甘蓝型杂交油菜主要农艺性状灰色关联度分析

试用灰色系统理论关联度法对贵州省农科所油料所近年来选育的11个甘蓝型杂交油菜新组合进行单位面积的油菜籽产量等7个主要农艺性状的灰色关联度分析。分析结果表明：不同的杂交油菜组合同一性状与产量的关联度不同；同一组合内的不同农艺性状与产量的关联度也不同。其关联度顺序为：单株产量（r1=09067）＞株高（r2=0．8398）＞林有效分枝数（r3=0.7892）＞用粒数（r5=0．7237）＞林有效角果数（r4=0．4276）＞千粒重（r6=0．3767）。在甘蓝型杂交油菜的组合选育过程中，应注重选择单株生产力高、株高适度、单株有效分枝多的组合，同时要求所选择的组会角粒数，株有效角果数多。千粒重对同一组合材料是相对稳定的，变化幅度小，在育种过程中对千粒重的选择效果不明显。     

Seasonal Changes in the Photosynthetic Capacity of Winter Rape Plants under Different Nitrogen Regimes Measured in the Field

Winter rape (cv.'Falcon') grown under different nitrogen regimes (N₀, N₁₂₀; 0 and 120 kg.ha⁻¹, respectively) in northern Germany was investigated over the 1996 spring–summer season. Using a CO₂, H₂O diffusion porometer, diurnal courses or net photosynthesis and respiration were measured in situ and were related to microclimatic conditions and leaf water relations. Photosynthesis was modelled and daily CO₂ gain was calculated. In contrast to the N₁₂₀ plants, plants of the low nitrogen plot (N₀) grew less densely and their leaves behaved more like sun leaves. Increased nitrogen supply had little influence on photosynthetic capacity but it increased productivity through higher leaf area index and an extended period of photosynthetic activity. N₁₂₀ plants also appeared to be better acclimated to hot, summer conditions. Higher nitrogen supply substantially increased seed production with the yield of the N₁₂₀ plants being 16% of the N₀ plants.     

Harvest index versus grain/straw-ratio. Theoretical comments and experimental results on the comparison of variation

Summary The variation of the two parameters, harvest index and grain/straw-ratio, has been theoretically compared by applying the relative measure coefficient of variation. The harvest index exhibits a clear superiority (= lower variation) compared to the grain/straw-ratio.Applications to ten European winter oilseed rape cultivars and lines are in an excellent agreement with the theoretical findings.     

Note on the Effect of Non-regular Spatial Patterns of Plants on Yield per Area Based on a Logarithmic Relationship between Single Plant Yield and Individual Area

Based on several simplifying assumptions, a previously developed stochastic approach allows an estimation of the effects of non-regular spatial patterns of the distribution of individual plants on yield per area (F). In this approach, two random variables were attached to each plant: single plant yield (E) and individual space per plant (A). The latter was estimated by the area of Thiessen-polygons. Yield per area was calculated theoretically by the expectation of the ratio E/A. Based on a logarithmic relationship between E and A the expectation of E/A can be expressed by an approximation which depends on the mean and on the variance of the individual plant spaces. An improvement of this approximation can be easily obtained by including skewness and kurtosis of the distribution of individual plant areas. Finally, all theoretical concepts and results were applied to an experimental data set of winter oilseed rape ( Brassica napus L.).     

2010—2019年西藏中南部春油菜生育期变化特征

为了解气候变暖背景下高原春油菜生育期对气候变化的响应特征,本研究利用2010—2019年西藏泽当农业气象观测站春油菜生育期资料和1981—2019年逐日气象资料,采用线性回归方法分析了西藏中南部春油菜生育期变化特征。结果表明：（1）1981—2019年春油菜生长季日照时数和平均风速呈显著减少趋势,减幅分别为-22.37 h/10 a、-0.32 (m/s)/10 a,其他气象要素均为不同程度的增加趋势,暖湿化气候特征明显。但2010—2019年春油菜营养生长期、生殖生长期以及全生育期的热量资源（平均气温、平均最高气温、平均最低气温和≥0℃积温）和光照资源（日照时数）趋于减少,水分资源（降水量、相对湿度）和平均风速呈增加趋势。（2）2010—2019年春油菜现蕾、抽薹、开花和绿熟4个生育期无明显变化,播种期和出苗期为推迟趋势,而五真叶期与成熟期呈提早趋势。营养生长期、生殖生长期以及全生育期的天数均呈缩短趋势,以全生育期天数缩短最为显著(-2.23 d/a)。（3）春油菜大部分生育期天数与日照时数、≥0℃积温有显著的正相关,与其他气象要素的相关性不显著。全生育期天数不仅与日照时数、≥0℃积温存在显著的正相关,还与平均相对湿度有着显著的负相关。2010—2019年春油菜全生育期天数随着日照时数和≥0℃积温的减少、平均相对湿度的增加呈缩短趋势。     

Reducing potential gene escape in time by appropriate post-harvest tillage—Evidence from field experiments with oilseed rape at 10 sites in Europe

Persistence of oilseed rapeseed in soil can result in weed problems but also reduce oil quality of following rape crops or result in unwanted gene escape which is particularly relevant in the context of genetically modified oilseed rape. In this paper data from 13 field experiments at sites in England, Austria and Germany are presented where tillage operations were tested that potentially reduce the build-up of a seed bank. In the majority of experiments seed losses were artificially simulated by broadcasting ca. 10,000 freshly ripened rapeseed m⁻² onto cereal stubbles. Oilseed rapeseedlings in autumn, the seed bank in winter–spring and yields of the following crop winter wheat were assessed as a function of tillage regime. During summer and autumn 19–70% of the seeds germinated and emerged. This part of the population was killed by following tillage operations or herbicide applications. However, 0–29%, in moist years 0–5%, of the initially broadcasted seeds developed dormancy and remained ungerminated in the soil until the following winter–spring.

Delaying incorporation of the seeds by leaving the stubble untouched for up to 4 weeks resulted in a reduced seed bank in almost every case. Also, repeated stubble tillage compared to an early single stubble tillage operation resulted in a smaller seed bank. The type of primary tillage (ploughing versus non-inversion cultivation) had no clear effect. No relation was found between the number of seedlings in autumn and the size of the seed bank the following winter–spring. Grain yield of the following crop winter wheat was not adversely affected by delayed stubble tillage.

The results indicate that stubble tillage aiming at a reduced seed bank of oilseed rape should focus on conditions avoiding induction of secondary dormancy rather than improving germination conditions. This means that, under the climatic conditions of central and western Europe, the stubble should be left untouched for several weeks after harvest before starting the usual tillage sequence with stubble tillage and ploughing or a non-inversion tillage sequence.     

石油污染物对油菜产量品质及生理指标的影响

通过盆栽试验,研究了石油污染物对油菜生物量和叶绿素含量、POD、硝酸还原酶活性、根活力、细胞膜透性和VC、总糖含量等一系列生理及品质指标的影响。研究结果表明：石油烃浓度低于500mg/kg时,对油菜生长具有一定的促进作用,表现为油菜产量、株高、硝酸还原酶活性增加,而且这个浓度时对油菜品质的影响也很小,但是当石油烃的浓度超过500mg/kg时,随着浓度的加大,对油菜的伤害也越来越严重了,表现为油菜产量、叶绿素含量、根活力、硝酸还原酶活性大幅降低,细胞膜透性和POD 大大增加,而且品质也随之下降。综合各项指标,石油烃对油菜的临界浓度暂定为500mg/kg。     

Effects of previous cropping on seed yield and yield components of oil-seed rape (Brassica napus L.)

Information about the effect of the preceding crop or crop combination on the seed yield of oil-seed rape is extremely scarce. Experiments were carried out in northwest Germany to investigate the effect of different preceding crops on the growth, seed yield and yield components of oil-seed rape. The two directly preceding crops, wheat and oil-seed rape, had only a negligible and non-significant effect on the seed yield of the following oil-seed rape crop. Oil-seed rape grown after wheat had more pods per plant, due to an increase in the number of pods on the higher category branches. In contrast, the seed yield and yield components were more affected by the cropping sequence, i.e. the crops 2 years before. Averaged over two experimental years, the greatest yields were observed in oil-seed rape following the sequence peas-wheat (694 g m⁻²), whereas the smallest seed yield occurred after 2 years of oil-seed rape cropping (371 g m⁻²). The differences in the seed yield were again associated with more pods per plant, which compensated for the lower number of plants m⁻², whereas the number of seeds per pod and the mean seed weight were almost unaffected by the previous cropping. It was not possible to relate the described differences to the crop development, since differences in the biomass caused by the previous cropping were only significant at maturity. Oil-seed rape grown after 2 years of oil-seed rape had the highest ratings of stem canker (Leptosphaeria maculans) as well as verticillium wilt (Verticillium dahliae). But the general level of the diseases was low, and therefore other causes for the effects described must be considered.     

Emergence and performance of volunteer oilseed rape (Brassica napus) in different crops

Volunteer oilseed rape (OSR, Brassica napus L.) causes various agronomic problems in crop rotations and can contribute to gene dispersal by pollen and by seed admixture. A 4-year field experiment (2008–2011) was set up in south-west Germany to investigate the performance of volunteers derived from two OSR cultivars with different levels of seed dormancy. Volunteers of a high-dormancy (HD) and a low-dormancy (LD) OSR cultivar were deliberately generated by spreading 10,000 seeds m⁻² on a field in August 2008 and 2009. Four different crops were grown on that area in the first year following the seed rain: winter wheat (Triticum aestivum L.), winter turnip rape (Brassica rapa L.), spring barley (Hordeum vulgare L.) and field pea (Pisum sativum L.). In the second year, maize (Zea mays L.) was sown uniformly across all plots. Numbers of OSR seedlings emerging in early autumn shortly after seed rain were not connected with the size of the soil seed bank in early spring of the following year. The seeds of the HD-cultivar formed a much greater soil seed bank (up to 14% of the initially spread seed number) compared with the LD-cultivar (up to 1.3%) in the soil layer of 0 to 30 cm in early spring 2009 and 2010). Across all crops, considerably more volunteers of the HD-cultivar than of the LD-cultivar were present at several survey dates in the first year following seed rain. The highest number of volunteers originated from the HD-cultivar with up to 11 volunteers m⁻² in winter turnip rape compared with a maximum of 0.48 plants m⁻² in the other crops. Cultivar-specific differences in volunteer density were observed as well in maize two years after OSR seed rain. Flowering and seed setting volunteers were only present in 2010 and the flowering time was crucially overlapping with that of sown winter OSR. The reproductive ability (seeds produced m⁻²) of the LD-volunteers was five times lower in winter turnip rape than of the HD-volunteer; a similar trend was observed for the OSR volunteers in the other host crops.Strategies to definitely reduce unwanted effects of OSR volunteers, such as gene flow, should include the use of LD-cultivars with a low potential to form a soil seed bank, particularly if selective herbicides are not available, for instance in broad-leaved crops, or if the volunteers are herbicide-tolerant.     

在铀尾渣污染土中壤添加磷对植物生长及积累重金属的影响

在重金属污染土壤中添加化学稳定剂,可降低重金属的生物有效性,阻控重金属进入食物链。设计盆栽试验,在铀尾渣污染土壤中添加不同浓度的磷肥(0、30、60、120、240和480 mg kg^-1),调查磷对芥菜型油菜(Brassica juncea)和甘蓝型油菜(B. napus)的生长及植株积累重金属铀、镉、锌和铅含量的状况,分析添加磷肥前后植株内磷含量和土壤重金属DTPA提取态含量的变化。结果表明,添加磷肥前,铀尾渣污染土壤总氮、总磷、总钾和有机质的含量低,铀、镉、锌和铅的含量高,对两种油菜的生长有抑制作用;添加磷肥后,两种油菜体内磷含量增加,污染土壤中的铀、镉、锌和铅的DTPA提取态含量显著降低,其降幅分别为17.1%~70.5%、24.0%~57.6%、8.9%~32.4%和8.6%~55.8%;大幅度降低两种油菜体内的铀、镉、锌和铅含量,其含量与土壤中这些重金属DTPA提取态含量显著正相关;显著增加两种油菜的干重、株高、根长和叶绿素含量,显著降低其体内的SOD活性和MDA含量。因此在铀尾渣污染土壤中添加磷可有效减少重金属在油菜体内积累,降低重金属沿食物链传递的风险。