Biotechnology ofα-linolenic acid in oilseed rape(Brassica napus)using FAD2 and FAD3 from chia(Salvia hispanica)

α-Linolenic acid(ALA,18:3Δ9,12,15)is an essential fatty acid for humans since it is the precursor for the biosynthesis of omega-3 long-chain polyunsaturated fatty acids(LC-PUFA).Modern people generally suffer from deficiency of ALA because most staple food oils are low or lack ALA content.Biotechnological enrichment of ALA in staple oil crops is a promising strategy.Chia(Salvia hispanica)has the highest ALA content in its seed oil among known oil crops.In this study,the FAD2 and FAD3 genes from chia were engineered into a staple oil crop,oilseed rape(Brassica napus),via Agrobaterium tumefaciens-mediated transformation of their LP4-2A fusion gene construct driven by the seed-specific promoter P_(NapA).In seeds of T0,T1,and T2 lines,the average ALA contents were 20.86,23.54,and 24.92%,respectively,which were 2.21,2.68,and 3.03 folds of the non-transformed controls(9.42,8.78,and 8.22%),respectively.The highest seed ALA levels of T0,T1,and T2 plants were 38.41,35.98,and 39.19%respectively,which were 4.10-4.77 folds of the respective controls.FA-pathway enzyme genes(BnACCD,BnFATA,BnSAD,BnSCD,BnDGAT1,BnDGAT2,and BnDGAT3)and positive regulatory genes(BnWRI1,BnLEC1,BnL1L,BnLEC2,BnABI3,BnbZIP67,and BnMYB96)were all significantly up-regulated.In contrast,BnTT1,BnTT2,BnTT8,BnTT16,BnTTG1,and BnTTG2,encoding negative oil accumulation regulators but positive secondary metabolism regulators,were all significantly down-regulated.This means the foreign ShFAD2-ShFAD3 fusion gene,directly and indirectly,remodeled both positive and negative loci of the whole FA-related network in transgenic B.napus seeds.

Mechanical Harvesting Effects on Seed Yield Loss,Quality Traits and Profitability of Winter Oilseed Rape (Brassica napus L.)

China is one of the most important rapeseed producing countries in the world. Effective mechanical harvesting time for decreasing harvesting loss of winter oilseed rape has been becoming a critical factor. An elite cultivar Zhongshuang 11 （Brassica napus L.） was employed in two rounds of field experiments from 2009 to 2011. Seeds were sown with machine, three combine harvesting times namely combine harvesting A, B, and C （CHA, CHB, and CHC） were designed and manual harvesting （MH） as control was performed at maturity. The harvesting treatments were determined according to color of pod and seed in the field. Seed yield loss and quality in different treatments were evaluated. Results showed that both seed yields and harvesting losses in 2009-2010 were higher than that in 2010-2011, whereas seed oil contents in 2010-2011 were higher than that in 2009-2010. The highest yield appeared in CHB, which was significantly higher than that in MH. Furthermore, harvesting loss in CHB were 50% that in MH. Seed oil content and chlorophyll exhibited no obvious difference between CHB and MH. Economic profit analysis demonstrated that mechanical sowing/combine harvesting （MS/CH） showed an input/output ratio of 1：1.6, and it was 1：1.2 in mechanical sowing/manual harvesting （MS/MH）. Labor-cost accounted for more than 70% of the total cost in MS/MH, which led to low profitability to a great extent. Our results suggested that CHB was the optimum harvesting time for winter oilseed rape along the Yangtze River.

The Relationship of Color Formation with Related Enzymes and Protein Contents in the Seedcoat of Oilseed Rape (Brassica napus)

Three pairs of near-isogenic lines with different genetic backgrounds of yellow-seededand black-seeded rape (Brassica napus L.) were used as experiment materials to study therelationship of color formation in the seedcoat with enzyme activity and protein contentin it. The results showed that with similar genetic backgrounds, phenylalanine ammonia-lyase (PAL) and polyphenol oxidase(PPO) activities in the black-seeded lines were muchhigher than in their yellow-seeded counterparts and maximum PAL activity in the seedcoatoccurred comparatively late while no significant difference was present in glutaminesynthetase (GS) between the two types of rape. The plants were treated with red light,blue light, p-hydroxybenzoic acid (a PAL inhibitor), polyvinylpyridoxal (a PPO inhibitor),urea (a protein synthesis promoter) or chloramphenicol (CM, a plastid protein synthesisinhibitor) during seed development. It is speculated that PAL may be primarily responsiblefor coloration in the yellow seed; PPO may be the main factor contributing to thedarkness of the testa of the black genotypes; and nitrogen assimilation is, probably, notdirectly related to the difference in protein content observed between yellow- andblack-seeded genotypes, which may be induced mainly by PAL.

Effects of Boron Nutrition on ^45Ca Retranslocation and Distribution in Rape(Brassica napus L.)Cultivars

Using tracer techniques with the radioisotope 45Ca, the effects of boron supply from soil and nutrient solution on the retranslocation of 45Ca from leaves to other parts of rape plants were studied. Results indicated that only a small portion of foliar-applied 45Ca could be retranslocated to other parts of the rape plant. There was no pronounced effect of boron level in the soil on 45 Ca retranslocation. Increasing boron concentrations in the nutrient solution significantly reduced 45 Ca radioactivity in root and stem, but increased 45Ca uptake and 45 Ca translocation to the upper leaves of rape plants. It was suggested that45 Ca absorbed by newly developed roots was easily distributed to upper leaves of rape plants. Boron may alter distribution of calcium via its effect on root development or growth of newly developed roots.

SPAD chorophyll meter was suitable in nitrogen quick diagnosis,yield forecast and fertilization recommendation in rapeseed(Brassica napus L. )

Nitrogen （N） is one of the most important nutrients for oilseed rape （Brassica napus L . ） , but there is a lack of quick diagnosis and recommended fertilization. Three field experiments were con-ducted to seek the best diagnostic method and establish a fertilizer rate recommendation model. For ex-periment 1, six treatments as application N 0,90,180,240,300 and 400kg ha -1 were designed, and the general N nutrition diagnosis method as SPAD -502 chlorophyll meter, RQflex plus 10 nitrate reflectrom- eter and GreenSeeker - 505 spectrometer were used at eight leaf stage, tenth leaf stage and bolting stage of rape to determine the suitable nitrogen rapid diagnosis method and establish the model of yield forecast and N rate recommendation as topdressing. The experiment 2 was designed to validate the veracity of yield forecast model obtained from experiment 1. The experiment 3 was designed to test the accuracy of N rate recommendation model come from experiment 1. The results indicated that there is a preferable inter-relation between N application rates and rape yield for experiment 1 （ y = - 0. 0176x2 ＋ 11. 136x ＋797. 88 ,R2 =0. 9905 ＊ ＊ ） , which conform to the performance of yield variation with N application levels as shortage, appropriate and excessive rapeseed. For three diagnosis methods, nitrate reflectrometer could reflect rape N nutrition status to some extent, but which influenced by rapeseed physiological char-acteristics such as lower biomass at seedling stage and luxury absorption of N at bolting stage, and the re-liability and stability of diagnosis were inferior. Spectrometer is suitable for quick N nutrition diagnosis at bolting stage, but the stage of topdressing is too late to meet the demand of N support. SPAD meter could more suitable in quick N diagnosis of oilseed rapes since it could reflect rape N nutrition preferable, and it has some advantages such as the strong stability, easy measuring and lower cost in detection. By SPAD meter, model of yield forecast yforeCastyield =370. 517xSPAD value -13310.3 （x 〈42. 54） and recommended N rate yR_dedNrate =162.7-[（370.517xSPADTflliie- 13 10. 3 ）/10. 0617 - 76. 7398 ] （x〈42.54） were established. For experiment 2, the actual yield and forecast yield showed good correlation （y = 0. 5022 ＋2244. 3x, R2 =0. 7852 ＊ ） . For experiment 3 , the amount of topdressing N calculate from recommended N rate model were put forward, and the yield for different treatments had no significant difference. Total-ly ,SPAD chlorophyll meter could be used in quick N nutrition diagnosis, forecast yield and N recommen-dation of oilseed rape.

浙北地区优质甘蓝型油菜(Brassica napus L.)产量性状与产量的关系

对24个高产优质甘蓝型油菜品种(系)的单株产量及9个产量性状进行统计分析,结果表明,单株有效角果数、每角果实粒数、千粒重对单株产量的正效应达显著或极显著水平;单株有效角果数和每角果实粒数对产量的直接通径系数分别为0.9702和0.8439,且净效应均达极显著正值;而千粒重对产量的直接通径系数虽为正值且较大,但净效应呈负值;结角密度对产量的直接通径系数及净效应均为负值。研究结果分析,浙北优质甘蓝型油菜高产的育种方向,在选择合适结角密度的基础上,重点应放在每角果实粒数和单株有效总角果数两个主要目标性状的选择上,同时兼顾千粒重。

Analysis on Self-compatibility of Artificially Synthesized Brassica napus Lines from Different Cross Combinations

Brassica rapa cuhivars Qinghaidahuang and Menyuan small rape were used as female parents and separately interspecifically hybridized with Zhongchijie- lan to artificially synthesize a number of Brasica napus resources. Observation of meiosis, pollen fertility and pollen tube germination and analysis of self-compati- bility index of these artificial B. napus varieties were conducted. Results showed that pollen mother cells of artificial B. napus lines from two cross combinations all had normal chromosome behavior and high pollen fertility, but the selfing seed-setting and self-compatibility index varied extremely significantly; B. napus lines from cross combination Qinghaidahuang x Zhongchijidan are highly self-compatible, while B. napus lines from cross combination Menyuan small rape x Zhongchijielan are highly self-incompatible. This study analyzed the heredity laws of self-incompatibility trait in artificially synthesized lines and discussed applica- tion prospects of artificially synthesized self-incompatible B. napus lines in rapeseed production.

基于小孢子培养创制DW871矮秆彩色油菜新种质

彩色油菜具有油用和观赏价值,因易种植、花色鲜艳和开花时间长等特点备受关注。然而,目前报道彩色油菜多为高芥酸、高硫甙的高秆株型,不满足兼作观赏和油用推广应用要求。因此,选育品质优良、株型适宜的彩色油菜新种质是观赏油菜的育种目标之一。本研究中以具有特异花序性状、观赏价值大的DW871为基础材料,与普通彩色高秆油菜杂交后,F1代利用小孢子培养技术创制具有DW871特性同时品质优良的彩色花新种质。研究表明,采用前期集成的油菜小孢子培养技术,产胚率达到了312~507胚/蕾,共纯合到14株彩色花油菜,其中白色花5株,橘红色花4株,金桔色花5株。经过农艺性状调查和品质分析,从DH植株中筛选出的Y57是一株含有DW871特异花序、矮杆、金桔色花、品质“双低”的优良新种质,株高88 cm,一次分支数18个,含油量39%,蛋白质含量25.96%,芥酸为0.95%,硫苷为28.15μmol/g饼,是培育集观赏和油用价值的甘蓝型彩色油菜新种质,具有较高的利用价值和广阔的应用前景。

Analysis of Correlation between Yield and Quality Traits of Quality Hybrid Rapeseed

[Objective] This study aimed to investigate the correlation between yield and quality traits of rape. [Method] Taking ＂Sanbei 98＂ and ＂Youyan 599＂ as ex- periment materials, correlation between yield and quality traits of Brassica napus L. cultivars was explored by orthogonal rotation method. [Result] The results showed that： 1 In both the two varieties-Sanbei98 and Youyan599, erucic acid content had the largest coefficient of variation, but its average content was lower than 2% in both the two varieties （0.90% in Sanbei98 and 1.24% in Youyan599）, and the palmitic acid content had the smallest coefficient of variation. 2 In terms of the dif- ferences in quality traits at different yield levels, only the mean of eicosenoic acid content revealed significant difference in Sanbei98, and only the mean of seed-pro- tein content revealed significant difference in Youyan599, and there was no signifi- cant difference in any combined quality traits in both the two varieties. 3 The yield was negatively correlated with the erucic acid content or oil content, and posi- tively correlated with the content of seed-protein, linoleic acid, or linolenic acid, and the coefficient of correlation between the yield and either of the contents of glucosi- nolates, oleic acid, palmitic acid, stearic acid, and eicosenoic acid was smaller. ~, when the yield of a variety increased considerably, there was a certain decreasing trend in erucic acid content, oil content, the total amount of erucic chain fatty acids （El ＆ Er）, while there was an increasing trend in seed-protein content, linoleic acid content, linolenic acid content, saturated fatty acids （SFA）, the total amount of fat and protein （P ＆ F）, unsaturation index （IUFA）, unsaturated fatty acids （UFA）, the total amount of 18 carbon fatty acids （18-C FA）, unsaturated fatty acids [UFA/（Ei ＆ Er） ], and the sum of oleic acid and linoleic acid （OI ＆ Li）. 5 When the seed-pro- tein content is increased, the quality of rape oil cake is also improved; when the unsaturated index is increased, the oil stability is decreased. The increase in the total amount of unsaturated fatty acids, oleic acid and linoleic acid helps to increase in the total amount of fatty acids absorbed by human bodies. [Conclusion] This study provides a theoretical foundation for the cultivation of high-yielding and top- quality hybrid rape cultivars.

烟区不同类型油菜秸秆腐解及养分释放特性研究

本研究旨在探讨山东和四川烟区适合与烟草轮作的油菜品种,并分析其秸秆腐解及养分释放特性。通过采用尼龙网袋法,在室内模拟田间条件下对2种类型(白菜型和甘蓝型)的4个冬油菜品种进行培养,观察秸秆的腐解过程和养分释放情况。结果显示,培养前10 d,油菜秸秆快速腐解,各养分也快速释放,养分最终释放率表现为K>N>P>C;腐解进程中,秸秆碳氮比有所波动,但大致呈上升趋势;白菜型油菜秸秆的腐解程度、碳和氮的释放率高于甘蓝型油菜,而钾的释放率低于甘蓝型油菜,磷的释放率表现出地区差异;四川烟区油菜秸秆的腐解程度及碳、氮、磷素的释放率高于山东烟区,钾的释放率高于山东白菜型油菜;油菜秸秆腐解可显著提高供试土壤中有机质、氮、磷和钾素的含量,但不同烟区、不同类型油菜秸秆的增效程度有所差异。从秸秆还田利用的角度来看,2烟区中的白菜型油菜品种更适合与烟草轮作种植。

鄂中地区油菜专用肥施用效果

为明确油菜(Brassica napus L.)专用肥对鄂中地区直播油菜产量的提升效果,于2019—2021年在湖北省沙洋县开展了连续2年的田间试验,设置了不施肥、常规施肥、宜施壮专用肥和洋丰专用肥4个施肥处理,考察各处理下成熟期油菜产量、地上部生物量、地上部养分含量、地上部养分积累量以及肥料偏生产力等的差异。结果表明,与不施肥对照相比,常规施肥和专用肥处理均能显著提高油菜子产量;与常规施肥相比,专用肥处理总养分投入减少了41.3%,而两者油菜子产量无明显差异。施肥显著增加了油菜地上部生物量,促进了油菜地上部对养分的吸收。油菜专用肥处理显著提高了肥料偏生产力,与常规施肥处理相比,宜施壮专用肥和洋丰专用肥处理平均肥料偏生产力在2019—2020年、2020—2021年分别提高了80.6%和68.2%。综上所述,油菜专用肥在保障油菜高产稳产的同时,提高了肥料利用率。

微量元素在油菜种子引发中的调控作用及实用性

为了提高油菜(Brassica napus L.)种子活力以增强种子萌发和幼苗阶段的抗逆性,试验通过响应面分析方法对不同微量元素组合间效应进行比较分析,得出对油菜种子活力提升效果最佳的元素组合,并进一步验证了该组合对不同油菜品种生长发育和最终产量的影响。结果表明,Se(5.0 mg/L)、B(5.0 mg/L)、Zn(100.0 mg/L)、Mo(1.0 mg/L)对油菜种子萌发均具有明显的促进作用;响应面分析得出最佳微量元素配比组合为Se(6.7 mg/L)+B(7.5 mg/L)+Zn(82.3 mg/L)+Mo(4.6 mg/L),在此配比组合处理下,幼苗期可溶性蛋白质的累积量提高且幼苗的抗逆性也有明显增强;不同品种中的应用试验证明该配比组合处理可显著提高其单株产量(P<0.05)。

定量代谢组学比较分析蕾薹期油菜不同部位营养差异

本研究采用定量核磁共振(nuclear magnetic resonance,NMR)与高效液相色谱-串联质谱(high performance liquid chromatography-tandem mass spectrometry,HPLC-MS/MS)技术分析大地95油菜蕾薹期不同部位(茎、叶、花苞)小分子营养物的组成差异。结果表明,通过1H-NMR与HPLC-MS/MS分析在大地95菜薹茎、叶、花苞中共定性定量得到53种小分子化合物,其中具有显著差异的物质有亮氨酸、异亮氨酸、缬氨酸、γ-氨基丁酸、丙氨酸、脯氨酸、苯丙氨酸、乳酸、柠檬酸、琥珀酰胺、β-D-葡萄糖、α-D-葡萄糖、蔗糖、果糖、胆碱、甜菜碱、延胡索酸、黄芩素、阿魏酸、山柰酚、芥子碱、反式肉桂酸、橙皮素。糖类物质在油菜茎部的含量最高;而胆碱、琥珀酰胺、多数氨基酸、有机酸以及酚酸类物质主要在花苞中积累,叶部的优势代谢物以黄岑素、芥子碱和柠檬酸为主。通过分析代谢通路发现这些差异代谢物主要涉及植物的柠檬酸盐循环,黄酮和黄酮醇的生物合成,苯丙氨酸代谢,氨酰基-tRNA生物合成,缬氨酸、亮氨酸和异亮氨酸的生物合成,糖酵解/糖异生,苯丙氨酸、酪氨酸和色氨酸的生物合成等。本研究结果可为全面评估蕾薹期油菜的营养价值提供数据参考,并为选育营养丰富的油菜品种提供科学依据。

Nutrient deficiency limits population development,yield formation,and nutrient uptake of direct sown winter oilseed rape

Direct-sowing establishment method has great significance in improving winter oilseed rape（Brassica napus L.） production and guaranteeing edible oil security in China. However, nutrient responses on direct sown winter oilseed rape（DOR） performance and population development dynamic are still not well understood. Therefore, five on-farm experiments were conducted in the reaches of the Yangtze River（RYR） to determine the effects of nitrogen（N）, phosphorus（P）, and potassium（K） deficiencies on population density, dry matter production, nutrient uptake, seed yield, and yield components of DOR plants. Four fertilization treatments included the balanced NPK application treatment（NPK, 180 kg N, 39.3 kg P, 100 kg K, and 1.8 kg borax ha–1） and three nutrient deficiency treatments based on the NPK treatment, i.e., –N, –P, and –K. The results indicated that DOR population density declined gradually throughout the growing season, especially at over-wintering and pod-development stages. Nutrient deficiency decreased nutrient concentration in DOR plants, limited dry matter production and nutrient uptake, and thereby exacerbated density reduction during plants growth. The poor individual growth and reduced population density together decreased seed yield in the nutrient deficiency treatment. Averaged across all the experiments, seed yield reduced 61% by N deficiency, 38.3% by P deficiency, and 14.4% by K deficiency. The negative effects of nutrient deficiency on DOR performances followed the order of –N–P–K, and the effects were various among different nutrient deficiencies. Although N deficiency improved DOR emergence, but it seriously limited dry matter production and nutrient uptake, which in turn led to substantial plants death and therefore resulted in a very low harvested density. The P deficiency significantly reduced initial density, limited plants growth, and exacerbated density reduction. The K deficiency mainly decreased individual growth and yield, but did not affect density dynamic. Our results highlighted the importance of balanced NPK application in DOR production, suggesting that management strategy of these nutrients should be comprehensively considered with an aim to build an appropriate population structure with balanced plant density and individual growth.

Reaction of Oilseed Rape Cultivars to Sclerotinia Stem Rot in Field Environ- ments

Sclerotinia sclerotiorum (Lib.) de Bary, as an ubiquitous phytopathogenic Ascomycete fungus capable of infecting a wide range of plants, has increased in importance for oilseed rape production worldwide in recent years. The objective of this research was to determine the effectiveness of two measurements of disease rating in predicting the field reaction of cultivars to sclerotinia stem rot. One hundred and ten cultivars or lines of oilseed rape were repeatedly evaluated the disease severity index (DSI) and lesion length for their resistance to nine isolates of S. sclerotiorum in two field stations. There were greatly significant differences between two stations, among isolates, among population of cultivars for the disease severity index and lesion length, and also significant station×isolate interaction for lesion length and population×isolate interactions for DSI and lesion length, but interactions of station×isolate for DSI were not significant. Cultivars such as Pomorzanin and Lisek consistently had the lowest disease severity ratings in the field tests. However, most of cultivars were susceptible to sclerotinia stem rot in the field test. A positive correlation between the mean DSI and lesion length was found for both isolates (Sc23 and B1). The correlations ranged from 0.23 to 0.83 at various plots, with nine of the twelve correlations significant. The correlations for disease caused by different fungal isolates were statistically significant difference. These correlations ranged from -0.44 to 0.90, with nine of the thirty-two correlations significant. It indicated that resistance to some isolates was significantly correlated and selection of some varieties for resistance to one isolate appeared to improve resistance to other isolates.

Effects of harvesting method and date on yield loss and seed quality of rapeseed

China is one of the major rapeseed production countries in the world,but harvesting mechanization was still backward,and high harvest loss was a key inhibiting factor for rapeseed production.To obtain optimum harvesting date for winter rape in the Yangtze River Valley of China,artificial simulated combine harvesting and artificial two-stage harvesting were adopted to find correlations between harvesting date,rape variety,seed oil content,protein content,grain moisture rate,rapeseed straw moisture content,rapeseed unthreshing rate,grain drop loss rate,thousand seeds weight(TSW),and harvesting economic coefficient(HEC).Analysis of variance showed that rapeseed oil content,protein content and TSW were correlated with rape variety;HEC was correlated with harvesting method and rape variety.Rape variety was the dominant factor of rapeseed oil content,protein content,TSW and HEC.Grain moisture rate,un-threshing rate,grain drop loss rate and straw moisture content were correlated with harvesting method and date.Harvesting date was the dominant factor of rapeseed moisture rate,un-threshing rate,grain drop loss rate and straw moisture rate.Single factor tests further proved that harvesting date had less impact on rapeseed oil content,protein content,TSW and HEC.It showed little correlation with rapeseed quality except grain moisture rate.The optimum harvesting date could be known by change in straw moisture content.The combined harvesting should be carried out during the grain moisture content of 15%-20%with TSW stabilized in the highest level.The twostage harvesting cutting should be carried out at the grain moisture content of 35%-40%.This research offered a reference to harvesting method and date for rape cultivated in the Yangtze River Valley.

北方旱寒区甘蓝型冬油菜产量、品质及抗倒性的分析评价

2018—2019年,以34个强抗寒甘蓝型冬油菜品系为试验材料,对其产量、品质及抗倒性进行分析和评价,挖掘优异种质资源。结果表明:不同材料间的产量、品质及抗倒性存在较大差异,单株产量变异范围为6.50~36.67 g,平均产量为21.08 g,17NPZ240-1的产量最高;相关分析表明全株角果数(r=0.897**)和每角粒数(r=0.534**)与单株产量极显著正相关。各材料倒伏系数介于153.74~359.61,17NDL20-7的倒伏系数最低,抗倒性最强;相关分析表明抗折力(r=-0.501**)、重心高度(r=502**)、茎粗(r=-0.816**)、分枝部位(r=0.472**)和主花序长度(r=-0.679**)与倒伏系数呈极显著相关关系。品质性状中,含油量介于33.40%~49.54%,平均含量为43.32%,17DNL32-3的含量最高;蛋白质含量介于16.87%~27.24%,平均含量为21.18%,16NTS309-4的含量最高;油酸含量介于23.62%~68.81%,平均含量为45.92%,17NPZ242-1的含量最高;亚油酸含量介于10.62%~18.48%,平均含量为14.87%,亚麻酸含量介于5.41%~8.97%,平均含量为7.60%,芥酸含量介于0.15%~27.51%,平均含量为10.80%,17NPZ52-3的亚油酸、亚麻酸含量最高,芥酸含量最低;硫代葡萄糖苷含量介于18.47~70.35μmol·g^(-1),平均含量为34.41μmol·g^(-1),16NTS309-7的含量最低;相关分析表明油酸、亚油酸、亚麻酸和芥酸含量间存在显著相关关系(0.421≤r≤0.913)。9个性状的综合隶属函数值F介于0.25~0.77,相差0.52,品系间差异较大。聚类分析将34份甘蓝型冬油菜材料划分为3大类群,第Ⅰ类群包含17份材料,综合表现最好,但平均含油量最低;第Ⅱ类群包含4份材料,综合表现较弱,倒伏系数均值最高,其他8个性状的平均值都处于中等水平;第Ⅲ类群包含13份材料,综合表现最弱,但平均含油量最高,倒伏系数均值处于中等水平,其他7个性状的均值都处于最低水平。

氮肥用量对冬油菜籽粒产量和品质的影响

为探明不同氮肥用量对冬油菜籽粒产量和品质的影响,于2019/2020以及2020/2021年在湖北省武穴市开展田间试验,试验设置0、90、180、270、360 kg N hm^(-2)5个氮肥施用水平。在成熟期测定油菜籽产量、氮含量和油菜籽品质指标。结果表明,施氮显著提高冬油菜籽粒产量及氮含量,与不施氮相比,氮肥施用后平均增产1548 kg hm^(-2),平均增产率达32.9%,在施氮量为0~270 kg N hm^(-2)范围内,油菜籽产量随氮肥施用量显著增加,继续增施氮肥,油菜籽产量无明显变化或有下降趋势,施氮主要通过提高单株角果数来提高油菜籽粒产量。施氮显著增加了籽粒蛋白质含量,当施氮量达270 kg N hm^(-2)时籽粒氮含量和蛋白质含量最高。施氮显著降低籽粒含油量,氮肥用量每增加100 kg N hm^(-2),籽粒含油量下降1.6个百分点。随着氮肥用量的增加,籽粒硫甙、油酸、亚麻酸、芥酸以及饱和脂肪酸(棕榈酸和硬脂酸)呈升高趋势,亚油酸呈降低趋势,油菜籽粒品质整体呈降低趋势。综上所述,以追求高品质食用油为目标,同时兼顾油菜籽粒产量,氮肥适宜用量约为180kgNhm^(-2);以追求油菜籽粒产量并考虑油菜饼粕作饲料为目标时,氮肥适宜用量约为270 kg N hm^(-2)。

Stress response to nanoplastics with different charges in Brassica napus L.during seed germination and seedling growth stages

Nanoplastic pollution has become a significant problem in farmland systems worldwide.However,research on the effects of nanoplastics(NPs)with different charges on field crops is still limited.In our study,NPs with different charges,including unmodified polystyrene nanoplastics(PS),positively charged polystyrene nanoplastics(PS-NH_(2)),and negatively charged polystyrene nanoplastics(PSSO3H),were investigated for their impacts on seed germination and seedling growth of rape.The results showed that seed water uptake(after 12 h),seed germination,seed vigour,and relative root elongation were all significantly reduced under exposure to NPs(200 mg/L).Similarly,remarkable decreases in plant biomass(root weight,shoot weight),growth(root length,plant height),photosynthesis ability(chlorophyll a,chlorophyll b,carotenoids),essential nutrient uptake(Fe,Mn,Zn,Cu),and plant quality(soluble protein,soluble sugar,crude fibre content)of rape seedlings were also observed after exposure to NPs.Among the three kinds of NPs,PS-NH_(2)showed stronger effects.Moreover,superoxide dismutase,peroxidase,and catalase activities of rape seedlings were changed,and the content of malondialdehyde was significantly increased under exposure to NPs.Furthermore,positively charged PS-NH_(2)showed stronger effects on the phenotype,physiology,biochemistry,nutrient uptake,and plant quality of rape.Notably,a comprehensive toxicity evaluation revealed that PS-NH_(2)had the strongest toxicity to rape.The present study provides important implications for the interaction and risk assessment of NPs and crops in soil-plant systems.

Identification of QTLs for Branch Number in Oilseed Rape(Brassica napus L.)

Oilseed rape （Brassica napus L.） is one of the most important oil crops worldwide and provides about 50 percent of the vegetable oil supply in China （Yin et al., 2009）. The development of rapeseed varieties with higher yield is an effective measure to optimize balance between the supply and demand of edible vegetable oil. In oilseed rape, the number of silique per plant （SP） contributes most to the yield performance （Diepenbrock, 2000）. However, compared with the other two yield-component traits, seeds per silique （SS） and seed weight （SW）, SP is more sensitive to environmental changes （Li et al., 2007; Shi et al., 2009）. Therefore, it is difficult to perform the genetic improvement on SP trait directly in oilseed rape.