用麦蛾卵大量繁殖甘蓝夜蛾赤眼蜂(Trichogramma brassicae)

在2000年建成的麦蛾生产线基础上,经多次试验后完成了具有日生产赤眼蜂200万头生产能力的繁蜂设备,2001年最高日繁蜂量120万头。通过改进生产工艺和设备,扩大规模,提高繁蜂效率,日繁甘蓝夜蛾赤眼蜂1100万头,生产能力提高了5.5倍。生产成本比原来降低了47.3％。     

不同品种草坪型羊茅种子生产性能研究

经过3年的试验,对引自美国和加拿大的9种草坪型羊茅在引黄灌区的物候期、生长特性以及种子生产性能进行了较为系统的研究。结果表明,所有参试品种在银川地区均可良好结实,但结实性能差异极大,Lowgrow,Arid高羊茅和Ruby及Boreal紫羊茅的种子产量最高。通过试验认为,在宁夏引黄灌区建立草坪型羊茅种子生产基地是完全可行。     

Growing vegetables in developing countries for local urban populations and export markets: problems confronting small-scale producers

Vegetables attract high applications of pesticides, and farmers in developing countries use many acutely toxic insecticides to control pests on these crops. With the liberalisation of agricultural markets in developing countries, the number of small-scale farmers growing vegetables for both domestic and export markets is increasing. Demand for supplies of year-round and exotic fruit and vegetables has grown in industrialised countries, but with rising quality standards and traceability requirements it is difficult for small-scale farmers to benefit from this lucrative non-traditional agricultural export trade. The demand is high for vegetables in the expanding cities in developing countries, and farmers in peri-urban areas, or rural areas with good access to the cities, are in a position to find a growing market for their produce. Poor storage facilities will often mean that farmers are forced to sell at peak times when prices are low. Farmers rarely have access to training in pesticide use, and have only limited or no access to advice on the complicated management of pesticides. The Food and Agriculture Organisation of the UN is concerned about high levels of poor quality and adulterated pesticides on sale in developing countries. Surveys repeatedly show that without training, farmers are unable to make good crop decisions: recognition of pests and their predators is generally low, leading to decisions to spray to kill any insect; knowledge of product selection, application rates and timing is poor; different products are often combined in the belief that the effect will be greater; re-entry periods after spraying and essential harvest intervals are not known; and without knowledge of alternatives, farmers will often assume that the only solution to pest problems is to spray more frequently. From a consumer's point of view, few developing countries are able to monitor pesticide residues, particularly for produce grown for home consumption: most countries do not have laboratories for even simple residue testing. Changes in European Maximum Residue Limits means that export crops will be rejected if they contain residues at the Limit of Detection of pesticides not registered in Europe. Season-long field level training in Integrated Pest Management can help farmers to become better decision-makers, and to greatly reduce pesticide use while reducing risks to their own health and environment, producing safer products for consumers, maintaining yields, and increasing incomes.     

Fat-Tailed Sheep Traits as Affected by Docking

The literature mostly indicates that docking fat-tailed lambs initially reduces growth but that post-weaning growth and feed conversion efficiency then increase. The amount of fat deposited, the total separable lean meat to fat ratio and the meat quality all increase, while the percentage of bone in the carcase either decreases or does not change in the carcases of the docked lambs. Wool growth and characteristics are, in general, not affected and reproductive traits in ewes and lambs are improved by docking. The rectal temperature, respiration rate and pulse rate are decreased following docking. The concentrations of immunoreactive beta-endorphin and cortisol in the plasma and the incidence of foot stamping and restlessness, as indicators of stress, increase after docking. Other constituents of the blood are not significantly altered following docking or by the methods of docking. Docking of fat-tailed sheep using rubber rings at one day of age can be recommended. This revised version was published online in July 2006 with corrections to the Cover Date.     

Dairy Production and Reproduction by Crosses of Holstein,Jersey or Brown Swiss Sires with Holstein-Friesian/Gir Dams

The performance was compared of cows sired by Holstein, Jersey or Brown Swiss bulls out of Holstein-Friesian×Gir dams of 1/2 to 3/4 Holstein-Friesian content. The animals were kept in a single herd under the same management. The data were analysed by least-squares techniques under a model that included the fixed effects of breed of sire, Bos taurus fraction of the dam, parity, year and season of calving, and a random cow effect. Based on 480 observations, the milk yields per lactation for the Holstein, Jersey and Brown Swiss sired groups were 2821±163, 2320±61 and 2418±119 kg, respectively. The corresponding means for fat yield per lactation were 96.9±6.6, 86.8±2.5 and 92.8±4.8 kg; for protein yield per lactation were 85.3±5.1, 71.3±1.9 and 76.3±3.7 kg; for lactation length, 339±18, 283±7 and 313±14 days for fat percentage, 3.37±0.10, 3.73±0.04 and 3.77±0.07%; and for protein percentage, 3.02±0.05, 3.10±0.02 and 3.16±0.04%. The respective calving intervals were 487±24, 408±11 and 461±245 days. The yields of milk and protein per day of calving interval were similar in the Jersey and Holstein sired groups, while the former had higher yields of fat, implying that production economics might favour the smaller Jersey crosses in production systems in which the males were not reared. Crossing with Brown Swiss did not improve performance over the Holstein sired crosses.     

微卫星标记与丝羽乌骨鸡产蛋性能的关系研究

从鸡的遗传图谱中选择9个与产蛋性能相关的微卫星基因座,对在产蛋性能上有明显差异的丝羽乌骨鸡个体共170只进行标记基因型与产蛋性状的最小二乘分析,结果表明：有4个标记G31913、X82867、Z95315、G01672与丝羽乌骨鸡的4个月连产蛋量、开产蛋重及500日龄产蛋量间存在显著的关系。标记G31913中基因型AB所对应的开产体重最小二乘均值与其它基因型的对应值间的差异达显著或极显著,开产蛋重间无显著差异。标记Z95315的基因型CC所对应开产蛋重、开产体重最小二乘均值最高,并且均显著高于其余8种基因型所对应的开产蛋重、开产体重最小二乘均值。标记G01672基因型为EE、AE所对应开产蛋重最小二乘均值与基因型为CE、CC的对应值间差异显著;等位基因E与开产蛋重有显著正相关,等位基因C与开产蛋重有显著负相关。标记X82867基因型CD所对应500日龄产蛋量最小二乘均值显著低于AB型,4个月连产蛋量、300日龄产蛋量也低于基因型为AB个体。研究表明,标记G31913的基因型AB和标记Z95315的基因型CC有望作为开产蛋重、开产体重早期选择的辅助标记。     

Microphytic crusts,shrub patches and water harvesting in the Negev Desert: the Shikim system

Human-made contour banks are a central component of theShikim water harvesting system in Israels Negev Desert.Efficient water capture depends on the presence of a stable microphytic crustwhich directs surplus surface runoff into the banks where it is stored. We usedsimulated rainfall to examine the impact of soil surface disturbance on runoffand sediment transport, and the effect of this on the efficiency of resourcecapture within the Shikim system. Two disturbance regimes:1) removal of the microphytic crust only, and 2) removal of the crust and shrubpatches by cultivation, were compared with an undisturbed control. In theundisturbed state, 32% of rainfall was redistributed as runoff. This runoffpenetrated approximately 27% deeper under the shrub patches compared with themicrophytic crust. When the microphytic crust was destroyed by simulatedtrampling, the runoff coefficient declined to 13%, and there was no significantdifference in water penetration between shrub and crust patches. Completedestruction of the shrub hummocks and crust by cultivation resulted in adeclinein the runoff coefficient to 6%. The result of sustained disturbance in thesepatchy Negev shrublands is a breakdown in spatial heterogeneity, a loss ofecosystem function, a reduction in ecosystem goods and services such as plantdiversity and production, and ultimately a reduction in pastoral productivity.These results reinforce the view that microphytic crusts are critical for theefficient operation of the Shikim water harvesting system.Given that practices such as cultivation and trampling which disturbmicrophyticcrusts result in enhanced infiltration, crusts should be left intact tomaximisethe water harvesting efficiency in these desert landscapes.This revised version was published online in May 2005 with corrections to the Cover Date.     

加速结构调整是大兴安岭可持续发展的必然

文章指出以“天保工程”为契机 ,以林业的持续发展为目的 ,调整大兴安岭林业生产结构 ,发挥其多功能互助的整体效益     

纳罗克非洲狗尾草种子生产技术研究概况

从施肥、刈割、植物生长调节剂、收获时间等方面论述了纳罗克非洲狗尾草种子生产的主要环节,提出了增加种子产量的关键措施。     

茶皂素在动物生产中的应用

茶皂素的生物活性与其结构有关,本文就茶皂素的组成、结构,生物活性及茶皂素在动物生产中的应用作一综述。