Identification and virulence test of a new pathogen that causes verticillium striping on rapeseed in northwestern China

Five stems of rapeseed with abundant black microsclerotia were collected from Huangyuan County of Qinghai Province,China,and fungal isolates were obtained from the stems.They were identified based on morphology,molecular features and specific PCR detection.The results showed that the 10 fungal isolates belonged to Verticillium longisporum lineage A1/D3.One of the 10 isolates(HW7-1)was tested for virulence on three species of rapeseed,including B.napus Zhongshuang 9,B.rapa Qingyou 9 and B.juncea Tayou 2 by conidia inoculation of HW7-1 on roots of young seedlings.Control seedlings were inoculated with V.dahliae conidia or water alone.The seedlings of these treatments were transplanted in culture mix and incubated in a growth chamber(20℃).Results suggested that the control seedlings of three cultivars appeared quite healthy,while the seedlings inoculated with HW7-1 turned yellowing leaves,seedling stunting or even death after 22 days post-inoculation.V.longisporum was re-isolated from he yellow leaves,thus fulfilling Koch's postulates.Moreover,compared to the control treatments,inoculation with HW7-1 caused flowering delay and seed yield reduction on Tayou 2 with production of microsclerotia on the stems.To our knowledge,this is the first report of V.longisporum lineage A1/D3 on rapeseed in northwestern China.

Utilizing auxin dwarf genes to optimize seed yield and lodging resistance in rapeseed

Direct-seeding rapeseed production at high plant density raises the risk of lodging.We investigated the use of dwarf genes to improve rapeseed plant architecture to balance yield and lodging.Three genotypes with different plant architectures(dwarf sca^(HS5),semi-dwarf+/sca^(HS5),and tall ^(HS5))were evaluated under varying nitrogen rates(N1,N2,and N3:120,240,and 360 kg N ha^(-1))and plant densities(D1,D2,and D3:15,45,and 75 plants m^(-2))from 2019 to 2022.The results showed that increasing N rate positively influenced yield while decreasing lodging resistance in all genotypes.Increasing plant density(D2-D3)enhanced lodging resistance and yield in sca^(HS5) and+/sca^(HS5),but reduced yield in ^(HS5).Compared to the two parents,+/sca^(HS5) exhibited moderate expressions of IAA3,GH3.15,and SAUR30 in stems under N2D3,resulting in reduced plant height and increased compactness.Additionally,+/sca^(HS5) had a thicker silique layer than ^(HS5) by 14.7%,and it had a significant correlation between branch height/angle and yield.Increasing N rate led to increased lignin and pectin contents,while cellulose content decreased.Increasing plant density resulted in greater stem cellulose content and CSLA3/7 expression in sca^(HS5) and+/sca^(HS5),but decreased in ^(HS5).Compared to ^(HS5),+/sca^(HS5) exhibited higher expressions of ARAD1 and GAUT4,along with a 51.1%increase in pectin content,leading to improved lodging resistance under N2D3.Consequently,+/sca^(HS5) showed a 46.4%higher yield and 38.9%lodging resistance than ^(HS5) under N2D3,while sca^(HS5) demonstrated strong lodging resistance but lower yield potential.Overall,this study underscores the potential of utilizing auxin dwarf genes to optimize the trade-off between yield and lodging resistance in rapeseed and the possibility of maximizing yield potential by optimizing the plant architecture of+/sca^(HS5) through nitrogen reduction and dense planting.

Screening of glucosinolates degrading lactic acid bacteria and their utilization in rapeseed meal fermentation

Rapeseed meal is a promising food ingredient, but its utilization is limited by the presence of some potentially harmful ingredients, such as glucosinolates. Fermentation is a cost-effective method of detoxication but a food-grade starter culture with glucosinolates degradation capacity is required. In this study, 46 strains of lactic acid bacteria from traditional paocai brines were screened for their ability to glucosinolate degradation. The results showed that more than 50% of the strains significantly degraded glucosinolates. Two strains of Lactiplantibacillus(p7 and s7) with high capacity of glucosinolates degradation through producing enzymes were identified. Then,an optimized condition for rapeseed meal fermentation by p7 was established to degrade glucosinolates, which can achieve about 80% degradation. UPLC/Q-TOF-MS analysis showed that the degradation rate of individual glucosinolates was different and the degradation rate of gluconapin and progoitrin in rapeseed meal can reach more than 90%. Meanwhile, fermentation with p7 can improve safety of rapeseed meal by inhibiting the growth of Enterobacteriaceae and improve its nutritional properties by degrading phytic acid. The in vitro digestion experiments showed that the content of glucosinolates in rapeseed meal decreased significantly during gastric digestion. Meanwhile, fermentation with p7 can greatly improve the release of soluble protein and increase the contents of free essential amino acids, such as lysine(increased by 12 folds) and methionine(increased by 10 folds).

Comparative assessment of the frying efficiency of standard and low linolenic rapeseed oils: Principal Component Analysis (PCA)

In this research,the performance of regular rapeseed oil(RSO)and modified low-linolenic rapeseed oil(LLRO)during frying was assessed using a frying procedure that commonly found in fast-food restaurants.Key physicochemical attributes of these oils were investigated.RSO and LLRO differed for initial linolenic acid(12.21%vs.2.59%),linoleic acid(19.15%vs.24.73%).After 6 successive days frying period of French fries,the ratio of linoleic acid to palmitic acid dropped by 54.49%in RSO,higher than that in LLRO(51.54%).The increment in total oxidation value for LLRO(40.46 unit)was observed to be significantly lower than those of RSO(42.58 unit).The changes in carbonyl group value and iodine value throughout the frying trial were also lower in LLRO compared to RSO.The formation rate in total polar compounds for LLRO was 1.08%per frying day,lower than that of RSO(1.31%).In addition,the formation in color component and degradation in tocopherols were proportional to the frying time for two frying oils.Besides,a longer induction period was also observed in LLRO(8.87 h)compared to RSO(7.68 h)after frying period.Overall,LLRO exhibited the better frying stability,which was confirmed by principal component analysis(PCA).

Growth Dynamics of Rapeseed Leaves Based on MATLAB

[Ojective]The study aimed to simulate the growth dynamics of rapeseed leaves.[Method]Using nine rapeseed cultivars as experimental materials,the accumulation situation of rapeseed leaves was recorded and their growth dynamics were simulated by using MATLAB program.[Result]The leaf emergence rates of each genotype materials at different growth stages were determined to be:after spring>seedling stage>overwintering stage.All the related indices of the Logistic equation were higher than 0.976 7,commendably reflecting the growth dynamics of rapeseed leaves.[Conclusion]The study provided theoretical basis for the intelligentized cultivation and management and showed the practical guiding significance for the production of high quality rapeseed.

Analysis of Yield and Disease Resistance Traits of New Winter Rapeseed Varieties over the Past Twenty Years in China

Based on the results of the national regional trail for winter rapeseed in four groups,including the upper reaches,middle reaches and lower reaches of Yangtze River and Huang-Huai region in the past twenty years,new varieties of winter rapeseed showed upward trend in average yield,the yield level in Huang-huai group was higher than other groups.The changes of average effective pods per plant were not significant in any group,but the number of grain per pod and 1 000-grain weight showed increase trend.However,the increment of grains per pod in three Yangtze River groups was higher than that in Huang-Huai River group,while the increment of 1 000-grain weight was just opposite.The incidence rate of Sclerotinia sclerotiorum and viral disease in new varieties of winter rapeseed obviously decreased,and the incidence rate of S.sclerotiorum decreased lower than 5%.Genetic improvement for winter rapeseed should be focus on the number of grain per pod and 1 000-grain weight in the future,and yield level of new varieties in all four groups is expected to increase.

Study on the Optimization of Two-dimensional Electrophoresis Technology System for Rapeseed Proteome

[Objective] The research aimed to establish the two-dimensional electrophoresis（2-DE）technology which was suitable for the rapeseed proteome research.[Method] Xiangyou 17 was as the material.The sample preparation method,gel concentration and loading amount,etc.in 2-DE technology were optimized.[Result] The best extraction method of total protein of rapeseed was TCA-acetone method,and the protein spots on 2-DE map were the most.When IPG strip（pH 3-10）and 12% gel were used,and the loading amount was 250 μg,the two-dimensional electrophoresis map with the clear background,good repeatability and high protein spot resolution was obtained.[Conclusion] The research laid the foundation for carrying out the rapeseed proteomics research.

Preparation, friction and wear properties of hydrophobic lanthanum borate nanorods in rapeseed oil

Oleic acid (denoted as OA) surface-caped lanthanum borate nanorods, abbreviated as OA/LaBO3·H2O, were prepared via hydrothermal method. The microstructures of the as-prepared OA/LaBO3·H2O nanorods were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The friction and wear properties of OA/LaBO3·H2O nanorods in rapeseed oil were evaluated with a four-ball tribo-tester. The results show that the as-prepared OA/LaBO3·H2O nanorods are hydrophobic and display nanorods morphology with uniform diameter of about 50 nm and length of up to 500 nm. In the meantime, OA/LaBO3·H2O nanorods can obviously improve the anti-wear and friction-reducing capacities of rapeseed oil, and the optimal anti-wear and friction-reducing properties of rapeseed oil were obtained at an OA/LaBO3·H2O content of 1% (mass fraction).

Cloning and Expression of a Profilin Gene from Rapeseed

Profilin has recently been identified as an actin-binding protein in higher plants. A cDNA clone (designated Repro) encoding profilin gene was isolated from rapeseed ( Brassica napus L. cv. canadian Tween) using RT-PCR technique. Sequence analysis showed 82% similarity to Zea mays L. ZmPro3, 85% to Arabidopsis AthPRF1, 82% to Nicotiana tabacum L. NTPRO, 81% to Oryza sativa L. profilin A. A new full-length cDNA was obtained by 5'-RACE and 3'-RACE techniques. Sequence analysis showed that the size of full-length cDNA is 672 bp which contains a major open reading frame of 134 amino, acids, 5' and 3' untranslated regions and a long Poly (A) tail. Northern blot analysis showed that the profilin gene is a pollen and anther specific gene.

Friction and wear performances of magnesium alloy against steel under lubrication of rapeseed oil with S-containing additive

A S-containing additive, sulfuration modified rapeseed oil （named as SRO）, was prepared by chemical modification of rapeseed oil with sulfur compounds. The results indicate that the friction and wear of the magnesium alloy-steel tribomates could be effectively reduced by formulating SRO into rapeseed oil lubricant. The friction coefficients and the wear volumes of magnesium alloy decrease with increasing contents of SRO. The surface lubricated with SRO-doped rapeseed oil was characterized by less wear as compared with that lubricated with neat rapeseed oil. The enhanced anti-wear and friction-reducing abilities of rapeseed oil by SRO in the lubrication of magnesium alloy against steel were ascribed to the formation of a composite boundary lubrication film due to the strong adsorption of SRO and rapeseed oil onto the lubricated surfaces and their tribochemical reactions with magnesium alloy.

Analysis of Seed-specificity of Silencing fad_2 Gene Expression in Transgenic Rapeseed Line W-4(Brassica napus L.)

This study was to investigate the efficiency and specificity of RNAi silencing on the expression of endogenous fad2 gene in transgenic line W-4. [Method] The relative expression of fad2 gene in seeds at different developmental stages of 7th, 14th, 21st and 28th day after flowering （DAF） as wel as the root, stem, leaf at winter seedling stages of both the transgenic line W-4 and non-transgenic control Westar by real-time fluorescence quantitative PCR. [Results] The results showed the relative expression of fad2 gene was gradual y increasing with the days after flowering in the seeds of the control Westar, while it was found decreasing significantly since the 21st DAF in the seeds of the line W-4. The decline was up to 60% in comparison with the control Westar. However, no significant difference in the relative expression of fad2 gene in other organs like root, stem and leaf was observed between transgenic line W-4 and non-transgenic control Westar. Fatty acid composition analysis showed the oleic acid desaturation parameter（ODP） in seeds of the line W-4 was 0.07 in average, decreased by nearly 75% than control Westar which was 0.24 in average, while no significant difference in the seedling root, stem and leaf was measured between transgenic rapeseed and control. [Conclusion] The results above validated that RNA interference in transgenic rapeseed W-4 is at a seed-specific manner, not interfering with fad2 gene expression in organs such as the root, stem and leaf. The study also found that the period of fad2 gene expres-sion decline was wel coincided with the expression of napin gene, both appeared at the 21st DAF, indicating that the expression of dsRNA of fad2 gene is precisely control ed by the napin promoter.

Effects of Interaction between Density and Nitrogen Rate on Growth and Yield of No-tilling and Direct Sowing Rapeseed in Chengdu Plain

[Objective] The aim was to explore the optimal density and nitrogen rate of no-tilling and direct sowing rapeseeds in Chengdu plain. [Methods] Effects of in- teraction between density and nitrogen rate on the growth and yield of direct sowing rapeseed under no-tillage condition were investigated with Chuanyou 58 as materials and a split-plot experiment adopted. [Results] In Chengdu Plain, the yields of rape- seed changed from increasing to decreasing with increase of density and nitrogen rate. Both of density and nitrogen rate had significant effects on growth and yield of rapeseed and the latter overweighed in the effect. In addition, interaction of the two had negative effects on rapeseed yield. The yield of rapeseeds achieved the highest at 3 395.25 kg/hm^2 with interaction of density at 30.00×10^4 plant/hm^2 and nitrogen rate at 180.00 kg/hm^2; the theoretical maximal yield was 3 403.41 kg/hm^2 with interaction of density at 40.80×10^4 plants/hm^2 and nitrogen rate at 198.90 kg/hm^2. [Conclusion] In Chengdu Plain, the optimal density and nitrogen rate are 30.00×10^4-45.00×10^4 plant/hm^2 and 180.00-198.90 kg/hm^2, respectively.

Fatty Acid Composition and Seed Quality Traits of the Transgenic Rapeseed W-4(Brassica napus L.) with Down-regulated Expression of fad2 Gene

To clarify the effect of down-regulated expression of fad2 gene on the seed nutritional quality of rapeseed, the fatty acid composition, amino acid composi- tion, oil content, protein content, crude fiber content and glucosinolate content in the seeds of both transgenic line W-4 and its control Westar were compared. The re- sults showed that the oleic acid content in W-4 was 86.03%±0.20%, which was 29.36% higher than that in the control （P〈0.01）; the linoleic acid content was 2.86%± 0.01%, which was reduced by 84.03% compared with that in the control （P〈0.01）; the linolenic acid content in W-4 was 3.04%±0.04%, reduced by 57.60% （P〈0.01）; the palmitic acid content in W-4 was 3.23%±0.07%, reduced by 18.63% （P〈0.01）; the eicosenoic acid content in W-4 was increased by 18.46% compared with that in the control （P〈0.01）; the erucic acid content in W-4 was increased by 13.15% （P〈 0.05）; there was no significant difference in stearic acid content between the treat- ment and control groups （P〉0.05）. The amino acid composition analysis showed that total 18 amino acids, including 8 essential amino acids, were detected in both W-4 and Westar; there were no significant differences in contents of the 18 amino acids between the treatment and control groups except that of tyrosine （P〉0.05）; the contents of oil, proteins, glucosinolates and crude fiber in W-4 were 45.40%± 0.17% （P〉0.05）, 18.18%±0.91% （P〉0.05）, 18.20%±1.21% （P〉0.05） and 12.29%± 0.04% （P〉0.05）, respectively. All the results above showed that the down-regulated expression of fad2 had great effects on fatty acid composition and accumulation in rapeseed seeds, but had no significant effects on other seed quality traits, such as oil content, protein content, crude fiber content and glucosinolate content.

Application of Special Controlled Release Fertilizer in Direct-seeding of Rapeseeds

In the east of Hunan Province, the research introduced new-type special controI ed-reIease fertiIizer for rapeseed, ＂Yishizhuang＂, and expIored its appIications in direct-seeding of rapeseed production. The resuIts showed that the appIication of special controI ed reIease fertiIizer for rapeseeds avoids earIy decIine of rapeseed resuIting from fertiIizer Ioss by one-off appIication, improves the number of green Ieaf before winter, and extends photosynthetic Iifespan of pods, which significantIy increases yields. What＆#39; more, with higher output-input ratio, the fertiIizer takes ad-vantages in saving cost, Iabor and increasing yield.

Genetic Improvement Progress and Productive Effect of Rapeseed in Henan Province

The research progress and major achievements on genetic breeding, het- erosis utilization of rapeseed in Henan Province were summarized, with the aim to provide technical guidance for rapeseed genetic breeding in the future work. Faced with the problems of lack of special varieties, highly demand for healthy oil and high production cost in rapeseed production in recent years, the breeding goals of rapeseed have been adjusted from high yield, high quality and disease resistance to high oil, high oleic acid, adaptative to mechanization, late planting resistance. The breeding technologies mainly focused on the isolated microspore culture, molecular marker assisted selection, and the corresponding high efficiency technical systems were constructed. The innovative research on excellent germplasm resources were carried on, which created and established breeding populations and distinctive new germplasm resources with diverse variations such as high oil content, high oleic acid content and low linolenic acid, cold resistance, drought resistance, pod shatter resistance and different flower color variations. A series of rapeseed hybrids of dou- ble low varieties with strong heterosis and high oil contents were released and these hybrids significantly improved seed yield, quality and resistance. The average yield of rapeseed in Henan Province was 22.49% higher than the national average yield in 2003-2015. All of the achievements provided strong technical support for the upgrading of rapeseed varieties and increasing both production and income.

Strategies and Suggestions for the Development of Mechanized Rapeseed Production in Sichuan

Mechanization is the future direction of rapeseed production in Sichuan. A series of technology tests for rapeseed mechanized production have been carried out in terms of variety selection, key agronomic measures and machinery in the main production area of Sichuan in recent years. In the research, the agronomic techniques, including variety selection for mechanical production, key agronomic measures and mechanical harvesting were analyzed. Based on the present condi- tions, strategy and suggestions for the development of mechanized rapeseed produc- tion in Sichuan also were presented.

Effects of the Application of Controlled Release Nitrogen Fertilizer on Rapeseed Yield, Agronomic Characters and Soil Fertility

In order to study the effects of controlled release nitrogen fertilizer （CRNF） application on rapeseed, a simulated experiment was carried out with 3 types of paddy soils in Dongting Lake area for 4 consecutive years of applying CRNF under double rice cropping system after planting rapeseed crop in the fallow season. The effects of CRNF application on rapeseed yield, agronomic characters and soil fertility were studied in this paper. The results showed that CRNF application improved the growth of rapeseed plant and increased rapeseed yield of CRNF treatments in the purple calcareous clayed paddy soil （PCS） and alluvial loamy paddy soil （ALS） which respectively increased by 12.2% and 9.8% compared with applying urea, re- spectively. The rapeseed yield in 70% CRNF treatment obviously decreased com- pared with urea treatment. The contents of available N and organic carbon in soil increased by 25.0% and 3.2% in CRNF treatment in the ALS after rapeseed crop, respectively; and available N increased by 13.5% in the PCS. Both rapeseed yield and soil fertility in CRNF treatment and 70% CRNF treatment were lower than those in CK treatment in the reddish yellow clayed paddy soil （RYS）. The results al- so indicated that the functions of CRNF application on rapeseed yield increase and soil nitrogen fertility improvement were very obvious in the PCS and ALS.

Correlation Analysis Between Yield Components and Yield Per Plant of Double-low Hybrid Rapeseed

[Objective] The experiment aimed to study the relation between yield components and yield per plant of double-low hybrid rapeseed and provide reference for breaking yield limitation of rapeseed and culturing new double-low hybrid rapeseed variety. [Method]The yield components and yield per plant of two cross combination of double-low hybrid rapeseed (B02, D04) and Shuza 6 were correlatively analyzed and compared, besides, the path analysis was also carried on to them. [Result] Among B02, D04 and Shuza No.6, effective pod number per plant and seeds per silique, seeds per pod and 1 000-grain weight were all negative correlation. In high yield hybrid, pod number per plant, seeds per pod had more impaction on yield per plant than 1 000-grain weight and the difference was at 0.01 significant level. In the control variety Shuza No.6, the impactions of pod number per plant and seeds per pod on yield per plant were bigger than that of 1 000-grain weight on yield per plant, however, the difference was not significant. [Conclusion] The improvement of effective pod number per plant was an important aim of breeding work of double low rapeseed breeding in Sichuan ecological region.

Effects of Planting Density, Duration of Disclosing Plastic Film and Nitrogen Fertilization on the Growth Dynamics of Rapeseed under No-tillage Cultivation

[ Objective] This study was to understend the optimized combination of planting density, duration of disclosing plastic film and nitrogen fertilization under no-tillage cultivation. [ Method] Quadratic polynomial regression and saturated D-optimal design were employed to investigate the effects of planting density, duration of disclosing plastic film and nitrogen fertilization on the dynamics growth of rapeseed under no-tillage cultivation.[ Result] Within the experimental range, the growth dynamics of no-tillage cultivated rapeseed assumed a rise-fall tend. For the effects to the growth dynamics of no-tillage cultivated rapeseed, nitrogen application amount was higher than planting density and duration of disclosing plastic film. The interaction effect between planting density and duration of disclosing plastic film was higher than that between nitrogen application amount and planting density, and between nitrogen application amount and duration of disclosing plastic film. [ Conclusion] The optimized combination of these factors for dynamic growth of rapeseed under no-tillage cultivation was determined to be： planting density of per hectare 154 925 individuals, duration of disclosing plastic film of 110 d, nitrogen application amount of 315 kg/hm^2.

Effects of Nitrogen Application Amount during Various Periods on Yield of High Grade Hybrid Rapeseed

[Objective] The paper was to study the nitrogen application amount and nitrogen application model for high grade hybrid rapeseed （Brassica napus L.） to get high yield. [Method] With ＂Youyan 599＂ and ＂Sanbei 98＂ as materials, using quadratic regression orthogonal gyration combination design, the impact of nitrogen application amount during various periods on rapeseed yield was studied. [Result] The combinations of factors to obtain the highest yield index （2 898.211 kg / hm 2 ） of ＂Youyan 599＂ were as follows： living rape fertilizer 89.27 kg / hm 2 , opening fertilizer 120 kg / hm 2 , 12 th lunar month fertilizer 101.12 kg / hm 2 , total nitrogen application amount 310.39 kg / hm 2 . The proportions of living rape fertilizer, opening fertilizer and 12th lunar month fertilizer were 28.76%, 38.66% and 32.58%, respectively. The combinations of factors to obtain the highest yield index （2 870.14 kg/hm 2 ） of ＂Sanbei 98＂ were as follows： living rape fertilizer 120 kg / hm 2 , opening fertilizer 120 kg / hm 2 , 12 th lunar month fertilizer 37.55kg / hm 2 , total nitrogen application amount 277.55 kg / hm 2 . The proportions of living rape fertilizer, opening fertilizer and 12 th lunar month fertilizer were 43.24%, 43.24% and 13.53%, respectively. The combinations of factors to obtain the highest yield index of two combined varieties （2 813.82 kg/hm 2 ）were as follows： living rape fertilizer 120 kg/hm 2 , opening fertilizer 120 kg/hm 2 , 12 th lunar month fertilizer 76.23 kg/hm 2 , total nitrogen application amount 316.23 kg/hm 2 . The proportions of living rape fertilizer, opening fertilizer and 12 th lunar month fertilizer were 37.95% , 37.95% and 24.11% , respectively. [Conclusion] The paper provided theoretical basis for high yield cultivation of high grade hybridized rapeseed.