed to build a new classification system of cotton quality, using GIS platform, ecological index and cotton color feature to evaluate and forecast the spacial distribution of cotton fiber quality.

Based on the data of annual accumulated temperature of ≥10 ℃, July mean temperature and frost-free period from 52 meteorological stations in northern Xinjiang during 1961―2012, the spatial distributions of heat resources were analyzed by using mixed interpolation method based on ArcGIS, the change trends of heat elements were studied by using the linear regression method, and the variations in different periods of 1961―1970, 1971―1980, 1981―1990, 1991―2000 and 2001―2012 were analyzed also. Based on the above analyses, the cotton-planting climate zoning for northern Xinjiang in different periods were completed respectively with the climate indicators of cotton-planting zoning. And the variation of areas suitable, secondly suitable, risk and unsuitable for cotton in different periods were contrasted and analyzed. The main results were as follows: Heat resource was very obviously different in different regions of northern Xinjiang, generally, annual accumulated temperature of ≥10 ℃, July mean temperature and frost-free period were higher or longer in plain and basin areas than in mountain areas. In the background of global warming, the three indicators showed an increasing trend with rates of 75.657 ℃, 0.218 ℃and 4.36 d every 10 years respectively in recent 52 years. Under the joint effects of the above-mentioned climate factors, the areas suitable for cotton planting had a substantial expansion, and the areas secondly suitable and unsuitable for cotton reduced to different extents, but the areas risk for cotton planting did not change significantly. Compared with 1960s, the areas suitable for cotton planting increased 6.54164×10⁴ km², and the areas risk and unsuitable for cotton reduced by 0.99982×10⁴ km² and 5.28675×10⁴ km² respectively in 2001―2012. It is important to promote the development of cotton industry in the areas suitable for cotton planting increased in northern Xinjiang.