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Sinapis arvensis, belonging to the genus Sinapis of the family Brassicaceae, has good agronomic characters that make it a valuable genetic resource for crop improvement and is a cytoplasmic source of heterologous cytoplasmic male sterility (CMS). In addition, S. arvensis has played an important role in the evolution of the six major cultivated Brassica species involved in the triangle of U. Using next-generation sequencing, we assembled and revealed the gene composition of S. arvensis cytoplasmic genome. The chloroplast genome comprises 153,590 bp, with 112 individual genes, including 4 rRNA, 29 tRNA, and 79 protein-coding genes. The mitochondrial genome comprises 240,024 bp, with 54 genes, including 18 tRNA, three rRNA and 33 protein-coding genes. Genome structure and evolutionary analysis indicated that the sequences of the S. arvensis organellar genomes were more similar to those of Brassica nigra and B. carinata than to those of other Brassicaceae species. Four mitochondrial open reading frames displaying chimeric structural features and encoding hypothetical proteins with transmembrane domains may account for the infertility of Nsa CMS previously derived from somatic cell hybridization between B. napus and S. arvensis. These results will not only contribute to utilize the germplasm resource of S. arvensis, and comprehend the evolution of organelle genomes within the Brassicaceae family, but also help to identify genes conditioning the alloplasmic male sterility of Nsa CMS in B. napus.

In this study, the biomass (Sinapis arvensis) was pretreated with acidic (H2SO4, HCI), alkaline (NaOH, KOH) and high temperature water (HTW) after this samples pyrolyzed at 350, 450 and 550 °C. GC–MS, FT-IR, Elemental, 1H NMR and SEM analysis methods were used in the characterization of the products obtained at the end of the pyrolysis process. It has been determined that alkaline and acidic pretreatment increase the liquid product yield and also support the formation of high energy value biochar. According to the liquid product content obtained as a result of pyrolysis, HTW and alkaline pretreatments are more effective in the formation of mono aromatics, and acidic pretreatments are more effective in the production of aliphatic.

Our study is in line with the valorization of Tunisian medicinal and aromatic plants in order to discover new bioactive natural products. So the aim was to characterized the physico-chemical properties and yield of the essential oil obtained by hydrodistillation from the leaves of Tunisian Tetraclinis articulata (Vahl.) Masters. Thirty one compounds were identified using gas chromatography (GC) and gas chromatography–mass spectrometry (GC/MS): they accounted for 91% of the essential oil composition with a majority of monoterpenes hydrocarbons (62.80%), in particular α-pinene (56.21%) and β-myrcene (3.08%). Further investigations allowed the identification of oxygenated monoterpenes, which represented 18.98%, with 1,8-cineole as the major compound of this fraction. The oil antifungal activity was assessed towards five phytopathogenic fungi. The strongest activity was observed against Botrytis cinerea with 71.17% inhibition. The oil herbicidal properties were tested on Sinapis arvensis L. and Phalaris canariensis L. Results indicated that T. articulata essential oil completely inhibited the seed germination of S. arvensis L. at high concentration (4 μl/ml), while at low doses (1 and 2 μl/ml), it delayed the germination and reduced the seedling growth of both weeds tested. Indeed, the use of these essential oils causes inhibition of weeds germination by setting their vegetative growth.

As a member of the large Brassicaceae family, yellow mustard (Sinapis alba L.) has been used as an important gene pool for the genetic improvement of cash crops in Brassicaceae. Understanding the phylogenetic relationship between Sinapis alba (S. alba) and other Brassicaceae crops can provide guidance on the introgression of its favorable alleles into related species. The chloroplast (cp) genome is an ideal model for assessing genome evolution and the phylogenetic relationships of complex angiosperm families. Herein, we de novo assembled the complete cp genome of S. alba by integrating the PacBio and Illumina sequencing platforms. A 153,760 bp quadripartite cycle without any gap was obtained, including a pair of inverted repeats (IRa and IRb) of 26,221 bp, separated by a large single copy (LSC) region of 83,506 bp and a small single copy (SSC) region of 17,821 bp. A total of 78 protein-coding genes, 30 tRNA genes, and four rRNA genes were identified in this cp genome, as were 89 simple sequence repeat (SSR) loci of 18 types. The codon usage analysis revealed a preferential use of the Leu codon with the A/U ending. The phylogenetic analysis using 82 Brassicaceae species demonstrated that S. alba had a close relationship with important Brassica and Raphanus species; moreover, it likely originated from a separate evolutionary pathway compared with the congeneric Sinapis arvensis. The synonymous (Ks) and non-synonymous (Ks) substitution rate analysis showed that genes encoding “Subunits of cytochrome b/f complex” were under the lowest purifying selection pressure, whereas those associated with “Maturase”, “Subunit of acetyl-CoA”, and “Subunits of NADH-dehydrogenase” underwent relatively higher purifying selection pressures. Our results provide valuable information for fully utilizing the S. alba cp genome as a potential genetic resource for the genetic improvement of Brassica and Raphanus species.

Biofuel crops as an alternative to fossil fuels are a component of the energy mix in many countries. Many of them are introduced plants, so they pose a serious threat of biological invasions. Production of allelopathic compounds can increase invasion success by limiting co-occurring species in the invaded environment (novel weapons hypothesis). In this study, we focused on plant chemistry and production of allelopathic compounds by biofuel crops (hybrid sorrel Rumex tianschanicus x Rumex patientia and miscanthus Miscanthus sinensis) in comparison with invasive knotweed (Fallopia sachalinensis) and cultural meadow species. First, we tested the impact of leachates isolated from hybrid sorrel, miscanthus, knotweed and cultural meadow species compared to deionized water, used as a control, on seed germination of mustard (Sinapis arvensis) and wheat (Triticum aestivum) cultivated on sand and soil. Secondly, we studied the effect of leachates on the growth of soil fungal pathogens Fusarium culmorum, Rhizoctonia solani, Sclerotinia solani and Cochliobolus sativus. Finally, we tested the effect of litter of hybrid sorrel, miscanthus, knotweed and cultural meadow litter mixed with soil on population growth of Enchytraeus crypticus and Folsomia candida. Miscanthus and knotweed litter had a higher C:N ratio than the control meadow and hybrid sorrel litter. Miscanthus and hybrid sorrel litter had a higher content of phenols than knotweed and cultural meadow litter. Leachates from hybrid sorrel, miscanthus and knotweed biomass significantly decreased seed germination of wheat and mustard in both substrates. Soil fungal pathogens grew less vigorously on agar enriched by leachates from both biofuel crops than on agar enriched by knotweed and leachates. Litter from hybrid sorrel, miscanthus and knotweed significantly altered (both ways) the population growth of the soil mesofauna.

Native plant species growing on contaminated sites in an urban environment successfully develop under strong anthropogenic pressure and thereby may have the potential for phytoremediation. The concentrations of potentially toxic metals were measured in leaves, roots, stems, and inflorescences of fifteen Brassicaceae plant species from the urban park of Botanical Garden of Komarov Botanical Institute. The potential of phytoextraction and phytostabilization of the species was evaluated considering the concentration of Cd, Cu, Ni, Pb, Zn in the plant organs, and the bioconcentration factor (BCF) and the translocation factor (TF). The metal content in plant organs varied with plant species. The study of metal accumulation in plants showed that Brassica campestris has the potential for the simultaneous phytoextraction of three metals Zn, Cd, and Cu, and Rorippa palustris – of two metals Zn and Cd. According to received data, species Sinapis arvensis and Thlaspi arvense can be considered adequate candidates for soil Zn and Pb phytostabilization and soil conservation.

Uncultivated feral host plants of insect pests often serve as reservoirs of the herbivores during temporal periods when crops are not grown, and as a consequence, understanding responses of herbivore biocontrol agents to these hosts is important when formulating strategies for pest management. Sinapis arvensis L., Erysimum cheiranthoides L. and Capsella bursa-pastoris (L.) Medicus are among the most common brassicaceous weeds in crucifer-growing areas worldwide, and can serve as hosts for the diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae). We evaluated the cascading effects of these weeds on fitness of the parasitoid Diadegma insulare (Cresson) (Hymenoptera: Ichneumonidae) reared on host larvae of P. xylostella that consumed weed leaves. Percentage parasitism of host larvae by D. insulare was highest on S. arvensis and lowest on C. bursa-pastoris in both the free-choice and no-choice situations. Values of several fitness correlates for D. insulare differed when parasitized host larvae fed on different weed species. Egg to adult development was fastest on S. arvensis and slowest on C. bursa-pastoris. Relative growth rates of pupae and adults were highest on S. arvensis whereas relative consumption rates were highest on E. cheiranthoides. Female wasps reared on hosts that consumed S. arvensis and E. cheiranthoides lived longer in the absence of food than those reared on C. bursa-pastoris. Potential impacts of these wild brassicaceous species on D. insulare populations and their role in pest management are discussed.

In Denmark, several political initiatives have been taken to reduce use of pesticides and fertilizer in order to avoid unwanted side effect of the increasing cropping intensification. Based on two nation wide surveys we investigate flora changes and discuss the changes in relation to biodiversity, crop yield, agricultural management and climate. Our assumption is that the surveys are representative for the country. We present frequency analyses of 90 species recorded in 157 fields surveyed in 1987–89, and in 167 fields surveyed in 2001–04. Based on 4910 circular sample plots in unsprayed areas, we studied flora changes in four crops and showed that the frequency of many weed species have increased. Particularly some winter annual species (e.g. Veronica arvensis L. and Viola arvensis Murray), grass weeds ( Poa annua L., Apera spica-venti (L.) P. Beauv.) and nitrophileous species (e.g. Capsella bursa-pastoris (L.) Medik, Cirsium arvense (L. Scop.) , Galium aparine L., Fallopia convolvulus (L.) A. Lowe, Tripleurospermum inodorum (L.) Sch. Bip.) have been favoured. Some weeds have declined in some crops but increased in other crops (e.g. Chenopodium album L., Geranium pusillum L.), while only a few species declined in one crop without increasing in other crops (e.g. Elytrigia repens (L.) Desv. ex Nevski; Sinapis arvensis L). Our data indicate that continuously increasing productivity (increasing yields) seems to be possible simultaneously with enhancing the frequency of the wild flora in arable crops.

In order to investigate the effect of trifluralin, pronamide, haloxyfop-p methyl, propaquizafop and isoxaben on weed control and oilseed rape yield, a two year field experiment was conducted at Darab, Iran, during 2004–2005 and 2005–2006 growing seasons. Herbicides reduced weed biomass compared with the weedy check. In 2004–2005, at 16 WAP (weeks after planting), application of trifluralin plus propaquizafop plus isoxaben at 1200 + 200 + 250 g a.i./ha and trifluralin plus haloxyfop-p methyl plus isoxaben at 1200 + 100 + 500 g a.i./ha provided best control (80%) of wild mustard (Sinapis arvensis L.), compared to other treatments. At 8 and 16 WAP, wild mustard control decreased to 47 and 42%, respectively, when trifluralin was applied alone at 1400 g a.i./ha. In 2005–2006 at 16 WAP, maximum reduction in wild mustard biomass (82%) was achieved with trifluralin plus propaquizafop plus isoxaben at 1200 + 200 + 250 g a.i./ha. In both years, all herbicide treatments controlled fumitory (Fumaria officinalis L.) 64–96%. In 2004–2005, at 16 WAP, wild oat (Avena fatua L.) biomass reduction by trifluralin plus propaquizafop plus isoxaben at 1200 + 200 + 250 g a.i./ha was 95%. In 2005–2006, at 8 and 16 WAP, minimum biomass reduction of wild oat (37–53%) was observed with trifluralin at 1200 and 1400 g a.i./ha. In both years, at 8 and 16 WAP, the most effective herbicide treatments were trifluralin plus propaquizafop plus isoxaben and trifluralin plus haloxyfop-p methyl plus isoxaben regardless of the dose applied and provided maximum reduction in total weed biomass (77–89%) compared to other treatments. Results of both years showed that all herbicide treatments increased oilseed rape grain yield as compared with the weedy check but percentage of oil was not affected by various herbicide treatments. Maximum grain yield was obtained with trifluralin plus haloxyfop-p methyl plus isoxaben at 1200 + 100 + 500 g a.i./ha.

International audience; Vegetation cover may affect weed seed predation by modifying the habitat quality for predatory organisms. Post-dispersal weed seed predation was measured by placing ‘seed cards’ in two perennial crops (alfalfa, cocksfoot) with and without crop cutting and in plots with bare soil. Each treatment was repeated four times in a randomized complete block design. Vegetation cover was measured by canopy light interception. Predation trials lasted two weeks and were repeated three times. Seed predation rates varied among three weed species (highest for Viola arvensis, intermediate for Alopecurus myosuroides, lowest for Sinapis arvensis). Vertebrate exclusion cages (12 mm × 12 mm openings) strongly reduced seed predation rates. Positive relationships were observed between vegetation cover and seed predation rates by both vertebrates and invertebrates for all weed species and trials, except when overall predation rates were very low. Predation rates were highest in uncut alfalfa, lowest on bare soil, but 16–64% of this variation could equally be explained by vegetation cover. The factorial design indicated that cutting had a stronger impact than crop species (legume or grass). Results suggest that weed seed predation may be enhanced by maintaining a high and temporally extended vegetation cover.

In order to evaluate the competitive ability (CA) of canola cultivars against wild mustard, two experiments were conducted at the Gorgan Institute in Iran during the 2005–2007 cropping seasons. The experimental factors were canola cultivars (1st year: Zarfam, Option500, Hayola330, Hayola401, Talayh, RGS003 and Sarigol; 2nd year: Zarfam, Hayola330, RGS003 and Option500) and weed density (1st year: control and 30 plants m −2 ; 2nd year: control, 4, 8 and 16 plants m −2 ). The result of the first year of experiment indicated that the grain yield and competitive indices differed significantly between the cultivars. Cultivar Zarfam showed a high ability to withstand competition (AWC = 47%), high competitive indices (CI = 1.79 and CI 2 = 10 1.83) and low grain yield in the weed-free plots (1729 kg ha −1 ). The cultivar Option500, a less competitive cultivar had the lowest ability to withstand competition (AWC = 4%) and the lowest competitive indices (CI = 0.09 and CI 2 = 0.11) amongst the cultivars. However, the cultivar Option500 showed more grain yield in the weed-free plots (2333 kg ha −1 ) than cultivar Zarfam. In the second year of the experiment, the result of the yield loss models showed that the lowest and highest yield loss belonged to cultivars Zarfam and Option500 (50 and 95% respectively). A comparison of different empirical models revealed that the empirical yield loss model based on weed relative leaf area was more reliable for predicting canola yield loss according to a high coefficient of determination ( R 2 = 0.99). The relative damage coefficient ( q ) of the weed relative leaf area model showed that wild mustard was more competitive than canola ( q > 1).

Levels of sinalbin (4-hydroxybenzylglucosinolate) and 28 other glucosinolates were determined in leaves and roots of 20 species that were either phylogenetically close to Sinapis alba, Sinapis arvensis, or Sinapis pubescens (tribe Brassiceae, Brassicaceae), or were expected to contain arylalkyl nitrilase activity. Comparison with a molecular phylogenetic tree based on ITS DNA sequences identified two separate occurrences of sinalbin. The first in a group of species related to S. alba (including members of the genera Coincya and Kremeriella); and the second in S. arvensis, nested among sinalbin deficient species. Significant 4-hydroxyphenylacetonitrile degrading enzyme activity was found in both S. alba and S. arvensis, but in S. alba the major product was the corresponding carboxylic acid, while in S. arvensis the major product was the amide. Both investigated enzyme activities, nitrilase and nitrile hydratase, were specific, accepting only certain arylacetonitriles such as 4-hydroxy and 4-methoxyphenylacetonitrile. Only the S. alba enzyme required an oxygen in para position of the substrate, as found in sinalbin. Indole-3-acetonitrile, arylcyanides, and arylpropionitriles were poor substrates. The nitrilase activity of S. alba was quantitatively comparable to that reported in the monocot Sorghum bicolor (believed to be involved in cyanogenic glycoside metabolism). Glucosinolates derived from methionine were found in all Sinapis clades. Glucosinolate patterns suggested a complex evolution of glucosinolates in the investigated species, with several apparent examples of abrupt changes in glucosinolate profiles including chain length variation and appearance of glucosinolates derived from branched-chain amino acids. NMR data for desulfated homosinalbin, 9-methylsulphonylnonylglucosinolate, 3-methylpentylglucosinolate and related glucosinolates are reported, and a facultative connection between sinalbin and specific nitrilases is suggested.

Three field trials were conducted over a 3-year period (2003, 2004 and 2005) near Exeter, Ontario to determine if dimethenamid tank-mixed with reduced doses of imazathapyr applied preplant incorporated (PPI) can be used as an efficacious, environmentally acceptable, and economically feasible weed management strategy for broad spectrum weed control in white and kidney beans. There was no additional injury in white or kidney beans with the imazethapyr plus dimethenamid tank-mix treatments evaluated. Based on regression analysis, the dose of imazethapyr required to provide a minimum of 95% control of Amaranthus retroflexus , Ambrosia artemesiifolia , Chenopodium album , Sinapis arvensis , and Setaria viridis was reduced significantly when tank-mixed with dimethenamid (1000 g ha −1 ). There was no adverse effect on the yield of white and kidney beans with any of the herbicides evaluated. The low application dose of imazethapyr compared to dimethenamid (75 vs. 1000 g ai ha −1 , respectively) resulted in an environmental impact (EI) of imazethapyr that was seven-times less than dimethenamid. The application of dimethenamid at 1000 g ai ha −1 or imazethapyr at 15 g ai ha −1 produced the lowest profit margins. Application of higher doses of imazethapyr alone and tank-mixing dimethenamid with imazethapyr increased the profit margins for both white and kidney beans. Based on these results, dimethenamid tank-mixed with reduced doses of imazathapyr applied PPI results in acceptable weed control, crop yield and net returns with an acceptable minimal increase in environmental impact.

The genetic basis for auxinic herbicide resistance of a wild mustard biotype is unknown, although the physiological basis of its resistance is well characterized. Since the auxinic herbicide-resistant (R) biotype and normally susceptible (S) wild mustard plants are genetically diverse, development of completely homozygous R and S lines is a prerequisite for isolation and subsequent characterization of the resistance gene. Completely homozygous lines can be produced using either in vitro microspore culture or by conventional breeding methods (i.e., several generations of selfing); the former being a less time consuming method. With this in mind, microspore culture was used to produce homozygous wild mustard plants. However, despite altering many variables, only a few cotyledonary stage embryos and haploid plantlets could be produced. Upon transfer to soil only one doubled haploid plant established. This plant was self-sterile, cross compatible and resistant to auxinic herbicides. This is the first report describing production of a microspore-derived doubled haploid of wild mustard. However, because only one R doubled haploid plant could be produced, conventional breeding methods (i.e., repeated selfing) will be required for production of both R and S wild mustard plants that are completely homozygous.

An experiment on the effect of row distance and weed control on the herbage yield and some characteristics of Trifolium resupinatum was conducted in 1998–1999 in Bornova, Izmir, Turkey. Row distances were 20, 30 and 40 cm and the herbicides were imazethapyr, imazamox and bentazone. The dry matter yields of clover were highest in 20 cm row distance in both years. The highest crude protein rate was found in 30 cm row distance and bentazone application in second year. The highest crude protein yields were taken from the 20 and 30 cm row distances in both years. Imazethapyr was unsuitable for weed control in Persian clover. In case of a problem originated from the broad-leaved weeds such as Anagallis caerula, Fumaria parviflora, Matricaria chamomilla, Polygonum aviculare, Sinapis arvensis and Stellaria media, bentazone was a suitable herbicide for Persian clover, whereas in the case of presence of broad-leaved weeds and wild oat (Avena sterilis) imazamox was a suitable herbicide for controlling these weeds. Although the herbicide application did not have an important effect on the green herbage yield of Persian clover, it is thought that it is possible to achieve a satisfactory herbage yield by using imazamox. The most suitable row distance was found to be 20 cm in the trial.

Although plant–animal interactions like pollination and herbivory are obviously interdependent, ecological investigations focus mainly on one kind of interaction ignoring the possible significance of the others. Plants with flowers offer an extraordinary possibility to study such mutualistic and antagonistic interactions since it is possible to measure changes in floral traits and fitness components in response to different organisms or combinations of them. In a three factorial common garden experiment we investigated single and combined effects of root herbivores, leaf herbivores and decomposers on flowering traits and plant fitness of Sinapis arvensis. Leaf herbivory negatively affected flowering traits indicating that it could significantly affect plant attractiveness to pollinators. Decomposers increased total plant biomass and seed mass indicating that plants use the nutrients liberated by decomposers to increase seed production. We suggest that S. arvensis faced no strong selection pressure from pollen limitation, for two reasons. First, reduced nutrient availability through leaf herbivory affected primarily floral traits that could be important for pollinator attraction. Second, improved nutrient supply through decomposer activity was invested in seed production and not in floral traits. This study indicates the importance of considering multiple plant–animal interactions simultaneously to understand selection pressures underlying plant traits and fitness.

An auxinic herbicide-resistant biotype of wild mustard was discovered in western Canada in a field sprayed once each year for ten years with combinations of 2,4-D, MCPA and dicamba. Earlier research suggests that the resistance may be due to altered binding of auxinic herbicides to an auxin-binding protein (ABP) in wild mustard. To further elucidate the role of ABP in inducing auxinic herbicide responses in wild mustard, a series of in vitro experiments were initiated. A protocol for generating cell suspensions of both auxinic herbicide-resistant (R) and -susceptible (S) wild mustard was developed from callus cultures. Auxinic herbicide-induced physiological responses (e.g. cell elongation or lateral root formation) of R and S biotypes were compared with ABP1 antisense tobacco (NAS1), as well as to ABP1 over-expressing Arabidopsis in cell suspension and seed culture experiments, respectively. Upon treatment with either NAA (synthetic auxin) or picloram (auxinic herbicide), there was an increased cell elongation in the S biotype and wild-type tobacco, whereas there was no cell elongation in cell suspensions of the R biotype and NAS1. A dose–response assay measuring picloram-induced lateral root formation in the in vitro seed cultures of wild mustard and Arabidopsis showed excessive lateral root formation in the S biotype (0.5–10 μM) and ABP1 over-expressing Arabidopsis (1 μM). These results correlate with the differences between ABP (a potential auxin receptor) levels in R and S wild mustard and this difference may be a possible mechanism of resistance to auxinic herbicides.

There is limited information on the effect of flufenacet plus metribuzin on selected weed species in soybeans ( Glycine max ) in Ontario. Field trials were conducted at two Ontario locations (Exeter and Ridgetown) in 1998 and 1999 to evaluate the tolerance of soybeans to pre-emergence applications of a flufenacet plus metribuzin mixture at doses from 0.67 to 1.68 kg ai ha −1 . The application of flufenacet plus metribuzin caused visual crop injury at 7, 14, and 28 days after treatment (DAT), but resulted in no yield reduction in soybeans compared to weed-free control at all doses evaluated. The PRE application of metribuzin plus flufenacet at the lowest dose (0.67 kg ha −1 ) provided full season control of Chenopodium album L. (common lambsquarter), Amaranthus retroflexus L. (redroot pigweed), and Ambrosia artemesiifolia L. (common ragweed). Higher doses (1.00 g ha −1 ) were needed to effectively control Sinapis arvensis L. (wild mustard) and Setaria viridis (L.) Beauv. (green foxtail) while the highest dose (1.68 kg ai ha −1 ) was required for the control of Abutilon theophrasti Medic. (velvetleaf). At 28 DAT, the biologically effective dose for 50%, 80%, and 90% control of Chenopodium album L. was 0.2, 0.6 and 0.7 kg ha −1 , for 50%, 80%, and 90% control of Setaria viridis (L.) Beauv. was 0.7, 0.9 and 1.1 kg ha −1 and for 50%, 80%, and 90% control of Sinapis arvensis was 1.0, 1.1, 1.3 kg ha −1 , respectively. This research concludes that soybeans were tolerant to flufenacet plus metribuzin at all doses evaluated. Weed species differed in their sensitivity to the herbicide mixture. Chenopodium album L. was the most sensitive to flufenacet plus metribuzin followed by Setaria viridis (L.) Beauv. followed by Sinapis arvensis L.

Two experiments were undertaken to compare seed survival and potential persistence problems of transgenic oilseed rape modified to contain either, stearic acid, or lauric acid, as well as their parental lines. Two conventional varieties (Mars and Starlight) as well as two weed species (Sinapis arvensis and Brassica nigra) were used in the experiments. The first experiment simulated seed loss to the environment at both planting and harvest time with germination characteristics of the lines/species considered. The second experiment investigated seed loss to the environment on either cultivated or uncultivated land and simulated losses to field margins or roadside verges during transit. None of the line/species used was able to reach sexual maturity due to the competitive effect of the vegetation in the plots, and after 7 years, there was no evidence that any of the line/species had survived. Seed persistence varied between both line/species and according to when seed were deposited. The trials provide evidence to suggest that the conventional varieties and the weed species used were more likely to persist in the environment than either of the modified lines or their parents.

Previous studies have suggested that phenolics from legume green manures may contribute to weed control through allelopathy. The objective of this study was to determine how decomposition of red clover (Trifolium pratense L.) residue affects phytotoxicity to a weed species, wild mustard (Sinapis arvensis L.). Red clover (1.25 g), 30 g acid washed sand, and 5 ml of microbial inoculant were incubated in the dark at 14°C. The incubations were conducted in sand to allow the determination of decomposition phytotoxicity effects without being confounded by soil sorption effects. Aqueous extracts were collected at 0, 1, 2 and 5 weeks. The extracts were analyzed for dissolved organic carbon (DOC) and phenolic carbon (PhC). Phytotoxicity of the extracts was estimated by comparing root elongation under sterile laboratory conditions. The red clover extract significantly reduced radicle growth in the bioassay, but there was no significant change in the degree of phytotoxicity over the 5-week decomposition period. Although the concentration of DOC decreased with increasing decomposition, the PhC concentration was not significantly affected. This suggests that in the absence of soil sorbants, the phytotoxic compounds are stable throughout the 5-week incubation period and are phenolic in nature. This study demonstrates that the potential exists for using legume green manures to be a component of a sustainable weed management system, but indicates that soil characteristics need to be factored in evaluating the potential for this weed control tool.

Previous studies have suggested that phenolics from legume green manures may contribute to weed control through allelopathy. The objective was to determine if red clover (Trifolium pratense L.) residue amended field soils expressed phytotoxicity to a weed species, wild mustard (Sinapis arvensis L.). Field plots involving incorporation treatments of wheat (Triticum aestivum L.) stubble or wheat stubble plus 2530 kg ha−1 red clover residue, were sampled at −12, 8, 21, 30, 41, 63, and 100 days after residue incorporation (DAI). Soil–water extracts (1 : 1, m : v) were analyzed for plant nutrients and phenolic content. Phytotoxicity of the extracts was measured using a laboratory wild mustard bioassay. There was a 20% reduction of radicle growth in the green manure treatment in comparison with the wheat stubble treatment, but only at the first sample date after residue incorporation (8 DAI). The radicle growth reduction had the highest correlation with the concentration of soluble phenolics in the soil : water extracts. Bioassays using aqueous extracts of the clover shoots and roots alone predicted a radicle growth reduction of 18% for the quantity of clover amendment rate used in the field plots. The close agreement of the predicted and observed root growth reduction at 8 DAI further supports clover residue as the source of the phytotoxicity. This study demonstrates that the potential exists for using legume green manures to reduce the amounts of synthetic herbicides needed for weed control.

The effects of IAA and the auxinic herbicides picloram and MCPP on the flash-induced nucleotide-independent light-scattering signal from picloram-resistant (R) and- susceptible (S) wild mustard ( Sinapis arvensis L.) protoplasts were studied. We previously demonstrated that an increase in H+ efflux leads to a decrease in amplitude of the light-scattering signal. In this study, IAA increased H+ efflux (i.e., decreased the signal amplitude) in both R and S protoplasts in direct proportion to the IAA concentration. When the signal amplitudes from picloram-treated R and S biotype were compared, they were different. Picloram, which adversely affects the S biotype in vivo and in vitro , increased H+ efflux (reduced signal amplitude) in S protoplasts but did not affect H+ efflux in R. MCPP, which adversely affects both biotypes in vivo and in vitro , increased H+ efflux in both biotypes. Preincubation of S protoplasts with IAA did not alter the effects of picloram or MCPP on H+ efflux (i.e., increased efflux). Conversely, preincubation of R protoplasts with IAA reduced MCPP-mediated H+ efflux thereby reducing the adverse affects of MCPP. These results support our hypothesis that the physiological basis for this auxinic herbicide resistance in the wild mustard biotype is associated with their altered binding to auxin binding sites.

Auxin- and auxinic herbicide-induced volume changes in enzymatically isolated protoplast suspensions from both auxinic herbicide-susceptible (S) and picloram-resistant (R) wild mustard ( Sinapis arvensis L.) biotypes were monitored by right-angle light scattering. The scattering profile of the volume change induced by IAA consisted of an initial shrinkage phase followed by swelling in both biotypes. Kinetic analysis of the swelling phase indicated two first-order processes for the S protoplasts, whereas a single first-order process was observed for the R. In the presence of picloram, only a swelling phase was observed for the S protoplasts, whereas both shrinkage and swelling phases were observed in R protoplasts. When protoplasts from the R biotype were incubated with dicamba or MCPA, which are effective to varying degrees against this biotype, the scattering profiles were similar to those observed for the S biotype with picloram. Simultaneous incubation of R protoplasts with picloram and the calcium channel blocker verapamil reduced the initial shrinkage phase. The differences in response between R and S protoplasts to IAA and the auxinic herbicides at the cellular level suggest certain similarities with respect to the dynamics of protoplast volume changes and provide insight into auxin and auxinic herbicide action.

Levels of the 11 major glucosinolates and two other characteristics (thousand seed weight and colour) were determined in samples of the mustard seed (of Sinapis alba, Brassica nigra and Brassica juncea ) and in samples of the seed of similar Brassica plants ( Sinapis arvensis and Brassica napus ) available from the local testing stations, the local producers and suppliers. The aim of the work was to rationalize the mustard seed quality control using multivariate statistical methods discriminating the individual oilseed types. The data obtained from 19 oilseed samples were subjected to principal components analysis (PCA). PCA conducted with only six original variables (sinigrin, gluconapin, progoitrin and glucoibervirin level, thousand seed weight and colour) was able to separate clusters of Sinapis alba and Brassica napus seeds. A new PCA conducted with a reduced set of four variables (gluconapin, progoitrin and glucoibervirin level and thousand seed weight) readily distinguished between the seeds of Brassica nigra, Brassica juncea and Sinapis arvensis . An acceptable grouping of samples (percent of grouped cases correctly classified was 100) was achieved by stepwise linear discriminant analysis. Only seven variables (thousand seed weight, levels of progoitrin, gluconapin, glucoibervirin, glucoerucin, gluconasturtiin and 4-hydroxyglucobrassicin) contributed to adequate differentiation of B. juncea, B. nigra. and S. arvensis seeds

The effect of the auxinic herbicides dicamba, mecoprop, MCPA, and picloram on seedling development of an auxinic herbicide-resistant and -susceptible biotype of wild mustard ( Sinapis arvensis L.) was studied. When treated with dicamba, MCPA, and picloram differences in the seedling dose-response characteristics were observed between the two biotypes. Conversely, following mecoprop treatment there were no differences between the response of the herbicide susceptible and resistant biotypes. Some characteristics of the resistant and susceptible wild mustard biotype auxin-binding protein (ABP) preparations were examined. Although, both ABP preparations appear to have similar substrate ([ 3 H]indole-3-acetic acid ([ 3 H]IAA) binding) and time course profiles, Scatchard analysis revealed differences between the biotypes; the resistant biotype lacks a high-affinity population of ABP which is present in the susceptible biotype. The effects of the auxinic herbicides on specific [ 3 H]IAA binding to ABP preparations from the resistant and susceptible biotypes were also examined. Mecoprop and MCPA were the most potent inhibitors of [ 3 H]IAA binding to the susceptible biotype ABP preparations, followed by dicamba and picloram. The same pattern of inhibition was also observed when the effect of these herbicides on seedling growth was examined in the susceptible biotype. When picloram and dicamba were used to inhibit [ 3 H]IAA binding and seedling growth, the susceptible biotype was significantly more sensitive to inhibition than the resistant biotype ABP preparations; however, no differences between the two biotypes were observed following MCPA or mecoprop treatment. Our results suggest the effects of various auxinic herbicides on the binding of [ 3 H]IAA to ABP preparations and seedling growth correlate with the effect of these herbicides on whole plants. This data suggests there is a relationship between ABP binding activity and sensitivity to auxinic herbicides and this relationship may explain the mechanism of auxinic herbicide resistance in this wild mustard biotype.

Physiological and morphological characteristics of an auxinic herbicide-susceptible (S) and -resistant (R) biotype of wild mustard (Sinapis arvensis L.) were examined. Plants of the R biotype were shorter, more branched, and had a smaller root system than the S biotype. Leaves of the R biotype were smaller, darker green, and had a higher chlorophyll content than those of the S biotype. The R plants, at the four-leaf stage of development, were more tolerant to cold temperature (7°C) than the S biotype. The percentage of seed germination at 24, 30, and 35°C was higher in the R than the S biotype. At 5°C no difference in percentage of germination between the biotypes was observed, however, the R biotype seedlings were approximately two times longer than the S biotype. When compared to controls, benzyladenine and thidiazuron inhibited seedling growth of the susceptible biotype at 0.1, 1, and 10 mg/liter, whereas only concentrations of 10 mg/liter were inhibitory to the R biotype. Senescence occurred more rapidly in leaf disks of the S biotype. Furthermore, the cytokinin levels, as determined by a cucumber greening bioassay, were higher in the R than in the S biotype, suggesting that some of the differences reported may be a direct consequence of differences in hormonal equilibrium within the biotypes.

Ethametsulfuron methyl (methyl 2-[[[[(4-ethoxy-6-methylamino-1,3,5-triazine-2-yl)amino]carbonyl]amino]sulfonyl]benzoate, formerly DPX-A7881) is a sulfonylurea herbicide for postemergence broadleaf weed control in spring oilseed rape (Brassica napus L.), including canola varieties. Plant response data are presented demonstrating the tolerance of spring oilseed rape to application of 64 g a. i./ha ethametsulfuron methyl while sensitive weeds including Chenopodium album, Sinapsis arvensis, and Amaranthus retroflexus are controlled at rates of 16 g a. i./ha or lower, under greenhouse conditions. The relative tolerance of different weed species and oilseed rape varieties to this sulfonylurea herbicide is related to the rate at which the compound is metabolized to inactive metabolites. Ethametsulfuron methyl is metabolized with a half-life of 1.2-2.5 hr in tolerant oilseed rape, while sensitive weed species or oilseed rape varieties metabolize this herbicide more slowly, with half-lives ranging from 5 to 14 hr. Metabolites of ethametsulfuron methyl were isolated from canola seedlings and analyzed using thermospray liquid chromatography/mass spectrometry (LC/MS), packed capillary LC/MS, and cochromatography with authentic standards. The major early metabolites are O-desethyl ethametsulfuron methyl, which was confirmed by cochromatography with an authentic reference standard, and N-desmethyl-O-desethyl ethametsulfuron methyl. O-Desethyl ethametsulfuron methyl is herbicidally inactive in whole plant studies and is a poor inhibitor of acetolactate synthase, the target site for sulfonylurea herbicides. Additional data are presented which show that the concentration in foliage of ethametsulfuron methyl applied postemergence to oilseed rape at 30 g a.i./ha declines from an initial value of 890 ppb to less than 0.5 ppb 60 days after treatment, and the total radiolabeled burden is only 5 ppb. Thus, the ability of oilseed rape to rapidly metabolize ethametsulfuron methyl accounts for its tolerance to this herbicide and, along with growth dilution, contributes to an extremely low residue lever 60 days after treatment.

Field studies were conducted in Manitoba in 1991 and 1992 to evaluate lentil (Lens culinaris) tolerance to several new broad-spectrum herbicides. Lentils exhibited good tolerance to flurtamone applied soil incorporated in the fall preceding planting, but this treatment failed to control Sinapis arvensis L. Lentils also exhibited good tolerance to dimethenamid applied early postemergence in the spring, but this herbicide controlled only Setaria viridis (Beauv.) L. Flurtamone at 400–600 g a.i. ha−1 was non-toxic to moderately phytotoxic to lentils when applied postemergence to the crop. Imazethapyr injured lentils in both years, and injury increased with rate of application. Lentil yields were reduced at higher rates of imazethapyr application.

Field experiments on soil solarization were conducted in a Mediterranean climate at ICARDA in northern Syria from 1985 to 1988. Fifty-seven species from 25 families were included in this study. Of these, 46 were reduced in numbers as a result of the treatment; five species were increased, six were unaffected. After 20, 30, 40 and 50 days of solarization, weed dry weight was reduced by 84, 87, 86 and 94%, respectively, in a lentil crop and by 61, 76, 81 and 85% in a faba bean crop. Most annual weeds, especially Sinapis arvensis, were controlled up to 100%. Low to zero control or even stimulation occurred with weed species having bulbs (Muscari racemosum, Bellevalia sp., Ornithogalum narbonense), heat-tolerant seed (Coronilla scorpioides, Scorpiurus muricatus), a deep-lying root system or other perennial organs (e.g. Gladiolus aleppicus, Aristolochia maurorum, Leontice leontopetalum, Geranium tuberosum). A higher number of Muscari racemosum plants m−2 was encountered after solarization, indicating stimulation by the treatment. The numbers and dry weight of this weed after 20 days of solarization were increased by 85 and 87% in faba bean and lentil, respectively. Dry weight of spring and summer weeds after 50 days of solarization decreased by 89.2 and 90.3%, respectively. The maximum temperature reached at 5 cm soil depth under the plastic was 57°C.

Following foliar application of picloram (100 g a.i. ha−1) to biotypes of wild mustard (Sinapis arvensis L.) resistant (R) or susceptible (S) to auxinic herbicides, ethylene and its precursors, ACC (1-aminocyclopropane-1-carboxylic acid) and MAAC (1-malonylaminocyclopropane-1-carboxylic acid), as well as ACC synthase were quantified. Severe epinasty occurred within 24 hr after picloram was applied to the S biotype with concomitant increases in ACC synthase, ACC, MACC, and ethylene. No epinasty occurred in the R biotype, nor was there an increase above basal levels of ACC synthase, ACC, MACC, and ethylene in this biotype. Both biotypes became epinastic when fumigated with 120 μl liter−1 of ethylene. Furthermore, when the tissues from both biotypes were supplied with exogenous ACC (1 mM) after pretreatment with aminooxyacetic acid (1 mM), an inhibitor of ACC synthase, both biotypes produced ethylene thereby indicating that ethylene-forming enzyme was not impaired in the resistant biotype. These results suggest that picloram-induced ethylene biosynthesis in the S biotype of wild mustard results from de novo synthesis of ACC synthase; however, this is not the case in the R biotype. Furthermore, sensitivity differences between the two biotypes are related to regulation of picloram-induced ethylene biosynthesis and resistance may be due to a different interaction of the herbicide with primary target site(s) such as the auxin-binding protein(s).

Under controlled environment conditions, ED50 values (dose required to reduce growth by 50%) determined from total plant dry weights in response to foliar-applied ethametsulfuron (DPX-A7881; (methyl-2-[(4-ethoxy-6-methylamino-1,3,5-triazin-2-yl)carbamoylsulfonyl]benzoate) were 148 and 0.85 g ai/ha for commercial brown mustard (Brassica juncea) and wild mustard (Sinapis arvensis), respectively. There was little or no difference in absorption of the herbicide between the two plant species, with >95% absorbed after 12 hr in both species. Approximately 8 and 10% of the recovered radioactivity was translacated out of the treated leaf 72 hr after application to commercial brown mustard and wild mustard, respectively. Acetolactate synthase extracted from the two species was equally sensitive to DPX-A7881 (I50 approximately 15 nM), indicating that selectivity was not due to differences in the herbicide target site between the two species. DPX-A7881 was metabolized more rapidly in commercial brown mustard than in wild mustard; approximately 38, 27, 20, 5, 2, and 3.5% of the recovered radioactivity remained as DPX-A7881 in commercial brown mustard and 64, 57, 35, 29, 25, and 19% remained in wild mustard 12, 24, 36, 48, 72, and 96 hr after treatment. Two common metabolites were formed in each species; one of these accounted for 93 and 67% of the extractable 14C activity in commercial brown mustard and wild mustard, respectively, after 72 hr. The second metabolite constituted less than 25% of the recovered 14C activity at all sampling times, with little difference between the two species. It is proposed that this difference in the rate of metabolism of DPX-A7881 may constitute the basis of selectivity of the herbicide between tolerant commercial brown mustard and sensitive wild mustard.

The efficacy of imazamethabenz-methyl, desmedipham and DPX-A7881 {methyl 2-[(4-ethoxy-6-methyl-amino-1,3,5-triazin-2-yl)carbamoyl-sulphanoyl] benzoate}, for the selective control of Sinapis arvensis L. in safflower (Carthamus tinctorius L.) cv. Saffire, was studied in field experiments from 1987 to 1989. Imazamethabenz-methyl applied at 350–500g a.i.ha−1) to S. arvensis at, or up to, the six-leaf stage consistently resulted in >90% control of the weed with acceptable safflower tolerance. Desmedipham at 500 g a.i.ha−1 resulted in satisfactory S. arvensis control in 1987 while DPX-A7881 at 11 and 22g a.i. ha−1 controlled S. arvensis only in 1989, with measurable crop injury in the same 2 years. Seed weight and size as measured by 1000-kernel weights and 0.51 weights was not affected by any of the treatments. Oil content of safflower seed was reduced by DPX-A7881 treatments in 1989 only.

One laboratory and three field experiments were conducted to determine physiological mechanisms through which barley (Hordeum vulgare L.) monocrops and barley-pea (Pisum sativum L.) intercrops suppressed growth and seed production of two weedy species of mustard (Brassica kaber (DC) L.C. Wheeler and B. hirta Moench). The study quantified the negative effects of nitrogen (N) and light deficits on mustard's photosynthetic performance, and the reduction in mustard's access to N and light resources that resulted from the presence of barley and pea. The work demonstrated that crop competition for resources was paralleled by reductions in mustard's photosynthetic performance, above-ground biomass and seed production. It also showed that the negative effects of the crops on mustard's resource status, photosynthetic performance, and yield could be overcome, at least partially, by application of N fertilizer or use of a pea cultivar that intercepted less light. Mustard suffered most from crop competition when N fertilizer was not applied and when a long-vined pea cultivar that produced abundant leaf area was used in the intercrop mixtures. Instantaneous measurements of net photosynthesis, made on individual leaves early in the growing season, predicted 59–74% of the variation in mustard's final above-ground biomass and seed production.

Relationships between mycorrhizal infection of several weed species and infection of three crop plants were examined under laboratory conditions (pot experiments with Chenopodium album L., spring wheat and lettuce) and field conditions (with C. album, Galinsoga parviflora Cav., Sinapis arvensis L., Sonchus oleraceus L., spring wheat, and maize). The mycorrhiza formation of weeds growing in the vicinity of crop plants was only promoted by crops strongly dependent on mycotrophic nutrition; the infection intensity of these crops themselves also increased. With facultatively mycotrophic crops, on the contrary, mycorrhizal infection can be negatively affected by the weed species.

The qualitative and quantitative composition of sterols in the free form and esterified to fatty acids was studied in seed oils from Brassica napus , B. campestris, B..iuncea, B. nigra, Sinapis alba and S. aruefisis ( Brassica kaber ). Sitosterol, followed by campesterol, predominated in both the free and the esterified sterols. The free sterols were richer in brassicasterol ( ca 10–20%) than the steryl esters (3–10%). Small amounts of δ 5 -avenasterol and δ 7 -stigmastenol were also found in the Brassica oils, often more in the esterified than in the free form. The quantity of sterols was studied only in Brassica campestris , which had ca 0.3 % in the free as well as in the esterified form. In Sinapis alba, ca 10% of the sterols in the free form and 20 % in the esterified sterols were δ 5 -avenasterol. This compared to only a few per cent in both the free and esterified sterols in the Brassica oils. Similarly, ca 2 % of cholesterol was found among the sterols of Sinapis alba but only traces in the Brassica oils. The similarity of sterol compositions among the cultivated brassicas and wild mustard ( Sinapis arvensis ), and the specific characteristics of the sterols in white mustard ( Sinapis alba ) adds further weight to the suggestion that wild mustard should be treated as Brassica kaber and strengthens the generic separation of Sinapis alba .

Field research conducted over six location years has indicated that lathyrus ( Lathyrus sativus L.) is a poor competitor with annual weed species. Failure to control annual weeds reduced lathyrus seed yields by 54–95%, depending on the weed species present and their density. Weed competition also reduced thousand-seed weight. Preplant soil-incorporated applications of trifluralin and postemergence applications of sethoxydim controlled wild oat ( Avena fatua L.) and green foxtail ( Setaria viridis (L.) Beav.). Trifluralin failed to control wild mustard ( Sinapis arvensis L.), an important broad-leaved weed in western Canada, but this weed was controlled by both preplant soil-incorporated and postemergence applications of metribuzin. Lathyrus exhibited excellent tolerance to these herbicides, which are currently registered for use on high-acreage crops in Canada.

Summary Charlock, or wild mustard (Sinapis arvensis L.), is an annual weed that grows in winter cereal crops in Europe. Frequently, drought conditions affect the growth of the mother plant, and the seeds show a remarkable morphological heterogeneity in weight, size and colour at the moment of dispersal. Under a wide range of environmental conditions (water, temperature, oxygen and light), the percentage of germination is always lower than five per cent. Exogenous gibberellic acid applications (>_ 750 /M GA3) break dormancy and also reveal a physiological heterogeneity in the seeds. Independently of the GA3 concentration used, germination of red seeds (the smaller ones) is always higher than that of black seeds. Histological studies show that the seed coat structure (epidermis, macrosclereid cells, pigmented cells and aleurone-like cells) does not differ significantly (p >0.05) between the two types of seeds. Excised embryos of red and black seeds germinate and develop perfect seedlings even after five years of dry storage (RH :S 20% and T = SoC). Abscisic acid analysis by GC-MS has shown the presence of similar amounts in the two types of seed. This leads to the following hypothesis: Red and black seeds have the same level of inhibitors, but red seeds can leak their inhibitor more rapidly. This is supported by the fact of similar levels of abscisic acid in red and black seeds at maturity. Similar quantities of GA3 absorbed by the two types of seeds is also in favour of the same hypothesis.

The 7-glucosides and 3,7-diglucosides of kaempferol and isorhamnetin were identified in leaves and flowers of Sinapis arvensis . Additionally, the 3-sophoroside-7-glucosides of kaempferol, quercetin and isorhamnetin were found in leaves of S. arvensis and Brassica oleracea . Two dimensional surveys of leaf extracts of 27 species and cultivars of Brassica and Sinapis showed that the same pattern occurred in most species. B. tournefortii and S. flexuosa were exceptional in having flavonol 3-monosides and 3-diglycosides instead. The results suggest that it is the glycosidic patterns, rather than the distribution of the flavonol aglycones, which are likely to be of taxonomic value for distinguishing groups of species or genera within the Cruciferae.