Effect of time of application and amount of nitrogen fertilizer on seed yield and concentration of oil in canola (Brassica napus)

The seed (grain) yield increases (responses) and concentration of oil in seed responses of canola (Brassica napus L.) to applications of fertilizer nitrogen (N), as urea (46% N), was measured in eight field experiments in south-western Australia (SWA). Nitrogen was applied at five different times of application, either at sowing or at three to four weekly intervals until 12–16 weeks (0, 3, 6, 9, 12 or 0, 4, 8, 12, 16) after seedling emergence. Canola, sown in late May to early June, was grown on a range of soil types in different locations of SWA. The greater the amount of N applied and the closer N was applied to the sowing of the canola seed usually gave the largest seed yield increase at both higher rainfall sites (> 500 mm) and lower rainfall sites (<350 mm). Maximum seed yield of canola were reached within nine weeks after seedling emergence. The exception was for a sandy soil (Fluventic Lithic Xerochrept; Brown Tenosol) at Narrogin where applications of N at six, nine, or 12 weeks after emergence gave higher yields compared to N applied earlier mainly due to N leaching in June and July.

The amount of N required for 90% of maximum seed (N_90%Y) yield ranged from five to 58 kg N ha^?1 with the amount depended on location and growing season. For six of the eight sites the higher amounts of N for N_90%Y were required at sowing and three weeks after emergence. Similarly, N use efficiency (NUE, kg grain produced kg N applied^?1) tended was highest for either the N applied at sowing or within three to four weeks after emergence of seedlings. The exception was for a sandy soil at Narrogin where applications of N at six, nine, or 12 weeks after emergence gave higher NUE compared to N applied earlier. N use efficiency decreased as the amount of N increased for all times of N application. Generally, the amount of N applied decreased the oil concentration of canola seed at each time of application. However, the effect of the time of application of N fertilizer on the decrease in oil concentration of canola seed was largest with the highest N level applied at 12 or 16 weeks after seedling emergence. The percentage the oil concentrations decreased as the amount of N applied increased varied with location and growing season. Further research work is required to elucidate the interaction between the growing season, possible rainfall and temperature, and the effects of N on grain yield and oil concentration in seed.     

Isolation and identification of the most efficient plant growth-promoting bacteria associated with canola (Brassica napus)

 Thirteen of the most abundant Gram-negative bacteria which are able to grow in N-depleted culture conditions were isolated from the rhizoplane and endorhizosphere of canola (Brassica napus) and identified by 16S rDNA sequence analysis. Eight of these bacteria induced a significant increase in root dry weight ranging from 11 to 52%. Phylogenetic positioning based on 16S rDNA sequences indicated that at least four genera are represented, Pseudomonas, Variovorax, Agrobacterium and Phyllobacterium. The most important direct plant growth-promoting-rhizobacteria effect was found with both isolates belonging to the Phyllobacterium. Received: 18 April 2000     

Effect of nitrogen fertilizer on the concentrations of oil and protein in canola (brassica napus) seed

The oil and protein concentration response of canola (Brassica napus L.) to application of nitrogen (N), applied as urea (46%), was measured in 210 field plots done in 1994 and 1995 in south‐western Australia (WA). The canola was grown on a range of soil types deficient in N for maximum seed production. The sites were sown in late May to early June. The concentration of oil in the canola seed decreased concomitantly with an increase in protein. In all experiments, in both years, there was no relationship between the seed yield and the resultant oil or protein concentration. The addition of the oil plus protein concentration in the canola seed was an approximately constant 62% in the both years.     

Weed management in canola (Brassica napus L): a review of current constraints and future strategies for Australia

ABSTRACT

Weeds are a major constraint to canola (Brassica napus L.) production, reducing grain yield and quality. The repeated use of pre- and post- emergent herbicides to control several grasses and broadleaf weeds has escalated the problem of herbicide resistance in weeds. The development of herbicide-tolerant canola cultivars has increased the flexibility of weed management but has also increased the risks of outcrossing with wild relatives and weed shifts to resistance. Herbicide-resistant weed species, and the related biological repercussions, pose a major threat to sustainable weed management. These developing risks have led researchers to examine integrated weed management (IWM) techniques for sustainable weed control. Weed control strategies using non-chemical tactics have valid roles for managing weeds. However, in broad-acre commercial fields, the effectiveness of several non-chemical selections are less proven than commercial chemical herbicides. Canola competition and allelopathy for weed suppression are potential components for integrated weed management in canola. This review examines current chemical and non-chemical options available for developing IWM strategies for profitable canola production, as well as future research directions.     

Glyphosate-resistant and -susceptible soybean (Glycine max) and canola (Brassica napus) dose response and metabolism relationships with glyphosate

Experiments were conducted to determine (1) dose response of glyphosate-resistant (GR) and -susceptible (non-GR) soybean [Glycine max (L.) Merr.] and canola (Brassica napus L.) to glyphosate, (2) if differential metabolism of glyphosate to aminomethyl phosphonic acid (AMPA) is the underlying mechanism for differential resistance to glyphosate among GR soybean varieties, and (3) the extent of metabolism of glyphosate to AMPA in GR canola and to correlate metabolism to injury from AMPA. GR50 (glyphosate dose required to cause a 50% reduction in plant dry weight) values for GR (Asgrow 4603RR) and non-GR (HBKC 5025) soybean were 22.8 kg ae ha-1 and 0.47 kg ha-1, respectively, with GR soybean exhibiting a 49-fold level of resistance to glyphosate as compared to non-GR soybean. Differential reduction in chlorophyll by glyphosate was observed between GR soybean varieties, but there were no differences in shoot fresh weight reduction. No significant differences were found between GR varieties in metabolism of glyphosate to AMPA, and in shikimate levels. These results indicate that GR soybean varieties were able to outgrow the initial injury from glyphosate, which was previously caused at least in part by AMPA. GR50 values for GR (Hyola 514RR) and non-GR (Hyola 440) canola were 14.1 and 0.30 kg ha-1, respectively, with GR canola exhibiting a 47-fold level of resistance to glyphosate when compared to non-GR canola. Glyphosate did not cause reduction in chlorophyll content and shoot fresh weight in GR canola, unlike GR soybean. Less glyphosate (per unit leaf weight) was recovered in glyphosate-treated GR canola as compared to glyphosate-treated GR soybean. External application of AMPA caused similar injury in both GR and non-GR canola. The presence of a bacterial glyphosate oxidoreductase gene in GR canola contributes to breakdown of glyphosate to AMPA. However, the AMPA from glyphosate breakdown could have been metabolized to nonphytotoxic metabolites before causing injury to GR canola. Injury in GR and non-GR canola from exogenous application of AMPA was similar.     

Reliable detection and identification of genetically modified maize, soybean, and canola by multiplex PCR analysis

Multiplex PCR procedures were developed for simultaneously detecting multiple target sequences in genetically modified (GM) soybean (Roundup Ready), maize (event 176, Bt11, Mon810, T14/25), and canola (GT73, HCN92/28, MS8/RF3, Oxy 235). Internal control targets (invertase gene in corn, lectin and beta-actin genes in soybean, and cruciferin gene in canola) were included as appropriate to assess the efficiency of all reactions, thereby eliminating any false negatives. Primer combinations that allowed the identification of specific lines were used. In one system of identification, simultaneous amplification profiling (SAP), rather than target specific detection, was used for the identification of four GM maize lines. SAP is simple and has the potential to identify both approved and nonapproved GM lines. The template concentration was identified as a critical factor affecting efficient multiplex PCRs. In canola, 75 ng of DNA template was more effective than 50 ng of DNA for the simultaneous amplification of all targets in a reaction volume of 25 microL. Reliable identification of GM canola was achieved at a DNA concentration of 3 ng/microL, and at 0.1% for GM soybean, indicating high levels of sensitivity. Nonspecific amplification was utilized in this study as a tool for specific and reliable identification of one line of GM maize. The primer cry1A 4-3' (antisense primer) recognizes two sites on the DNA template extracted from GM transgenic maize containing event 176 (European corn borer resistant), resulting in the amplification of products of 152 bp (expected) and 485 bp (unexpected). The latter fragment was sequenced and confirmed to be Cry1A specific. The systems described herein represent simple, accurate, and sensitive GMO detection methods in which only one reaction is necessary to detect multiple GM target sequences that can be reliably used for the identification of specific lines of GMOs.     

Sampling and modeling for the quantification of adventitious genetically modified presence in maize

The coexistence of genetically modified (GM) and non-GM crops is an important economic and political issue in the European Union. We examined the GM content in non-GM maize crops in Spain in 2005. Both the standing crop and the harvest were tested, and the %GM DNA was quantified by real-time polymerase chain reaction. We compared the level of GM as a function of distance from known GM source fields in a 1.2 km2 landscape. The distribution of GM was compared to predictions from previous studies, and good agreement was found. Control and monitoring of adventitious GM presence in non-GM crops can only be achieved by fit-for-purpose sampling and testing schemes. We used a GM dispersal function to simulate non-GM crops in the studied zone and tested the accuracy of five different sampling schemes. Random sampling was found to be the most accurate and least susceptible to bias by GM spatial structure or gradients. Simulations showed that to achieve greater than 95% confidence in a GM labeling decision of a harvest (when treated as a single marketed lot), 34 samples would be needed when the harvest was outside 50% of the GM threshold value. The number of samples required increased rapidly as the harvest approached the GM threshold, implying that accurate labeling when the harvest is within +/-17% of the threshold may not be possible with high confidence.     

Phosphate-solubilizing rhizobacteria enhance the growth and yield but not phosphorus uptake of canola (Brassica napus L.)

The ability of phosphate-solubilizing rhizobacteria to enhance the growth and phosphorus uptake of canola (Brassica napus L., cv. Legend) was studied in potted soil experiments in the growth chamber. One hundred and eleven bacteria isolated from the rhizosphere of field-grown plants, and a collection of nine bacteria known to be effective plant growth-promoting rhizobacteria (PGPR), were screened for P-solubilization in vitro. All rhizobacteria were identified using whole-cell fatty acids methyl ester (FAME) profiles. The best P-solubilizing isolates were two Bacillus brevis strains, B. megaterium, B. polymyxa, B. sphaericus, B. thuringiensis, and Xanthomonas maltophilia (PGPR strain R85). The P-solubilizers were tested for their effects on growth and P-uptake of canola plants in a P-deficient soil amended with rock phosphate. Although some of the P-solubilizing rhizobacteria significantly increased plant height or pod yield, none increased P-uptake. The most effective inoculant was a B. thuringiensis isolate which significantly increased the number and weight of pods and seed yield without rock phosphate. Xanthomonas maltophilia increased plant height, whereas the other bacilli increased the number on weight of pods. These results demonstrate the potential use of these P-solubilizing rhizobacteria as inoculants for canola, but indicate that P-solubilization was not the main mechanism responsible for positive growth response. Received: 8 February 1996     

不同硼肥对油菜产量和品质的影响及其在油稻轮作中的后效

通过盆栽土培和田间试验,研究两种具有缓释特性的硼肥Etibor-48(Na2B4O7·5H2O,EB)和Colemanite (Ca2B6O11·5H2O,CB)对油菜产量和品质的影响及其在油稻轮作中的后效.盆栽试验结果表明,EB和CB各处理第一季油菜产量显著高于不施硼处理(-B),与硼砂处理(B)比较也有较大提高;安...     

Effect of phosphorus,potassium, and chloride nutrition on cold tolerance of winter canola (Brassica napus L.)

Winter varieties of canola (Brassica napus L.) are susceptible to winterkill. Measurements of photosynthetic efficiency and survival of field-grown canola were used to evaluate the effect of chloride (Cl), potassium (K), and phosphorus (P) nutrition on winter field survival in northwestern USA. In a growth chamber experiment, effects of calcium chloride (CaCl₂), potassium chloride (KCl), ammonium chloride (NH₄Cl), or sodium chloride (NaCl) on the ability to tolerate subfreezing temperatures were evaluated. In the field, overwinter survival was higher, and greater photosynthetic activity continued later into the autumn in plants with increased sap Cl concentrations. In the greenhouse experiment, significantly greater survival occurred in plants with higher sap Cl concentrations, but only in plants that had not been cold acclimated. These results suggested that a greater concentration of chloride ion in the sap of canola plants is related to an increased ability to tolerate subfreezing temperatures, but other processes resulting from cold acclimation may largely obscure this effect.     

First application of a microsphere-based immunoassay to the detection of genetically modified organisms (GMOs): quantification of Cry1Ab protein in genetically modified maize

An innovative covalent microsphere immunoassay, based on the usage of fluorescent beads coupled to a specific antibody, was developed for the quantification of the endotoxin Cry1Ab present in MON810 and Bt11 genetically modified (GM) maize lines. In particular, a specific protocol was developed to assess the presence of Cry1Ab in a very broad range of GM maize concentrations, from 0.1 to 100% [weight of genetically modified organism (GMO)/weight]. Test linearity was achieved in the range of values from 0.1 to 3%, whereas fluorescence signal increased following a nonlinear model, reaching a plateau at 25%. The limits of detection and quantification were equal to 0.018 and 0.054%, respectively. The present study describes the first application of quantitative high-throughput immunoassays in GMO analysis.     

不同甘蓝型油菜品种磷素籽粒生产效率的配合力及遗传参数分析

以22个甘蓝型油菜品种(系)为亲本(17个母本,5个父本),按NCⅡ设计配成175=85个F1,在不施磷肥（CK）和施P2O5 150 kg/hm2（P150）两个处理条件下,对不同品系油菜磷素籽粒生产效率进行配合力和遗传参数分析。结果表明, 磷素籽粒生产效率（PUEs）杂交组合平均值在P150和CK处理中分别比亲本平均值高6.41%和7.64%。离中亲优势的正向组合数明显多于负向组合数,超亲优势的正向组合数（超高亲）明显多于负向组合数（超低亲）,表明PUEs存在杂种优势。PUEs的遗传参数在P150处理和CK处理中一般配合力方差相对较小,特殊配合力相对较大,PUEs遗传以非加性效应（显性效应及上位性效应）为主。在两个肥力水平下,品系9（ZS-3）的一般配合力较高,620（SY07湘05499）、 1320（NY-14湘05499）、 1421（湘05487YY-7）三个组合的特殊配合力较高。     

Effects of soil tillage,canola (Brassica napus L.) cultivars and planting date on canola yield,and oil and some biological and physical properties of soil

Determination of different agronomical properties including soil-related parameters for enhanced canola (Brassica napus L.) production can be of great significance. Hence, the objectives were to determine the effects of different tillage systems, canola cultivars and different planting dates on: (i) canola yield and oil, and (ii) soil moisture and microbial carbon (C) and nitrogen (N). Two field experiments were planned as split-plot experiments in three replicates. The main plots were different tillage systems including no-tillage (NT), minimum tillage (MT) and conventional tillage (CT), and the subplots were the combination of different canola cultivars (PF and Hyola 401) and different planting dates (PD): 8 and 23 September and 7 October. Soil moisture under CT and PF was significantly less than that of MT and NT, and Hyola 401, respectively. Carbon and N microbial biomass was the highest at NT and on the first PD. The tillage method and planting date also significantly affected canola yield, oil content and the amount, and the number of earthworms. We may conclude that although the amount of yield was the highest at CT, it may be more agronomically sustainable to plant canola under NT or MT earlier during the autumn growing season.     

Coherence between legal requirements and approaches for detection of genetically modified organisms (GMOs) and their derived products

Analytical methods for the qualitative and quantitative detection of genetically modified (GM) products may serve multiple purposes. Legal requirements differ among jurisdictions, ranging from no requirements to mandatory use of event-specific quantitation and implementation of production chain traceability. Although efforts have been taken to harmonize the analytical methodology at national, regional, and international levels, no normative international standards have yet been established. Lack of coherence between analytical methodologies and their applicabilities, on the one hand, and legislation, on the other hand, is a major problem. Here, key points where coherence is lacking are discussed. These include the definition of units of measurements, expression of GM material quantities, terminology, and inconsistent legal status of products derived from related but slightly different transformation routes. Finally, recommendations to improve the coherence are brought forward, including guidance to stakeholders for prediction of product-specific GM material quantities from gene ratios in the originating seed.     

不同磷水平外源独脚金内酯和独脚金内酯抑制剂对油菜根系形态和产量的影响

为明确外源独脚金内酯及其抑制剂对不同磷水平油菜根系形态和地上部生长的影响,本研究采用营养液培养和根箱土培试验,研究正常磷(250μmol/L)和低磷(5μmol/L)水平下外源独脚金内酯(GR24)和独脚金内酯合成抑制剂(TIS108)对甘蓝型油菜中双11号根系发育、地上部生长、磷和生长素含量、分枝数和产量等的影响。结果表明,在0～5μmol/L范围内,随着营养液GR24浓度的增大,油菜根系和地上部生长受到的抑制越来越严重。在0～1μmol/L范围内,随着营养液TIS108浓度的增大,油菜根和地上部生物量逐渐增加,在0.1μmol/L时达到最大;在1～5μmol/L范围内,随着营养液TIS108浓度的增大,油菜根和地上部生长受到的抑制程度加剧,在5μmol/L时抑制作用达到最大。低磷和正常磷处理外源添加GR24(5μmol/L)油菜根系生长均受到抑制,添加TIS108(0.1μmol/L)油菜根系生长均受到促进。GR24对油菜根系生长的抑制主要表现为主根长和总根长变短,根系总表面积和总体积变小,根尖数减少,根干重降低,根系磷含量降低,根系生长素含量降低,但地上部生长素含量增加。TIS108对油菜根系生长的促进作用主要表现为主根长和总根长增加,根系总表面积和总体积增大,根尖数显著增加,根干重增加,根系磷含量增加,根系生长素含量增加,地上部生长素含量降低。土培盆栽试验结果表明低磷处理喷施GR24油菜株高增加,分枝数减少,地上部干重减小,产量降低;低磷处理喷施TIS108株高降低,分枝数增加,地上部干重增大,产量增加。综上可知,利用外源独脚金内酯合成抑制剂能够调控油菜根系形态,地上部分枝数和产量,在作物减磷增效中具有较好的应用前景。     

Primers and probes development for specific PCR detection of genetically modified common bean (Phaseolus vulgaris) Embrapa 5.1

The genetically modified common bean Embrapa 5.1, developed by Brazilian Agricultural Research Corporation (Embrapa), is the first commercial GM plant produced in Latin America. It presents high resistance to the Bean golden mosaic virus. In this work, primers and probes targeting a taxon-specific reference DNA sequence for the common bean (Phaseolus vulgaris L.) and a construct-specific DNA sequence of Embrapa 5.1 GM common bean were successfully developed. The primers and probes showed high specificity for the target detection. Both methods showed suitable efficiency and performance to be used as an endogenous target for detection of common bean DNA and for construct-specific detection of GM common bean Embrapa 5.1, respectively. Both real-time PCR assays proved to be valuable for future assessment of interlaboratory studies.     

不同硼水平对双低油菜华双4号产量和品质的影响

以甘蓝型常规油菜品种中油821(双高品种)为对照,通过盆栽试验研究了不同硼水平对甘蓝型双低油菜华双4号子粒产量和品质的影响。结果看出,两个油菜品种在缺硼条件下,施硼量从B 0.3 mg/kg增加到B 2.5 mg/kg时,单株角果数、每角粒数和子粒产量显著增加,但增加到B 5.0 mg/kg时,每株角果数、每角粒数和子粒产量显著降低,硼过量影响产量建成。在硼缺乏和硼过量条件下,华双4号的减产程度均高于中油821,表明双低优质油菜华双4号对缺硼和硼过量的反应较常规双高油菜中油821敏感。硼缺乏或过量时,两个品种子粒含油量和油酸含量均表现降低的趋势,而蛋白质含量呈增加趋势。本试验的结果表明,合理施用硼肥对子粒产量的影响大于对品质的影响,而高产优质品种华双4号更应注重硼肥的合理施用;我国栽培油菜的土壤有效硼的适宜浓度可以提高至B 1.0 mg/kg.但硼肥的安全施用应当控制在土壤有效硼含量为B 2.5 mg/kg以下。     

PCR-ELISA for the semiquantitative detection of Nile perch (Lates niloticus) in sterilized fish muscle mixtures

A PCR-ELISA technique was developed for the semiquantitative detection of Nile perch (Lates niloticus) in experimentally sterilized fish muscle mixtures. Specific oligonucleotides derived from the 5S rDNA gene of Nile perch were selected. A forward primer, together with a reverse digoxigenin-labeled primer, permitted the amplification of specific 185 bp DNA fragments showing DNA intensities proportional to the contents of Nile perch muscle tissue in the fish mixtures. A biotinylated probe immobilized onto streptavidin-coated microplates was used to capture the digoxigenin-labeled fragments that were detected with peroxidase antidigoxigenin conjugate. Subsequent enzymatic conversion of substrate gave distinct absorbance differences when assaying fish binary mixtures containing different percentages of Nile perch muscle.     

Universal primer-multiplex-polymerase chain reaction (UP-M-PCR) and capillary electrophoresis-laser-induced fluorescence analysis for the simultaneous detection of six genetically modified maize lines

To meet the labeling and traceability requirement of genetically modified (GM) maize and their products for trade and regulation, it is essential to develop a specific detection method for monitoring the presence of GM content. In this work, six GM maize lines, including GA21, Bt11, NK603, Bt176, Mir604, and Mon810, were simultaneously detected by universal primer-multiplex-polymerase chain reaction (UP-M-PCR), and the amplicons for the six event-specific genes as well as the endogenous Ivr gene were successfully separated by the method of capillary electrophoresis-laser-induced fluorescence (CE-LIF). The UP-M-PCR method overcame the disadvantages in conventional M-PCR, such as complex manipulation, lower sensitivity, amplification disparity resulting from different primers, etc., and in combination with CE-LIF, it obtained a high sensitivity of 0.1 ng for both single and mixed DNA samples. The established method can be widely used for the qualitative identification of the GM maize lines.     

农杆菌介导的油菜遗传转化研究进展

综述油菜遗传转化中再生体系的建立、农杆菌侵染方法、适宜菌株及载体选择等方面的研究进展,并对转化中寄主基因型、目的基因及其启动子的选择、筛选方法、外源基因稳定性等方面存在的问题进行了分析与讨论,为优化油菜等芸薹属的遗传转化提出可行性建议.