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Wheat is one of the three major staple foods in the world. Although wheat is highly nutritional, it has a variety of allergenic components that are potentially fatal to humans and pose a significant hazard to the growth and consumption of wheat. Wheat allergy is a serious health problem, which is becoming more and more prevalent all over the world. To address and prevent related health risks, it is crucial to establish precise and sensitive detection and analytical methods as well as an understanding of the structure and sensitization mechanism of wheat allergens. Among various analytical tools, mass spectrometry (MS) is known to have high specificity and sensitivity. It is a promising non immune method to evaluate and quantify wheat allergens. In this article, the current research on the detection of wheat allergens based on mass spectrometry is reviewed. This review provides guidance for the further research on wheat allergen detection using mass spectrometry, and speeds up the development of wheat allergen research in China. [ABSTRACT FROM AUTHOR]

Common bunt disease of wheat in China is caused mainly by Tilletia foetida. However, reliable approaches for determining disease-associated biochemical markers are rarely reported. Here, a headspace-solid-phase microextraction coupled with headspace GC-tandem mass spectrometry (HS-SPME-GC-MS) was used to screen volatile substances in infected wheat, and an optimal chemical marker was selected to establish analytical methods for disease determination. Non-targeted screening of 13 volatile compounds unique to diseased wheat allowed a metabolite with rotten fish-like smell, trimethylamine (TMA), to be selected as the inspection marker. Subsequently, two analytical methodologies, HS-SPME-GC-MS and headspace gas chromatography with flame ionization detection (HS-GC-FID), were established to determinate the TMA content in wheat. The linear relationship, recovery and reproducibility of the methods were validated. The limit of detection (LOD) was 0.02 µg/kg for the former method, 5000-fold lower than that for the latter. When analysing samples, HS-SPME-GC-MS showed excellent sensitivity and allowed for the determination of 0.05% infected kernels among whole wheat grains. Therefore, TMA determination using HS-SPME-GC-MS is an effective alternative method to detect wheat common bunt disease occurring at extremely low infection rate. [ABSTRACT FROM AUTHOR]

The dissipation and residues of trifloxystrobin and tebuconazole in wheat under field conditions were investigated using high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) after QuEChERS extraction. The method was validated using blank samples spiked at different treatment levels. The recovery rates of trifloxystrobin, trifloxystrobin acid, and tebuconazole in wheat grains, wheat plants, and straw ranged from 82% to 109%. The relative standard deviations (RSDs) ranged from 0.4% to 14%. The half–lives of trifloxystrobin and tebuconazole in wheat plants were 5.8–7.6 and 6.1–8.9 d. A terminal residue analysis showed that a dose of 144 g a.i. ha−1 applied twice at an interval of 7 d resulted in the maximum residue levels for trifloxystrobin and tebuconazole in wheat grain samples 28 d after the last application (i.e. 0.023 mg kg−1 and 0.047 mg kg−1, respectively). The median residue levels were 0.02 mg kg−1 and 0.01 mg kg−1, respectively. The risk quotients (RQ) for trifloxystrobin and tebuconazole in wheat grains were 0.0011 and 0.00073, respectively, which were significantly lower than RQ = 1. The total RQ values for trifloxystrobin and tebuconazole in all registered crops were 0.10415 and 0.36859, respectively, which were also lower than RQ = 1. Based on this analysis, trifloxystrobin and tebuconazole residues in wheat grains would not affect the health of the general population in China. [ABSTRACT FROM AUTHOR]

Improvements in grain yield and nitrogen (N)-use efficiency (NUE) are being sought to combat the excessive application of N fertilizer in the rice-wheat rotation system in China. Improving N-uptake efficiency (NUpE) is expected to explore the synergy of grain yield and NUE, but the accumulation and remobilization of N in wheat with high NUpE is still obscure. A 2-year field experiment was conducted to study how to improve NUpE through crop management of planting densities, N application splits, and wheat growth stages when the last N was topdressed. In both years, NUpE was significantly positively related to grain yield and NUE. Comparing with the low and medium NUpE groups (grouping the treatments using cluster analysis of NUpE), the high NUpE group had more total N accumulation as a result of absorbing abundant N from re-greening (Zadoks growth stage, GS25) to anthesis (GS60), and higher N accumulation in grains mainly due to increasing N remobilization from the vegetative organs. Our results indicated that improving the planting density (from 150 to 225 plants m−2) promoted N accumulation before stem elongation (GS30). Late application of more N fertilizers (N application splits 3:1:3:3 versus 5:1:2:2) and relatively early application of the last N portion [topdressing when the flag leaf was visible (GS37) or at booting (GS45) versus topdressing at heading (GS55) or anthesis] boosted N accumulation from stem elongation to anthesis. Finally, a combination of agronomic measures was proposed to achieve high yield and NUE through promoting pre-anthesis N accumulation and NUpE. [ABSTRACT FROM AUTHOR]

Studies on subsequent effects of Cu pollution on mineral nutrients uptake in different tissues of crops grown in sierozem are limited. A pot experiment was conducted to reveal the effects of exogenous Cu on the accumulation and translocation of Cu and the interaction with nutrients in different tissues of wheat in Cu-polluted sierozem in northwest China. Results showed that the average concentration of Cu in different tissues of wheat was roots > stems and leaves > grains > shells. The bioaccumulation factor (BCF) of Cu in different parts of wheat was roots > stems and leaves > grains > shells. There was a weak translocation of Cu from sierozem to tops of wheat. Furthermore, the translocation ability of Cu from roots to tops of wheat was increasingly weak with increasing Cu stresses. Micronutrients (Fe, Mn and Ca) distribution in different wheat tissues indicated that uptake and upward translocation of these kinds of micronutrients could be affected by high soil Cu concentration. The addition of Cu in sierozem promoted the Mn absorption in wheat tissues, which may also be helpful to solve the lack of Mn in wheat caused by the Cu shortage in sierozem. [ABSTRACT FROM AUTHOR]

Developing agricultural mechanization services has been an important approach to pushing smallholder farmers engaging modern agricultural production in China. However, whether smallholder farmers prefer adopting agricultural mechanization services is still under-analysed. In this paper, we use data covering 3,440 wheat farmers collected from Henan province in China to investigate the links between farm size and the adoption of agricultural mechanization services. The results indicate that an inverted U-shaped relationship between farm size and the adoption of agricultural mechanization services exists. We also find that small farms can input more family labour, and large farms tend to invest in self-owned machinery assets. Our analysis implies that the development of agricultural mechanization services is not inevitable to attract farmers with alternative elements, and smallholder farmers may not be the major groups involved in the market of social services in agriculture in the future. [ABSTRACT FROM AUTHOR]

Winter wheat is a staple food crop for most of the world's population, and the area and spatial distribution of winter wheat are key elements in estimating crop production and ensuring food security. However, winter wheat planting areas contain substantial spatial heterogeneity with mixed pixels for coarse- and moderate-resolution satellite data, leading to large errors in crop acreage estimation. This study has developed a phenology-based approach using moderate-resolution (1 km per pixel) satellite data to estimate sub-pixel planting fractions of winter wheat. Based on unmanned aerial vehicle (UAV) observations, the unique characteristics of winter wheat with high vegetation index values at the heading stage (May) and low values at the ripening stage (June) were investigated. The differences in vegetation index between heading and ripening stages increased with the planting fraction of winter wheat, and therefore the planting fractions were estimated by comparing the NDVI differences of a given pixel with those of predetermined pure winter wheat and non-winter wheat pixels. This approach was evaluated using aerial images and agricultural statistical data in an intensive agricultural region, Shandong Province in North China. The method explained 85% and 60% of the spatial variation in municipal- and county-level statistical data, respectively. More importantly, the predetermined pure winter wheat and non-winter wheat pixels can be automatically identified using MODIS data according to their NDVI differences, which strengthens the potential to use this method at regional and global scales without any field observations as references. [ABSTRACT FROM AUTHOR]

A pot experiment was conducted to study chemical speciations and bioavailability of cadmium (Cd) and lead (Pb) in the gray calcium soil from northwestern China, and accumulation and translocation of Cd and Pb in wheat (Triticum aestivum L.) grown on the soil was also studied. The results showed that significant changes of Cd and Pb fractions in the soil and Cd and Pb concentrations in the wheat were observed with increasing soil Cd and Pb concentrations, and both Cd and Pb in exchangebale fraction in the soil made the greatest contribution to the accumulation of Cd and Pb in the wheat. Higher bio-concentration factors (BCFs) and translocation factors (TFs) for Cd and lower BCFs and TFs for Pb were observed in the wheat, respectively, and Cd had much higher accumulation than Pb in the edible parts of the wheat. Therefore, Cd has higher risk than Pb when people eat the wheat. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the Al dietary exposure of young Chinese children aged 0–3 years via formulae, complementary foods and wheat-based foods. Al residue data were obtained from the national food contamination monitoring programme from 2013 to 2016, encompassing 13,833 samples of 12 food items with a detection rate of 76.0%. Food consumption data were gathered from the China National Food Consumption Survey conducted in 2015, comprising 20,172 children aged 0–3 years old. The mean dietary exposure to Al for the general population of young Chinese children was estimated at 0.76 mg/kg bw/week, which does not exceed the PTWI. The 97.5th percentile intakes of Al reached 3.42 mg/kg bw/week, more than 1.7 times the PTWI. Wheat-based foods contributed 80.5% of the Al intake for the general population of young Chinese children, while formulae and complementary foods accounted for 19.5% of the total intake. The dietary intake of Al from formulae and complementary foods accounted for 6.0% and 1.6% of PTWI, respectively. These findings suggested that dietary exposure to Al among the general population of young Chinese children was lower than the PTWI and that there are no health concerns related to this level of Al intake. However, more attention should be placed on the health risks associated with Al exposure from wheat-based foods for young consumers with high food consumption in China (97.5th percentile) [ABSTRACT FROM AUTHOR]

The negative impact of rapid urbanization in developing countries has led to a deterioration of urban and regional air quality. Much attention has been given to the impact of fine particulate pollution on urban public health. However, very little attention has been given to its impact on the regional ecosystem such as the agricultural ecosystem. Thus, we evaluate the direct impact of air pollution on the reduction of wheat photosynthesis by fine particulate matter (PM2.5) pollution in the world’s most heavily polluted area, the North China Plain, using remote sensing observations and ground measurements. We found the following to be true: (1) Heavy PM2.5 pollution could significantly reduce wheat photosynthesis and cause an expositional relationship between the PM2.5 concentration and wheat photosynthesis (R2 = 0.9824, P < 0.05); (2) Heavy PM2.5 pollution makes up 2% for the reduction in wheat photosynthesis at all wheat-plant farmlands in the North China Plain, approximately covering an area of 354,400 km2; (3) Increasing heavy PM2.5 pollution significantly reduced wheat photosynthesis by 87% in wheat-planted farmland during 1999-2011. We hope the results presented here could draw attention to the effect of PM2.5 pollution on the agricultural ecosystem and encourage further studies to evaluate the feedback of atmospheric pollution on the agricultural ecosystem using remote sensing. Abbreviation: Northern China Plain (NCP); normalized difference vegetation index (NDVI); The Moderate Resolution Imaging Spectroradiometer (MODIS); fine particulate matter (PM2.5) [ABSTRACT FROM AUTHOR]

Field trials were carried out during 2011-2013 in three locations on 10 wheat genotypes. Traits that were investigated included grain weight, grain-filling duration, grain-filling rates and the lag phase from flowering to the commencement of effective grain filling. The grain-filling duration and rate were fitted by Richard’s equation in thermal time (growing degree-days (GDD), base temperature 9ºC). A combined ANOVA across environments showed that the grain weight was mainly affected by genotype, while most of the other grain-filling characters were influenced by the environment and G × E interactions. Grain filling lasted between 362 to 400 GDD and included a lag phase that ranged from 67 to 86 GDD. Both the effective and maximum rates of grain filling ranged from 0.12 to 0.15 mg GDD−1 and 0.18-0.22 to GDD−1, respectively. The lag phase was positively correlated with grain weight and rates of grain filling, whereas days to anthesis were significantly negatively correlated with the lag phase and both rates of grain filling. Temperature during grain filling was negatively correlated with the lag phase. The variation in grain weight was positively associated with the rate of grain filling, which, in turn, was related to the grain number per unit area. A compensating variability existed among the genotypes in both the grain number and grain-filling rate. The study of genotypic stability demonstrated that Chuanmai42 and Chuanmai104 had high grain weight and stability among most of the grain-filling parameters, and also had high grain yield. Chuanmai42 and Chuanmai104 were the best genotypes for improving the yield potential and grain weight stability. [ABSTRACT FROM AUTHOR]

Fifty different kinds of wheat from 10 provinces in China were chosen as samples to be milled into flour. Dumpling wrappers were made from the flour and their texture qualities and rheological properties, disulfide content, sulfhydryl content, and gluten secondary structure were determined. The web structure formed by the gluten was observed under scanning electron microscopy. These results showed that the flour’s rheological properties, apart from extensibility, were significantly correlated with several aspects of the texture of the dumpling wrapper, and the degree of softening showed negative correlations, most closely with the texture quality of the dumpling wrapper. Disulfide played an important role in forming the gluten web, its content showing significant correlations with the rheological properties of the flour and the texture quality of the dumpling wrapper. The disulfide content in gluten was positively correlated with the hardness and quality of the cooked product; the sulfhydryl content showed no significant correlations with the rheological properties of the flour and the texture of the dumpling wrapper. The gluten secondary structure showed some correlation with the rheological properties of the dough, but little with the texture quality of the dumpling wrapper. Under observation by scanning electron microscopy, the weak structure was loose with large interspaces, while the strong structure was compact with few interspaces. [ABSTRACT FROM AUTHOR]

The use of a new controlled-loss-fertilizer (CLF) to reduce nitrogen loss from the Danjiangkou Reservoir of China was explored. Specifically, a three-year experiment was conducted to identify the optimum fertilizer rate for CLF used in wheat production. The treatments included four CLF levels, 20% (20% F), 35% (35% F), 50% (50% F), and 100% (100% F), of the local recommended fertilization dose (LRFD), and traditional fertilizers with the same dose as 50% F as the control (CF). Treatment 50% F with an equivalent fertilizer rate decreased nitrogen (N) runoff loss and leaching loss by 21.6% and 24.5%, while leading to a 9.8% increase in soil residual mineral N when compared to CF. Treatments 50% F and 100% F produced higher wheat yield than the other treatments. At the same fertilizer rate, the grain yield of the 50% F treatment was 5.5% higher than that of CF. Regression analysis of the yield relative to the CLF rate revealed that the optimum CLF rate was about 77% of the LRFD. Overall, the results indicate that CLF with 77% of the LRFD could be the optimum rate for minimizing nitrogen loss and increasing yield and should be considered for wheat production in the area. [ABSTRACT FROM AUTHOR]

Oral cancer is keeping its 4th rank on the death causing cancers among Taiwan males, and its metastatic and recurrent rates remain high and a life-threatening issue to the citizens. Fermented wheat germ extract (AVEMAR) is used in clinical cancer nutritional therapy in gastrointestinal cancers but not in oral cancer yet. In this study, the potential of AVEMAR to inhibit tumor proliferation and metastasis of oral cancer was first investigated. Antiproliferative activity of AVEMAR was determined in human oral squamous carcinoma SCC-4 cells by MTT methodology. Wound-healing migration, transwell invasion, and Western blotting assays were carried out to examine the in vitro antimetastatic effects and involved signaling molecules for AVEMAR in oral cancer cells. AVEMAR at 0.2–1.6 mg/ml significantly inhibited the cell viability with IC50values of 1.19 and 0.98 mg/ml for 24-h and 48-h treatment. Furthermore, AVEMAR could induce cell apoptosis and inhibit the migration and invasion of metastatic SCC-4 cells at a similar dose range. Notably, AVEMAR suppressed the expression of matrix metalloproteinase (MMP)-2 and urokinase plasminogen activator (u-PA), but not MMP-1 or MMP-9, in SCC-4 cells. These results strongly support the antiproliferation and in vitro antimetastatic capacity of AVEMAR which may extend its contributions from cancer nutrition supplements to preventive agent for oral cancer. [ABSTRACT FROM AUTHOR]

Crop production in the dryland farming areas of northern China is constrained by low and variable rainfall. This article presents the analysis of the relationships between variations in rainfall and yields of winter wheat and spring maize. The analysis is based on data from both several short-term and our ongoing long-term field experiments in dryland farming research projects in Tunliu, Linfen, Shouyang, and Luoyang. Grain yields of wheat and maize ranged from 1,548 to 5,169 and from 2,612 to 8,789 kg ha-1respectively, with differences up to above 200% (between dry and wet years). Wheat yields are sensitive to growing season rainfall but also correlated to water use (ET), whereas maize yields are sensitive to the critical time of water supply (especially June rainfall) but not correlated to ET. The ratio of grain yields to soil water at sowing is an important indicator, showing close relationships between yields and soil water-related ratio within the rainfed crops site. Comparison between the indices of water use efficiency (WUE) and precipitation use efficiency (PUE) suggests that the index WUE is more grain-related indicator than the PUE used for assessing rainfed crop water use by both maize and wheat. The index PUE should be used in caution, especially for wheat crops in dry years. Our results indicate that options to alleviate crop moisture stress must be tailored to the rainfall pattern. This holds especially for conservation tillage with response nutrient management practices that aim at enhancing water use efficiency. [ABSTRACT FROM AUTHOR]

Excessive use of nitrogen fertilizer in crop production in China leads to environmental problems, and farmers’ lack of knowledge is the primary constraint. The public extension system, however, lacks the accountability and capability to deliver ecoagricultural extension services to farmers. Previous studies show that extension staff had little incentive to deliver extension services because they were overwhelmed by assigned non-extension activities. By applying a combined incentive scheme of cash rewards and political motivation on extension agents from 2009 to 2010, we found that knowledge training effectively reduced nitrogen use by 7% with no impact on yields in wheat production in two locations in Shandong Province, a major grain production region in north China. As such, improving nitrogen management has a great potential for a low-carbon agriculture in China and should be included into the extension program. However, the effectiveness of the training depends largely on the institutional capacity of the local extension system, which varies by region. In counties where extension employees were overwhelmed by assisting township administrations, a pure economic incentive without a long-term commitment was not effective. In the future, China faces challenges with delivering low carbon technologies through the existing agricultural extension system. [ABSTRACT FROM AUTHOR]

Recent emphasis on the recovery of plant remains from archaeological sites in East Asia permits an analysis of prehistoric cultural contact between East and West. Here we evaluate three prominent hypotheses for the introduction of wheat, a Near Eastern domesticate, to East Asia, specifically northern China. Existing evidence points to a nearly synchronous appearance of the plant, from the Inner Asian Mountains to the Yellow Sea, c. 4600–4200 years ago. Archaeological data, including the spatial distribution of directly dated wheat grains, argue against a wave of wheat-farming colonists, but point to the gradual in situ adoption of novel exotics by a diverse array of pre-existing agricultural peoples. Logic borrowed from the diffusion of innovations literature accounts for the near synchronous appearance of wheat over an enormous area, and allows for the occasional observation of anomalously older evidence without having to imagine such evidence as the origin of the diffusion. [ABSTRACT FROM AUTHOR]

To explore effective and ecofriendly means of controlling wheat flag smut (WFS) using biocontrol agents, three endophytic strains (58-2-1, 37-1 and YC-1) ofBacillussp. were isolated from winter wheat plants in China and identified asBacillus thuringiensisbased on their 16S rDNA sequences as well as phenotypic characteristics. Four morphological (leaf length, root length, dry weight and tiller numbers) and one physiological [root vigour (RV)] parameters of wheat plants treated by strains 58-2-1 and 37-1 were significantly enhanced compared to the control. The soluble sugar contents in the roots of wheat samples treated by the two strains were significantly lower than the control. The resistance of wheat varieties to WFS was investigated by inoculation tests. Of the 12 wheat varieties tested, 6 (Yunhan-618, Bainongaikang-58, Kaimai-20, Zhengmai-9023, 04-zhong-36 and Yanzhan-4110) were identified as WFS-highly resistant (HR), 3 (Pumai-9, Jinboshi-1 and Yunong-202) WFS-moderately resistant (MR), 1 (Yubao-1) WFS-susceptible (S) and 2 (Yumai-012 and Yunong-416) WFS-highly susceptible (HS) varieties. TheUrocystis tritici-induced yield loss on the S/HS varieties was significantly higher than that on the HR/MR ones. The strains 58-2-1 and 37-1 had control efficacies of 6.7–100% (av.54.8%) and 33.3–100% (av. 66.5%) on 9 and 7 out of 12 varieties, respectively. The strains 58-2-1 and 37-1 had enhanced yields of 10.2–54.9% (av. 32.9%) and 2.8–43.4% (av. 24.8%) on 10 and 8 out of 12 varieties, respectively. This is the first report on endophyticB. thuringiensisstrains isolated from wheat plants with the abilities to suppress WFS and to enhance yields on multiple wheat varieties. [ABSTRACT FROM AUTHOR]

Water scarcity and nitrate contamination in groundwater are serious problems in the North China Plain (NCP). The objective of this study was to compare the effects of farmer's practice and optimal water and nitrogen management on nitrate leaching, and water and nitrogen use efficiencies (WUE, NUE) during winter wheat season in the NCP. A winter wheat experiment with four treatments (traditional irrigation plus traditional fertilizer, W1N1; traditional irrigation plus optimal fertilizer, W1N2; optimal irrigation plus traditional fertilizer, W2N1; optimal irrigation plus optimal fertilizer, W2N2) was conducted from October 1999 to June 2001 in Beijing suburban. The soil–plant system, water and solute transport model was calibrated and validated based on the data collected from the experimental field, then the model was used to simulate the water movement, nitrogen (N) transport, and crop growth process. The results showed that the simulated soil water content, nitrate concentration in the soil profile, leaf area index, crop N uptake, and grain yield were all in good agreement with the measured data. The simulated results indicated that the improved management of water and fertilizer practice could increase crop yield, and reduce water drainage, nitrate leaching, and gaseous N loss compared to farmers' practice. WUE and NUE under improved practice were 1.36 kg m−3and 34.9 kg kg−1N−1in 2000, 1.07 kg m−3and 31.5 kg kg−1N−1in 2001, respectively. Compared to farmers' practice, the optimal management practice can save water about 4–19%, water drainage decreased 50–65%, N leaching reduced over 90% and gaseous N loss decreased about 70%, at same time leading to an increase in WUE and NUE by 10.6% and 10.3% in 2000, 64.5% and 98.3% in 2001, respectively. [ABSTRACT FROM AUTHOR]

A pot experiment was conducted to study the bioaccumulation and translocation of cadmium (Cd) in wheat (Triticum aestivum L.) and maize (Zea mays L.) grown in the Cd-polluted oasis soil in northwest China. The results showed that Cd in the unpolluted oasis soil was mainly bound to carbonate fraction (F2) and Fe-Mn oxide fraction (F3). However, a marked change of the Cd fractionation was observed with increasing soil Cd concentrations, where the concentrations of Cd in F1 (exchangeable fraction), F2 and F3 increased significantly (P< 0.001 for F1, F2 and F3). The correlation analysis between the fraction distribution coefficient (FDC) of Cd in the soil and Cd concentration accumulated in the two crops showed that Cd in F1 fraction in the oasis soil made the greatest contribution on the accumulation of Cd in the two crops. Higher bioconcentration factors (BCF) of Cd were observed in the two crops' shoots compared with grains, and low translocation factors (TF) of Cd in the grains were observed for both crops. Cd had a higher accumulation in the edible parts of the wheat, but lower accumulation in those of the maize. Therefore, wheat grown in Cd-polluted oasis soil has a higher risk to human health, whereas maize has a lower risk suggesting that wheat is not suitable for cultivation as crop and consumption by humans in the Cd-polluted oasis soil, but that maize is suitable for plantation. [ABSTRACT FROM AUTHOR]

The article focuses on the past success and future challenges related to food security of China. It mentions that China's farm sector met the food needs for nearly 22 percent of world's population with only seven percent earth's arable land and states that increasing population along with the expansion of the economy has brought a challenge to China to feed its growing middle class. Several charts are presented depicting rice and wheat production in China by region and consumption of soybeans.

The article presents a study on assessing genetic diversity and changes of bread wheat using agronomic traits and microsatellite markers in Qinghai Province, China. It also studied the average value of plant height, effective spikelets per ear and internode length under spike. It also discusses the use of 189 microsatellite markers to examine genetic diversity at a molecular level which showed the average number of alleles, genetic diversity index and allelic richness.

Flaveria bidentis (L.) Kuntze, an invasive plant, poses a serious threat to the structure and function of the native ecosystem in Hebei Provience, China. However, little is known about the allelopathic activity of the residues of this plant species. In this study, the impact of the phytotoxicity of unburnt (UR) and burnt (BR) residues of the exotic invasive weed on the growth of wheat (Triticum aestivvm L.) was assessed. Extracts prepared from both UR and BR reduced the shoot length, root length and dry weight of wheat significantly compared with the control, thereby indicating the presence of some water-soluble allelochemicals in F. bidentis residues. Growth studies conducted in soil amended with UR and BR extracts or residues also revealed phytotoxic effects towards wheat. A significant amount of phenolics was detected in the residue extracts and in residue-incorporated soil. The phenolic content rose with increasing residue concentration, thereby showing their direct involvement in the observed growth inhibition. The inhibition of wheat growth by the burnt residue and its water extracts was similar to that of unburnt residue, so burning it is not a good way to eliminate the allelopathic effects of the residue of F. bidentis on native plants. [ABSTRACT FROM PUBLISHER]

Soil contamination with heavy metals can lead to losses in agricultural yield and affect human health as the metals enter the food chain, which has become a worldwide problem. Compared with other heavy metals, lead (Pb) contamination is high because of its long persistence in soil and highly toxic effects on crop production and human health. Wheat is the world's most widely grown cereal and can be cultivated in a wide range of soils. Recently, wheat has been grown widely in northern China. The aims of the present studies are to investigate the effect of Pb on antioxidative metabolisms and chlorophyll synthesis of wheat 'Jinan No. 17.' Moreover, calcium ion (Ca2+) levels and bioaccumulation of Pb in the leaves of wheat were investigated. The soil was artificially contaminated with different concentrations of Pb [0, 100, 500, and 2000 Pb mg kg-1 dry weight (DW) soil as lead nitrate, Pb(NO3)2]. The catalase (CAT) activity and glutathion (GSH), chlorophyll a, chlorophyll b, and total chlorophyll contents in the leaves of wheat were analyzed with a spectrophotometer at different stages of wheat growth. Calcium levels and bioaccumulation of Pb in the leaves of wheat were studied with inductively coupled plasma sector field mass spectrometry (ICP-SF-MS). The results indicated that Pb stress can increase the content of GSH in leaves of wheat, thereby affecting the activity of CAT. Both low and high concentrations of Pb stimulated chlorophyll synthesis at early stages of wheat growth and inhibited chlorophyll synthesis at later stages of wheat growth. Furthermore, Ca and Pb in leaves of wheat increased with increasing concentrations of Pb on day 34 as determined with ICP-SF-MS. [ABSTRACT FROM AUTHOR]

Two strains of Fusarium sinensis sp. nov. were isolated from the seeds and roots of wheat (Triticum aestivum L.) in Shandong Province, China. They are superficially similar to F. dlaminii in producing fusiform-to-reniform and napiform microconidia and chlamydospores in almost the same size range as F. dlaminii. However the colonies and chlamydospores of F. sinensis resemble those of species in sections Roseum, Gibbosum and Discolor. Phylogenetic analysis of partial translation elongation factor 1α (EF-1α) sequence data indicates that F. sinensis is closely related to but distinct from the F. avenaceum/F. tricinctum/F. acuminatum species complex. [ABSTRACT FROM AUTHOR]

A long-term double cropping wheat (Triticum aestivum L.) and corn (Zea mays L.) experiment was conducted at Qiyang, Hunan, China, to study the effects of inorganic fertilizers on grain yields and soil properties and to identify the possible causes of yield trends. Six treatments of unfertilized control, N, NP, NK, PK, and NPK were included. The treatments (N, NP, NK, and NPK) where inorganic nitrogen (N) was added showed significant (P<0.05) yield declines of 76 to 114 kg ha-1 yr-1 for wheat and 94 to 260 kg ha-1 yr-1 for corn, respectively, except for corn yield in the NPK treatment in which the decline was not significant during a 15-yr (1990-2005) period. Comparatively, the decline amounts in corn were much higher than in wheat. The yields of wheat and corn remained unchanged in the PK treatment. The total organic carbon (C), total N, phosphorus (P), and available P, potassium (K), copper (Cu), and zinc (Zn) contents of soil were either increased or decreased during the study period. Both the decreases of exchangeable calcium (Ca2+) and magnesium (Mg2+) and increases of exchangeable hydrogen (H+) and Al3+ contents of soil in the treatments where inorganic N was applied were significant (P<0.05). The same four treatments showed significant pH declines ranging from 0.07 to 0.12 yr-1. Several lines of evidence point to decline of soil pH due to inorganic N fertilizer added as leading to the overall yield decline of wheat and corn. However, the yields of both crops increased significantly after lime application. In the long term, the farmers should be encouraged to use adequate lime based on a balanced approach to ensure sustainable productivity. [ABSTRACT FROM AUTHOR]

CO2 flux was measured continuously using the eddy covariance technique in a wheatmaize rotation system in the North China Plains from October 2002 to October 2006. The annual and seasonal variation of ecosystem respiration and the bio-environmental controls on them were investigated. The results show that ecosystem respiration (Rec) in the cropland increased exponentially with soil temperature at 5 cm depth. The temperature sensitivity coefficient (Q10) for ecosystem respiration varied from 3.5 to 5.4 for wheat and from 2.4 to 4.5 for maize. In the wheat growing season, monthly average R0 (ecosystem respiration at 0°C) increased linearly with soil temperature and logarithmically with leaf area index (LAI). Monthly average Q10 decreased logarithmically with R0. Residual Rec was significantly correlated with LAI. After considering LAI, the modified Q10 model could estimate Rec better than before. The simulation results show that annual ecosystem respiration in the wheat-maize rotation system in the North China Plains was 1327, 1348, 1040 and 1171 gC m-2 yr-1 for the 4 years of the study. As a 4-year average, seasonal mean ecosystem respiration in wheat (2.60 gC m-2 day-1) was much lower than in maize (6.09 gC m-2 day-1). However, integrated ecosystem respiration for the wheat growing season (566 gC m-2) was slightly higher than that for maize (520 gC m-2). These account for 46.4 and 42.6% of the annual values, respectively. [ABSTRACT FROM AUTHOR]

Site-specific nitrogen (N) fertilizer management based on soil Nmin (soil mineral N) and the plant N status (sap nitrate analysis and chlorophyll meter (SPAD) reading test) has been shown to be effective in decreasing excessive N inputs for winter wheat in the North China Plain, but the multiple sampling of soil and plants in individual fields is too time-consuming and costly for producers and farmers. In this study, a color digital camera was used to capture wheat canopy images at a specific growth stage to assess N needs. Treatments included a farmer's N treatment (typical farmer practice), an optimum N treatment (N application based on soil-plant testing), and four treatments without N (one to four cropping seasons without any N fertilizer input). Digital images were analyzed to get red, green, and blue color-band intensities for each treatment. Normalized intensities of the red, green, and blue color bands were well correlated with soil Nmin, SPAD readings, sap nitrate concentration, and total N concentration of winter wheat. This research indicated the potential of using a digital camera as a tool combined with an improved Nmin method to make N fertilizer recommendations for larger fields. [ABSTRACT FROM AUTHOR]

Conserving irrigation water resources is a most important measure for sustainable wheat production in the North China Plain. In the present study, the effect of phosphorus (P) application for saving irrigation water was evaluated. The application of fertilizer P increased nitrogen and phosphorus uptake, shoot biomass, head number, seed number and, consequently, grain yield, and increased soil water use and seasonal evapo-transpiration. The lower the volume of irrigation water applied, the more obvious were these effects. When winter wheat was basally fertilized with 88.5 kg P 2 O 5 /ha and irrigated with 90 mm at the jointing stage, the highest fertilizer P use efficiency, apparent P recovery and net profit (due to irrigation and/or fertilizer P) were obtained. The results suggested that fertilizer P should be used for saving irrigation water resources in the North China Plain. [ABSTRACT FROM AUTHOR]

Studies a major gene for resistance to carbendazim in field isolates of Gibberella zeae in China. Sensitivity levels among isolates; Phenotypic characterization of carbendazim resistance; Inheritance of technical grade carbendazim resistance in asexual and self-crossed reproduction.

Wheat samples of the 1998 and 1999 crops from Puyang, an area in Henan Province, PR China with a previous human red mould intoxication episode, were analysed for trichothecenes and zearalenone (ZEA). For the 1998 Puyang crop, deoxynivalenol (DON) was the predominant toxin detected abundantly and frequently at a level of up to 14000 μgkg[sup -1] (mean 2850 μgkg[sup -1]) in 30 of 31 (97%) wheat samples. Among these were 21 (70%) with a DON level that exceeded the Chinese regulation of 1000 μgkg[sup -1]. Nivalenol (NIV) and 15-acetyl-DON (15-ADON) were also found at 578 μgkg[sup -1] (one sample) and 59- 1800 μgkg[sup -1] (mean 365 μgkg[sup -1], 20 samples), respectively. ZEA co-occurred in 21 samples at 9- 1400 μgkg[sup -1] (mean 209 μgkg[sup -1]). Twenty-five (89%) wheat samples from Zhumadian, a region without a history of human red mould intoxication in the same province, contained low levels of DON (53-1240, mean 223 μgkg[sup -1]) with seven (25%) co-contaminated with ZEA (10-217, mean 108 μgkg[sup -1]). All were free from 15-ADON and NIV. Significant differences in DON, 15-ADON and ZEA concentrations between both areas were found. DON (<1000 μgkg[sup -1]) and ZEA (5-113 μgkg[sup -1]) were also detected in the 1999 Puyang wheat. Proper environmental conditions for Fusarium species surviving winter combined with unusual high precipitation during wheat flowering were responsible for a high concentration of Fusarium mycotoxins in the 1998 Puyang wheat. [ABSTRACT FROM AUTHOR]

Spectra of wheat measured in the field in an oil-bearing area north of Changyi, south of the Yellow River delta in eastern China, were analysed to study the relations between spectral characteristics and hydrocarbon microseepage. Along two transects over known petroleum reservoirs, ethane gas contents measured in soil show high values above the oil-water contacts and faults. Delta carbonate contents also showed high values at these contacts. Both features are indicative of hydrocarbon microseepage. The red-edge positions of wheat spectra were calculated and found to be positioned at 744.43nm in areas of microseepage and 738.26nm in areas with no microseepage; a 7nm shift to longer wavelength (red shift). Furthermore, a regression analysis of the red-edge inflection point positions versus delta carbonate and ethane shows a statistically significant correlation indicating a possible relation between microseepage and spectral properties of wheat. This research demonstrates that at a field scale remote sensing can potentially be used to detect hydrocarbon microseepages in areas of agricultural monoculture. [ABSTRACT FROM AUTHOR]

Psathyrostachys huashanica Keng belongs to the genus Psathyrostachys within the Gramineae family, is a rare and endangered herb plant endemic to China. In the current work, we first developed its whole chloroplast (cp) genome sequence. The cp genome of P. huashanica is 136,632 bp in size, including a large single copy (LSC) region of 81,803 bp, a small single copy (SSC) region of 12,763 bp, and a pair of inverted repeats (IRs) of 21,033 bp. The genome contains 114 genes, including 78 protein-coding genes, 32 tRNA genes, and 4 rRNA genes. The GC content in cp genome, LSC, SSC, and IR regions were 38.5, 36.5, 32.6, and 38.5%, respectively. The phylogenetic analysis showed P. huashanica is closely related to Triticum genus. [ABSTRACT FROM AUTHOR]

Elymus nutans is an alpine plant, which plays an important role in maintaining ecological system and the development of animal husbandry in the Tibetan region of China. However, the population of wild E. nutans notably decreased in recent years with overgrazing and ecological environment deterioration, and the germplasm resources have been threatened. This study reported a complete circular chloroplast genome of E. nutans, which was 134,147 bp in length, containing a pair of inverted repeats (IRs) of 10,541 bp separated by one small single copy (SSC) region of 14,036 bp and one large single copy (LSC) region of 99,029 bp. A total of 123 genes, including 87 protein-coding genes, 32 transfer RNA genes and four ribosomal RNA genes were predicted from the chloroplast genomes. The overall GC content of the chloroplast genome was 38.34% and the corresponding values of the IR, SSC and LSC were 48.7%, 32.4% and 37.0%, respectively. The results of phylogenetic analysis showed that wild E. nutans was clustered closely with Triticum aestivum. [ABSTRACT FROM AUTHOR]