Rape Cultivars Research Articles

Effect of Nitrogen and Sulphur Fertilization on Winter Oilseed Rape Yield

Oilseed rape is one of many crops with high nutritional requirements, particularly for nitrogen (N) and sulphur (S). Both macronutrients affect important physiological plant functions and are essential for the proper growth and development of oilseed rape. The objective of the experiment was to investigate the impact of nitrogen and sulphur fertilization on the yield of the winter oilseed rape cultivar LG Absolut. The experiment was conducted during the 2019/2020, 2020/2021, and 2022/2023 growing seasons on Haplic Cambisol soil formed from loess, with medium levels of mineral nitrogen and sulphur. In the experiment, two nitrogen fertilization treatments (150 and 200 kg ha−1) were compared in combination with three additional sulphur fertilization rates (20, 40, and 60 kg ha−1). The results demonstrated that the effectiveness of N and S fertilization varied between individual years. On average, the highest seed yields were obtained with the application of 200 kg N ha−1 combined with sulphur, regardless of the rate. This was attributed to a significant increase in soil–plant analysis development (SPAD) values, the number of pods per plant, and the thousand-seed weight. The increase in seed yield with the higher nitrogen rate without sulphur ranged from 0.36 to 0.57 t ha−1 compared to the lower rate (control 150 N kg ha−1). Supplementary sulphur fertilization increased seed yield ranging from 0.22 to 0.76 t ha−1. The protein content in the seeds increased, while the fat content decreased, following the application of the higher nitrogen rate. The decrease in fat content was mitigated by higher rates of sulphur. The application of 60 kg S ha−1 yielded similar results of the tested parameters to the lower rates. Therefore, for soils with moderate levels of mineral nitrogen and sulphur, it is recommended to fertilize winter oilseed rape with 200 kg N ha−1 combined with 20 or 40 kg S ha−1.

SeqSNP-Based Targeted GBS Provides Insight into the Genetic Relationships among Global Collections of Brassica rapa ssp. oleifera (Turnip Rape).

Turnip rape is a multi-purpose crop cultivated in temperate regions. Due to its ability to fit into crop rotation systems and its role as a food and feed source, spring-type turnip rape cultivation is on the rise. To improve the crop's productivity and nutritional value, it is essential to understand its genetic diversity. In this study, 188 spring-type accessions were genotyped using SeqSNP, a targeted genotyping-by-sequencing method to determine genetic relationships between various groups and assess the potential effects of mutations within genes regulating major desirable traits. Single nucleotide polymorphism (SNP) alleles at six loci were predicted to have high effects on their corresponding genes' functions, whereas nine loci had country/region-specific alleles. A neighbor-joining cluster analysis revealed three major clusters (I to III). About 72% of cluster-I accessions were of Asian origin, whereas 88.5% of European accessions and all North American accessions were placed in cluster-II or cluster-III. A principal coordinate analysis explained 65.3% of the total genetic variation. An analysis of molecular variance revealed significant differentiation among different groups of accessions. Compared to Asian cultivars, European and North American cultivars share more genetic similarities. Hence, crossbreeding Asian and European cultivars may result in improved cultivars due to desirable allele recombination. Compared to landraces and wild populations, the cultivars had more genetic variation, indicating that breeding had not caused genetic erosion. There were no significant differences between Swedish turnip rape cultivars and the NordGen collection. Hence, crossbreeding with genetically distinct cultivars could enhance the gene pool's genetic diversity and facilitate superior cultivar development.

The Influence of Nitrogen and Sulfur Fertilization on Oil Quality and Seed Meal in Different Genotypes of Winter Oilseed Rape (Brassica napus L.)

Adequate nitrogen (N) and sulfur (S) fertilization of oilseed rape crops is necessary to obtain good-quality oil and post-extraction rapeseed meal. The aim of this study was to determine the effect of different doses of N fertilization (100, 160 and 220 kg ha−1) and S (0, 30, 60 and 90 kg ha−1) on the value of seeds of three winter oilseed rape genotypes. Two winter oilseed rape genotypes obtained by mutagenesis (cultivar Polka and breeding genotype PN440) were characterized by changed fatty acid profile. The cultivar Polka, type HO (high oleic), had a high content of oleic acid (C18:1, 78.0%) and the breeding genotype PN440, type HOLL (high-oleic and low-linolenic), had a high content of oleic acid (C18:1, 75.0%) and a low content of linolenic acid (C18:3, 3.0%). We also used the canola type of winter oilseed rape cultivar, Monolit. The analysed winter oilseed rape genotypes responded similarly to the N and S fertilization factors with regard to the content of crude fat and total protein in the seeds and the composition of fatty acids in the oil. N fertilization increased the content of glucosinolates (GLS-alkenyl, indole and total) in seeds, whereas S application decreased the content of saturated fatty acids (stearic acid-C18:0) in oil and increased the content of alkenyl and total glucosinolates (GLSs) in seeds. A significant interaction between N and S was observed for crude-fat and total-protein content. This study suggests that ensuring an adequate supply of both nitrogen and sulfur in the soil is essential for optimizing meal and oil quality in different types of winter oilseed rape cultivars. Proper management of these nutrients can lead to improved oil content and overall crop performance.

Novel sources of resistance to bacterial leaf blight in the USDA Brassica rapa collection

Bacterial leaf blight (BLB), caused by Pseudomonas cannabina pv. alisalensis (Pcal), is a devastating disease that has spread worldwide over the past twenty years. Pcal can infect all Brassica crops and leads to yield losses of Brassica leafy greens across the Southeastern US every year. There are no commercial cultivars of turnip greens with resistance to Pcal and no effective bactericides available. We report the first identification of resistant sources in Brassica rapa L. against bacterial leaf blight, caused by Pcal. The USDA accessions of B. rapa (275 accessions) were screened through multiple tests in greenhouse trials. The three commercial cultivars tested exhibited an intermediate response across all tests and re-tests. Three accessions (Ames 7572, PI 649171, and PI 649183) with significant resistance were identified in the B. rapa germplasm collection. The identified accessions are an important source for development of B. rapa cultivars resistant to Pcal and introgression of the resistant loci into B. napus cultivars.

Alone or Combined Effect of Seaweed and Humic Acid Applications on Rapeseed (Brassica napus L.) under Salinity Stress

Organic fertilisers and biostimulants play a very important role in the germination, seedling stage, yield and quality of plants. Seaweed and humic acid are organic substances known for their positive effects. Therefore, the aim of this study was to investigate the effects of humic acid, seaweed extract and their combined applications against salt stress in oilseed rape at the seedling development stage. The effects of foliar application of seaweed extract (SW1, SW2, SW3) (0, 10, 20 mL), humic acid (HA1, HA2, HA3) (0, 10, 20 mL) and SW + HA (SW1 + HA1, SW2 + HA2, SW3 + HA3) (0, 10(5 + 5 mL L− 1 SW + HA), 20 mL L− 1 (10 + 10 mL L− 1 SW + HA)) on resistance to salt concentrations (S1, S2, S3) (0, 50, 100 mM) in oilseed rape cultivar (Elvis) under greenhouse conditions. In this study, seedling length (SL), root length (RL), total chlorophyll (Total Chl), carotenoids (Crt), electrolyte leakage (EL), malondialdehyde (MDA), superoxide dismutase (SOD), total phenolic compounds (TPC), relative water content (RWC) and proline (Pro) parameters were examined. Both applications played a significant role in reducing the negative effects of salt stress on all parameters studied. The combined application of SW + HA resulted in a remarkable increase in SL, RL TPC, SOD and RWC. In particular, the SW3 + HA3 dose played a more effective role in the antioxidant protective mechanism against stress. According to the PCA analysis, the studied parameters could be divided into 3 different groups. It was concluded that SW and HA can be evaluated as an effective natural, eco-friendly material that can be used to increase the resistance of plants to salt stress. In conclusion, in this study all applications are compared with each other, it has been determined that SW + HA is more effective application in reducing the effects of salt stress than others.

Foliar application of commercial humic substances for possible increase of nutrient status and yield of oilseed rape

Inconsistent results on the effects of humic substances (HS) on yield and nutrient status of important food crops, including oilseeds, confirm the need for further research on different HS products to match their use to actual field conditions. The aim of this study was to evaluate the effect of foliar application of commercially produced peat- and vermicompost-derived HS preparations on nutrient status and yield of spring oilseed rape (Brassica napus). The field experiment was carried out in Stende State Cereals Breeding Institute, Latvia, during the vegetation season of 2012, using the spring oilseed rape cultivar ‘Perfect’. Although foliar sprays of HS were applied during the critical stages of crop development from rapid growth to flowering, they were ineffective in improving the supply of the deficient nutrients (N, K, B, Zn, Cu) in leaves. Moreover, both tested HS products caused a decrease in Cu and B content in the seeds, which resulted in a negative trend in oilseed rape seed yield. Therefore, the conducted experiment demonstrated that foliar application of both HS preparations was ineffective to promote nutrient status and did not contribute to spring oilseed rape yield.

Pathotype Characterization of Plasmodiophora brassicae by European Clubroot Differential and Williams Sets in China.

Clubroot disease caused by the soil-borne Plasmodiophora brassicae is devastating to Brassicaceae crops and spreading rapidly in China in recent years, resulting in great yield losses annually. Virulence of P. brassicae populations specializes and is in dynamic change in the fields. Information on the pathotypes and their distributions is crucial to control the clubroot disease. Presently, the pathotypes of P. brassicae prevalent in China, however, are not well determined. In this study, we used 16 Brassica hosts, including the European Clubroot Differential (ECD) and Williams sets, to designate the pathotypes of 33 P. brassicae populations from 13 provinces. The 33 P. brassicae populations could be divided into 26 pathotypes by the ECD set or seven pathotypes by the Williams set, revealing ECD16/15/31 and ECD16/31/31 or P4 and P2 as the predominant pathotypes. We found that the Brassica rapa differentials ECD01 to ECD04 showed stable and high levels of resistance to most pathotypes of P. brassicae in China, thereby providing valuable resources for clubroot-resistance breeding of Brassicaceae crops. The ECD set exhibited much higher discernibility and further divided the isolates that belonged to the P4 pathotype into 10 ECD pathotypes. Isolates of ECD16/23/31 and ECD16/15/31 were strongly virulent on Huashuang 5R, the first and widely used clubroot-resistant cultivar of oilseed rape in China. As we learn, 26 pathotypes are the most diverse populations of P. brassicae characterized until now in China. Our study provides new insights into virulence specialization of P. brassicae and their geographical distributions, contributing to exploitation of clubroot-resistant resources and the field layout of the present resistant Brassica crops in China.

Enhancing yield and oil content in oilseed rape hybrids: Insights from line × tester and SIIG approaches.

The production of high-oil-yielding hybrid varieties is a primary objective in oilseed rape (Brassica napus L.) breeding programs. Biometric genetic experiments such as line × tester provide valuable insights into the genetic structure of traits associated with high oil yield. In this study, 21 winter hybrids of oilseed rape were evaluated, which were generated by crossing three restorers with seven CMS lines. The experiment was conducted using a line × tester experiment based on a completely randomized block design. Phenological, agronomic, yield, and oil yield components were assessed in this study. The ideal genotype selection index (SIIG) methodology was also employed to identify superior hybrids based on all studied traits simultaneously. Significant differences were observed between the obtained hybrids and the check cultivars. Heritability analysis revealed that phenological traits were primarily controlled by additive effects, while agronomic and qualitative traits were mainly influenced by non-additive gene effects. Both broad-sense and narrow-sense heritability exhibited a wide range, underscoring the importance of genetic variance. Notably, the hybrids T1 × L5, T1 × L6, and T3 × L1 showed significant specific combining ability values of 394.74, 541.73, and 1236.79, respectively, making them the top specific combinations for increasing seed yield. Based on the SIIG index, hybrids T3 × L1, T1 × L5, T1 × L3, and T2 × L3 emerged as high-oil-yielding hybrids with desirable agronomic traits. The identified superior hybrids by line × tester and SIIG approaches hold promise for the development of high-yielding oilseed rape cultivars with desirable agronomic traits in oilseed rape breeding programs.

Exploring Genetic Variation in Brassica rapa for Improved Yield and Fatty Acid Profiles

Brassica rapa is one of the most widely cultivated oilseed crops and is known for a variety of benefits across the globe. Brassica rapa is one of the key Brassica species. Together with significant oil concentrations, it is distinguished by a high concentration of macro and micronutrients. Oilseed rape cultivars have high amounts of erucic acid and glucosinolate which may increase health risks. The current study was carried out in 2021 in the research area of the Department of Plant Breeding and Genetics at the University of Agriculture, Faisalabad. The goal of the experiment was to find Brassica rapa accessions with improved yield and fatty acid-related characteristics from the germplasm by screening and choosing them. One hundred accessions of B. rapa were screened for better yield and fatty acid-related traits in a randomized complete block design. Data were obtained for many morphological and fatty acid-related characteristics. Analysis of variance, mean comparison, correlation, and principal component analysis were performed on the recorded data. Three testers; 26240, 26283, and 26215 and ten lines; 28244, 40961, 40970, 40975, 40977, 40978, 40979, 40980, 40981 and 40982 were selected on a mean performance basis. The highest mean value was shown by 40975, and 40977 lines for most of the traits. The findings demonstrated that there was significant genetic variation in the oil content and mix of fatty acids across the species under study. This suggests that the oil extracted from the seeds of these lines may be appropriate for both industrial and human use. The selected accessions should be further assessed for various yield and fatty acid-related traits to modify their value for edible purposes. They may also be utilized as a favourable germplasm in the breeding program.

Pollen Count Dynamics in Rapeseed Stamens in Early Spring

Abstract Pollen contains vegetative and generative cells that influence the seed set. Accurate pollen assessments help understand the breeding biology of oilseed rape. In order to evaluate the number of pollen grains in a large number of samples, an effective method should be designed. A new method was established to evaluate the pollen counts of five oilseed rape cultivars. This method mainly relies on 5% sucrose + 0.1% agar solution to suspend the pollen and uses a standard curve corresponding to the absorbance and the number of pollen grains to estimate the number of pollen grains. The linear fit formula of this standard curve was precision, and the R2 value between the pollen count and absorbance reached 0.998. Furthermore, the variation in the pollen counts at three flowering stages and on two kinds of stamens was assessed. The pollen count per flower varied significantly among oilseed rape cultivars and flowering stages (GLM: p<0.001). Moreover, the number of pollen grains on long-stamen anthers was significantly higher than that on short-stamen anthers (GLM: p<0.001). In conclusion, we established a rapid, accurate method for quantifying pollen grains based on absorbance determined in a liquid suspension by light spectroscopy, which is a feasible method. In addition, the number of pollen grains under different physiological conditions also provides basic data for oilseed rape breeding.

Cloning and functional analysis of the BrCUC2 gene in Brassica rapa L.

The CUP-SHAPED COTYLEDON2 (CUC2) gene plays an important role in the formation of apical meristem and organ edges in plants. The apical meristematic tissue of Brassica rapa (B. rapa) is associated with cold resistance, however, the role of the CUC2 gene in cold resistance of B.rapa is unclear. In this study, we used bioinformatics software to analyze the structure of BrCUC2 gene, real-time fluorescence quantitative PCR to detect the expression level of BrCUC2, constructed transgenic Arabidopsis thaliana by the flower dipping method and subcellular localization for functional validation. The results showed that, we isolated a 1104 bp open reading frame of BrCUC2 from the winter B. rapa cultivar 'Longyou 7'. The BrCUC2 contains a highly conserved domain belonging to the NAM superfamily. Its homologus CUC genes contain similar conserved motifs and are closely related to Brassica oleracea (B.oleracea), and the N-terminal of amino acid sequence contains NAC domain. BrCUC2 protein was localized in the nucleus and self-activation tests showed that pGBKT7-BrCUC2 had self-activation. Tissue-specific expression analysis and promoter β-Glucuronidase (GUS) activity showed that BrCUC2 had high expression levels in B. rapa growth points and A. thaliana leaf edges, stems and growth points. After low-temperature stress, BrCUC2 showed greater expression in 'Longyou 7,' which presents strong cold resistance and concave growth points, than in 'Longyou 99,' which presents weak cold resistance and protruding growth points. BrCUC2 promoter contains multiple elements related to stress responses. BrCUC2 overexpression revealed that the phenotype did not differ from that of the wild type during the seedling stage but showed weak growth and a dwarf phenotype during the flowering and mature stages. After low-temperature treatment, the physiological indexes and survival rate of BrCUC2-overexpression lines of Arabidopsis thaliana (A. thaliana) were better than those of the wild type within 12h, although differences were not observed after 24h. These results showed that BrCUC2 improved the low-temperature tolerance of transgenic A. thaliana within a short time. It can provide a foundation for the study of cold resistance in winter B. rapa.

Beneficial impact of multi-bacterial inoculation on growth of selected Brassicaceae seedlings in a greenhouse culture

Modern agriculture requires the development of new eco-friendly and cost efficient methods of crop production. In this study we tested if engineering Brassica microbiome by supplementation it with an inoculum composed of selected microorganisms can accelerate seedling growth and be a substitute for inorganic fertilizers. We hypothesised that the multiorganismal inoculum will be more efficient and affect a wide range of plants compared to inoculation with a single microorganism. We developed and examined several new multispecies inocula in the cultivation of different Brassica oleracea, B. rapa, Eruca sativa and Lactuca sativa cultivars. Every microorganism used for biotization was isolated from Arabidopsis arenosa (Brassicaceae) and tested for plant growth promoting properties. Of all the inocula tested, one (T4) containing only bacteria (Chryseobacterium lathyri, Bacillus cereus, Lysinibacillus fusiformis, Pseudomonas protegens) proved to be particularly efficient in increasing the fresh biomass of most B. oleracea and B. rapa cultivars cultured in the growth chamber. None of the bacteria used in the inoculum was able to activate plant growth individually. Thus, T4 inoculum was evaluated in a large-scale greenhouse culture of young Brassica vegetables. The results confirmed the positive effect of inoculation on the growth of selected Brassica crops, but it differed according to the plant genotype. What is more, the T4 inoculation proved to be as effective for increasing plant biomass as synthetic fertilizers. None of the inocula tested improved the growth of plants from genus other than Brassica.

A new set of international Leptosphaeria maculans isolates as a resource for elucidation of the basis and evolution of blackleg disease on Brassica napus

AbstractA collection of isolates of the fungi Leptosphaeria maculans and L. biglobosa, which cause blackleg disease on Brassica napus (canola/oilseed rape) and other Brassicaceae species, was assembled to represent the global diversity of these pathogens and a resource for international research. The collection consists of 226 isolates (205 L. maculans and 21 L. biglobosa) from 11 countries. The genomes of all 205 L. maculans isolates were sequenced, and the distribution and identity of avirulence gene alleles were determined based on genotypic information and phenotypic reactions on B. napus lines that hosted specific resistance genes. Whilst the frequencies of some avirulence alleles were consistent across each of the regions, others differed dramatically, potentially reflecting the canola/oilseed rape cultivars grown in those countries. Analyses of the single‐nucleotide polymorphism (SNP) diversity within these L. maculans isolates revealed geographical separation of the populations. This "open access" resource provides a standardized set of isolates that can be used to define the basis for how these fungal pathogens cause disease, and as a tool for discovery of new resistance traits in Brassica species.

Integrated Analysis of the Transcriptome and Metabolome of Brassica rapa Revealed Regulatory Mechanism under Heat Stress.

Affected by global warming; heat stress is the main limiting factor for crop growth and development. Brassica rapa prefers cool weather, and heat stress has a significant negative impact on its growth, development, and metabolism. Understanding the regulatory patterns of heat-resistant and heat-sensitive varieties under heat stress can help deepen understanding of plant heat tolerance mechanisms. In this study, an integrative analysis of transcriptome and metabolome was performed on the heat-tolerant ('WYM') and heat-sensitive ('AJH') lines of Brassica rapa to reveal the regulatory networks correlated to heat tolerance and to identify key regulatory genes. Heat stress was applied to two Brassica rapa cultivars, and the leaves were analyzed at the transcriptional and metabolic levels. The results suggest that the heat shock protein (HSP) family, plant hormone transduction, chlorophyll degradation, photosynthetic pathway, and reactive oxygen species (ROS) metabolism play an outstanding role in the adaptation mechanism of plant heat tolerance. Our discovery lays the foundation for future breeding of horticultural crops for heat resistance.

Comprehensive evaluation on safe utilization potential of ten oilseed rape cultivars in a cadmium contaminated soil

Oilseed rape (Brassica napus L.) planting could be a promising approach for the safe utilization of cadmium (Cd) contaminated soil. However, comprehensive evaluation on safe utilization potential of oilseed rape was lacked, including phytoextraction efficiency, health risk, and economic benefits. In this study, ten oilseed rape cultivars were planted in Cd-contaminated soils immobilized with limestone and a comprehensive evaluation was performed on the safe utilization potential. Results showed that the highest biomass of rapeseed (1363-1569 kg ha−1) was found in Zhongshuang 11, Xiangzayou 787, and Luoyouza 101. Zhongyouza 19, Zhongshuang 11 and Dadi 199 had the highest Cd phytoextraction efficiency (3.31-3.76 g ha−1). The Cd concentrations in all the rapeseeds ranged from 0.18–0.45 mg kg−1 and were lower than the limit of food security standards, but oil Cd concentrations of three cultivars (Fengyou 730, Dadi 199, and Yangguang 50) were 0.90-1.56 times higher than those in the reference oils (0.04-0.05 mg kg−1). Target hazard quotient (THQ) suggested that the Cd in all the oils were under the acceptable level for adults and children, whereas only of three cultivars (Huihaoyou 26, Luoyouza 101, and Zhongshuang 11) were at acceptable level at incremental lifetime cancer risk (ILCR) value. Based on the yields and market price of rapeseed, Luoyouza 101, Xiangzayou 787, and Zhongshuang 11 had the highest economic benefits (9812-11300 CNY ha−1). Overall, the comprehensive evaluation indicates that Zhongshuang 11 is the most suitable for the safe utilization of Cd contaminated soil.

Relationships between Flower Opening Time, Environmental Conditions, Corolla Opening Size and Nectar Production in Five Winter Oilseed Rape (Brassica napus L.) Cultivars in China

Abstract Oilseed rape is an economically important crop and provides a good nectar resource. In this study, the nectar secretion characteristics of five winter oilseed rape (Brassica napus L.) cultivars in China were examined throughout the daytime. The correlations of corolla opening size, air temperature and relative humidity with nectar production were also determined. Different daily patterns of nectar secretion were detected in flowers opening at different times of the day, and similar trends were observed among cultivars. The nectar volume and nectar sugar concentration in flowers that opened before 9:00 peaked on the first day. The nectar volume of flowers that opened at 11:00 peaked on the second day, and the nectar sugar concentration peaked on the first day. The total nectar yield of flowers opening before 9:00 (4.422–5.265 μl) was lower than that of flowers opening at 11:00 (7.982–10.646 μl). The average nectar sugar concentration of flowers opening before 9:00 (18.4–23.3%) was higher than that of flowers opening at 11:00 (15.3–17.5%). The nectar volume was positively correlated with air temperature and relative humidity, while the nectar sugar concentration was positively correlated with air temperature and negatively correlated with relative humidity. The nectar volume and nectar sugar concentration were positively correlated with corolla opening size. The glucose/fructose ratio ranged from 0.89 to 1.44. These results will contribute to a better understanding of the nectar secretion patterns of B. napus L. and will support further studies assessing the melliferous potential of B. napus L. and the temporal dynamics of plant-pollinator interactions.

Non-vernalization requirement for flowering in Brassica rapa conferred by a dominant allele of FLOWERING LOCUS T

We identified and characterized a dominant FT allele for flowering without vernalization in Brassica rapa, while demonstrating its potential for deployment in breeding to accelerate flowering in various Brassicaceae crops. Controlling the timing of flowering is key to improving yield and quality of several agricultural crops including the Brassicas. Many Brassicaceae crops possess a conserved flowering mechanism in which FLOWERING LOCUS C (FLC) represses the transcription of flowering activators such as FLOWERING LOCUS T (FT) during vernalization. Here, we employed genetic analysis based on next-generation sequencing to identify a dominant FT allele, BraA.FT.2-C, for flowering in the absence of vernalization in the Brassica rapa cultivar 'CHOY SUM EX CHINA 3'. BraA.FT.2-C harbors two large insertions upstream of its coding region and is expressed without vernalization, despite FLC expression. We show that BraA.FT.2-C offers an opportunity to introduce flowering without vernalization requirement into winter-type brassica crops, including B. napus, which have many functional FLC paralogs. Furthermore, we demonstrated the feasibility of using B. rapa harboring BraA.FT.2-C as rootstock for grafting to induce flowering in radish (Raphanus sativus), which requires vernalization for flowering. We believe that the ability of BraA.FT.2-C to overcome repression by FLC can have significant applications in brassica crops breeding to increase yields by accelerating or delaying flowering.

Aphids on Aphid-Susceptible Cultivars Have Easy Access to Turnip Mosaic Virus, and Effective Inoculation on Aphid-Resistant Cultivars of Oilseed Rape (Brassica napus).

Plant viruses improve transmission efficiency by directly and indirectly influencing vector behavior, but the impact of plant cultivars on these modifications is rarely studied. Using electropenetrography (EPG) technology, a comparative study of the effects of turnip mosaic virus (TuMV) infection on quantitative probing behaviors of the cabbage aphid (Brevicoryne brassicae) was conducted on two oilseed rape cultivars ('Deleyou6' and 'Zhongshuang11'). Compared to mock-inoculated plants, cabbage aphids on infected plants increased the frequency of brief probing, cell penetration, and salivation. Additionally, aphids on infected 'Deleyou6' prolonged cell penetration time and decreased ingestion, but not on infected 'Zhongshuang11', suggesting that aphids were more likely to acquire and vector TuMV on the aphid-susceptible cultivar 'Deleyou6' than on resistant cultivars. TuMV also affected aphid probing behavior directly. Viruliferous aphids reduced the pathway duration, secreted more saliva, and ingested less sap than non-viruliferous aphids. In comparison with non-viruliferous aphids, viruliferous aphids started the first probe earlier and increased brief probing and cell penetration frequencies on the aphid-resistant cultivar 'Zhongshuang11'. Based on these observations, viruliferous aphids can be inoculated with TuMV more efficiently on 'Zhongshuang11' than on 'Deleyou6'. Although aphid resistance and TuMV infection may influence aphid probing behavior, oilseed rape resistance to aphids does not impede TuMV transmission effectively.

Effect of fungicide treatment and nitrogen fertilisation on the yield of two breeding types of winter oilseed rape cultivars

The effect of three fungicide treatment programmes and the level of spring nitrogen fertilisation on the seed yield of two types ofcultivars of Brassica napus L. sown at two different seeding rates was studied in a field experiment. The subject of the study was anopen-pollinated cultivar ‘Casoar’ and a restored hybrid cultivar ‘Visby’. Three plant protection programmes, two levels of spring nitrogenfertilisation (160 and 220 kg N⋅ha1), and two different seeding rates for each cultivar (‘Visby’—50 and 70 seeds⋅⋅m2; ‘Casoar’—60 and 80 seeds⋅m2) were included. The most intensive protection programme comprised three fungicide treatments: first in autumn at the six-leaves-unfolded stage—BBCH 16, second in spring at the stem elongation stage—BBCH 33, and third at the full flowering stage—BBCH 65. One of two less intensive programmes of plant protection included fungicide application in autumn at the sixleaves-unfolded stage—BBCH 16 and at the full flowering stage—BBCH 65, while the second included fungicide application in spring at the stem elongation stage—BBCH 33 and at the full flowering stage—BBCH 65. The effectiveness of the protection programmes and nitrogen fertilisation was influenced by the intensity of abiotic stress factors. The average yield from the plots protected against pathogens was significantly higher than that from the untreated plots. The increase of nitrogen fertilisation from 160 to 220 kg⋅ha1 also caused a significant increase of average seed yield. The yield of cultivar ‘Visby’ was higher and less dependent on the seeding rate compared to cultivar ‘Casoar’.Keywords: Winter oilseed rape; Cultivars; Disease control; Nitrogen fertilisation; Seeding rate; Sclerotinia sclerotiorum; Leptosphaeria spp.; Alternaria spp. Botrytis cinerea.

Crop weather relationship in oilseed rape (Brassica napus) for north-west foothills of Himalayas, India

Agrometeorological indices have a strong correlation with growth, yield attributes and yield of crop and can be effectively used to select suitable cultivar for specific environmental conditions. Therefore, to study the cumulative effect of weather variables in terms of agrometeorological indices on cultivars of oilseed rape (Brassica napus L.) sown under different sowing environments, field experiments were conducted at the research farm of Agrometeorology section, Sher-e-Kashmir University of Agricultural Sciences and Technology, Jammu, Jammu and Kashmir during winter (rabi) season of 2018–19 and 2019–20. The treatments were comprised of 3 sowing environments, viz. 42nd SMW (standard meteorological week), 44th SMW and 46th SMW along with 3 cultivars (GSL-1, ONK-1 and DGS-1) of oilseed rape in factorial randomized block design with 3 replications. The pooled data of 2 years revealed that allthe cultivars of oilseed rape sown in 42nd SMW accumulated higher growing degree days (GDD), photothermal units (PTU) and heliothermal units (HTU) with higher rate of dry matter accumulation in comparison to 44th SMW and 46th SMW sown crop. The agrometeorological indices, viz. GDD, PTU and HTU were significantly positively correlated with growth parameters, yield attributes and yield at vegetative stage, while, PTU and HTU were negatively correlated at reproductive stage of the crop. Due to the significant impact of weather variables, the seed yield of all the oilseed rape cultivars decreased when the sowing was delayed from 42nd SMW to 46th SMW during both the years. Among cultivars, GSL-1 recorded significantly higher seed yield followed by ONK-1 and DGS-1.