Winter Oilseed Rape Research Articles

The impact of foliar application of biostimulators on the morphological characteristics of the leaf rosette of winter rape plants

The field experiment was caried out in three growing seasons (2013–2016) at the Agricultural Experimental Station – Zawady (52°03'N and 22°33'E) belonging to the University of Natural Sciences and Humanities in Siedlce, Poland. The experiment was set up in a split-plot configuration with three replications. The examined factors were: I – morphotypes of winter oilseed rape: population (Poznaniak), hybrid restored with a semi-dwarf type of growth (PX104), hybrid restored with a traditional type of growth (Konkret); II – four types of biostimulators: 1. control variant, 2. biostimulator Tytanit® (titan), 3. biostimulator Asahi®SL (sodium ortho-nitrophenol, sodium para-nitrophenol, sodium 5-nitroguaiacol), 4. biostimulator Silvit® (active silicon, potassium oxide, boron – form of pure element, zinc – form of pure element). The aim of the study was to evaluate the effect of biostimulators containing various active substances on the morphological characteristics of winter oilseed rape plants in the leaf rosette stage (number of rosette leaves, tap root length, height of the growth cone) and on the fresh and dry mass of the above-ground rosette and the root system of traditional and semi-dwarf winter oilseed rape morphotypes type of growth under changing climatic conditions. The genetic factor significantly influenced the morphological features of plants, marked in autumn by inhibition of vegetation. The population variety Poznaniak developed more rosette leaves, greater length of the tap root, and fresh and dry mass of the rosette and the root system as compared to the restored hybrids. The applied biostimulators significantly influenced plant parameters determined in the fall before the vegetation inhibition. After the use of a biostimulator containing the active substance in the form of sodium o-nitrophenol, sodium para-nitrophenol and sodium 5-nitroguajakol, a significantly higher value of the tested features was obtained compared to the control variant. Regardless of the type of biostimulator used, the height of the growth cone was the same as in the control object. The most favourable parameters of the leaf rosette were obtained in the first and second periods of summer-autumn vegetation and winter dormancy, while in extreme drought conditions during sowing and a fairy dry period of emergence, its weakest features were obtained. Natural growth stimulants are becoming an increasingly common elements of agricultural plant agrotechnics. Their use has a positive effect on the growth and development of plants and increases the resistance of plants to the adverse effects of stress factors.

The Impact of Sowing Date on Soil Mineral Nitrogen Uptake Efficiency and Fertilizer N Uptake Efficiency for Winter Oilseed Rape (Brassica napus L.) in Ireland

Nitrogen (N) application on winter oilseed rape (Brassica napus L.; WOSR) in the mild Atlantic climate of Ireland is based on a soil N Index system, which does not take into account any variations in crop N demand prior to the main spring dressing of N fertilizer. This study tests whether UK- canopy management (CM) principles for oilseed rape N fertilization are applicable for oilseed rape grown in Ireland. The tested principles included (i) final N uptake of unfertilized crops will be equivalent to the soil mineral N (SMN) and N in the crop measured at the end of winter, i.e., soil N uptake efficiency (SNUpE) = 1; and (ii) the (apparent) N fertilizer N uptake efficiency, (FNUpE) is 0.6 (60%). Three years of field trials were carried out from 2017/18 to 2019/20 on different sites based on a split-plot design. Three sowing dates (SD): mid-August (SD1), End-August (SD2) and mid-September (SD3) were set as main plots and five N application strategies namely, CM standard, CM higher yield, CM low N rate, Fix225 and zero-N were set at subplot level. Results from unfertilized plots demonstrated that the ratio of final crop N uptake at harvest to the combined post-winter SMN + crop N was 1.13 and 1.14 on the two early sowing dates but 1.68 for the latest sowing. Additionally, SMN was not systematically impacted by SD, except in site-year-2. Instead, crop N content in spring had the biggest influence when calculating soil N supply for the season. More mineralization occurred through the growing season resulting in SNUpE of above 100% on all SDs. This additional available N (AAN) was quantified as 11 kgN·ha−1 on average for SD1 and SD2 and 38.6 kgN·ha−1 for SD3. FNUpE values were calculated closest to the economical optimum N rate (Nopt) and were 0.534, 0.574 and 0.486, respectively for SD1, SD2 and SD3. The Nopts at each SD were 157 kgN·ha−1 (SD1), 148 kgN·ha−1 (SD2) and 175 kgN·ha−1 (SD3) and the respective yields at each Nopt were 4.93 t ha−1, 4.90 t·ha−1 and 4.34 t·ha−1. This study shows the UK–CM principles were applicable in the mild Irish climate; however, values of SNUpE and FNUpE differ from one site-year-SD to another. Mid-August to early September sowing dates produced higher post-winter crop N content due to SMN uptake, and this results in a lower Nopt than the later SD. Sowing later led to a higher Nopt due to a combination of lower post-winter N uptake and lower FNUpE, although the effect of these factors was partially offset by a greater AAN. Measurements of SNS post-winter, an estimate of N mineralization during the growing season, together with a consideration of the sowing date helped determine the scope for reduction in fertilizer while achieving high yield and high FNUpE. Among different N rate strategies, CM standard and CM high yield were closest to the Nopt for having lower N rates at the maximum economical yield point.

Identification of SSR Markers Associated with Yield-Related Traits and Heterosis Effect in Winter Oilseed Rape (Brassica Napus L.)

The identification of markers responsible for regulating important agronomic traits in rapeseed supports breeding and increases the seed yield. Microsatellite (SSR) markers are mainly used as ‘neutral’ genetic markers but are also linked with many biological functions. The objective of this study was identification of microsatellite markers associated with important agronomic traits affecting the seed yield of winter oilseed rape and with the heterosis effect for these traits. The plant material consists of four parental lines, 60 doubled haploid (DH) lines, 60 single cross hybrids, and 60 three-way cross hybrids. The association between molecular markers and observed traits was estimated using regression analysis. Among 89 SSR markers, 43 were polymorphic, and 15 were selected for mapping because they demonstrated stability in both years of observation. These markers were physically mapped in the rapeseed reference genomes and their immediate vicinity was searched to identify candidate genes associated with the studied traits. Six markers (BrGMS3837, BnEMS1119, BrGMS2901, BnGMS0509, BrGMS3688, BrGMS4057), which showed a positive estimation effect in our association analysis, and thus increased the value of a given trait or heterosis effect, turned out to be linked with genes that could be responsible for the development and growth of plants.

What regulates the rhizodeposition of winter oilseed rape during growth?

PurposeThe goal of this work was to contribute to a better understanding of the process of rhizodeposition in crops and to find helpful approaches for creating a simple model of rhizodeposition. For this purpose, we tested three hypotheses about the relationships and changes in the relative C partitioning coefficients and their ratios. In particular, we analyzed the relationships between root growth, belowground respiration, rhizodeposition and other traits during plant growth.MethodsThe ranges of variation in ^{14}C partitioning coefficients and various plant traits were determined after ^{14}C labeling of four winter oilseed rape genotypes in three developmental stages.ResultFor all genotypes, we found very strong and significant correlations between the percentages of freshly assimilated C used for rhizodeposition and root growth. In addition, we showed that the ratios of the relative ^{14}C fluxes in the root-soil-soil gas system changed significantly during plant development and that the relative and absolute C fluxes of rhizodeposition followed different trends. The root growth rate and the change in the ratio of the percentages of ^{14}C in rhizodeposition and root tissue over time were the key factors that determined the absolute amount of rhizodeposited C. We also found that the C partitioning in a taproot system leading to root growth and rhizodeposition was similar to that of an adventitious root system.ConclusionBased on our results, we conclude that using the identified key factors in combination with a root growth model, a simple model can be generated to describe rhizodeposition.

New Control Methods Against the Cabbage Stem Flea Beetle in Oilseed Rape Crops

Cabbage stem flea beetle (CSFB) is one of the most damaging pests of oilseed rape (OSR) grown in the UK. An intensive research effort is underway in the UK and throughout OSR growing regions of continental Europe to develop new control methods for this pest. In the first article of a series of three, we review this research and consider approaches to this pest problem that may be available immediately and in the short-term. Agronomic practices (sowing date, seed rate, crop defoliation, companion crops, etc) are being investigated and several of these approaches are already being used on farm. The use of physically acting biopesticides such as fatty acids, while not yet being used may also provide an effective solution and could be available in the short-term. Each of these approaches has the potential to form part of future Integrated Pest Management (IPM) programmes but importantly none should be seen as simple replacements for conventional synthetic insecticides. Solutions that may be available in the medium and longer-term will be discussed in the next articles. The cabbage stem flea beetle (CSFB), Psylliodes chrysocephala (Coleoptera: Chrysomelidae) is one of the most important pests of winter OSR crops in central and northern European countries. The adult beetle causes 'shot holing' feeding damage on cotyledons and true leaves of young winter OSR plants in late summer-early autumn. The larvae feed inside petioles and stems of the plants, causing additional damage. The focus on making food production more environmentally friendly means reduced chemical inputs, protecting nontarget species and overall biodiversity. This led to the withdrawal of systemic synthetic neonicotinoid pesticide seed treatments in many crops (oilseed rape included) in 2013. Since the withdrawal of neonicotinoid seed treatments, there has been a reliance on pyrethroid insecticides. This has been seen with a shift in the use of insecticides in oilseed rape, with CSFB the target for 28% of insecticide applications in 2012 (before neonicotinoid seed treatments were withdrawn) to 75% in 2020. The result of this shift has been the development of resistance to this group of insecticides in CSFB population. This situation has become so severe that some UK populations of CSFB are now 100% resistant to the pyrethroid insecticide lambda-cyhalothrin. These changes have led to the area of oilseed rape grown in the UK being halved (756,000 hectares in 2012 versus 307,000 hectares in 2021), with growers citing CSFB as one of the main reasons for this decrease. At the same time, the number of insecticide spray rounds has increased from two to three between 2012 and 2020, with these applications dominated by the use of pyrethroids. The most widely used pyrethroid insecticide, lambda-cyhalothrin, has also increased as a proportion of the insecticide-treated area from 32% in 2012 to 76% in 2020. Additional surveys by Fera, completed as part of the CropMonitor information service, between 2009 and 2020 show that the number of CSFB larvae per plant increased from an average of 0.5 larvae per plant in the years before the withdrawal of neonicotinoids, to more than 2 larvae per plant the following year in 2014 in East England, and almost 5 larvae per plant in 2019 in the South West of England. Here we present solutions that are currently available or that could be made available in the short-term. We consider how each of these approaches could be used in Integrated Pest Management (IPM) programmes.

The Impact of Using Different Doses of Biomass Ash on Some Physical Properties of Podzolic Soil under the Cultivation of Winter Oilseed Rape.

This two-year study was focused on the effect of the application of different biomass ash doses on selected soil physical properties, i.e., soil moisture (SM), bulk density (BD), penetration resistance (PR), and soil stability in water measured by the content of readily dispersible clay (RDC), following control and mineral NPK fertilization in the cultivation of winter oilseed rape (Brassica napus L. var. napus). A one-factor field experiment conducted on podzolic soil (control, NPK, 100, 200, 300, 400, 500 kg K2O·ha−1) showed that the use of biomass combustion ash significantly improved soil moisture at all depths and variants, and especially at a depth of 30–35 cm in the 500 kg·ha−1 variant, i.e., by 2.99% v/v, compared to NPK. In turn, the moisture content in the 30–35 cm layer increased by 3.19% v/v in all variants in both years compared to the control. In 2020 and 2021, bulk density in the 0–5 cm layer treated with a dose of 500 kg·ha−1 exhibited a positive 0.15 and 0.12 Mg·m−3 decrease, respectively, compared to the control. In both years, the BD values in the 30–35 cm layer were reduced by 0.14 and 0.16 Mg·m−3 compared to the control. The PR values decreased in the treatments with doses of 300, 400, and 500 kg·ha−1, especially in 2021. The RDC content was found to decline in both years, i.e., 2020 and 2021, upon the application of even the lowest dose (100 kg·ha−1) in all the analysed layers. The reduction in the RDC content, especially in the 0–5 cm layer, is very important for soil structure stability and to protect the soil environment. This layer is most susceptible to crusting, which results in poor aeration and weak plant emergence during drought and/or periods of excessive moisture. It may also increase surface runoff and intensify soil erosion processes.

Meat and Bone Meal and the Energy Balance of Winter Oilseed Rape—A Case Study in North-Eastern Poland

A two-year field experiment was conducted in Poland to determine energy efficiency (EE) in the production of winter oilseed rape (WOR) in different fertilization: (i) zero-fertilization; (ii) 158 kg N ha−1, 45 kg P ha−1 and 145 kg K ha−1 as mineral fertilizer (NPK); (iii) 1.0 Mg ha−1 meat and bone meal (MBM), 79 kg N ha−1 and 145 kg K ha−1 as mineral fertilizer; (iv) 1.5 Mg ha−1 MBM, 40 kg N ha−1 and 145 kg K ha−1 as mineral fertilizer; and (v) 2.0 Mg ha−1 MBM and 145 kg K ha−1 as mineral fertilizer. The replacement of NPK with MBM decreased energy inputs in WOR production by 20−55%. The NPK had a greater (16–21%) effect on seed yield formation than MBM. The replacement of NPK with MBM decreased the energy output of seeds (14–21%) and total biomass (12–20). The replacement of NPK with MBM decreased (6–13%) the energy gain from seed production. The application of MBM improved the EE ratio in the production of seeds (10–81%) and total biomass (11–85%) relative to NPK. The EE ratio of WOR production increased with a rise in MBM doses.

Analysing Farmers’ Herbicide Use Pattern to Estimate the Magnitude and Field-Economic Value of Crop Diversification

We present an on-farm approach to measure the effect of crop diversification on farmers’ field economic values. Eleven years of data (2010–2020) on the chemical herbicide use, tillage practices and crop yields of 17 farms in north-eastern Germany were examined for winter wheat (WW) and winter oilseed rape (WOSR). We used a common conceptual framework to classify farmers’ crop sequences according to their susceptibility to weeds (‘riskiness’). Linear mixed models were used to analyse the relationship between crop sequence, tillage practice (inversion/non-inversion) and the response variables ‘total herbicide costs’, ‘crop yield’ and ‘economic income’. Our results indicate that farmers in the area surveyed commonly grow crop sequences with a high risk of weeds. The driving forces behind this classification are high ratios of winter cereals and WOSR in the sequences. The most interesting result of our analysis is that farmers’ total herbicide costs (THCfy) significantly decreased from a higher to a lower riskiness class. Diversified crop sequences decreased the THCfy for WW by up to 12 EUR ha−1 and for WOSR by 19–56 EUR ha−1. Considering the crop diversification effects, the combined influence of tillage and crop sequence seems to be important. Significant differences in crop yield between the riskiness classes were found in WW and WOSR solely in non-inversion tillage systems. Hence, the analysis of farmers’ ‘economic income’ revealed the great impact of crop diversification for non-inversion tillage systems. Indeed, we found that simplifying both crop sequence diversity and tillage intensity implies higher herbicide costs and, thereby, higher economic input. The best strategy for reducing herbicide costs in WW and WOSR cropping is to increase the use of summer crops or field grass as previous crops.

Deacclimation-Induced Changes of Photosynthetic Efficiency, Brassinosteroid Homeostasis and BRI1 Expression in Winter Oilseed Rape (Brassica napus L.)-Relation to Frost Tolerance.

The objective of this study was to answer the question of how the deacclimation process affects frost tolerance, photosynthetic efficiency, brassinosteroid (BR) homeostasis and BRI1 expression of winter oilseed rape. A comparative study was conducted on cultivars with different agronomic and physiological traits. The deacclimation process can occur when there are periods of higher temperatures, particularly in the late autumn or winter. This interrupts the process of the acclimation (hardening) of winter crops to low temperatures, thus reducing their frost tolerance and becoming a serious problem for agriculture. The experimental model included plants that were non-acclimated, cold acclimated (at 4 °C) and deacclimated (at 16 °C/9 °C, one week). We found that deacclimation tolerance (maintaining a high frost tolerance despite warm deacclimating periods) was a cultivar-dependent trait. Some of the cultivars developed a high frost tolerance after cold acclimation and maintained it after deacclimation. However, there were also cultivars that had a high frost tolerance after cold acclimation but lost some of it after deacclimation (the cultivars that were more susceptible to deacclimation). Deacclimation reversed the changes in the photosystem efficiency that had been induced by cold acclimation, and therefore, measuring the different signals associated with photosynthetic efficiency (based on prompt and delayed chlorophyll fluorescence) of plants could be a sensitive tool for monitoring the deacclimation process (and possible changes in frost tolerance) in oilseed rape. Higher levels of BR were characteristic of the better frost-tolerant cultivars in both the cold-acclimated and deacclimated plants. The relative expression of the BRI1 transcript (encoding the BR-receptor protein) was lower after cold acclimation and remained low in the more frost-tolerant cultivars after deacclimation. The role of brassinosteroids in oilseed rape acclimation/deacclimation is briefly discussed.

Preceding crop influences on the development and yields of the winter oilseed rape (Brassica napus L.)

The evidence about the influence of the preceding crops on the oilseed rape growth and development is scarce. Therefore, a study in three vegetation seasons of the winter oilseed rape (2017/2018, 2018/2019, and 2019/2020) was conducted. The experiment was situated in the experimental field of the department of „Agriculture and herbology” at the Agricultural University of Plovdiv, Bulgaria. The experiment was conducted by the long plots method. The following crop rotations were under evaluation: 1. Winter wheat – winter oilseed rape; 2. Winter oilseed rape – winter oilseed rape; 3. Maize – winter oilseed rape. All evaluated parameters of the winter oilseed rape as plant height at the end of vegetation, number of primary branches and silique plant-1, seed yield, absolute mass of 1000 seeds, hectoliter seed mass as well as seed oil content were influenced by the preceding crop. The highest results of the studied indicators for the rotation of winter wheat – winter oilseed rape were recorded. The lowest obtained results for the rotation maize – winter oilseed rape were found, and medium results were accomplished for the oilseed rape monoculture.

Influence of Elevated Temperatures on Resistance Against Phoma Stem Canker in Oilseed Rape.

Cultivar resistance is an important tool in controlling pathogen-related diseases in agricultural crops. As temperatures increase due to global warming, temperature-resilient disease resistance will play an important role in crop protection. However, the mechanisms behind the temperature-sensitivity of the disease resistance response are poorly understood in crop species and little is known about the effect of elevated temperatures on quantitative disease resistance. Here, we investigated the effect of temperature increase on the quantitative resistance of Brassica napus against Leptosphaeria maculans. Field experiments and controlled environment inoculation assays were done to determine the influence of temperature on R gene-mediated and quantitative resistance against L. maculans; of specific interest was the impact of high summer temperatures on the severity of phoma stem canker. Field experiments were run for three consecutive growing seasons at various sites in England and France using twelve winter oilseed rape breeding lines or cultivars with or without R genes and/or quantitative resistance. Stem inoculation assays were done under controlled environment conditions with four cultivars/breeding lines, using avirulent and virulent L. maculans isolates, to determine if an increase in ambient temperature reduces the efficacy of the resistance. High maximum June temperature was found to be related to phoma stem canker severity. No temperature effect on stem canker severity was found for the cultivar ES Astrid (with only quantitative resistance with no known R genes). However, in the controlled environmental conditions, the cultivar ES Astrid had significantly smaller amounts of necrotic tissue at 20°C than at 25°C. This suggests that, under a sustained temperature of 25°C, the efficacy of quantitative resistance is reduced. Findings from this study show that temperature-resilient quantitative resistance is currently available in some oilseed cultivars and that efficacy of quantitative resistance is maintained at increased temperature but not when these elevated temperatures are sustained for a long period.

Comparison of the Effect of Fertilization with Ash from Wood Chips on Bacterial Community in Podzolic and Chernozem Soils for the Cultivation of Winter Oilseed Rape: A Preliminary Study

The aim of the research was to investigate whether different doses of ash from biomass combustion (Salix viminalis L. willow) have an impact on the number and community of soil bacteria. The experiment was carried out on podzolic and chernozem soils in a one-way field experiment (control, NPK, 100, 200, 300, 400, 500 kg K2Oha−1). The ash from the biomass was characterized by pH 12.83 ± 0.68 and high content of macronutrients. Samples were taken from the 0–5 cm layer of soil under the cultivation of winter oilseed rape (Brassica napus L. var. Napus) in April and September 2021. The plate count method with PCA solid medium was used to determine the number of microorganisms, and mass spectrometry (MALDI-TOF MS) was used to analyze the microbiological community. The research showed an increase in the number of microorganisms after the use of the biomass ash fertilizer in the variants with ash doses from 200 to 500 kg K2Oha−1. The highest amount of soil bacteria in both tested soils was determined in these variants. In total, 44 bacterial species of 5 genera were identified in all variants: Bacillus, Paenarthrobacter, Pseudarthrobacter, Pseudomonas, and Rhodococcus. An important factor in the growth of the number of bacteria, in addition to the dose of biomass ash, was soil moisture, which in September was significantly higher than in April 2021 in both soils.

Response of new forms of winter oilseed rape with modified fatty acid composition to nitrogen and sulfur fertilization

In a field experiment conducted at the Łagiewniki Farm (west Poland) in the years 2015–2018, the reaction to fertilization with nitrogen (100, 160 and 220 kg N/ha) and sulfur (0, 30, 60 and 90 kg S/ha) of three forms of winter oilseed rape (WOR) (Brassica napus L.) with different quality of oil characteristics was studied. The Monolit variety with typical fatty acid composition for the double-improved cultivars, was compared with two forms with changed fatty acid composition obtained using chemically induced mutagenesis: the variety Polka—type with high oleic acid content (C18:1, 78%) and the line PN440—type with increased oleic acid content (C18:1, 75%) and reduced linolenic acid content (C18:3, 3%). The studied WOR genotypes reacted similarly to fertilization factors. A significant increase in seed yield (8%–14%, 0.26–0.4 t/ha) was visible up to the maximum nitrogen (N) dose (220 kg/ha). Sulfur fertilization increased seed yield by 4%–7% (0.15–0.22 t/ha). A significant interaction between N and S has been demonstrated. The highest seed yield at moderate N fertilization (160 kg/ha) was ensured by a 30 kg/ha S dose, while at a high N dose (220 kg/ha) the highest yield was observed at application of 60 kg S/ha. Regardless of the N dose, the highest net and marginal effectiveness of 1 kg S (about 6 kg of seeds) for all investigated forms of oilseed rape was observed at the lowest S dose (30 kg S/ha). Sulfur fertilization increased (by 3.5%–5.5%) the efficiency of the N used.

Hoeing as a Possibility for Mechanical Weed Control in Winter Oilseed Rape (Brassica napus L.)

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.

Analysis of winter oilseed rape damages caused by Brassicogethes aeneus (Fabricius, 1775) in various regions of Poland, in 2009–2019

A significant problem in the cultivation of plants, including winter oilseed rape in Poland is the increasing threat from pests, the appearance of new species and the increasing their activity, especially in the context of the observed climate changes. One of them is common across the country with varying degrees of pollen beetle – Brassicogethes aeneus (F.). The effect of the pest’s feeding is a weak or no silica formation, and thus an unfavorable effect on the obtained seed yield. The aim of the study was to analyze the damage of winter oilseed rape caused by pollen beetle in various regions of Poland in the years 2009–2019. The summary of the monitoring results of the pollen beetle showed the changing intensity of this pest occurrence over the selected years.

Yield of Winter Oilseed Rape (Brassica napus L. var. napus) in a Short-Term Monoculture and the Macronutrient Accumulation in Relation to the Dose and Method of Sulphur Application

The objective of this study was to assess the yield efficiency of sulphur-enhanced fertilisers, depending on the dose and application method, in a short-lived (three-year) monoculture of winter oilseed rape under the climate and soil conditions of south-eastern Poland. The experiment was carried out between 2010 and 2013 on winter oilseed rape (Brassica napus L. var. napus) of the Orlando variety, fertilised with different sulphur doses—0, 20, 40 or 60 kg S ha−1 applied in different method—soil application sowing, foliar application in the spring, and soil application sowing + foliar application in the spring (combined application). Following the harvest, seed and straw yields and the content of macroelements (N, S, P, K, Ca and Mg) in the seed and straw samples were determined. The harvest indices were also established for each of these elements. The impact of sulphur on winter oilseed rape yield depended significantly on both the dose and the application method. Even at the lowest dose (20 kg·ha−1), sulphur materially increased seed yield, regardless of the application method. With autumn soil application and foliar application, differences between the lowest dose and the higher doses (40 and 60 kg·ha−1) were not significant. However, with combined application, the highest dose (60 kg·ha−1) significantly increased yield compared to the lower doses. In general, all the fertilisation approaches significantly increased the N, P, K, Ca and Mg contents compared to the control sample, but the differences between them were not substantial. Each of the sulphur application approaches decreased the harvest index for sulphur. The foliar application of each of the doses decreased the harvest indices for N, P, K and Ca. The soil application of 20 kg·ha−1, and the mixed application of 40 and 60 kg·ha−1, all increased the harvest indices for P, K and Ca.

Meteorological Variables That Affect the Beginning of Flowering of the Winter Oilseed Rape in the Czech Republic

Winter oilseed rape (Brassica napus) is one of the most cultivated oilseeds in the Czech Republic and belongs among major pollen allergens. Pollen allergies have an extensive clinical impact worldwide, and as well as in the Czech Republic. In this paper, meteorological variables such as mean air temperature, maximum and minimum air temperature, precipitation total and number of rainy days in the period 1991–2012 were studied using the PhenoClim phenological model to find the best predictor of the beginning of flowering of the Brassica napus in the Czech Republic. In addition, temporal and spatial evaluations of the beginning of flowering of the Brassica napus were examined at individual stations in different climatic zones within the same period. In total, three phenological stations at altitudes from 270 m asl to 533 m asl located in warm (W2), medium warm (MW7) or cold (C7) climatic zones were used for detailed evaluation. Based on the observation results at selected stations, the beginning of flowering of the Brassica napus advanced progressively in timing (nearly −15 days) in the 1991–2012 period. The base temperature and temperature sums were calculated for the beginning of flowering of the winter oilseed rape using the PhenoClim computer tool. As the most accurate predictor for the beginning of flowering of the Brassica napus, the mean air temperature was determined. The optimal start day for calculation was 30th January, the threshold (base temperature) was 6.0 °C and the temperature sum was 157.0 °C. The RMSE value was 4.77 and the MBE value was −3.00. The simulated data had a good correlation with the real observed data (the correlation coefficients were within the range from 0.56 to 0.76), and the PhenoClim model results indicate using them in the forecast modeling of the beginning of flowering of the Brassica napus in the Czech Republic.

Greenhouse Gas Emissions and Crop Yields From Winter Oilseed Rape Cropping Systems are Unaffected by Management Practices

Winter oilseed rape is traditionally established via plough-based soil cultivation and conventional sowing methods. Whilst there is potential to adopt lower cost, and less intensive establishment systems, the impact of these on greenhouse gas emissions have not been evaluated. To address this, field experiments were conducted in 2014/2015 and 2015/2016 to investigate the effects of 1) crop establishment method and 2) sowing method on soil greenhouse gas emissions from a winter oilseed rape crop grown in Ireland. Soil carbon dioxide, nitrous oxide and methane emission measurements were carried out using the static chamber method. Yield (t seed ha−1) and the yield-scaled global warming potential (kg CO2-eq. kg−1 seed) were also determined for each management practice. During crop establishment, conventional tillage induced an initially rapid loss of carbon dioxide (2.34 g C m−2 hr−1) compared to strip tillage (0.94 g C m−2 hr−1) or minimum tillage (0.16 g C m−2 hr−1) (p < 0.05), although this decreased to background values within a few hours. In the crop establishment trial, the cumulative greenhouse gas emissions were, apart from methane, unaffected by tillage management when sown at a conventional (125 mm) or wide (600 mm) row spacing. In the sowing method trial, cumulative carbon dioxide emissions were also 21% higher when plants were sown at 10 seeds m−2 compared to 60 seeds m−2 (p < 0.05). Row spacing width (125 and 750 mm) and variety (conventional and semi-dwarf) were found to have little effect on greenhouse gas emissions and differences in seed yield between the sowing treatments were small. Overall, management practices had no consistent effect on soil greenhouse gas emissions and modifications in seed yield per plant countered differences in planting density.

Uncovering Trait Associations Resulting in Maximal Seed Yield in Winter and Spring Oilseed Rape.

Seed yield is a complex trait for many crop species including oilseed rape (OSR) (Brassica napus), the second most important oilseed crop worldwide. Studies have focused on the contribution of distinct factors in seed yield such as environmental cues, agronomical practices, growth conditions, or specific phenotypic traits at the whole plant level, such as number of pods in a plant. However, how female reproductive traits contribute to whole plant level traits, and hence to seed yield, has been largely ignored. Here, we describe the combined contribution of 33 phenotypic traits within a B. napus diversity set population and their trade-offs at the whole plant and organ level, along with their interaction with plant level traits. Our results revealed that both Winter OSR (WOSR) and Spring OSR (SOSR); the two more economically important OSR groups in terms of oil production; share a common dominant reproductive strategy for seed yield. In this strategy, the main inflorescence is the principal source of seed yield, producing a good number of ovules, a large number of long pods with a concomitantly high number of seeds per pod. Moreover, we observed that WOSR opted for additional reproductive strategies than SOSR, presenting more plasticity to maximise seed yield. Overall, we conclude that OSR adopts a key strategy to ensure maximal seed yield and propose an ideal ideotype highlighting crucial phenotypic traits that could be potential targets for breeding.

QTL Genetic Mapping Study for Traits Affecting Meal Quality in Winter Oilseed Rape (Brassica Napus L.).

Rapeseed (Brassica napus L.) meal is an important source of protein, but the presence of anti-nutritional compounds, such as fibre and glucosinolates, still limits its use as a livestock feed. Understanding the genetic basis of seed fibre biosynthesis would help to manipulate its content in seeds of oilseed rape. Here, we applied high-resolution skim genotyping by sequencing (SkimGBS) and characterised 187,835 single-nucleotide polymorphism (SNP) markers across a mapping population subsequently used for a genetic mapping study (R/qtl). This approach allowed the identification of 11 stable QTL related to seed quality traits and led to the identification of potential functional genes underlying these traits. Among these, key genes with a known role in carbohydrate metabolic process, cell wall, lignin, and flavonoid biosynthesis, including cellulase GH5, TT10/LAC15, TT4, and SUC2, were found. This study furthers the understanding of the molecular mechanisms underlying seed fibre content and provides new markers for molecular breeding in B. napus.