Stability of the cleistogamous trait during the flowering period of oilseed rape

At the field scale, the co-existence of different farming production systems requires strategies to prevent gene flow between adjacent crops. Oilseed rape produces pollen dispersed by wind and insects and the risks of pollen mediated gene flow are significant for this crop. Cleistogamy, the trait of non-opening flowers, could be used to reduce pollen flow. Cleistogamous oilseed rape genotypes were obtained by INRA in France and were bred in order to improve the stability of this trait. In this paper, we examine the reliability of the cleistogamous trait for two inbred lines. The flower opening level was measured at different dates during the flowering period in six field experiments (three sites × 2 years). The results showed that some flowers were partially opened with rates varying from 0.5% to 33% principally depending on genotypes, trials (site and year) and recording dates. Given that other studies have shown that cleistogamy could reduce pollen dispersal, we consider that, even when partially unstable, cleistogamy could be beneficially used in combination with other means in a containment strategy.     

Evaluation and use of a spatio-temporal model of cropping system effects on gene escape from transgenic oilseed rape varieties: Example of the GeneSys model applied to three co-existing herbicide tolerance transgenes

Gene flow between coexisting oilseed rape varieties and rape volunteers cannot be solely studied on field experiments. Previously, a model (GeneSys: [Colbach, N., Clermont-Dauphin, C., Meynard, J.M., 2001. GeneSys: A model of the inluence of croping system on gene escape from herbicide-tolerant rapeseed crops to rape volunteers. I. Temporal evolution of a population of rapeseed volunteers in a field. Agric. Ecosyst. Environ. 83, 235–253; Colbach, N., Clermont-Dauphin, C., Meynard, J.M., 2001. GeneSys: A model of the inluence of croping system on gene escape from herbicide-tolerant rapeseed crops to rape volunteers. II. Genetic exchanges among volunteer and cropped populations in a small region. Agric. Ecosyst. Environ. 83, 255–270]) was therefore developed to quantify the effects of cropping systems on gene flow from rapeseed varieties to rape volunteers in time and in space. In the present work, the model was improved to simulate simultaneously the spread of three different genes. Four different regions were then surveyed from 1995 to 2001: one region comprised only farmers’ fields with frequent rape crops in the rotations; the three remaining regions comprised the French experimental GMO platforms with 2–3 GM and one non-GM rape variety as well as neighbour farmers’ fields. For all these fields, cropping history was recorded during the study and for at least three previous years. In the first region, rapeseed volunteers were assessed in crops as well as on road and field margins in 1 year. In the three remaining regions, volunteer densities and genotypes were assessed each year after harvest and rape harvest genotypes determined during 2 years. The comparison of simulated and observed data showed that the model usually satisfactorily predicts volunteer densities and genotype proportions as well as harvest genotype proportions. Several problem areas were identified: volunteers in road and field margins were usually badly predicted; the model frequently underestimated volunteer densities in spring crops; gene flow via pollen dispersal was underestimated when the distance from the pollen source increased. The model was then used to simulate the spread of herbicide-tolerant rape volunteers in a region grown with one or several GM herbicide-tolerant varieties and more particularly the stacking of several resistance genes in individuals. The simulations also showed the contamination of the harvest of non-GM rape varieties by GM seeds resulting from gene flow.     

冬油菜苗期化学除草效果和经济效益研究

为筛选出经济、高效、安全的化学除草方法,有效控制油菜田间杂草危害,提高油菜产量和种植效益,通过试验,研究了2种化学除草剂不同使用浓度的安全性和苗期化学除草效果,并以人工除草和不除草方法为对照,对比分析不同除草方法的投入和产出情况。结果表明：不同除草方法间油菜产量差异显著;化学除草方法对油菜田间杂草有较好的防除效果,并可显著降低油菜生产的劳动力和生产成本投入,进而提高经济效益;不同化学除草方法均于施药35天后表现出较好的除草效果;每公顷用21.2%喹·胺·草除灵悬浮剂900 mL于油菜4—5叶期、杂草3—4叶期兑水900 kg及时喷施的方法除草效果好,对油菜生长安全,可以作为冬油菜田的苗期化学除草方法在生产上应用。     

江苏省冬油菜生育期内低温事件的年际变化及对产量的影响

为探讨气候变化对我国油菜生产带来的可能影响,选取江苏省地区52个气象站1961—2012年日气温资料及冬油菜产量逐年数据,采用M-K趋势检验探求冬春季节8种低温指数的变化趋势,并依托一阶差分法探讨低温指数与产量的数量关系。结果表明：（1）1961-2012年间省内大部分地区冬春季节低温事件的总天数、连续低温事件的场次、强度及持续性呈现出显著的减弱趋势;（2）不同类型低温指数中,FI1（越冬期日最低气温<-5℃的总天数）与CI4（蕾薹期连续日最低气温<0℃天气的最长持续时间）对冬油菜产量的负效应最为显著;（3）各站点产量对FI1及CI4敏感性分析表明江苏省北部地区冬油菜种植对低温灾害事件更为敏感;（4）1961-2012年间江苏大部分地区FI1及CI4的减少趋势给研究区冬油菜产量带来了一定幅度的增产。     

基于生命周期法的中国2004—2015年油菜生产氮足迹分析

The loss of reactive nitrogen in agriculture has increasingly become serious, systematic analysis of reactive nitrogen emissions from agricultural production is conducive to promoting the green and healthy development of agriculture in China. Based on the statistical data of crop yield and farmland investment in the oilseed rape production of China, the spatiotemporal dynamic change of nitrogen footprint (NF) and its composition of oilseed rape during 2004-2015 in China was estimated using the theory of NF and life cycle assessment method in the agricultural sector. The NF of oilseed rape was 7572.0 g N-eq ha ^-1 during 2004-2015, and decreasing year by year, with an average annual decline of 1.0%. The main components of the NF were from fertilizer application (20%) and NH₃ emission (54%) in the oilseed rape production. Obvious differences also were observed among mainly agricultural provinces in China, that is, the higher nitrogen footprint per area (NF_a) and nitrogen footprint per yield (NF_y) in Inner Mongolia, Shanghai, and Jiangsu region. The NF_a and NF_y in high yield region were significantly higher than those in low yield region. Among them, the NF of nitrogenous fertilizer, phosphate fertilizer and compound fertilizer increased by 80.6%, 76.9%, and 57.8%, respectively (P < 0.05). The NF_a of rapeseed in China showed a trend of increase with the increase of rapeseed yield, but there was no significant correlation. The results suggest that improving crop management practices that limit fertilizer consumption is an important measure for the green and healthy development of rapeseed in China.     

气候变化对重庆油菜生产的影响

为了研究重庆特殊的生态气候条件与油菜生产发展的关系,基于重庆1983—2013年气象资料和油菜生产状况,分析重庆近30年来气候变化特征及其对油菜生产的影响。结果表明：分析期内重庆年平均气温变化呈现显著的曲线上升趋势,日照时数呈现显著减少趋势（在0.05水平上通过显著性检验）;重庆近30年降雨量突变发生比较频繁,线性变化趋势不明显,但相邻年份间降水量差异较大,1998年降水量为1363.5 mm是分析期内降水量最多的一年,以此为突变点,此后呈下降趋势。菌核病发病指数与3月和4月平均气温相关系数为-0.682^*达显著水平,菌核病发病指数与降雨量和日照时数相关性不显著;重庆油菜面积与温度呈显著负相关(P=-0.568^*),单产与温度相关性不显著。日照时数与油菜单产呈显著负相关(P=-0.544^*),与油菜面积相关性不显著。降雨量的线性变化趋势不明显,而且相邻年份间降水量差异较大,与油菜面积和单产相关性均不显著。     

Leaf glucosinolate profiles and their relationship to pest and disease resistance in oilseed rape

Summary Glucosinolates are sulphur-containing glycosides which occur within vegetative and reproductive tissue of oilseed rape. Following tissue damage, glucosinolates undergo hydrolysis catalysed by the enzyme myrosinase to produce a complex array of products which include volatile isothiocyanates and several compounds with goitrogenic activity. Many of these products have been implicated in the interaction betweenBrassica and their pests and pathogens and some may have a role in defence mechanisms. Low glucosinolate (00) oilseed rape cultivars have been shown to possess similar concentrations of leaf glucosinolates as high glucosinolate (0) oilseed rape cultivars. Likewise, despite considerable speculation to the contrary, 00 cultivars have been shown not to be more susceptible to pests and pathogens than 0 cultivars. The potential to enhance pest and disease resistance of oilseed rape by manipulating the leaf glucosinolate profile without reducing seed quality is discussed.     

Hybridization of radish (Raphanus sativus L.) and oilseed rape (Brassica napus L.) through a flower-culture method

Summary Hybridization between radish and oilseed rape has been cumbersome, requiring elaborate embryo rescue techniques. With a modified flower culture method, we have achieved successful hybridization between radish and (transgenic) oilseed rape without the laborious and technically demandingin vitro ovule or embryo rescue techniques.The hybrid nature of the intergeneric hybrids was demonstrated using morphological traits, and DNA analyses. The described method will facilitate the generation ofRaphanobrassica hybrids useful for biosafety studies of the potential for transgenes to spread in weedyCruciferae as well as for breeding programs aimed at introducing useful radish genes, e.g. nematode resistance genes, into oilseed rape.     

蜜蜂授粉在油菜生产中的作用研究

为探明蜜蜂授粉在油菜生产中作用和经济重要性,采用蜜蜂授粉依赖度模型,从蜜蜂对油菜授粉服务价值、油菜生产对授粉蜂群需求量2个方面评价蜜蜂授粉在油菜生产中作用。结果表明,2018年蜜蜂对国内油菜的授粉服务价值约104.19亿元,相当于油菜年产值661.41亿元的15.75%。蜜蜂对四川省、湖北省、湖南省油菜生产的授粉价值均在10亿元以上。国内油菜生产对授粉蜂群的需求量较大,约需1637.65万群以上蜜蜂授粉,该数量已超国内目前蜂群总量908.84万群,其中,湖南省和四川省油菜生产对授粉蜂群的需求量最大,约占国内现有蜂群总量的1/3以上。由此可见,蜜蜂授粉是油菜生产重要的生产投入,应当逐步提高民众对蜜蜂授粉经济价值的认识,大力推广油菜蜜蜂授粉技术。     

Assessing the risks of wind pollination from fields of genetically modified Brassica napus ssp. oleifera

Summary Intensive research over the past 10 years has produced many genetically-mofified lines of oilseed rape with market potential. Assessment of these lines in statutory trials prior to their release as cultivars is necessary, owing to concern over the likelihood of transgene escape from such crops. Here, we examine the movement of airborne pollen grains from oilseed rape fields and assess their capacity for long-range geneflow.Pollen dispersal from isolated rape fields was monitored over two seasons and related to the distribution of fields and feral (domesticated plants growing outside cultivations) populations of the crop in Tayside and North East Fife regions of Scotland. Airborne pollen density declined with distance and at 360 m was 10% of that at the field margin. Pollen counts of 0–22 pollen grains m³ were observed 1.5 km from source fields and apparently were sufficient in number to allow seed set on emasculated bait plants. Oilseed rape pollen has greater capacity for long-range dispersal than had been suggested by small-scale field trials. Mean separation of oilseed rape fields in the survey area was 410 m and the mean distance from feral populations to commercial fields was 700 m. Sixty percent of feral populations with more than 10 plants occurred downwind and within 2 km of an oilseed rape field. Provided that the flowering biology of genetically-modified oilseed rape does not differ from the conventional crop, these data suggest that transgene movement to non genetically-modified fields or feral populations is likely following commercial release.     

Superior performance of two homozygous diploid lines from naturally occurring polyhaploids in oilseed rape (Brassica napus)

Summary Homozygous diploids in oilseed rape were produced by pipetting drops of 0.1 per cent colchicine into the leaf axils of rooted cuttings from naturally occurring polyhaploids after removing the waxy covering with a scalpel. Trial results from spring and winter rape showed that occasional homozygous diploid lines yielded consistently more oil per ha than the parental varieties. Prospects for breeding oilseed rape as a self-fertilised crop are discussed.     

Risk assessment of genetically modified crops. Potential of four arable crops to hybridize with the wild flora

Summary The proposed introduction of genetically modified organisms into the environment has caused public and scientific concern. In response to this concern governments have set up biosafety regulations. In this paper a step-by-step scheme is described by which the safety of genetically modified organisms can be assessed. The first step is to determine the level of safety concern for the unmodified organism. Important aspects of the safety concern of the unmodified organism are the potential to hybridize with the wild flora and the ability of the crop to run wild. These aspects have been investigated by a desk study for four agricultural crops (potato, beet, oilseed rape and maize). Maize and potato are genetically isolated from the wild flora. Beet and oilseed rape on the contrary can potentially hybridize with wild relatives in the Netherlands. The risk assessment of the latter two species should focus entirely on the effects of the introduced genetic material.     

芽孢杆菌Bam22对油菜根肿病的防治效果研究

由芸薹根肿菌(Plasmodiophora brassicae)侵染引起的根肿病是限制油菜生产的主要病害之一,苗期即可发病,目前该病害的主要防治措施有选用抗病品种和使用化学药剂,但农药残留问题日益突出,故提出采用生物防治的策略防控油菜根肿病。笔者采用拌种与苗期灌根的方式研究了芽孢杆菌(Bacillus Bam22)对油菜根肿病的田间防治效果,苗期调查结果表明芽孢杆菌Bam22拌种处理(T1)和芽孢杆菌Bam22+高岭土拌种处理(T2)较清水对照(CK)的发病率降低了3.4%~20%,防效达44%~52%;T1、T2与药剂对照氰霜唑拌种处理(T3)的株高和发病率无明显差异,但防效提高20%~40%。花期调查结果表明T1和T2处理较清水对照(CK)的发病率降低了10%~13%,防效介于28%~51%;T1、T2处理较药剂对照(T3)的发病率降低了6.67%~10%,防治效果提高了5%~22%,单株产量增加了23.97%~34.29%。以上研究结果表明,采用芽孢杆菌Bam22拌种结合苗期灌根,能够有效降低油菜苗期和花期根肿病的发病率,显著降低油菜的产量损失率。芽孢杆菌Bam22对油菜根肿病有较好的控制效果,具有开发成为生物农药的潜力。     

Inheritance of progoitrin and total aliphatic glucosinolates in oilseed rape (Brassica napus L)

Inheritance of progoitrin and total aliphatic glucosinolate concentrations were investigated in oilseed rape, using parental, F₁, F₂ and first backcross generations, derived from a cross between resynthesized spring rape and a double-low spring rape cultivar. Progoitrin and total aliphatic glucosinolate concentrations were measured in mature seeds of single plants from these generations, using micellar electrokinetic capillary chromatography. For progoitrin, an additive/dominance model of gene action adequately explained the variation among the generation means, but for total aliphatic glucosinolate concentration, non-allelic interactions were also detected. Predictions based on estimates of the genetic parameters indicated that recombinant inbred lines, rather than second cycle hybrids, appeared to offer a better prospect of reducing glucosinolate concentrations in this material. Estimates of the minimum number of genes controlling these two characters were broadly in line with the number required for the known stages of their biosynthesis. This revised version was published online in July 2006 with corrections to the Cover Date.     

梨花和油菜花挥发性气味物质的鉴定及差异分析

为了解花朵中挥发性气味物质对吸引传粉昆虫采集所起到的作用,采用固相微萃取(SPME)和气相色谱-质谱联用(GC-MS)技术,检测梨花和油菜花全花、花药、花蜜中挥发性气味物质成分,并进行主成分及与昆虫采集相关性分析。鉴定梨花中挥发性气味物质成分有9种,氧烷类为主要挥发性气味物质,占44.44%,通过主成分分析,气味贡献物主要来自于二甲基硫醚、十四甲基环七硅氧烷、苯丙腈、苯甲醛等化合物。油菜花中挥发性气味物质成分有23种,酯类和氧烷类为主要气味挥发性物质,分别占8.7%和16.09%,气味贡献物主要来自于反-2-己烯醛、异硫氰酸-2-苯乙酯、4-异硫氰酸根合-1-丁烯、二甲基三硫醚、二甲基二硫醚等化合物;花药的挥发性气味物质种类比花蜜中更丰富。传粉昆虫调查发现,试验地共有传粉昆虫4目10科11种,梨和油菜传粉昆虫数量上有显著差异(P<0.05),但各成分与采集昆虫数量均没有显著相关性(P>0.05)。研究发现梨花和油菜花挥发性气味物质成分有显著差异,将为研究气味物质主要贡献物在吸引传粉昆虫中发挥的作用提供参考。     

长江流域直播冬油菜氮磷钾硼肥施用效果

冬油菜直播种植的推广应用对提高我国油菜籽总产量和保障食用油安全有重要意义。2009-2010年度在长江流域6个冬油菜主产省布置36个大田试验,研究当前生产条件下我国直播冬油菜的氮磷钾硼肥施用效果和肥料利用率,比较农民习惯施肥与推荐施肥的差异,并与移栽油菜施肥效果进行对比,以探讨直播冬油菜的施肥管理措施。结果显示,在推荐施肥量和施肥方法条件下,氮磷钾硼肥配合施用(NPKB)处理直播冬油菜的油菜籽产量和产值平均分别为2001 kghm^–2和8205元hm^–2,显著高于农民习惯施肥(FFP)处理,施用效果为N > P > B > K。NPKB配合施用显著促进直播冬油菜的养分吸收,N、P、K累积量分别为104.2、20.4和160.2 kg hm^–2。NPKB配施条件下,直播冬油菜的氮、磷、钾肥表观利用率平均分别为35.8%、22.3%和45.9%,明显高于农民习惯施肥的20.8%、7.2%和28.0%。说明合理施肥对直播冬油菜生产有重要作用,现阶段应积极推行氮磷钾硼肥配施技术,并根据生长发育特点和养分吸收规律调整肥料的施用时期和比例。     

油菜菌核病发生流行与气象因素关系及预测模型研究

油菜菌核病是中国油菜上的主要病害之一,为了明确气象因素与发病间的关系,提高预测能力,利用嘉兴市1980-2010年的气象因子与油菜菌核病田间实际发生数据进行相关性分析。结果表明：3月下旬-4月上旬降雨量、4月上旬的雨日数与病害呈极显著正相关,4月中旬日照时数呈显著负相关,气温对油菜菌核病影响较小。在相关性分析的基础上,采用逐步回归分析法,利用降雨量、雨日、日照、气温等气象因子组建了6个病害预测模型,历史回测检验结果：模型5和模型6发病程度（级）拟合程度高,预测能力强,适宜于嘉兴本地乃至浙北地区。     

Inheritance of cleistogamic flowering in durum wheat (Triticum durum)

Summary Generally durum wheat flowers are chasmogamous but very rarely, cleistogamy may be observed. Genetic studies based on six crosses and back crosses showed that chasmogamy was determined by a single dominant gene Cl, plants homozygous for the recessive allele, cl, were cleistogamous. The flowering behaviour phenotypes were unaffected by environmental conditions. Cleistogamy was attributed to poorly developed lodicules and stiff perianth.     

Agronomic traits and gene containment capability of cleistogamous rice lines with the superwoman1-cleistogamy mutation

Pollen-mediated transgene flow is a major concern for the production of genetically modified (GM) rice. Cleistogamy is a useful tool for preventing this form of gene flow. We previously identified the cleistogamous rice mutant superwoman1-cleistogamy (spw1-cls) and determined its molecular genetic mechanism. In the present study, we cultivated spw1-cls over five years to examine effects of cleistogamy on agronomic traits. Simultaneously, we cultivated cleistogamous backcross lines created by continuous backcrossing with “Yumeaoba” (a japonica cultivar) as the recurrent parent and by application of a DNA marker. In these experimental cultivations, spw1-cls and its backcross lines showed almost equal or slightly lower, but acceptable, agronomic traits compared with each control line. We also conducted natural crossing tests in paddy fields to assess the gene containment capability of spw1-cls. In a series of field experiments, there was no natural crossing between spw1-cls (pollen donor) and pollen recipient lines, but the wild-type donor and recipient lines were crossed. Thus, the cleistogamy of the spw1-cls mutation is able to inhibit natural crossing effectively, without significant loss of commercial benefits, such as yield. We conclude that spw1-cls cleistogamy is a practical tool for gene containment in GM rice cultivation.     

Components of a Cytoplasmic Male Sterility System in Resynthesized and Cultivated Forms of Oilseed Rape (Brassies napus L.)

Male sterile Brassica napus L. plants were found in breeding material which was used for the development of yellow-seeded oilseed rape. The genetic studies indicated that the male sterility was conditioned by the presence of maintamer genes in the nuclear backgrounds of two newly resynthesized B. napus lines, No7076 and No7406, in combination with a male sterility-inducing cytoplasm (S) which is frequently found in cultivated forms of B. napus. Test crosses with nap maintainer and restorer lines support the conclusion that the observed male sterility is of nap type. Furthermore, the Eco RI restriction pattern of mitochondrial DNA of the (S) cytoplasm was identical to that of the nap cytoplasm. Hence, we conclude that we have uncovered a new source of maintainer lines for the nap system which could potentially lead to the production of a better maintainer/restorer system for use in hybrid oilseed rape breeding programmes. However, more work is needed to reduce the glucosinolate content of the maintainer lines and to determine the factors controlling the phenotypic expression of the system.