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At least 937 records · Page 52Linked to original sources
PubMed2003

[Measurement of evapo-transpiration and crop coefficient of irrigated spring wheat in Naiman sandy cropland].

Lysimeter experiments were conducted with spring wheat during cropping seasons to measure the crop evapo-transpiration at Naiman region, and reference evapo-transpiration during these seasons was calculated with FAO Penman-Monteith and other four methods. The relationship between FAO Penman-Monteith and other reference evapo-transpiration methods was established, and the crop coefficients for spring wheat based on crop evapo-transpiration and reference evapo-transpiration were also developed. The results showed that the average weekly ETc of spring wheat was less than 3 mm.d-1 in the seedling phase. With the LAI increased, the average weekly ETc reached the peak of 6.49 mm.d-1 (at heading phase), and declined to 1.94 mm.d-1 during maturity phase. The local precipitation in the year of experiment did not satisfy the water demand for wheat production, and seedling, jointing, heading phases of spring wheat were the key phases in the course of water management. The differences in ETr estimates between FAO Penman-Monteith and Penman and FAO Blaney-Criddle methods were obviously lower than those between FAO Penman-Monteith and Makkink and Priestley-Taylor methods. The calculated values of crop coefficient for spring wheat at the four crop growth phases (initial, crop development, reproductive and maturity) were 0.45, 0.90, 1.11 and 0.52, respectively. The coefficient at maturity stage differed considerably from those suggested by FAO-24.

Crops, Agricultural↗
PubMed2003

[Features of recombination of nuclear genome in back crossed offspring of barley-wheat hybrids Hordeum vulgare L. (2n=14) x Triticum aestivum L. (2n+42) with the use of SSR-analysis].

The backcross progenies of the barley-wheat hybrids Hordeum vulgare L. (2n = 14) x Triticum aestivum L. (2n = 42) and two alloplasmic lines derived from them were studied using microsatellite markers of barley and wheat. The F1 hybrids and first backcross plants BC1 contained the genetic material of both cultivated barley and the cultivars of common wheat involved in developing of these hybrid genotypes. The genomes of BC3, BC4, and alloplasmic lines contained no microsatellite markers of the cultivated barley, whereas chromosomes of each homeologous group of common wheat were identified. In chromosomes of backcross progenies BC3, BC4, and alloplasmic lines yielded by backcrosses of hybrids and various common wheat cultivars, microsatellite markers of the parental wheat cultivars were shown to undergo recombination.

Cell Nucleus↗
PubMed2003

[Effects of sowing times on the spike differentiation of different wheat varieties under the climate of warm winter].

Spike differentiation processes and freezing damage of three wheat varieties were studied by sowing in different stages. The results showed that under the condition of weather changing warm, the time of entering each stage of spike differentiation of wheat of strong spring variety was earlier than that of wheat of spring variety and semi-winter variety. Sowing times had more effects on durative time of the elongation stage, single-prism stage and two-prism stage of the spike differentiation. Under sowing early, the stronger the springness of wheat was, the quicker it developed, the higher spike differentiation phases it reached before winter, and the more serious freezing damage it suffered in wintering. According to this, the semi-winter varieties of wheat should be adopted first and arranged in pairs with spring varieties in wheat production, and the sowing times should not be too early as the weather becoming warm.

Climate↗
PubMed2004

[Comparative studies on proteins of cytoplasmic male-sterile wheat and its maintainer by 2D-PAGE in Triticum aestivum].

By using 2D-PAGE techniques, protein compositions have been studied at different developmental stage leaf (seedling, tillering, shooting and booting stages) and pollen mother cells (PMC) (meiotic, 1-nucleus and 2-3 nuclei stages) in male sterile wheat and its maintainer. The results indicated that a specific protein (33KD/pI6.3) identified at the shooting and booting stage leaves in male-sterile wheat, but this protein species has not been identified in the male fertile wheat. Four protein species, 53KD/PI5.5, 50KD/PI5.7, 48KD/PI5.6, 20KD/PI7.5 were detected at the 2-3 nuclei stages, which was thought key stage of pollen fertility lost in male-sterile wheat, and these protein species were not be seen in male-fertile wheat. According above experiment results, five protein species which detected in leaf and PMC might participate in fertility regulation and related to the male-sterility of male-sterile wheat.

Electrophoresis, Gel, Two-Dimensional↗
PubMed2003

Identification of physiological races of Blumeria graminis f. sp. tritici and evaluation of powdery mildew resistance in wheat cultivars in Sistan province, Iran.

Powdery mildew of wheat caused by Blumeria graminis f. sp. tritici (Bgt) is one of the most important fungal diseases in Iran. During the years 1998-2001, wheat fields in Sistan province were surveyed and powdery mildew infected samples were collected from various areas and transferred to the laboratory. In the greenhouse, fungal spores were purified and inoculated onto susceptible wheat cultivars using single pustule and single spore procedures. Selected pure isolates were inoculated onto the first leaves of eight differential wheat varieties for identifying physiological races. The results showed the existence of Bgt races 5, 11, 14, 19, 21, 24, 27, 28, 31, 32, 44, 50, 53, 58, 66, 73 and 84 in Sistan. These races were new to Sistan province and Iran as a whole. Among 17 races studied, races 11, 53 and 73 were important dominant races thus constituting 40% of total population. Race 53 constituted 16% of all isolates and was the dominant race in the area with 62.5% pathogenicity. Therefore, this race was introduced as the most virulent race during the period of this study. This study showed that Bgt isolates were compatible with host plant genes pm8, pm3 and pm3b but incompatible with gene pm4b. Powdery mildew resistance was evaluated using race 11 on 70 wheat cultivars during seedling stage as well as adult plant under both greenhouse and field conditions between 1999 and 2001. Among wheat lines tested for resistance against powdery mildew, cultivar Hirmand resembled the differential line Weihenst M1 in that both may possess gene pm4b and showed no symptoms under the greenhouse and field conditions. Cultivar Chamran was found to be highly resistant whereas Sorkhtokhm was susceptible. Other cutivars showed partial and gradual resistance against the powdery mildew disease.

Ascomycota↗
PubMed2004

[Effect of reduced N application on N utilization and balance in winter wheat-summer maize cropping system].

A field trial on a calcareous soil was carried out at an experimental station of China Agricultural University with the objective of assessing the effect of reduced nitrogen application on N utilization and N balance in a winter wheat-summer maize cropping system. Before this study, the trial has been conducted for one rotation cycle of wheat and maize with four-fixed N rates of 0, 120, 240 and 360 N kg.hm-2 per crop. In this study, each plot was divided into two sub-plots for two N application rates: normal N application(original rate) and reduced N application(reduced rate). The results showed that the grain yields of wheat and maize reached the platform at N rate of 120 kg.hm-2(N120), and then almost kept the same level regardless of the further increase of N rate(N240 and N360). The N uptake by wheat and maize followed the similar tendency like their yield. The grain yield and N uptake of wheat were not significantly declined with the half reduction of original N rate except the treatment N120. However, the same items in maize significantly declined with the further reduction of N fertilizer to zero. The residual NO3-N(main source of mineral N) in reduced N sub-plots was significantly lower in 0-1 m soil layer, but not different in 1-2 m soil layer compared with those receiving original N rate, indicating that 1-2 m soil NO3-N could hardly be utilized by crops. N balance calculation further showed that the N recovery by crops could be largely raised by the reduction of N fertilizer, while the apparent N loss rate decreased in wheat-maize rotation, respectively. Thus, the reduction of fertilizer N under high N rate can significantly increase N use efficiency and reduce NO3-N accumulation and apparent N loss.

Crops, Agricultural↗
PubMed2004

Fingerprinting of common wheat cultivars with an Alw44I-based AFLP method.

A simplified AFLP method, based on methylation-sensitive Alw44I restriction endonuclease, has been developed and evaluated for fingerprinting 15 wheat cultivars. The selected germplasms represented groups of spring and winter wheats with and without the 1BL.1RS translocation. Ten selective primers yielded 57 markers, including 19 polymorphic bands. Three markers (15.8%) were specific to wheat carrying the 1BL.1RS translocation, thus conflicting with the frequency expected by random marker distribution (2.4%), and suggesting qualitative differences in DNA methylation among winter wheat cultivars with the 1BL.1RS translocation. Mean Dice's similarities ranged from 0.85 to 0.99, thus all cultivars could be identified by the banding profile. Winter wheat cultivars, with and without the 1BL.1RS chromosome, were slightly more similar to one another (0.959) than spring wheat cultivars (0.952). Five (9%) specific markers were obtained from cultivars Sicco, Cheyenne, Fenman, Disponent and Chinese Spring.

Chromosomes, Plant↗
PubMed2004

[Anaphylactic reactions after intake of products with wheat].

BACKGROUND: Food allergy is common in small children. Sensitisation to wheat is frequent, reactions to ingested wheat more seldom and mostly associated with atopic eczema and exercise-induced anaphylaxis. MATERIAL AND METHODS: Eleven children with severe reactions after ingestion of small amounts of wheat were referred to us for further diagnostic procedures. Skin prick tests, total and specific IgE as well as oral provocation test were performed. RESULTS: All but two children had strongly positive skin prick tests results to wheat. The same two children had specific IgE to Immunocap f4 (a-amylase) < 10 kUa/L while the nine other children had specific IgE to f4 > 29 kUa/L. All children had general reactions when provoked orally with small amounts of wheat with the need for administration of adrenalin and in most cases oral steroids. INTERPRETATION: It is important to identify children at risk for general reactions to wheat, as cereals are staple foods in our community. Identification of the proteins involved in serious reactions is essential.

Anaphylaxis↗
PubMed2004

[Development of bakery products for greater adult consumption based on wheat and rice flour].

The present investigation was developed as a contribution to Guatemalan's elderly food and nutrition. Its main objective was to evaluate the chemical, nutritional and sensory quality of bread prepared from the partial substitution of wheat flour with rice flour. Wheat flour substitutions with rice flour in the order of 15, 20, 30, 40, 50 and 60% were evaluated. Differences with the control (100% wheat bread) were found during the process of preparation, as well as texture, volume, height, weight and specific volume. Important effects in dough handling were noted specifically in the 40, 50 and 60% rice bread. Thus, a sandy texture was found in breads of higher rice levels. The bread protein quality increased with the level of substitution; however the protein quality difference between the wheat bread and the bread with 60% rice flour did not achieve statistical significance. Based on a statistical analysis of the physical properties the bread with 30 and 40% rice flour was selected, and through a preference test between these last two, the 30% rice flour bread was selected as the sample best suited to the present study's purposes. This bread was not different to wheat bread in many nutritional parameters, although in others it showed to be superior. Each serving size of bread has a weight of 80 grams (2 slices) that contributes adequate quantity of calories, protein and sodium, although a little less dietary fiber than 100% wheat bread.

Aged↗
PubMed2005

Inheritance of seed dormancy in Tibetan semi-wild wheat accession Q1028.

Tibetan semi-wild wheat (Triticum aestivum ssp. tibetanum Shao) is one of the Chinese endemic hexaploid wheat genetic resources, distributed only in the Qinghai-Xizang Plateau of China. It has special characters, such as a hulled glume and spike disarticulation. However, seed dormancy, another important character for wheat resistance to pre-harvest sprouting, was rarely reported. Seed dormancy of more than 10 Tibetan semi-wild wheat accessions was evaluated, and their germinations were 0% or near 0% with both treatments of threshed seeds and intact spikes at hard dough stage. Tibetan semi-wild wheat accession Q1028 was investigated for its seed dormant characters by testing the seed germination percentages of intact spikes, seeds with bract powder, normal seeds, seeds with pierced coat, and sectioned embryos. It was observed that embryo dormancy of Q1028 accounted for its seed dormancy. Using threshed seeds and intact spikes at hard dough stage, the inheritance of seed dormancy was carried out using the F1, F2, F3 and F2BC1 populations of the cross between Q1028 and a wheat line 88-1643, susceptible to preharvest sprouting. The germinations of seeds and intact spikes in F1 plants were 1.0% and 0.9%, respectively. It indicated that seed dormancy of Q1028 was inherited as a dominant trait. From the genetic analysis of the F2, F3 and F2BC1 populations it was found that the strong seed dormancy of Q1028 was controlled by two dominant genes.

Adaptation, Physiological↗
PubMed2005

[Simulating net primary production of rice and wheat crops: model validation and scenario prediction].

A model developed by the authors was validated against a total of 98 independent data sets to simulate net primary production (NPP) of rice and wheat crops. These data sets come from literature review and include field measurements conducted in different regions of China with various rates of N application. Model validation indicates that NPP of rice and wheat crops in main cultivated-area of China can be well simulated from weather, soil and N fertilization. A comparison between the simulated (y) and the observed NPP (x) resulted in a regression of y = 1.05x- 16.8 (r2= 0.771,p < 0.001, n = 98). Model scenario prediction for Nanjing area suggests that the increase of atmospheric CO2 concentration will enhance carbon fixation, while the increase of air temperature will reduce carbon fixation by rice and wheat crops. Effect of global warming on the wheat carbon fixation is less than on the rice. Under present and future scenario with atmospheric CO2 concentration of 540 micromol x mol(-1) and temperature increment of 1-4 degrees C, N fertilization will enhance carbon fixation of rice and wheat crops. The enhancement for wheat is more significant than that for rice crop. However, the application of N will not significantly improve the carbon fixation, even reduce rice NPP when the N application rate is higher than 150 kg x hm(-2).

Biomass↗
PubMed2005

RNA silencing of Waxy gene results in low levels of amylose in the seeds of transgenic wheat (Triticum aestivum L.).

In this study, the level of amylose was reduced in wheat seeds by RNAi strategy. Because the synthesis of amylose is catalyzed by the granule-bound starch synthase I (GBSSI or WAXY protein), the Waxy gene of wheat was isolated from wheat seeds by using RT-PCR. Southern analysis confirmed that there were three Waxy genes in wheat genome. Northern hybridization showed that Waxy mRNA accumulated in seeds following pollination. By RNAi strategy,the 683 bp sense and antisense fragments in reverse orientation separated by a 150 bp intron were cloned into pCAMBIA 3300 just downstream of the maize ub/1 promoter. By Agrobacteriurn-mediated wheat transformation method, four transgenic plants (Cultivar Yangmai 10) were identified by PCR, RT-PCR and leaf painting assay. The level of amylose in the endosperm were significantly reduced in transgenic seeds as checked by iodine staining and analysis of amylose content. The results indicated that RNA silencing of Waxy gene resulted in low level of amylose in the seeds of transgenic wheat.

Amylose↗
PubMed2005

[Sequence analysis of alpha-amylase inhibitors genes with resistance to insects in wheat and Aegilops].

The alpha-amylase inhibitors have been proposed as possibly important weapons against pests. Thus, it is of importance to identify the specificity of them. Based on the EST data of alpha-amylase inhibitor genes that were retrieved from NCBI, BBSRC and GrainGenes, two PCR primers were designed. The coding sequences of 24 kD dimeric alpha-amylase inhibitors with resistance to insects in 17 wheat and Aegilops accessions were investigated and 17 new genes were obtained. Only one 24 kD alpha-amylase inhibitor gene was found in each diploid wheat and Aegilops accession, whereas 8 genes were characterized from one hexaploid wheat variety, indicating that the 24 kD alpha-amylase inhibitors in hexaploid wheat were encoded by multi-gene. The deduced amino acid sequences of 2 genes from common wheat and 1 gene from Ae. tauschii were the same as the sequence of the inhibitor 0.19, and the deduced amino acid sequence of another gene from common wheat was similar to the inhibitor 0.53 with only one amino acid difference. The amino acid sequences of 24 kD dimeric alpha-amylase inhibitors shared very high coherence (91.2%). These results suggest that the alpha-amylase inhibitors in 24 kD family were derived from common ancestral genes by phylogenesis.

Amino Acid Sequence↗
PubMed2006

Diagnostic detection and genetic analysis of wheat stripe rust resistant gene YrCN19.

DNA samples of 19 wheat cultivars or lines were screened with the primer pair Xgwm410, a diagnostic marker of wheat stripe rust resistant gene YrCN19. The results showed that the wheat cultivars or lines CN19, XK5, AIM5 and AIM6 produced the amplicon Xgwm410/391, which co-segregated with the resistance of YrCN19, but other cultivars or lines did not produced it. Pedigree analysis and resistance test showed that CN19, XK5, AIM5 and AIM6 carried wheat stripe rust gene YrCN19. Genetic analysis proved that the resistance to wheat stripe rust of CN19, XK5, and AIM5 inherited in single dominant gene genetic law (3 resistant: 1 susceptible). The results also proved that the resistance descent in the cross combination Yanfu188/AIM6 complied with the single dominant gene genetic law (3 resistant: 1 susceptible), while the resistance inheritance in other cross combinations (CN18/AIM6, Lu955159/AIM6 and Shu3110/ AIM6) complied with two gene complementary genetic law (9 resistant: 7 susceptible). The results suggested that the resistance expression and separation of YrCN19 was distinct in the various genetic backgrounds or cross combinations. This study would expedite the exploitation and utilization of YrCN19 in wheat resistant breeding.

Basidiomycota↗
PubMed2006

[Quantitative relationships between leaf area index and canopy reflectance spectra of wheat].

Based on the change patterns of leaf area index (LAI) and canopy spectral reflectance of wheat at different growth stages and nitrogen application rates, this paper investigated the relationships of LAI with canopy reflectance and spectral parameters, and brought forward the sensitive spectral parameters and quantitative equation for predicting wheat LAI. The results showed that with increasing nitrogen application rate, wheat LAI and its canopy reflectance at near infrared (760 to approximately 1220 nm) increased, whereas the reflectance at visible band (460 to approximately 710 nm) decreased. From jointing to maturity, the LAI and the reflectance of short bands in near infrared increased initially and decreased then, whereas the reflectance of visible light and long bands in near infrared was in adverse, with the lowest value appeared at booting stage. Wheat LAI was negatively correlated with the reflectance of visible light, but positively with that of short bands in near infrared, with the highest correlation coefficient at 810 nm. It was proposed that wheat LAI could be well monitored by vegetation indices RVI (810, 510) and DVI (810, 560). PVI and TSAVI were proved to be the spectral indices in monitoring wheat LAI, and higher accuracy was obtained with combined RVI (810, 510), DVI (810, 560) and PVI.

Ecosystem↗
PubMed2006

Surface-exchange of NOx and NH3 above a winter wheat field in the Yangtze Delta, China.

A four-dynamic-chamber system was constructed to measure NOx and NH3 surface-exchange between a typical wheat field and the atmosphere in the Yangtze Delta, China. The average fluxes ofNO, NO2 and NH3 were 79, -5.6 and -5.1 ngN/(m2 x s), and 91, -1.8 and 23 ngN/(m2 x s), respectively for the wheat field and the bare soil. The NO flux was positively correlated with soil temperature and the fluxes of NO2 and NH3 were negatively correlated with their ambient concentrations during the investigated period. The compensation point of NO2 between the wheat field and the atmosphere was 11.9 microg/m3. The emissions of NO-N and NH3-N from the urea applied to the wheat field were 2.3% and 0.2%, respectively, which indicated that the main pathway of N loss from the investigated winter wheat field was NO. Application of a mixture of urea and lignin increased the emissions of NO, but also greatly increased the yield of the winter wheat.

Agriculture↗
PubMed2006

[Study on mechanism of enhanced UV-B radiation influencing on N2O emission from soil-winter wheat system].

To study the influencing mechanisms of enhanced UV-B radiation on the emission of N20 from soil-wheat system, outdoor pot experiments with simulating 20% supplemental level of UV-B were conducted. Results indicate that the enhanced UV-B had no significant impact on the emission of N20 from soil-wheat system in turning- green stage, but declined the N2O flux and the rate of the system's respiration in elongation stage. The impact mechanisms of enhanced UV-B radiation on the N2O flux were to directly change the nitrogen metabolism process of wheat plant, such as significantly increasing soluble protein, total nitrogen and total phosphorus in wheat leaves. But the effects of UV-B radiation on soil N2O emission may be indirect, namely, UV-B treatment by working on wheat plant significantly increased the soil available nitrogen, soil microbial biomass C and N, and also changed the ratio of soil microbial C: N(from 5.0 to 6.8) in winter-wheat rhizosphere.

Biodegradation, Environmental↗
PubMed1990

Cloning of ubiquitin activating enzyme from wheat and expression of a functional protein in Escherichia coli.

The initial step in the conjugation of ubiquitin to substrate proteins involves the activation of ubiquitin by ubiquitin activating enzyme, E1. Previously, we purified and characterized multiple species of E1 from wheat germ. We now describe the isolation and characterization of a cDNA clone encoding E1 from wheat. This clone (UBA1) was isolated from a cDNA expression library with anti-wheat E1 antibodies. It contained an open reading frame coding for 1051 amino acids and directed the synthesis of a protein that comigrated with a wheat germ E1 of 117 kDa. UBA1 was confirmed as encoding E1 by (i) comparison of the peptide map of the protein product of UBA1 synthesized in Escherichia coli with that of purified E1 from wheat, and (ii) amino acid sequence identity of peptides generated from purified E1 with regions of the derived amino acid sequence of UBA1. The isolation of two additional cDNAs closely related to UBA1 indicated that E1 was encoded by a small gene family in wheat. Nonetheless, a single poly(A+) mRNA size class of 4 kilobases hybridized with UBA1. When expressed in E. coli, the product of UBA1 catalyzed the formation of a thiol ester linkage between ubiquitin and an ubiquitin carrier protein. The ability of E. coli containing UBA1 to synthesize an active protein will allow us to identify domains important for E1 function using in vitro mutagenesis.

Amino Acid Sequence↗