Understanding seed moisture desorption and adsorption isotherms is important for seed quality maintenance and better predicting seed storage lifespan. Freshly harvested oilseed rape and barley seeds were dried and then rehydrated twice. Seed equilibrium relative humidity (eRH) and moisture content (MC) were determined at different humidity levels so that two cycles of desorption and adsorption could be constructed. In addition, seeds were dried to 30% RH and then rehydrated to 50% RH for five cycles to determine whether they shift to the adsorption isotherm. Monolayer MC was determined using the Gugenheim-Anderson-de Boer model. Storage experiments were conducted for seeds equilibrated at 30, 40, 50, 60 and 70% RH for two cycles of desorption and adsorption at 45°C. Isotherm curves’ shapes were similar for oilseed rape and barley, although spanning a greater MC range in barley. The hysteresis effect was observed for oilseed rape and barley seeds when dried over silica gel at <10% RH. However, this effect was only observed for barley seeds when dried to 30% RH, but not for oilseed rape seeds. Longevity was greater for adsorbing seeds than desorbing seeds at a given eRH, however, there was no significant difference in σ (the standard deviation of the normal distribution of seed deaths over time)–MC log–log relationship. The relationship shifted for seeds on the second cycle. In conclusion, if seed lots are stored at a specific RH, reaching equilibrium by desorption or adsorption can strongly influence their longevity. Also, when seeds of different species are dried to low RH, they will respond differently to a subsequent increase in RH, which could profoundly affect their longevity.

Sampling flower-visiting insects in agricultural fields at large spatial and temporal scales is significant for understanding local insect pollinator communities. The most commonly used method, pan trap, has been criticized due to its attractant bias. A window trap (also referred to as the flight-intercept trap) is a non-attractant sampling method, which has been applied in forests and grasslands, but rarely in agricultural fields. We aim to test whether we can replace pan traps with window traps in agricultural fields by comparing species richness and species composition between the two methods, and to show whether flower-visiting insects collected in both traps can reflect flower-visiting activity recorded by camera observation. We conducted a 2-year study to compare the performance of these sampling methods in an oilseed rape field. Results showed that the relative abundance of dominant flower-visiting species was highly correlated between the window trap and the pan trap samples, while window traps caught more individuals and higher (rarefied) species richness than pan traps. The species composition of window traps was more similar to each other than that of pan traps. The proportion of honey bees (Apis spp.) collected in both traps underestimated their flower-visiting activity recorded by camera observations, while sweat bees (Halictidae) and butterflies (Lepidoptera) were overestimated. Our study suggests that the window trap has the potential to serve as an alternative sampling method of flower-visiting insects to the pan trap. However, we need to be cautious when using specimens caught in both traps as a proxy of their flower-visiting activity.

Phelipanche ramosa is a major weed holoparasite characterized by a broad host range with a suboptimal development on numerous hosts, suggesting inter- or intra-species specificities. Seeds of P. ramosa germinate after exposure to exogenous chemicals exuded by surrounding host roots such as strigolactones, the concentrations of these germination stimulants varying between hosts. In France, P. ramosa is characterized by genetically differentiated populations presenting varying germination rates and a host specificity. The objective of our study was to investigate the sensitivity of seeds of two P. ramosa populations harvested on tobacco and oilseed rape, to a set of GR24 concentrations, a synthetic strigol analogue. The assessment of the germination rate was based on in vitro experiments. Seeds of P. ramosa were placed in Petri dishes with various concentrations of GR24. The cumulative number of germinated seeds of P. ramosa was counted several times after application of the treatment. Cumulative germination curves were analysed using a three-parameter log-logistic model and a time-to-event approach. The results show that the germination rate of P. ramosa seeds depends on the GR24 concentration and the duration of stimulation, but also that the response to these two factors varies greatly according to the origin of the P. ramosa seeds. The difference in germination speed between P. ramosa populations further shows distinct responses at the intraspecific level, thus suggesting that the specialization of P. ramosa probably occurs at least from the first stage of the holoparasite cycle.

Field studies were conducted to study the interaction of sethoxydim or fluazifop-P with clopyralid and/or ethametsulfuron applied as tank mixtures to canola. Control of the indicator species barley, broadbean, and wild mustard with the tank mixtures was comparable to, or sometimes better than, that attained with each herbicide alone. Canola tolerated all herbicides applied individually and all tank mixtures of these herbicides except fluazifop-P and ethametsulfuron. Tank mixtures of fluazifop-P and ethametsulfuron, with or without clopyralid included in the mixture, suppressed early growth of canola in two of four tests and reduced seed yield in one. Sethoxydim, clopyralid, and ethametsulfuron combined in tank mixtures provide an effective POST alternative for selective control of grass and broadleaf weeds in canola.

Postemergence control of broadleaf weeds in canola with DPX A7881 was studied under controlled-environment and field conditions. DPX A7881 controlled weeds of the Cruciferae family such as wild mustard, field pennycress, and flixweed, which are not controlled with existing herbicides used for weed control in canola. Weed control was better when DPX A7881 was applied at the two-leaf than at the six-leaf stage of the weeds. At the two-leaf stage, control of flixweed was achieved with 15 g ai/ha of DPX A7881; 20 to 30 g ai/ha was required for control of wild mustard and field pennycress. Control of redroot pigweed required 30 g ai/ha. Common lambsquarters was not controlled in this study with DPX A7881 up to 60 g ai/ha. Control of weeds with DPX A7881 increased canola yields in this study without altering the important quality components: oil content, 1000-kernel weight, and green seed content. DPX A7881 provides a postemergence alternative to existing herbicides for broadleaf weed control in canola.

The interaction of DPX-A7881 and clopyralid applied as tank mixtures was studied under controlled environment and field conditions on several commonly occurring weeds in canola. Control of wild mustard and wild buckwheat was not affected by mixing these herbicides. DPX-A7881 controlled wild mustard, and clopyralid controlled wild buckwheat independently of the other herbicide. However, redroot pigweed and common lambsquarters were controlled better with DPX-A7881 plus clopyralid than with either herbicide alone. The herbicides interacted in an additive to synergistic manner on redroot pigweed depending on the rate of each herbicide. DPX-A7881 and clopyralid interacted synergistically at all rates on common lambsquarters. Plant height, date of flowering, seed yield, and quality data all indicated that canola completely tolerated DPX-A7881 and clopyralid applied alone or in combination.

This study investigated the induction and loss of dormancy in oilseed rape (Brassica napus). Twenty genotypes were preliminary screened; from these, two genotypes, RGS003 and Hayola 308, which possess high potential for dormancy induction (HSD) and medium potential to induce secondary dormancy (MSD), were selected. The stratification of seeds at alternating temperatures of 5–30°C (in dark) significantly relieved secondary dormancy, but dormancy was not fully released. The ψb(50) values were −1.05 and −1.06 MPa for the MSD and the HSD before dormancy induction. After inducing dormancy, the ψb(50) values for the MSD and the HSD were increased to −0.59 and −0.01 on day 0 stratification at 20°C. The hydrothermal time (θHT) value was low for one-day stratification for HSD in comparison with other stratification treatments. Water stress can induce dormancy (if the seeds have the genetic potential for secondary dormancy) and warm stratification (in dark) can only reduce the intensity of dormancy. The seeds with a high potential of dormancy induction can overcome dormancy at alternating temperatures and in the presence of light. It can, therefore, be concluded that a portion of seeds can enter the cycle of dormancy ↔ non-dormancy. The secondary dormant seeds of B. napus cannot become non-dormant in darkness, but the level of dormancy may change from maximum (after water stress) to minimum (after warm stratification). It seems that the dormancy imposed by the conditions of deep burial (darkness in combination with water stress and more constant temperatures) might be more important to seed persistence than secondary dormancy induction and release. The dormancy cycle is an important pre-requisite in order to sense the depth of burial and the best time for seed germination.

Weed management strategies can influence insect infestations in field crops, yet no attempts have been made previously to manipulate weed populations in canola for integrated weed and insect management. Field studies were conducted during 2003 to 2005 at Lacombe and Beaverlodge, Alberta, Canada to manipulate weed and root maggot, Delia spp. (Diptera: Anthomyiidae), interactions in canola. Densities of monocot weeds were varied by altering herbicide applications, with rates ranging from 0 to 100% of the rate recommended. Weed populations declined, and yields were variable with increased herbicide rates. Root maggot damage decreased with increases in monocot weed dry weight for both canola species at both study sites. Results support the hypothesis that heterogenous environments, arising from mixed populations of monocot weeds with canola, minimize opportunities for females of Delia spp. to complete the behavioral sequence required for oviposition, leading to reduced infestation levels in weedy systems. However, effects of dicot weeds on root maggot infestations varied between sites as a result of site-related differences in weed species complexes. When wild mustard was common, crop damage increased, because this weed can serve as an alternate host for root maggots. The study emphasizes the importance of adopting crop management practices that are compatible for both weed and root maggot control.

The presence of volunteer canola is becoming a significant agro-ecological concern, given the large-scale use of herbicide-tolerant varieties in some areas. Our goal was to estimate the frequency and persistence of volunteer canola in Québec cropping systems by surveying fields that included a single canola crop since 1995. A survey was conducted in 131 fields in the main canola-growing areas of Québec: in the Saguenay-Lac Saint-Jean region and the Québec City–La Pocatière area. Volunteer canola plants were counted in 0.25-m2 quadrats every 10 m along a W pattern, and every 15 m along the margins of 88 fields. Volunteer canola plants were found in 90% of the fields surveyed and in a wide range of crops, including cereal, corn, and soybean. Average densities of 4.9 and 3.9 plants/m2 were found 1 yr after canola production in fields and field margins, respectively. Volunteer canola densities decreased significantly over time. However, volunteer plants were still present at low densities 4 and 5 yr after production. Dense stands of volunteer canola were found before postemergence herbicide application in no-till fields (9.8 ± 4.1 plants/m2), suggesting that, contrary to what was suggested in the literature, seeds could become dormant in no-till as well as in tilled systems. A small proportion of the volunteer canola plants observed in no-till fields near Québec City and Ottawa included plants that had overwintered, either originating from fall-germinated seedlings, harvested adult plants that had grown new leaves before the onset of winter, or spring regrowth from the base of unharvested adult plants from experimental plots. The presence and persistence of low densities of volunteer canola may not have been a cause of concern until now. However, producers should be made more aware of the potential short-and long-term problems associated with potential gene flow between different herbicide-tolerant canola (HT canola) varieties and also between HT canola and related weed species.

A field in which Brassica napus volunteers were not controlled by several applications of glyphosate was investigated in 1998. This field had been planted with glufosinate-resistant and imidazolinone-resistant B. napus in 1997 and was adjacent to a field that had grown glyphosate-resistant B. napus. Mature volunteer B. napus were collected on a 50- by 100-m grid in the field. Progeny from 34 volunteers were sprayed with glyphosate at 440 g ae ha−1, and the survivors were sprayed with either glufosinate or imazethapyr at 400 or 50 g ai ha−1, respectively. Where seed numbers permitted (14 volunteers), seedlings were also sprayed sequentially with glyphosate, glufosinate, and imazethapyr, at 440 g ae ha−1, 400 g ai ha−1, and 50 g ai ha−1, respectively. In total, 15 volunteers had progeny that were between 66 and 82% resistant to glyphosate, consistent with the predicted 3:1 resistant : susceptible ratio. Volunteer B. napus plants with glyphosate-resistant seedlings were most common close to the putative pollen source; however, a plant with glyphosate-resistant progeny was collected 500 m from the adjacent field edge. Seedlings from all nine volunteers collected from the glufosinate-resistant area showed multiple resistance to glyphosate and glufosinate, whereas seedlings from 10 of 20 volunteers collected from the imidazolinone-resistant area showed resistance to imazethapyr and glyphosate. DNA extraction and restriction fragment length polymorphism (RFLP) analysis of seedlings confirmed that mature B. napus volunteers were hybrids resulting from pollen transfer rather than inadvertent seed movement between fields. Two seedlings from the 924 screened were resistant to all three herbicides. Progeny from these self-pollinated individuals were resistant to glyphosate and glufosinate at the predicted 3:1 resistant : susceptible ratio and resistant to imazethapyr at the predicted 15:1 resistant : susceptible ratio. Sequential crossing of three herbicide-resistant varieties is the most likely explanation for the observed multiple herbicide resistance. Integrated management techniques, including suitable crop and herbicide rotations, herbicide mixtures, and nonchemical controls should be used to reduce the incidence and negative effect of B. napus volunteers with multiple herbicide resistance.

Field-scale experiments were conducted at several western Canada locations to determine the importance of early weed removal over variable landscapes. In eight of 10 cases, imidazolinone-resistant (IR) canola yield decreased linearly as herbicide application (15/15 g/ha imazamox/imazethapyr or 15/15 g/ha imazamox/imazethapyr plus 150 g/ha clopyralid) was delayed beyond the one- to two-leaf stage. In two of 10 cases, canola oil content also decreased as herbicide treatment was delayed. Canola yields at all environments (location by year combinations) averaged 2,073, 1,872, or 1,650 kg/ha when treated at the one- to two-, three- to five-, or six- to seven-leaf stage, respectively. Assuming canola prices from a low of $250/t to a high of $650/t, growers could lose $50 to $131/ha, respectively, by delaying herbicide application from the one- to two- to the three- to five-leaf stage, or $106 to $275/ha, respectively, by delaying herbicide application from the one- to two- to the six- to seven-leaf stage.

Many conditions need to be satisfied for gene flow to occur between a transgenic crop and its weedy relatives. Flowering overlap is one essential requirement for hybrid formation. Hybridization can occur between canola and its wild relative, wild radish. We studied the effects of wild radish plant density and date of emergence, canola (glyphosate resistant) planting dates, presence of other weeds, and presence of a wheat crop on the synchrony of flowering between wild radish and canola (as a crop and volunteer). Four field experiments were conducted from 2000 to 2002 in St-David de Lévis, Québec. Flowering periods of wild radish emerging after glyphosate application overlapped with early-, intermediate-, and late-seeded canola 14, 26, and 55%, respectively, of the total flowering time. Flowering periods of early-emerging wild radish and canola volunteers in uncropped treatments overlapped from mid-June until the end of July, ranging from 26 to 81% of the total flowering time. Flowering periods of wild radish and canola volunteers emerging synchronously on May 30 or June 5 as weeds in wheat overlapped 88 and 42%, respectively, of their total flowering time. For later emergence dates, few flowers or seeds were produced by both species because of wheat competition. Wild radish density in canola and wild radish and canola volunteer densities in wheat did not affect the mean flowering dates of wild radish or canola. Increasing wild radish density in uncropped plots (pure or weedy stands) hastened wild radish flowering. Our results show that if hybridization is to happen, it will be most likely with uncontrolled early-emerging weeds in crops or on roadsides, field margins, and uncultivated areas, stressing the need to control the early flush of weeds, weedy relatives, and crop volunteers in noncrop areas.

Early weed removal in canola gives the crop a competitive advantage over weeds and is therefore widely recommended for optimal crop production, but no studies have been undertaken previously to determine the effect of this practice on insect infestations. Four field experiments were conducted at Lacombe and Beaverlodge, AB, Canada, in 1999–2001 for a total of 10 site-years to determine the effect of time of weed removal on root maggot (Delia spp.) egg deposition and larval damage to taproots. The experiments also investigated the effects of other factors such as cultivar, seeding date, herbicide application rate, fertilizer rate and placement, and use of a nitrification inhibitor on root maggot damage and oviposition. Damage to taproots and oviposition declined by approximately 6 and 23%, respectively, with a delay in weed removal from the two- to six-leaf stage of canola development. The effect of time of weed removal on root maggot damage and egg density sometimes varied with site and cultivar, but the main effect of time of weed removal was more prominent (smaller P values) than interactions with site. The most plausible explanation for this effect relates to the behavioral sequence of events that precedes oviposition in mated, gravid female flies. Heterogeneous environments, such as weedy backgrounds in canola plantings, minimize opportunities for females of Delia spp. to complete the behavioral sequence required for oviposition, leading to reduced infestation levels in weedy systems. However, yield improvements achieved with early weed removal exceeded the yield benefit derived by lowered root maggot pressure when weeds were removed later. Nevertheless, current efforts to reduce pesticide use in agriculture may promote broader adoption of cultural control strategies for weed and root maggot management. In some situations, it may then be appropriate to ameliorate root maggot damage by maintaining some weedy background.

Knowledge about genetic diversity among Brassica napus cultivars developed for many growing regions and their possible use as potential inbred lines for hybrid seed production is limited. We studied the genetic diversity and relationships among B. napus accessions using Sequence Related Amplified Polymorphism (SRAP) markers, which preferentially amplify open reading frames. A total of 60 spring-type B. napus accessions were screened using 20 SRAP primers, which revealed 162 polymorphic fragments with an average of eight markers per primer combination. Genetic similarity estimates ranged from 40 to 100, which indicated sufficient diversity among the accessions. The majority of the accessions were uniquely identified by the markers with the exception of near-isogenic inbred lines. Cluster analysis displayed five major groups. The first major cluster comprised 23 accessions mostly of Australian origin, whereas the second cluster included 13 accessions mostly of Canadian origin. The accessions in the first and second clusters were identified as maintainers of cytoplasmic male sterility. The two restorer lines R-111 and R-101 along with their corresponding backcross progeny constituted the third cluster. Scandinavian cultivars made the fourth separate cluster. One cultivar Salam and its respective inbred line were the most divergent lines. Variations in the number of markers between open-pollinated cultivars and their respective selfed inbred lines were also observed. The clustering pattern mostly supported their respective pedigree and characteristic traits. Genetic diversity in genetically distinct groups in the tested maintainer and restorer lines can be exploited for hybrid development in B. napus.

Winter rape has a life cycle which necessitates rapid testing of seed quality for the seed production sector, namely between July after harvest of the previous crop and August when the next crop establishment begins. As this crop is the fourth most important crop in France, and the most important oilseed crop, the French seed testing station GEVES has managed several research programmes to study seed quality in this species. These collaborative programmes have not only associated seed science with seed technology but also informatics and electronic engineering to provide seed testing tools that are already used by the seed sector, such as conductivity, or innovative tools, such as germination time courses monitored by computer imaging. Forthcoming tools have also been looked at in order to control seed storage potential, which is often used nowadays to anticipate the next season. Biochemical markers have been studied, including seed-specific biotinylated proteins or enzymes involved in free radical (reactive oxygen species) scavenging, such as catalase. Both are well correlated with seed ageing and have been tested to provide an ELISA-like assay for seed testing laboratories. Germination monitoring by computer imaging is now used by research and breeding institutes to phenotype varying seed material, including genotype or mutant collections, primed or ageing seed lots, etc. The next step in seed quality testing in oilseed rape is to characterize variation in germination and seed vigour in order to stabilize optimal yield. This aim constitutes a new international project involving high-throughput phenotyping and genotyping of a large collection of genetically diverse rapeseed genotypes (double haploid populations or diverse cultivars).

The objectives of this study were to investigate the effect of dietary lipid source on the growth and carcass characteristics of lambs sourced from a range of crossbred hill ewes. Over a 2-year period, 466 lambs representing the progeny of Scottish Blackface (BF × BF), Swaledale (SW) × BF, North Country Cheviot (CH) × BF, Lleyn (LL) × BF and Texel (T) × BF ewes were sourced from six commercial hill flocks and finished on one of four diets: grass pellets (GP), cereal-based concentrate (CC), CC enriched with oilseed rape (CR) and CC enriched with fish oil (CF). Dry matter intake (DMI) was highest (P < 0.001) in lambs offered GP; however, carcass weight gain (CWG) and feed conversion efficiency were higher (P < 0.001) in lambs fed concentrate-based diets. For lambs offered concentrate-based diets, DMI and live weight gain were lower (P < 0.001) for CF than CC or CR. Lambs with T × BF dams achieved a higher (P < 0.05) daily CWG and CWG/kg DMI than BF × BF, SW × BF or LL × BF dams. When lambs were slaughtered at fat score 3, CH × BF, LL × BF and T × BF dams increased carcass weight by 0.8 to 1.4 kg (P < 0.001) and conformation score (CS) by 0.2 to 0.4 units (P < 0.001) compared with BF × BF or SW × BF dams. However, breed effects on carcass conformation were reduced by 50% when lambs were slaughtered at a constant carcass weight. Diets CC and CR increased carcass weight by 0.8 to 1.6 kg (P < 0.001) and CS by 0.1 to 0.3 units (P < 0.001) compared with GP and CF. Both, dam breed and dietary effects on carcass conformation were associated with an increase (P < 0.001) in shoulder width of the lambs. Lambs fed CF and slaughtered at a constant carcass weight had more subcutaneous fat over the Longissumusdorsi (P < 0.05), Iliocostalisthoracis (P < 0.001) and Obliquus internusabdominis (P < 0.001) compared with those fed CC. However, these effects were removed when lambs were slaughtered at a constant fat score. At both endpoints, lambs from T × BF dams contained less (P < 0.05) perinephric and retroperitoneal fat than SW × BF or LL × BF dams fed GP or CC, respectively. The results from this study show that using crossbred ewes sired by CH, LL or T sires will increase carcass weight and improve carcass conformation of lambs sourced from hill flocks. Inclusion of oilseed rape in lamb finishing diets had only minor effects on performance compared with a standard CC but feeding fish oil or GP impacted negatively on lamb growth and carcass quality.

The cabbage stem weevil (Ceutorhynchus pallidactylus (Mrsh.)) (Col., Curculionidae) is a serious pest of winter oilseed rape (Brassica napus L. var. oleifera Metzg.) in central and northern Europe. Although host-plant resistance is a key tool in integrated pest management systems, resistant genotypes are not yet available for this species. Resynthesized rapeseed lines (B. oleracea L.×B. rapa L.) are broadening the genetic diversity and might have potential as sources of resistance to pest insects. The host quality, of nine resynthesized rapeseed lines and six genotypes of B. napus to cabbage stem weevil, was evaluated in laboratory screening tests and in a semi-field experiment. In dual-choice oviposition tests, female C. pallidactylus laid significantly fewer eggs on five resyntheses and on swede cv ‘Devon Champion’ than on the moderately susceptible oilseed rape cv ‘Express’, indicating a lower host quality of these genotypes. Results of laboratory screenings were confirmed in a semi-field experiment, in which twelve genotypes were exposed to C. pallidactylus females. The number of larvae was significantly lower in two resyntheses and in cv ‘Devon Champion’ than in oilseed rape cv WVB 9. The total, as well as individual, glucosinolate (GSL) content in the leaves differed substantially among the genotypes tested. The amount of feeding by larvae of C. pallidactylus, as measured by a stem-injury coefficient, was positively correlated with the indolyl GSL compounds 3-indolylmethyl and 4-methoxy-3-indolylmethyl, and with the aromatic GSL 2-phenylethyl, whereas it was negatively correlated with 4-hydroxy-3-indolylmethyl. Thus, the composition and concentration of GSL compounds within the plant tissue might be a key factor in breeding for pest resistance in oilseed rape.

While significant progress has been made on the modification of crops for the benefit ofproducers, the same cannot be said in regards to eliciting the potential impact that thesecrops may have on the wider landscape and the diversity of life therein. Managementimpacts can create difficulties when making policy, regulation and licensing decisions inthose countries where agriculture has a significant social and ecological position in thelandscape. To begin to gauge the potential impacts of the management of a selection of GMcrops on an agricultural landscape, four key biodiversity stressors (Chemicals,Introgression, Nutrients and Management: CINMa) were identified and a grading systemdeveloped using published data. Upon application to five selected GM crops in a case studyarea, CINMa identifies areas in the wider landscape where biodiversity is likely to benegatively or positively impacted, as well as agricultural zones which may benefit fromthe land use change associated with the management of GM crops and their associated postmarket environmental monitoring.

Pollen-mediated gene flow in space is well documented and isolation distances are recommended to ensure genetic purity of Brassica napus seed crops. Isolation in time could also contribute to gene flow management but has been little investigated. We assessed the effects of asynchronous and synchronous flowering on intraspecific B. napus gene flow by seeding adjacent plots of transgenic spring canola cultivars, either resistant to glyphosate or glufosinate, over a 0–4 week interval and measuring outcrossing rates and seed-set. Outcrossing rates, evaluated in the center of the first adjacent row, were reduced to the lowest level in plots flowering first when the seeding interval > 2 weeks. Increasing the time gap increased outcrossing rates in plots flowering second up to a seeding interval of two weeks. Flowers that opened during the last week of the flowering period produced fewer seed (< 10% of total seed production) and a smaller fraction of outcrossed seed (–25%). Observed time gap effects were likely caused by extraneous pollen load during the receptivity of productive seed-setting early flowers. Clearly, manipulation of B. napus flowering development through staggered planting dates can contribute to gene flow management. The approach will need to be validated by additional site-years and increased isolation distances.

Monitoring for escape of genetically modified (GM) oilseed rape (Brassica napus) during transport can be performed by means of roadside evaluations in areas where cultivation of this GM crop is not conducted, such as in Japan. We performed a survey of oilseed rape plants growing along a 20-km section of Japan's Route 51, one of the main land transportation routes in central Japan for imports of GM oilseed rape from the Port of Kashima into Keiyo District. Oilseed rape plants were found each year, but the number of plants varied substantially during the three years of our study: 2162 plants in 2005, 4066 in 2006, and only 278 in 2007. The low number in 2007 was probably caused by roadwork. Herbicide-resistant individuals were detected in the three consecutive years (26, 8, and 5 individuals with glyphosate resistance), but glufosinate-resistant plants (9 individuals) were detected only in 2005. The roadside plants occurred mainly along the inbound lane from Kashima to Narita. These plants are likely to have their origin in seeds spilled during transportation of cargo from the port, since there are no potential natural seed source plants for B. napus near Route 51. This is the first detailed report on the transition and distribution of herbicide-resistant oilseed rape plants following loss and spillage along Japanese roads.