Rapeseed Research Articles

Strategic tillage of no-till decreased surface and subsurface losses of dissolved phosphorus.

Enrichment of soluble P on the surface layer of long-term no-till (NT) soils, and consequent increase in dissolved P losses, is a concern for which occasional plowing has been suggested as a remedy. We measured the effect of such strategic tillage (ST) on surface and subsurface P losses from 0.5-ha field plots on clay soil for 4years. Two NT plots had discharged threefold dissolved molybdate-reactive P (DRP) losses compared to annually plowed soil conventional tillage (CT). ST by plowing to 20-cm depth was applied on one of the NT plots, whereas the other remained under NT. ST done in July was sown with canola (Brassica napus ssp. oleifera) to establish plant cover before winter. Summed 4-year DRP loss from ST treatment was 60% lower compared to NT (0.78vs. 1.96kg ha-1), accompanied with 11% higher particulate P (PP) loss (4.39vs. 3.97kg ha-1). CT plots produced slightly lower DRP losses (0.53-0.76kg ha-1) than ST, but higher PP losses (6.02-7.96kg ha-1). Bioavailable P (BAP) losses from ST were lower than from the other treatments if >7% of PP turns bioavailable. After ST, soil P stratification first vanished, but started to develop again when NT was resumed. Occasional tillage of NT soils mitigates DRP losses over several years, and it was at the study site the preferred mitigation option in reducing BAP losses.

Effects of dietary fish to rapeseed oil ratio on steatosis symptoms in Atlantic salmon (Salmo salar L) of different sizes

Choline is recognized as an essential nutrient for Atlantic salmon at all developmental stages. However, its dietary requirement is not well defined. Choline plays a critical role in lipid transport, and the clearest deficiency sign is intestinal steatosis. The present work, aiming to find whether lipid source and fish size may affect steatosis symptoms, was one of a series of studies conducted to identify which production-related conditions may influence choline requirement. Six choline-deficient diets were formulated varying in ratios of rapeseed oil to fish oil and fed to Atlantic salmon of 1.5 and 4.5 kg. After eight weeks, somatic characteristics were observed, and the severity of intestinal steatosis was assessed by histological, biochemical, and molecular analyses. Fatty acid composition in pyloric intestine, mesenteric tissue, and liver samples was also quantified. The increasing rapeseed oil level increased lipid digestibility markedly, enhancing lipid supply to the fish. Moreover, small fish consumed more feed, and consequently had a higher lipid intake. In conclusion, the results showed that choline requirement depends on dietary lipid load, which depends on the fatty acid profile as well as the fish size.

The introgression of BjMYB113 from Brassica juncea leads to purple leaf trait in Brassica napus

The purple leaves of Brassica napus are abundant in anthocyanins, which are renowned for their role in conferring distinct colors, stress tolerance, and health benefits, however the genetic basis of this trait in B. napus remains largely unelucidated. Herein, the purple leaf B. napus (PL) exhibited purple pigments in the upper epidermis and a substantial increase in anthocyanin accumulation, particularly of cyanidin, compared to green leaf B. napus (GL). The genetic control of the purple leaf trait was attributed to a semi-dominant gene, pl, which was mapped to the end of chromosome A03. However, sequencing of the fragments amplified by the markers linked to pl indicated that they were all mapped to chromosome B05 from B. juncea. Within this B05 chromosomal segment, the BjMYB113 gene-specific marker showed perfect co-segregation with the purple leaf trait in the F2 population, suggesting that the BjMYB113 introgression from B. juncea was the candidate gene for the purple leaf trait in B. napus. To further verify the function of candidate gene, CRISPR/Cas9 was performed to knock out the BjMYB113 gene in PL. The three myb113 mutants exhibited evident green leaf phenotype, absence of purple pigments in the adaxial epidermis, and a significantly reduced accumulation of anthocyanin compared to PL. Additionally, the genes involved in positive regulatory (TT8), late anthocyanin biosynthesis (DFR, ANS, UFGT), as well as transport genes (TT19) were significantly suppressed in the myb113 mutants, further confirming that BjMYB113 was response for the anthocyanin accumulation in purple leaf B. napus. This study contributes to an advanced understanding of the regulation mechanism of anthocyanin accumulation in B. napus.

Effects of Low-Phosphorus Stress on Use of Leaf Intracellular Water and Nutrients, Photosynthesis, and Growth of Brassica napus L.

Phosphorus (P) deficiency is one of the main reasons limiting plant production of Brassica napus L. Exploring the dynamics of leaf intracellular substances and the correlations with photosynthesis and growth helps to understand the response mechanisms of B. napus L. to P deficiency. This study conducted experiments on B. napus L. plants by measuring the leaf electrophysiological parameters, leaf structure, elastic modulus (Em), photosynthesis, and growth indices under different P treatment conditions. The dynamics of leaf intracellular water and nutrients of B. napus L. were calculated and analyzed by using the electrophysiological parameters, and the plant tolerance threshold to low-P stress was discovered. The results indicated that the status of the leaf intracellular water and nutrients remained stable when the P concentration was not lower than 0.250 mmol·L−1, but maximized the photosynthesis and growth at a P level of 0.250 mmol·L−1. The 0.125 mmol·L−1 P concentration significantly decreased the mesophyll cell volume, and the palisade–sponge ratio and tightness degree of leaf tissue structure were remarkably increased. This led to an increase in cell elastic modulus, and significantly improved the water retention capacity of leaf cells. At the same time, the intracellular water use efficiency and total nutrient transport capacity of leaves remained stable. As a result, the photosynthesis and growth of plants were maintained at the same level as that of the control group. However, photosynthesis and growth were clearly inhibited with a further decrease in P concentration. Therefore, 0.125 mmol·L−1 was the tolerance threshold of B. napus L. to low P. With the help of electrophysiological information, the effects of the dynamics of intracellular substances on photosynthesis and growth of B. napus L. under low-P stress can be investigated, and the plant’s adaptive response can be revealed. However, the findings of the current hydroponic study are not directly applicable to field conditions with naturally P-deficient soils.

Interactive regulation of immune-related resistance genes with salicylic acid and jasmonic acid signaling in systemic acquired resistance in the Xanthomonas–Brassica pathosystem

Pathogen-responsive immune-related genes (resistance genes [R-genes]) and hormones are crucial mediators of systemic acquired resistance (SAR). However, their integrated functions in regulating SAR signaling components in local and distal leaves remain largely unknown. To characterize SAR in the Xanthomonas campestris pv. campestris (Xcc)–Brassica napus pathosystem, the responses of R-genes, (leaf and phloem) hormone levels, H2O2 levels, and Ca2+ signaling-related genes were assessed in local and distal leaves of plants exposed to four Xcc-treatments: Non-inoculation (control), only secondary Xcc-inoculation in distal leaves (C-Xcc), only primary Xcc-inoculation in local leaves (Xcc), and both primary and secondary Xcc-inoculation (X-Xcc). The primary Xcc-inoculation provoked disease symptoms as evidenced by enlarged destructive necrosis in the local leaves of Xcc and X-Xcc plants 7 days post-inoculation. Comparing visual symptoms in distal leaves 5 days post-secondary inoculation, yellowish necrotic lesions were clearly observed in non Xcc-primed plants (C-Xcc), whereas no visual symptom was developed in Xcc-primed plants (X-Xcc), demonstrating SAR. Pathogen resistance in X-Xcc plants was characterized by distinct upregulations in expression of the PAMP-triggered immunity (PTI)-related kinase-encoding gene, BIK1, the (CC-NB-LRR-type) R-gene, ZAR1, and its signaling-related gene, NDR1, with a concurrent enhancement of the kinase-encoding gene, MAPK6, and a depression of the (TIR-NB-LRR-type) R-gene, TAO1, and its signaling-related gene, SGT1, in distal leaves. Further, in X-Xcc plants, higher salicylic acid (SA) and jasmonic acid (JA) levels, both in phloem and distal leaves, were accompanied by enhanced expressions of the SA-signaling gene, NPR3, the JA-signaling genes, LOX2 and PDF1.2, and the Ca2+-signaling genes, CAS and CBP60g. However, in distal leaves of C-Xcc plants, an increase in SA level resulted in an antagonistic depression of JA, which enhanced only SA-dependent signaling, EDS1 and NPR1. These results demonstrate that primary Xcc-inoculation in local leaves induces resistance to subsequent pathogen attack by upregulating BIK1-ZAR1-mediated synergistic interactions with SA and JA signaling as a crucial component of SAR.

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

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

Enhanced root system architecture in oilseed rape transformed with Rhizobium rhizogenes

Transformation of plants using wild strains of agrobacteria is termed natural transformation and is not covered by GMO legislation in e.g. European Union and Japan. In the current study, offspring lines (A11 and B3) of Rhizobium rhizogenes naturally transformed oilseed rape (Brassica napus) were randomly selected to characterize the morphological traits, and the implications of such morphological changes on plant drought resilience. It was found that the introduction of Ri-genes altered the biomass partitioning to above- and under-ground parts of oilseed rape plants. Compared to the wild type (WT), the A11 and B3 lines possessed 1.2-4.0 folds lower leaf and stem dry weight, leaf area and plant height, but had 1.3-5.8 folds greater root dry weight, root length and root surface area, resulting in a significantly enhanced root: shoot dry mass ratio and root surface area: leaf area ratio. In addition, the introduction of Ri-genes conferred reduced stomatal pore aperture and increased stomatal density in the B3 line, and increased leaf thickness in A11 line, which could benefit plant drought resilience. Finally, the modulations in morphological traits as a consequence of transformation with Ri-genes are discussed concerning resilience in water-limited conditions. These findings reveal the potential of natural transformation with R. rhizogenes for drought-targeted breeding in crops.

Investigation of the quality of rapeseed oil derived from different varieties and growth periods based on GC-IMS technique

Rapeseed oil is consumed worldwide, and its quality is closely related to the raw rapeseed material. In this work, the quality and flavor differences of rapeseed oil from twelve varieties with two growth periods were studied. The results showed that different varieties responded differently to changes in growth periods, with the GXY1 variety having the greatest combined effect. Shortening the growth period may reduce the moisture and protein content and increase the oil content of rapeseed. It may also enhance the oleic acid content and decrease the linoleic acid content. A total of 62 aroma compounds were identified by gas chromatography-ion migration spectrometry (GC-IMS), with aldehydes being the main flavor compounds. The flavor fingerprint of rapeseed oil derived from different varieties was effectively constructed. Seven key aroma compounds with relative odor activity value (ROAV) > 1 were identified, which significantly influenced the flavor of rapeseed oil. This work may provide new insights for selecting favorable rapeseed varieties for industrial production of high-quality rapeseed oil.

Canola (Brassica napus) enhances sodium chloride and sodium ion tolerance by maintaining ion homeostasis, higher antioxidant enzyme activity and photosynthetic capacity fluorescence parameters.

Under salt stress, plants are forced to take up and accumulate large amounts of sodium (Na+ ) and chloride (Cl- ). Although most studies have focused on the toxic effects of Na+ on plants, Cl- stress is also very important. This study aimed to clarify physiological mechanisms underpinning growth contrasts in canola varieties with different salt tolerance. In hydroponic experiments, 150mM Na+ , Cl- and NaCl were applied to salt-tolerant and sensitive canola varieties. Both NaCl and Na+ treatments inhibited seedling growth. NaCl caused the strongest damage to both canola varieties, and stress damage was more severe at high concentrations of Na+ than Cl- . High Cl- promoted the uptake of ions (potassium K+ , calcium Ca2+ ) and induced antioxidant defence. Salt-tolerant varieties were able to mitigate ion toxicity by maintaining lower Na+ content in the root system for a short period of time, and elevating magnesium Mg2+ content, Mg2+ /Na+ ratio, and antioxidant enzyme activity to improve photosynthetic capacity. They subsequently re-established new K+ /Na+ and Ca2+ /Na+ balances to improve their salt tolerance. High concentrations of Cl salts caused less damage to seedlings than NaCl and Na salts, and Cl- also had a positive role in inducing oxidative stress and responsive antioxidant defence in the short term.

Unraveling the molecular response of Brassica napus hairy roots in the active Naphthol blue-black removal: Insights from proteomic analysis

Unraveling the molecular response of Brassica napus hairy roots in the active Naphthol blue-black removal: Insights from proteomic analysis

CaO catalysts supported on ZSM-5 zeolite for biodiesel production via transesterification of rapeseed oil

This paper deals with the effect of Si/Al ratio and form of zeolite support on the catalytic properties of the CaO catalysts in transesterification reaction of rapeseed oil with methanol. The reaction was conducted at 180 and 220 °C. To get the intended purposes of the work a various calcium oxide (CaO) catalysts supported on the ammonium and hydrogen forms of ZSM-5 zeolites with different Si/Al ratios were prepared by impregnation method. The results showed that the most active zeolite-based catalyst was 10%CaO/ZSM-5 (Si/Al = 50) system in the transesterification reaction at both temperatures 180 and 220 °C, which exhibited triglycerides (TG) conversion equal to 72.7 and 95.2% and fatty acid methyl esters (FAME) yield of 56.9 and 91.1%, respectively. High reactivity of this catalyst is explained by its acid-base properties, crystallite size of active phase, large external surface area and uniform distribution of the CaO on catalyst surface compared to the other investigated CaO systems supported on ZSM-5 zeolites. In addition, the analysis of the product obtained in the transesterification process carried out on the 10% CaO/ZSM-5 (Si/Al = 280) catalyst at 220 °C confirmed the presence of the following methyl esters of higher fatty acids: methyl oleate, methyl linoleate, methyl linolenate, methyl stearate, methyl eicosenoate, methyl palmitate, methyl palmitoleate, methyl nervonate and methyl arachidate.

Relationship between photosynthetic performance and yield loss in winter oilseed rape (Brassica napus L.) under frost conditions

Relationship between photosynthetic performance and yield loss in winter oilseed rape (Brassica napus L.) under frost conditions

Identification of genetic loci for salt tolerance in Brassica napus at the germination stage using a genome-wide association study

Brassica napus is a leading crop used to repair and utilize saline-alkali land. Cultivating salt-tolerant varieties of B. napus is therefore an effective means of increasing the productivity of saline-alkali land. However, the molecular regulation of salt tolerance during germination in B. napus is still unclear. In this study, seeds from an association panel containing 202 diverse accessions were treated with different concentrations of NaCl solution (200, 250, and 300 mM), and their relative germination rates (RGRs) were calculated on Days 3 and 7 after treatment. Based on phenotypic data obtained over six experiments, a total of 2749 single nucleotide polymorphisms (SNPs) significantly related to RGR were identified using a genome-wide association study (GWAS) analysis, and eight candidate genes were identified in candidate intervals. The RGR of seeds treated with 250 mM NaCl for 7 days was identified as a useful index of salt tolerance in B. napus, and 10 accessions with RGRs of 90–98 % were screened as excellent salt-tolerant germplasm resources. Finally, two of the identified SNPs were designed as SNP markers to screen salt-tolerant germplasm resources. These results provide a theoretical basis on which to determine the molecular mechanism of salt tolerance in B. napus at the germination stage.

Circadian Rhythm and Nitrogen Metabolism Participate in the Response of Boron Deficiency in the Root of Brassica napus

Boron (B) deficiency has been shown to inhibit root cell growth and division. However, the precise mechanism underlying B deficiency-mediated root tip growth inhibition remains unclear. In this study, we investigated the role of BnaA3.NIP5;1, a gene encoding a boric acid channel, in Brassica napus (B. napus). BnaA3.NIP5;1 is expressed in the lateral root cap and contributes to B acquisition in the root tip. Downregulation of BnaA3.NIP5;1 enhances B sensitivity in B. napus, resulting in reduced shoot biomass and impaired root tip development. Transcriptome analysis was conducted on root tips from wild-type B. napus (QY10) and BnaA3.NIP5;1 RNAi lines to assess the significance of B dynamics in meristematic cells during seedling growth. Differentially expressed genes (DEGs) were significantly enriched in plant circadian rhythm and nitrogen (N) metabolism pathways. Notably, the circadian-rhythm-related gene HY5 exhibited a similar B regulation pattern in Arabidopsis to that observed in B. napus. Furthermore, Arabidopsis mutants with disrupted circadian rhythm (hy5/cor27/toc1) displayed heightened sensitivity to low B compared to the wild type (Col-0). Consistent with expectations, B deficiency significantly disrupted N metabolism in B. napus roots, affecting nitrogen concentration, nitrate reductase enzyme activity, and glutamine synthesis. Interestingly, this disruption was exacerbated in BnaA3NIP5;1 RNAi lines. Overall, our findings highlight the critical role of B dynamics in root tip cells, impacting circadian rhythm and N metabolism, ultimately leading to retarded growth. This study provides novel insights into B regulation in root tip development and overall root growth in B. napus.

Exploring the impact of diesel-vegetable oil blends as an alternative fuel in combustion chambers

This study investigated using diesel-vegetable oil blends as an alternative fuel in combustion chambers. Vegetable oils, such as soybean and rapeseed oil, were blended with diesel fuel to create different blends, and the resulting properties were studied. It was found that vegetable oil blends had higher densities and flash points than pure diesel, which may affect combustion. Adding vegetable oil to the fuel reduced NOx and particulate matter emissions but had no significant impact on CO and CO2 emissions. Blends of vegetable oils were identified as promising alternative fuels for combustion chambers. In the experimentation, a combustion chamber was equipped with six swirl blades comprising two curved and one straight blade fired at different swirl angles (20°, 30°, 40°, 50°, and 60°) using VR1, VR2, VR3, and VR4 mix ratios of the blends. The results revealed that the maximum temperature for straight-edge blades was 50 °C, while curved-edge blades achieved a maximum temperature of 60 °C. Notably, due to the higher density and flash point of DIRO compared to DISO, the maximum temperatures of DISO blends tended to surpass those of DIRO blends. Furthermore, the study highlighted the superior combustion characteristics of curved blades, attributed to their swirling curved edges that elevated temperatures and enhanced turbulence. The optimal temperature was achieved using a 60 °C curved-edge blade swirling at a VR1 blend ratio in the DISO blend. Further exploration into additional features like pressure, emissions, and flame characteristics could contribute to supporting the use of these oil blends in diverse applications.

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.

Generation and characterization of a depigmented variant of Chlorella pyrenoidosa for application in food products

Microalgae are promising natural resources for an array of essential nutrients and health-promoting compounds. The past decade has witnessed their increasing popularity as a value-added ingredient in the food industry. However, some of their intrinsic properties, especially their typical green color and off-flavor, may compromise consumer acceptability and remain a key challenge for food scientists. This study aimed to generate and characterize a chemically induced pigment-deficient mutant (C49) of Chlorella pyrenoidosa. In contrast to the wild type (WT), C49 could not grow photoautotrophically or mixotrophically. However, when grown heterotrophically, it exhibited a growth curve similar to that of WT. Pigment analysis verified the presence of only trace amounts of chlorophylls (0.27 ± 0.02 mg/g) and carotenoids (0.036 ± 0.003 mg/g) in the C49 which were only ∼1.7% and ∼1% of those in the WT, respectively. C49 also had higher carbohydrate (62.75% ± 2.42%) and lower protein (26.54% ± 1.00%) content than the WT (37.41% ± 2.25% and 36.21% ± 1.97%, respectively). Genetic assays revealed inactivation of the phytoene desaturase gene as a key mechanism underlying the reduced xanthophyll-synthesizing capability of C49, thus causing its failure to accumulate chlorophyll and develop chloroplasts. Transcriptomic and RT-PCR analyses indicated that the high carbohydrate content was likely due to reduced starch degradation. Furthermore, C49 demonstrated an emulsifying capacity comparable to that of WT over a wide pH range (3–8) in oil-in-water emulsions consisting of 5% cell-disrupted homogenate in deionized water and rapeseed oil (1:1, v/v). The results of this study support that depigmented Chlorella pyrenoidosa possesses promising potential for application in the food industry.

A sensitive intelligent point-of-care test method for tert-butylhydroquinone in edible oil via a test strip with a smartphone

Tert-butylhydroquinone (TBHQ) is easily overused or illegally added to edible oil and attracts a growing concern because of its cytotoxic, liver-damaging, and carcinogenic effects. Thus, a sensitive and intelligent point-of-care testing (iPOCT) method is developed to fulfill the on-site monitoring. This iPOCT method depended on a fluorescent immunochromatographic assay within 15 min. Under optimization, the limit of quantification (LOQ) was calculated as 0.03 μg mL-1. The iPOCT method provided a low limit of detection (LOD) of 0.02 μg mL−1, a wide linear range of 0.03–100 μg mL−1, and great selectivity. Recoveries by the spiking experiments ranged from 97.4% to 103.5% with relative standard deviations (RSDs) of 2.4%–4.9% in soybean, peanut, rapeseed, and corn oil samples. The results showed that the iPOCT method is highly consistent with the high-performance liquid chromatography (HPLC) method.

The Effect of High-Temperature Heating on Amounts of Bioactive Compounds and Antiradical Properties of Refined Rapeseed Oil Blended with Rapeseed, Coriander and Apricot Cold-Pressed Oils

The Effect of High-Temperature Heating on Amounts of Bioactive Compounds and Antiradical Properties of Refined Rapeseed Oil Blended with Rapeseed, Coriander and Apricot Cold-Pressed Oils

ASYNAPSIS3 has diverse dosage-dependent effects on meiotic crossover formation in Brassica napus.

Crossovers create genetic diversity and are required for equal chromosome segregation during meiosis. Crossover number and distribution are highly regulated by different mechanisms that are not yet fully understood, including crossover interference. The chromosome axis is crucial for crossover formation. Here, we explore the function of the axis protein ASYNAPSIS3. To this end, we use the allotetraploid species Brassica napus; due to its polyploid nature, this system allows a fine-grained dissection of the dosage of meiotic regulators. The simultaneous mutation of all four ASY3 alleles results in defective synapsis and drastic reduction of crossovers, which is largely rescued by the presence of only one functional ASY3 allele. Crucially, while the number of class I crossovers in mutants with two functional ASY3 alleles is comparable to that in wild type, this number is significantly increased in mutants with only one functional ASY3 allele, indicating that reducing ASY3 dosage increases crossover formation. Moreover, the class I crossovers on each bivalent in mutants with one functional ASY3 allele follow a random distribution, indicating compromised crossover interference. These results reveal the distinct dosage-dependent effects of ASY3 on crossover formation, and provide insights into the role of the chromosome axis in patterning recombination.