Oilseed Rape Production Research Articles

Landscape crop diversity contributes to higher pollination effectiveness and positively affects rapeseed quality in Mediterranean agricultural landscapes

Pollination is crucial for biodiversity and food security. Heterogeneous agricultural landscapes have a positive effect on pollinator abundance and enhance crop production and quality. In this study, we explored the effects of three landscape features (past crop diversity measured as the Equivalent Richness of crop functional Groups in the previous year [ERGp], semi-natural habitat percentage [SNH], and mean field size [MFS]) and pollinator densities (wild bees [WB] and honey bees [HB]) on pollination and seed quantity and quality in rapeseed crops. Surveying the pollinator density in 20 rapeseed fields revealed a positive relationship with ERGp in the landscape. A pollinator exclusion experiment compared bagged and open-pollinated self-compatible rapeseed plants and revealed insect pollination effectiveness (fruits per flower and number of seeds per pod) and seed quality (oil content). Seed parameters were evaluated in relation to pollinator density (WB-HB) and landscape characteristics. The ERGp emerged as a crucial landscape feature that positively impacted WB density. When insect pollinators were excluded, plants exhibited reduced pollination effectiveness and seed quality. Analysis of open-pollinated plants highlighted ERGp as the most influential variable, positively affecting both sets of parameters. The MFS and SNH showed different but important relationships. Total tocopherol and α-tocopherol were positively correlated with pollinator density in HB, whereas WB showed a positive correlation with γ-tocopherol levels. Increased ERGp positively affected pollinator density and pollination effectiveness, thereby improving oilseed rape production quantity and quality. This study provides new insights into agroecosystem management and pollinator-friendly practices.

Biophoton emission-based approach of the effects of systemic insecticides on the survival of Eurydema ventralis Kolenati, 1846 (Hemiptera: Pentatomidae) and on the photosynthetic activity of oilseed rape

The choice of effective crop protection technologies is a key factors in the economical production of oilseed rape. Insecticides belonging to the group of active substances butenolides and diamides are active substances available as seed treatments in oilseed rape and promising control tools in the crop protection technologies. Our laboratory experiment demonstrated that the experimental insecticides flupyradifurone and cyantraniliprole are both effective against Eurydema ventralis (Hemiptera: Pentatomidae) when used as a seed and in-crop treatments, but there is a fundamental difference in their insect mortality inducing effects. Flupyradifurone was found to have a total mortality 96 h after application based on basipetal translocation. In the case of cyantraniliprole, the insecticidal effect of the same treatment was 27% less. The experiment showed that the acropetal translocation of the tested active substances after seed treatment did not induce efficacy comparable to that of the basipetal translocation. The study of the biophoton emission of the plants demonstrated a verifiable correlation between the different application methods of the insecticides and the photon emission intensity per unit plant surface area. In conclusion, the systematic insecticides tested, in addition to having the expected insecticidal effect, interfere with plant life processes by enhancing photosynthetic activity.

Evaluation of the effect of magnetic field on rapeseed growth and the causal agent of blackleg disease, Phoma lingam.

In recent years, with the increased production of oilseed rape, there has been a simultaneous enhancement in reports on pathogens causing diseases. Magnetic technology has been recognized as a new agricultural method aimed at improving health and crop production. In this work, the effect of magnetic fields was studied on the mycelial growth and conidia formation of Leptosphaeria maculans Gol125 and Leptosphaeria biglobosa KH36, the causal agents of Phoma stem cancer (blackleg) disease in rapeseed. In addition, seeds exposed to eight direct frequencies of magnetic fields were impregnated with pathogen suspension and grown under greenhouse conditions. The growth speed of both pathogen isolates decreased by 1-28% in GOL125 and 6-46% in KH36 over time in cultures exposed to magnetic fields. However, the number of conidia increased significantly under magnetic field exposure, reaching 5.4 × 107 and 7.7 × 107 SFU/ml in KH36 and GOL125 isolates, respectively. Furthermore, in greenhouse conditions, an increase in photosynthetic pigment levels was observed in almost all of the magnetic field-treated plants. In addition, disease incidence decreased by around 6% in the magnetic field-treated plants. This study represents the first evaluation of magnetic technology in controlling plant diseases. The use of magnetic fields may present a viable strategy for a sustainable production system; however, it requires further advanced studies to improve plant health and productivity.

Efficacy and toxic action of the natural product natamycin against Sclerotinia sclerotiorum.

Sclerotinia stem rot caused by Sclerotinia sclerotiorum seriously endangers oilseed rape production worldwide, and the occurrence of fungicide-resistant mutants of S. sclerotiorum leads to control decline. Thus, it is critical to explore new green substitutes with different action mechanisms and high antifungal activity. Herein, the activity and the action mechanism of natamycin against S. sclerotiorum were evaluated. Natamycin showed potent inhibition on the mycelial growth of S. sclerotiorum, and half-maximal effective concentration (EC50 ) values against 103 S. sclerotiorum strains ranged from 0.53 to 4.04 μg/mL (mean 1.44 μg/mL). Natamycin also exhibited high efficacy against both carbendazim- and dimethachlone-resistant strains of S. sclerotiorum on detached oilseed rape leaves. No cross-resistance was detected between natamycin and carbendazim. Natamycin markedly disrupted hyphal form, sclerotia formation, integrity of the cell membrane, and reduced the content of oxalic acid and ergosterol, whereas it increased the reactive oxygen species (ROS) and malondialdehyde content. Interestingly, exogenous addition of ergosterol could reduce the inhibition of natamycin against S. sclerotiorum. Importantly, natamycin significantly inhibited expression of the Cyp51 gene, which is contrary to results for the triazole fungicide flusilazole, indicating a different action mechanism from triazole fungicides. Natamycin is a promising effective candidate for the resistance management of S. sclerotiorum. © 2023 Society of Chemical Industry.

Effects of combined application of nitrogen and potassium on oil concentration and fatty acid component of oilseed rape (Brassica napus L.)

ContextNutrient inputs significantly affect the quality of rapeseed, yet comprehensive research on combined nutrient applications is lacking. ObjectiveTo investigate the effects of combined application of N and K on rapeseed traits, including N, K, oil, and protein concentrations, fatty acid component, seed yield and oil yield. MethodsA 2-year field experiment was conducted in the Yangtze River Basin involving the rapeseed cultivars H9 (low oil) and Z11 (high oil). Sixteen N and K fertilizer combinations encompassed four N rates (0, 90, 180, and 270 kg N ha−1) and four K fertilizer rates (0, 60, 120, and 180 kg K2O ha−1). ResultsThe results revealed that the combined application of N and K significantly affected rapeseed oil and protein concentrations by modulating the nutrient concentrations. Specifically, applying N reduced the oil concentration while applying K increased the oil concentration. Each 1.0% rise in seed K concentration corresponded to a 14.9% average increase in oil concentration, counterbalancing a 2.8% increase in N concentration. Additionally, the higher oil concentration of Z11was closely linked to its seed K concentration. In contrast, protein concentration increased with the N application and decreased with the K application. Furthermore, applying N reduced palmitic (C16:0) and stearic (C18:0) acid content and increased oleic (C18:1) acid content, which further increased with K. Combining the K application with the N treatment resulted in higher seed yield and oil yield compared to a single N application, which particularly benefited the high oil cultivar Z11. ConclusionUtilizing an N180K120 combination significantly improved rapeseed oil concentration, fatty acid composition, seed yield, and oil yield. ImplicationsThis study details the effects of applying K at various N fertilizer rates on enhancing rapeseed quality and yield, emphasizing the importance of the N and K ration in oilseed rape production.

Diversity of parasitoid wasps (Insecta, Hymenoptera) in oilseed rape fields in Serbia

Oilseed rape is an important crop grown worldwide and used for various purposes, including oil extraction and animal feed. In Europe, there are six major pest species and several other minor pests that can significantly affect oilseed rape production, requiring growers to effectively control them in order to ensure crop yield. The host-parasitoid complexes of these pests have been studied in detail and recorded mainly in western, central and northern Europe. As an abundant source of pollen and nectar, oilseed rape may also be attractive to other parasitoids that do not have direct trophic interactions with oilseed rape pest species. The aim of this study is to fill the knowledge gap regarding the wider parasitoid community in oilseed rape fields, particularly in southern Europe. During the two-year study, a total of 3135 specimens of primary and secondary parasitoids were sampled, of which 2855 were found in oilseed rape fields and 280 in semi-natural habitats. We found 153 taxa, of which 119 were found in oilseed rape fields and 87 in semi-natural habitats. We identified 31 genera (33 species) as parasitoids of oilseed rape pests, 54 genera (97 species) parasitising non-pest species and 10 genera (23 species) as possible parasitoids of oilseed rape pests. This study shows that the parasitoid community in oilseed rape fields is very diverse and that includes parasitoids of both oilseed rape pest and non-pest species.

Use of an unmanned aerial vehicle for monitoring and prediction of oilseed rape crop performance.

The flowering stage of oilseed rape (Brassica napus L.) is of vital interest in precision agriculture. It has been shown that data describing the flower production of oilseed rape (OSR), at stage 3, in spring can be used to predict seed yield at harvest. Traditional field-based techniques for assessing OSR flowers are based on a visual assessment which is subjective and time consuming. However, a high throughput phenotyping technique, using an unmanned aerial vehicle (UAV) with multispectral image (MSI) camera, was used to investigate the growth stages of OSR (in terms of crop height) and to quantify its flower production. A simplified approach using a normalised difference yellowness index (NDYI) was coupled with an iso-cluster classification method to quantify the number of OSR flower pixels and incorporate the data into an OSR seed yield estimation. The estimated OSR seed yield showed strong correlation with the actual OSR seed yield (R2 = 0.86), as determined using in-situ sensors mounted on the combine harvester. Also, using our approach allowed the variation in crop height to be assessed across all growing stages; the maximum crop height of 1.35 m OSR was observed at the flowering stage. This methodology is proposed for effectively predicting seed yield 3 months prior to harvesting.

Genetic Diversity and Population Structure of Leptosphaeria biglobosa from the Winter Oilseed Rape Region in China.

Phoma stem canker (blackleg), caused by the fungi Leptosphaeria maculans (anamorph Phoma lingam) and L. biglobosa, is one of the most devastating diseases in oilseed rape (Brassica napus L.) production worldwide. However, the population structure and genetic variation of L. biglobosa populations in China have rarely been investigated. Here, a collection of 214 fungal strains of blackleg from China (including Shaanxi, Jiangxi, Hubei, Jiangsu, Chongqing, Sichuan, Guangxi, Guizhou, Hunan, and Henan) and Europe (France and Ukraine) was identified as L. biglobosa. Three simple sequence repeat (SSR) markers were developed to characterize their population structure. The results showed that the Nei's average gene diversity ranged from 0.6771 for the population from Jiangsu to 0.3009 for the population from Hunan. In addition, most of the genetic variability (96%) occurred within groups and there were only relatively small amounts among groups (4.0%) (FST = 0.043, p = 0.042 < 0.05). Pairwise population differentiation (FST) suggested that significant genetic differentiation was observed between different L. biglobosa populations. Bayesian and unweighted average method analysis revealed that these L. biglobosa strains were clustered into three branches, and three European strains were similar to those from eastern China. The pathogenicity assay showed that those in Group III were significantly more virulent than those in Group I (t = 2.69, p = 0.016). The study also showed that Group III was dominant in Chinese L. biglobosa populations, which provides new insights for the further study of population evolution and the management of this pathogen.

Seasonal variation is a bigger driver of soil faunal and microbial community composition than exposure to the neonicotinoid acetamiprid within Brassica napus production systems

Neonicotinoid pesticides are widely used within agroecosystems. Due to their systemic nature and high solubility, neonicotinoids are frequently recorded in soil, water, untreated plant matter and non-target organisms. Studies have demonstrated their capacity to induce invertebrate mortality, however, very little research has been conducted beyond pollinator exposure, particularly under field conditions. Typically, many neonicotinoids are applied via seed-dressings, reducing their direct contact with pollinators, but offering an unintended soil-exposure pathway. Soil biology underpins many vital functions, from regulating water and gas flow, to maintaining physical soil structure. In this study we investigated the effect of a commercial neonicotinoid pesticide (Insyst®) on the abundance, richness, and composition of both the mesofaunal and microbial communities and associated metabolome during oilseed rape (Brassica napus L.) production. Our results showed that over a single growing season, foliar application of Insyst® (250 g ha−1, 50 g ha−1 of the active ingredient, acetamiprid) had no significant effect (P > 0.05) on the measured soil biological indexes. Seasonal variation was a significantly greater driver in regulating biological communities within the soil than Insyst® application. In addition, we showed that the active ingredient (acetamiprid) was rapidly degraded by the soil microbial community (theoretical half-life = 119 days) during the summer cropping season. These results help highlight the need for realistic field studies, as agricultural pesticides are never pure, often containing surfactants, adjuvants, or emulsifiers which alter their behaviour and ecotoxicity. Understanding the biological interactions of vital soil fauna with necessary pesticide usage will enable proper risk alleviation measures to maintain soil biological and ecological health.

Larger bees facilitate the deposition of oilseed rape pollen (Brassica napus L.)

Oilseed rape is the third-largest source of vegetable oil and the second-largest source of protein meal in the world. Pollinators are vital in the production of oilseed rape. However, pollination efficiency could be influenced by the morphology and foraging behaviors of pollinators. To evaluate the effect of pollinator size and foraging behavior on pollination efficiency, the intertegular distances (ITDs) of five bumble bees (Bombus pyrosoma, B. lantschouensis, B. melanurus, B. sichelii and B. sibiricus) and two honey bees (Apis mellifera and A. cerana) were evaluated. Their foraging activities and single visit depositions (SVDs) on oilseed rape were observed and counted. The ITDs of bumble bees were significantly larger than honey bees (P < 0.05). The single-visit duration of A. mellifera (2.43 ± 0.06 s) was significantly longer than other bees (P < 0.05). The interval time of the A. cerana was longer than other bees (P < 0.05). Larger bees tended to deposit more pollen on stigmas at each visit than smaller bees. The interspecific ITD of bees had a positive effect on SVD (P < 0.001). There was no correlation between ITD and SVD among individuals of the same species. In conclusion, the size of bees had a positive impact on pollination efficiency. Bees with a greater ITD deposited substantially more pollen and had a significantly shorter interval between flowers. Understanding the foraging behavior and pollination efficiency of these bee species and developing habitats to support them should enable growers to achieve resilient production.

Large-Scale Surveys of Blackleg of Oilseed Rape (Leptosphaeria biglobosa) Revealed New Insights into Epidemics of This Disease in China.

Blackleg of oilseed rape caused by Leptosphaeria maculans/L. biglobosa is a worldwide important disease, L. maculans is more virulent than L. biglobosa, thus, it causes a great concern for oilseed rape production. In China, blackleg (L. biglobosa) of oilseed rape was reported in 2000s, however, epidemiological features of blackleg have not been well elucidated. Moreover, whether L. maculans exists in China is still an open question. Therefore, a five-year survey was done in China to collect blackleg-occurrence data for characterizing the features of blackleg epidemics, and to identify the blackleg pathogens for assessing the risk of L. maculans invasion. The results showed that all the 19 surveyed provinces had blackleg on oilseed rape and the most frequently-occurring provinces are Gansu, Qinghai, Shaanxi and Hubei. Phoma stem canker was the most common symptom, which was associated with stem cracks on winter oilseed rape and with stem-weevil activities on spring oilseed rape. Temperature and rainfall were the main factors for blackleg epidemics on winter oilseed rape, whereas rainfall was the main factor for blackleg epidemics on spring oilseed rape. Brassica campestris and B. juncea oilseed rapes were more susceptible than B. napus to blackleg. Oilseed rapes cultivated under the continuous dry land-cropping pattern were more prone to blackleg than those cultivated under the paddy land/dry land-cropping pattern. All 6,015 fungal isolates from blackleg plant tissues belonged to L. biglobosa. These results are helpful for understanding of the blackleg epidemics of oilseed rapes and for management of this disease in China.

An improved multi-objective brainstorming algorithm with the application of rapeseed germination characteristics optimization

As one of the most important raw materials for daily edible oil, the annual production and quality of oilseed rape have a great impact on the daily lives of people and the development of the country. The germination quality of rapeseed directly affects the future yield and quality of oilseed rape, and seed germination vigor (SGV) and chlorophyll content (CC) are important factors affecting the quality of rapeseed germination. It is very necessary to make the rapeseeds have optimal germination characteristics and seed germination vigor at the early stage of germination by controlling the combination of each decision variable at the segmented harvest. The two objectives are coupled with each other to form a complex multi-objective optimization problem, which is important in the current research field of the rapeseed problem. To solve this problem, a modified brainstorming optimization algorithm based on OPTICS clustering, named MOPCBSO, is proposed in this study. The algorithm uses optics clustering as a new clustering method, chaotic mutation as a new updating method for individuals, and introduces an elite strategy and a tracking strategy. 19 benchmark test functions and nonparametric tests are adopted to examine the performance of the MOPCBSO compared with other optimization algorithms. The results show that the proposed algorithm has significant advantages over other algorithms in terms of convergence and comprehensiveness, demonstrating the effectiveness of the algorithm improvement. To optimize rapeseed germination characteristics, mathematical models are built, in which, cut-down time, after-ripening time and stubble height are selected as decision variables, while chlorophyll concentration and seed germination vigor in seeds as the target characteristics. The data of oliseed rape field trials were collected from 2020 to 2021 in Huanggang City, Hubei Province. Finally, the optimal solution for the germination characteristics of rapeseeds was obtained by the MOPCBSO, which provided an effective basis for the subsequent rapeseed production experiments.

Optimising the effect of nitrogen on winter oilseed rape grain yield in China: A meta-analysis

Winter oilseed rape is a nitrogen-sensitive oilseed crop with a crucial role in the Chinese edible oil market. However, there is a lack of systematic analysis of the effect of nitrogen (N) on the grain yield of winter oilseed rape. In this study, the response of the winter oilseed rape grain yield to N application was quantified and the key factors were identified, and we modeled the winter oilseed rape grain yield and economic benefits as functions of the N application rate. We found that the effects of N application on winter oilseed rape are sensitive to environmental factors and most agronomic management practices. Fertilizer management was the most important factor for improving the effectiveness of N application. We recommend two types of N management practices for winter oilseed rape production comprising basal application of controlled-release urea or combination application of basal and topdressing normal urea. In the latter case, the frequency of topdressing should be increased while ensuring that adequate basal fertilizer is applied. Other agronomic management practices such as direct seeding and increasing planting density may be important for further improving the effects of N application. The suitable N application levels for basal application of normal urea in the three production regions in northwest China, southwest China, and middle and lower reaches of the Yangtze River are 155.16–227.65 kg N ha–1, 219.15–225 kg N ha–1, and 259.38–284.36 kg N ha–1, respectively.

Recruitment of specific microbes through exudates affects cadmium activation and accumulation in Brassica napus.

Exploration of the mechanisms of cadmium (Cd) activation mediated by the rhizosphere process is important to advance our understanding of Cd accumulation in plants. In this study, two oilseed rape cultivars (L338, L351) with varied Cd accumulation traits were applied and the responses of their rhizosphere ecology to Cd stress were investigated by metabolome and microbiome. The results showed that shoot Cd accumulations in L338 accounted for 54.16% and 64.76% of those in L351 under low and high Cd contamination, respectively. Moreover, the cultivars response of rhizosphere process reflected that the lower pH and higher Cd mobility were assigned to the characters of L351, which were induced by the secretion of carboxylic acid (e.g. Acetaminophen cysteine, N-Fructosyl alliin) and the enrichment of bacterial taxa with the capacities of Cd resistant and activation (e.g. Sphingomonas, Flavobacterium, Neorhizobium, Altererythrobacter). Conclusively, the varied Cd accumulation traits of two oilseed rape cultivars were not only derived from the Cd transfer ability, it would be ascribed to Cd mobility regulated by rhizosphere processes as well. The results provide baseline data and a new perspective on the cultivar response of Cd accumulation, thus maintaining cleaner production of oilseed rape.

Chronic tropospheric ozone exposure reduces seed yield and quality in spring and winter oilseed rape

Oilseed rape (Brassica napus L.) is cultivated worldwide, producing 11.5% of global oilseeds at an economic value of 38 billion USD in 2020. It is sensitive to phytotoxic damage from exposure to tropospheric ozone (O3), a major air pollutant, which disrupts plant physiological processes and thus decreases biomass accumulation. As background ozone concentrations continue to increase globally, we investigated the impact of ozone exposure on seed and oil yield of a shorter-lived spring (cv. Click) and a longer-lived winter (cv. Phoenix) oilseed rape cultivar to ozone levels (treatments with peaks of 30, 55, 80, 110 ppbv) representative of typical European conditions where these cultivars are common. Thousand Seed Weight (TSW), an important measure of final yield, decreased more in Phoenix (40%) than Click (20%) with increasing ozone exposure. Click produced more racemes and many small seeds while Phoenix produced fewer racemes and larger seeds. However, seed quality declined more substantially in Click than Phoenix. The oil content in Click's seed significantly decreased with increased ozone exposure, while less desirable components (moisture, chlorophyll, ash) increased. Scaled to field-level, our findings imply substantial economic penalties for growers, with potential losses of 175–325 USD ha−1 in Click and 500–665 USD ha−1 in Phoenix under ozone concentrations typical of spring and summer periods in Europe. Decreased total yield would likely outweigh the benefits of any improvement in animal oilseed cake quality (increased protein and key micronutrients for livestock feed). Neither cultivar sustained visible injury at earlier growth stages, and Phoenix sustained photosynthesis even under high exposure, thereby making ozone an invisible threat. Our findings of reduced oilseed quantity and quality threaten oilseed rape production, but differences between the cultivars may also offer an opportunity for breeders and agronomists to identify and exploit variation in ozone tolerance in oilseed rape.

One-Time Root-Zone Nitrogen Fertilisation Allows High Yields and Labour Savings During Oilseed Rape Production in the Yangtze River Delta Region of China

One-Time Root-Zone Nitrogen Fertilisation Allows High Yields and Labour Savings During Oilseed Rape Production in the Yangtze River Delta Region of China

Assessment of energy saving and GHG reduction of winter oilseed rape production using sustainable strip tillage and direct sowing in three tillage technologies

GHG emissions, diesel fuel, material and working time costs are critical parameters in crop production that affect the environment and crop cultivation costs. The aim of this research was to investigate the impact of tillage technologies of different intensities and different sustainable sowing systems on the environment, working time, fuel, and energy efficiency. The studies were performed with winter oilseed rape (Brassica napus L.), which was grown using three tillage technologies: deep ploughing (DP), stubble cultivation (SC) and no-tillage (NT), and using two sustainable sowing systems: strip tillage (ST) and direct sowing (DS). The production of winter oilseed rape was the least harmful to the environment when using NT technology, where GHG emissions were about 21.2% lower compared to DP technology. The main negative impacts on the environment were GHG emissions from agricultural machinery, diesel, and nitrogen fertilizers. The highest yield (3935 kg ha−1) and the best energy efficiency ratio (7.44) were achieved by shallow stubble cultivation using a combination of strip tillage and sowing system. The conclusion of this research is that successful combination of sustainable tillage technologies and sowing systems can ensure high productivity of winter oilseed rape, as well as good energy efficiency with significantly cleaner production of crops.

Detekcija gubitaka semena uljane repice pre berbe analizom slike u okviru Fog računarstva

Losses in the production of oilseed rape can occur before harvest, caused by the spontaneous opening of mature pods and the fall of seeds on the ground. Different seed pods, among other things, ripen on the same plant at different times. So, in the cultivation of similar crops, one of the most critical moments is determining the right time for harvesting, because late harvest implies overripeness and opening of the shell, which leads to seed spoilage, losses and mechanical damage during threshing. One way of monitoring seed shedding and thus potential losses is by placing a container between rows of oilseed rape plants and monitor the number of seeds that fall from open shells. The presented model of the system, which consists of sensor devices with associated cameras, positioned above the position, has a function to transmit images of the current state. Central to this paper is an image analysis application that can be performed near sites on computer-aided devices within Fog Computing. In this way, the results of the analysis of images on the number of seeds in the container are obtained almost immediately and can be forwarded to the Cloud platform or directly to the user who will take appropriate action. By obtaining timely information on the number of scattered seeds, it is possible to organize the harvest in an optimal way in order to avoid losses and prevent over-ripeness of oilseed rape.

Oilseed Rape Yield Performance in the Clearfield® System under Varying Management Intensities

Oilseed rape production is under pressure due to a limited availability of herbicides. Therefore, the performance in terms of management intensity (MI) and herbicide strategy (HS) and the involved yield formation was evaluated in a two-year Clearfield® oilseed rape field experiment. Furthermore, weed density and weed composition were also investigated. The variants of MI were standard sowing density (StS; seed rate: 50 seeds m−2, primary tillage: plow, row width: 12 cm), reduced sowing density (RD; seed rate: 25 seeds m−2, primary tillage: plow, row width: 50 cm), and strip-till (ST; seed rate: 25 seeds m−2, primary tillage: strip tillage, row width: 50 cm). The variants of HS were preemergence strategy (PES; application of dimethachlor, napropamide, clomazone in preemergence and application of prapaquizafop in postemergence) and Clearfield® strategy (CLS; application of imazamox, quinmerac in preemergence, no postemergence herbicide application). In the first year of the trial, there were no interactions between the factors in terms of grain yield. Grain yield in StS was 3.85 t and 5.2% significantly lower than in ST, and the value of RD was not significantly different from StS and ST. Grain yield in CLS was 3.7 t and 2.7% lower than in PES. In the second year of the trial, the grain yield in ST CLS was significantly lower, and there were no significant differences between the other variants. Higher weed emergence was observed in CLS RD (2.7 to 4 times higher weed density compared to PES RD) and CLS ST (2.8 to 4.5 times higher weed density compared to PES ST). No significant differences existed between StS PES and StS CLS in both trial years. The Clearfield® system offers significant advantages in the control of cruciferous weeds. Although these did not occur on the trial fields, the Clearfield® system in this study showed to be an alternative to the more common pre-emergence system, especially with regard to the parameter grain yield.

Quantitative Trait Locus Mapping Combined with RNA Sequencing Reveals the Molecular Basis of Seed Germination in Oilseed Rape.

Rapid and uniform seed germination improves mechanized oilseed rape production in modern agricultural cultivation practices. However, the molecular basis of seed germination is still unclear in Brassica napus. A population of recombined inbred lines of B. napus from a cross between the lower germination rate variety ‘APL01’ and the higher germination rate variety ‘Holly’ was used to study the genetics of seed germination using quantitative trait locus (QTL) mapping. A total of five QTLs for germination energy (GE) and six QTLs for germination percentage (GP) were detected across three seed lots, respectively. In addition, six epistatic interactions between the QTLs for GE and nine epistatic interactions between the QTLs for GP were detected. qGE.C3 for GE and qGP.C3 for GP were co-mapped to the 28.5–30.5 cM interval on C3, which was considered to be a novel major QTL regulating seed germination. Transcriptome analysis revealed that the differences in sugar, protein, lipid, amino acid, and DNA metabolism and the TCA cycle, electron transfer, and signal transduction potentially determined the higher germination rate of ‘Holly’ seeds. These results contribute to our knowledge about the molecular basis of seed germination in rapeseed.