Search Results (25)

Oilseed radish (OR; Raphanus sativus var. oleiferus) is grown as a cover crop and develops a unique taproot, absorbing nitrogen left by the previous crop. The aim of this project was to investigate the resistance of OR cultivars (cvs.) to Plasmodiophora brassicae, the causal agent of clubroot disease. Twelve market cvs. were compared with cvs. of clubroot-resistant (CR) winter oilseed rape (OSR; Brassica napus) and other selected species of the Brassicaceae family. The study was performed as a replicated bioassay in a growth chamber using a specially composed mixture of field soils holding the natural inoculum of P. brassicae. The results show that the OR cultivars were infected, which implies that OR multiplies the pathogen. The susceptibility of the OR cultivars was not significantly different from that of the CR OSR cultivars Alister and Archimedes, but it was significantly different from that of the OSR cv. Mendel. The disease severity index (DSI) for OR cultivars ranged from 2.3 to 9.3, and disease incidence was 3–17%. The best performance was shown by black radish (Raphanus sativus var. niger) with a DSI of 0.3. For sustainable brassica crop production, we suggest avoiding OR as a cover crop in crop rotations, including OSR or other brassica crops, since there is a risk of increasing inoculum in the soil. Full article

White mold (Sclerotinia sclerotiorum de Bary) is one of the most important fungal diseases of winter oilseed rape (OSR). Since the pathogen can persist in the soil for a long time with its sclerotia, prevention and non-chemical methods (specifically biological agents) are important pillars in the integrated plant protection strategy against this pathogen. Mapping the intraspecific variability of the pathogen is an important step in the development of resistance to S. sclerotiorum. S. sclerotiorum isolates were collected from different OSR growing locations in Hungary during the 2020/21 and 2021/22 growing seasons. The morphological characteristics of sclerotia obtained from infected OSR stems were studied in the laboratory, and seedlings of four OSR hybrids were infected in vitro with isolates. The strains from four locations have different morphological characteristics. Significant differences in the level of aggressivity were also observed between strains; a correlation was also found between mycelial growth after 24 h, weight of sclerotia, and aggressivity. Among the four tested hybrids, OSR PT271 proved to be the most susceptible to most S. sclerotinia strains. Full article

The rotation patterns of summer rice–winter oil seed rape and summer rice–winter fallow are the main planting regimes in the rice ecosystem in southern China. However, the impact of local rotation patterns and landscape factors on the overwintering conservation of predators in spider and epigaeic beetle assemblages remains poorly understood. Here, we investigate the diversity and density of spiders and beetles over two consecutive winters (2019/2020 and 2020/2021), focusing on the impact of two rotation patterns (rice–fallow and rice–oilseed rape) and surrounding landscape compositions on predator diversity. The main findings of our research were that spiders were more abundant and had a higher activity density in the fallow rice fields (FRs) compared to the oilseed rape fields (OSRs), whereas ground beetles exhibited the opposite pattern. Specifically, fallow rice fields supported small and ballooning spiders (e.g., dominant spider: Ummeliata insecticeps), while OSRs supported larger ground beetles (e.g., dominant beetles: Agonum chalcomus and Pterostichus liodactylus). Moreover, the composition of spider assemblages were impacted by semi-natural habitats (SNHs) during overwintering, while ground beetle assemblages were influenced by overwinter planting patterns. Overall, our results suggest that different planting regimes and preserving semi-natural habitats are a strategic way to enhance species diversity and functional diversity of ground predators. It is, therefore, recommended that to conserve and improve predator diversity during overwintering, land managers and farmers should aim to maintain diverse planting regimes and conserve local semi-natural habitats. Full article

Winter oilseed rape (OSR) is becoming an increasingly popular crop in rotations as it provides a cash crop and reduces the incidence of take-all fungal disease (caused by Gaeumannomyces graminis) in subsequent wheat production. The exact mechanism of this inhibition of fungal pathogens is not fully understood; however, the selective recruitment of bacterial groups with the ability to suppress pathogen growth and reproduction is thought to play a role. Here we examine the effect of tillage practice on the proliferation of microbes that possess the phlD gene involved in the production of the antifungal compound 2,4-diacetylphloroglucinol (2,4-DAPG), in the rhizospheres of both winter oilseed rape and winter wheat grown in rotation over a two-year period. The results showed that conservation strip tillage led to a significantly greater phlD gene copy number, both in the soil and in the roots, of oilseed rape and wheat crops, whereas crop rotation of oilseed rape and wheat did not increase the phlD gene copy number in winter wheat. Full article

Brassica napus L., winter oilseed rape (OSR), is a major crop worldwide, with a wide range of uses and high profitability. Viruses, such as turnip yellows virus (TuYV), are becoming increasingly important, and in certain years, they can cause significant infestations in OSR. It is difficult to detect the presence of the virus during visual field inspections, as the symptoms it causes can be confused with either those caused by abiotic factors (e.g., low winter temperature, soil compaction, nutrient deficiencies, etc.) or by other viruses. The objective of this study was to determine the susceptibility of four commercial hybrids of oilseed rape to TuYV in Hungary and to determine the effect of the virus on phenotypic and yield parameters. The results showed that infection with the TuYV can be significant in OSR in some growing seasons. It was found that the appearance of visual symptoms (e.g., anthocyanin leaves) does not always confirm the presence of the virus (based on the ELISA (enzyme-linked immuno assay)), and it does not always detect a negative effect of TuYV on all phenotypic and yield parameters of the tested hybrids based on the results in one growing season. Full article

European agri-environment schemes include the use of flower-rich field margins to promote on-farm biodiversity, but species mixtures rarely include Brassicaceae. As pests of oilseed rape (OSR; Brassica napus) and their parasitoids are mostly brassica specialists, including brassica ‘banker plants’ in the mixtures would help support these important biocontrol agents and improve pest control throughout the crop rotation. We assessed the potential of six brassicaceous plants (replicated plots grown in the field) to enhance populations of parasitoids of OSR pests whilst minimising proliferation of their pest hosts. Fodder radish (Raphanus sativus) facilitated high production of parasitoids of the pollen beetle pest (Brassicogethes aeneus) but may proliferate Ceutorhynchus weevil pests due to low parasitism. Turnip rape (B. rapa) and the B. rapa hybrid ‘Tyfon’ showed potential to perform a trap cropping function for pests, but their early flowering phenology resulted in B. aeneus larvae escaping parasitisation, potentially assisting proliferation of this pest. Forage rape B. napus exhibited similarly high B. aeneus parasitoid production characteristics to R. sativus but did not potentiate problems with other pests, indicating that it would be a favourable banker plant option. Careful selection of plants in field margin mixtures is therefore needed to maximise their benefits and ideally the whole crop pest-beneficial complex needs to be studied, as focus on a single major pest risks unintended consequences with other pest problems. Full article

Rapid and accurate yield estimates at both field and regional levels remain the goal of sustainable agriculture and food security. Hereby, the identification of consistent and reliable methodologies providing accurate yield predictions is one of the hot topics in agricultural research. This study investigated the relationship of spatiotemporal fusion modelling using STRAFM on crop yield prediction for winter wheat (WW) and oil-seed rape (OSR) using a semi-empirical light use efficiency (LUE) model for the Free State of Bavaria (70,550 km²), Germany, from 2001 to 2019. A synthetic normalised difference vegetation index (NDVI) time series was generated and validated by fusing the high spatial resolution (30 m, 16 days) Landsat 5 Thematic Mapper (TM) (2001 to 2012), Landsat 7 Enhanced Thematic Mapper Plus (ETM+) (2012), and Landsat 8 Operational Land Imager (OLI) (2013 to 2019) with the coarse resolution of MOD13Q1 (250 m, 16 days) from 2001 to 2019. Except for some temporal periods (i.e., 2001, 2002, and 2012), the study obtained an R² of more than 0.65 and a RMSE of less than 0.11, which proves that the Landsat 8 OLI fused products are of higher accuracy than the Landsat 5 TM products. Moreover, the accuracies of the NDVI fusion data have been found to correlate with the total number of available Landsat scenes every year (N), with a correlation coefficient (R) of +0.83 (between R² of yearly synthetic NDVIs and N) and −0.84 (between RMSEs and N). For crop yield prediction, the synthetic NDVI time series and climate elements (such as minimum temperature, maximum temperature, relative humidity, evaporation, transpiration, and solar radiation) are inputted to the LUE model, resulting in an average R² of 0.75 (WW) and 0.73 (OSR), and RMSEs of 4.33 dt/ha and 2.19 dt/ha. The yield prediction results prove the consistency and stability of the LUE model for yield estimation. Using the LUE model, accurate crop yield predictions were obtained for WW (R² = 0.88) and OSR (R² = 0.74). Lastly, the study observed a high positive correlation of R = 0.81 and R = 0.77 between the yearly R² of synthetic accuracy and modelled yield accuracy for WW and OSR, respectively. Full article

Blackleg (Phoma) disease, caused by the ascomycete fungi Plenodomus biglobosus and P. lingam, threatens oilseed rape (OSR; Brassica napus) crops internationally. In many parts of the world, both species co-occur, but in China only P. biglobosus has so far been reported. Plenodomus biglobosus reproduces asexually (pycnidiospores), but also sexually (pseudothecia-yielding ascospores), via a heterothallic mating system requiring MAT1-1 and MAT1-2 genotypes. However, the roles of airborne ascospore inoculum in driving blackleg disease outbreaks in China are less well understood compared to elsewhere in the world. This is despite the very different agronomic cropping practices in parts of China, in which paddy rice and OSR are often grown in rotation; OSR stubble is often submerged under water for long periods potentially affecting pseudothecial development. Here, we indirectly investigate the potential role of sexual reproduction by developing new polymerase chain reaction (PCR) -based mating-type diagnostics for P. biglobosus and subsequently screening an international collection of 59 European and 157 Chinese isolates. Overall, in both Europe and China, P. biglobosus mating types did not deviate from a 1:1 ratio, such as is generally thought to occur under frequency-dependent selection in sexually reproducing pathogen populations. Both mating types were balanced in all the individual European countries tested (Austria, France, Poland, UK). Conversely, in China, mating types were only balanced in the eastern region; in the northern and southwestern regions there were skewed ratios, more typical of predominantly asexual reproduction, towards MAT1-1 and MAT1-2, respectively. The implications of these findings and future research directions for improved understanding of P. biglobosus epidemiology on OSR, particularly in China, are considered. Full article

Aerial seeding based on the unmanned agricultural aerial system (UAAS) improves the seeding efficiency of oilseed rape (OSR) seeds, and solves the problem of OSR planting in mountainous areas where it is inconvenient to use ground seeding machines. Therefore, the UAAS has been applied in aerial seeding to a certain degree in China. The effective broadcast seeding width (EBSW), broadcast seeding density (BSD) and broadcast seeding uniformity (BSU) are the important indexes that affect the aerial seeding efficiency and quality of OSR seeds. In order to investigate the effects of flight speed (FS) and flight height (FH) on EBSW, BSD and BSU, and to achieve the optimized parameter combinations of UAAS T30 on aerial seeding application, three levels of FS (4.0 m/s, 5.0 m/s and 6.0 m/s) and three levels of FH (2.0 m, 3.0 m and 4.0 m) experiments were carried out in the field with 6.0 kg seeds per ha. The results demonstrated that the EBSW was not constant as the FS and FH changed. In general, the EBSW showed a change trend of first increasing and then decreasing as the FH increased under the same FS, and showed a trend of decreasing as FS increased under the same FH. The EBSWs were over 3.0 m in the nine treatments, in which the maximum was 5.44 m (T1, 4.0 m/s, 2.0 m) while the minimum was 3.2 m (T9, 6.0 m/s, 4.0 m). The BSD showed a negative change correlation as the FS changed under the same FH, and the BSD decreased as the FH increased under 4.0 m/s FS, while it first increased and then decreased under the FS of 5.0 m/s and 6.0 m/s. The maximum BSD value was 140.12 seeds/m² (T1, 4.0 m/s, 2.0 m), while the minimum was 40.17 seeds/m² (T9, 6.0 m/s, 4.0 m). There was no obvious change in the trend of the BSU evaluated by the coefficients of variation (CV): the minimum CV was 13.01% (T6, 6.0 m/s, 3.0 m) and the maximum was 64.48% (T3, 6.0 m/s, 2.0 m). The statistical analyses showed that the FH had significant impacts on the EBSWs (0.01 < p-value < 0.05), the FS and the interaction between FH and FS both had extremely significant impacts on EBSWs (p-value < 0.01). The FH had extremely significant impacts on BSD (p-value < 0.01), the FS had no impacts on BSD (p-value > 0.05), and the interaction between FH and FS had significant impacts on BSD (0.01 < p-value < 0.05). There were no significant differences in the broadcast sowing uniformity (BSU) among the treatments. Taking the EBSW, BSD and BSU into consideration, the parameter combination of T5 (T9, 5.0 m/s, 3.0 m) was selected for aerial seeding. The OSR seed germination rate was over 36 plants/m² (33 days) on average, which satisfied the requirements of OSR planting agronomy. This study provided some technical support for UAAS application in aerial seeding. Full article

Pollination success is essential for hybrid oilseed rape (OSR, Brassica napus) seed production, and the pollination method has some influences on the OSR plant growth traits. In order to explore the roles of different pollination methods, four pollination methods of “unmanned agricultural aerial system” (UAAS), “natural wind + UAAS” (NW+UAAS), “honeybee” (HB), and “no pollinators” (NP) were set in a hybrid OSR field to investigate their effects on OSR plant traits and rapeseed yields in this study. The control check (CK) area with natural wind (NW) pollination was set as a reference for comparison. The experiments were conducted continuously for 20 days during the OSR plant early to full-bloom stage. The results based on the evaluated OSR plants showed that the growth traits and the rapeseed yields exhibited some differences under different pollination methods. The average plant height under NP pollination was maximum, which was 231.52 cm, while the average plant heights under the other pollination methods exhibited nearly no difference. Except for the HB pollination, the average first-branch heights of the evaluated plants all exceeded 100 cm under the other pollination methods. The average once branch quantity of all the evaluated plants under different pollination methods was 5–7. The average number of effective siliques per plant varied greatly. The average quantity of effective siliques in each OSR plant was about 160 under UAAS, NW+UAAS, and NW pollination, about 100 under HB pollination, and only 2.12 under NP pollination. The thousand-rapeseed weight was 7.32 g under HB pollination, which was the highest of all of the pollination areas. In terms of rapeseed yield, the average rapeseed yields per plant were all more than 10 g, except for the one under NP pollination; the yield per hectare was highest under NW+UAAS pollination, reaching 4741.28 kg, and the yield under NP pollination was lowest, which was only 360.39 kg. The research results provide technical support for supplementary pollination in hybrid OSR seed production. Full article

To study the influence of thiamethoxam exposure on colony strength and pathogen prevalence, an apiary (5 colonies) was placed in front of a plot sown with winter oilseed rape (wOSR), just before the flowering phase. Before sowing, the seeds were treated with an equivalent application of 18 g thiamethoxam/ha. For comparison, a second apiary (5 colonies) was located in front of a separate 750 m plot sown with untreated wOSR. Dead foragers at the entrance of hives were assessed every 2–3 days throughout the exposure period, while the colony strength (number of combs covered with adult honey bees and brood) and pathogens were monitored each month until the following spring. Foraging on the wOSR crop was confirmed by melissopalynology determination of the corbicular pollen collected periodically, while the chemical analysis showed that exposure to thiamethoxam was mainly through nectar. There was an increase in the accumulation of dead bees in the apiary exposed to thiamethoxam relating with the control, which was coped with an increment of bee brood surface and adult bee population. However, we did not find statistically significant differences between apiaries (α = 0.05) in terms of the evolution of pathogens. We discuss these results under hormesis perspective. Full article

To ensure the hybrid oilseed rape (OSR, Brassica napus) seed production, two important things are necessary, the stamen sterility on the female OSR plants and the effective pollen spread onto the pistil from the OSR male plants to the OSR female plants. The unmanned agricultural aerial system (UAAS) has developed rapidly in China. It has been used on supplementary pollination and aerial spraying during the hybrid OSR seed production. This study developed a new method to rapidly recognize the male OSR plants and extract the row center line for supporting the UAAS navigation. A male OSR plant recognition model was constructed based on the convolutional neural network (CNN). The sequence images of male OSR plants were extracted, the feature regions and points were obtained from the images through morphological and boundary process methods and horizontal segmentation, respectively. The male OSR plant image recognition accuracies of different CNN structures and segmentation sizes were discussed. The male OSR plant row center lines were fitted using the least-squares method (LSM) and Hough transform. The results showed that the segmentation algorithm could segment the male OSR plants from the complex background. The highest average recognition accuracy was 93.54%, and the minimum loss function value was 0.2059 with three convolutional layers, one fully connected layer, and a segmentation size of 40 pix × 40 pix. The LSM is better for center line fitting. The average recognition model accuracies of original input images were 98% and 94%, and the average root mean square errors (RMSE) of angle were 3.22° and 1.36° under cloudy day and sunny day lighting conditions, respectively. The results demonstrate the potential of using digital imaging technology to recognize the male OSR plant row for UAAS visual navigation on the applications of hybrid OSR supplementary pollination and aerial spraying, which would be a meaningful supplement in precision agriculture. Full article

The framework conditions for chemical weed control in oilseed rape (OSR) are becoming increasingly unfavorable in Central Europe. On the one hand, weed resistance is spreading and, on the other, there is a growing social desire to reduce or eliminate the use of chemical crop protection products. In a field experiment, hoeing, as a weed control measure performed two times per growing season (one time in autumn and one time in spring) in oilseed rape (Brassica napus; two varieties), was compared to chemical control by herbicides and a combination of hoeing and herbicide application (five treatments altogether). The chemical control by herbicides consisted of a broad-spectrum pre-emergence treatment and a post-emergence graminicide application. The trial was set up in each of three periods (years 2014/2015, 2015/2016, and 2016/2017) at the experimental station Ihinger Hof, University of Hohenheim, Stuttgart, Germany. The effect of the treatments on weed plant density, weed biomass at the time of harvesting, and on OSR grain yield was investigated. Weed plant density was measured four times per trial year, each time before and after hoeing. In 2015/2016 after spring hoeing, and in 2016/2017 at all data collection times, weed plant density was significantly higher in hoeing without herbicide application than in the other variants. No significant differences occurred at the other data collection times. The weed plant density ranged from 0.5 to 57.8 plants m⁻². Regardless of the trial year, pure hoeing always resulted in a significantly higher weed biomass at the time of harvesting than the herbicide applications or the combinations. The weed biomass at the time of harvesting ranged between 0.1 and 54.7 g m⁻². No significant differences in grain yield between hoeing and herbicide application occurred in all three trial years. According to the results, hoeing is a suitable extension of existing integrated weed control strategies in OSR. Full article

Mass-flowering crops, such as Oilseed Rape (OSR), provide resources for pollinators and benefit from pollination services. Studies that observe the community of interactions between plants and pollinators are critical to understanding the resource needs of pollinators. We observed pollinators on OSR and wild plants in adjacent semi-natural areas in Sachsen-Anhalt, Germany to quantify (1) the co-flowering plants that share pollinators with OSR, (2) the identity and functional traits of plants and pollinators in the network module of OSR, and (3) the identity of the plants and pollinators that act as network connectors and hubs. We found that four common plants share a high percentage of their pollinators with OSR. OSR and these plants all attract abundant pollinators in the community, and the patterns of sharing were not more than would be expected by chance sampling. OSR acts as a module hub, and primarily influences the other plants in its module that have similar functional traits. However, the plants that most influence the pollination of OSR have different functional traits and are part of different modules. Our study demonstrates that supporting the pollination of OSR requires the presence of semi-natural areas with plants that can support a high abundances of generalist pollinators. Full article

Pollination success is essential for hybrid oilseed rape (OSR, Brassica napus) seed production, but traditional pollination methods are not efficient. The unmanned agricultural aerial system (UAAS) has developed rapidly and has been widely used in China. When flying, the wind field generated by the rotors overcomes the UAAS gravity, and it blows and disturbs the crops below, which helps the pollen spread. In order to investigate the distribution law of the three-dimensional (direction x, y, z) airflow field, experiments involving three levels of flight speed (FS) at 4.0, 5.0, and 6.0 m/s, and three levels of flight height (FH) at 1.5, 2.0, and 2.5 m were conducted in the OSR field by using an electric four-rotor UAAS P20. The effects of FS and FH on airflow velocities ($v_x$, $v_y$, $v_z$) were analyzed. High-speed dynamic camera (HSDC) technology was used to capture the swings of OSR plants under airflow field disturbance. OSR pollen samples were collected during the experiments. The results showed that the airflow field in the direction x was mainly concentrated on the center of the flight path (S3), and the maximum wind velocity of direction x was 8.01 m/s (T1, S3). The direction x airflow field width was distributed almost symmetrically, but the center position shifted easily, due to crosswind. The airflow field in the direction y was distributed on both sides of the center flight path, and the velocity was generally larger, with the maximum at 7.91 m/s (T1, S2). The airflow field in the direction z was distributed irregularly, and the velocity was small. The FH had highly significant impacts on $v_x$ (p < 0.01), and the interaction of FS and FH had significant impacts on $v_x$ (0.01 < p < 0.05), while the FS had no significant impact on $v_x$ (p = 0.70804 > 0.05). The FS, FH, and interaction of FS and FH all had highly significant impacts on $v_y$ (p < 0.01). The swings of the OSR plant captured by the HSDC proved that the UAAS airflow field could effectively blow the OSR plant. The swing amplitude changes showed a positive correlation with airflow velocities ($v_x$) in general. Although the observed OSR plant swung forward and backward repeatedly, there was a law of first forward, and then backward, and forward again at the beginning of each swing. The pollen collected on the sampler verified that the UAAS airflow field could help with pollen spread. The research results provide technical support for UAAS application on supplementary pollination for hybrid OSR seed production. Full article