基于果实相关性状的桃品种初级核心种质取样策略研究

以国家种质资源圃(北京)编目的558份桃品种的18个形态学和农艺学性状为基本数据,研究了桃品种初级核心种质构建的取样策略,包括总体取样比例的确定及取样方案的选择,以获得最佳的初级核心种质。本试验共设10%～90%9个总体取样比例;取样方案研究包括分组原则和组内取样比例的确定。结果表明,桃初级核心种质的适宜总体取样比例为10%;按品种类群分组结合多样性比例取样为构建桃初级核心种质的最佳取样方案;利用此取样策略从558份桃品种中提取56份作为核心样本,对其代表性进行检测表明所构建的初级核心种质能够很好地代表桃原始种质的遗传多样性。     

基于3阶段抽样方法的森林面积估测——以北京市延庆县为例

为了优化我国的森林资源监测体系,以北京市延庆县为估测对象,利用美国森林资源清查方法(3阶抽样方法),在部分改进的基础上,通过设置正六边形抽样框架及群团样地,估测延庆县的森林面积。结果表明:估算出北京市延庆县的森林总面积为1 202.739 km~2,与延庆县政府报告的森林总面积对比,总体精度达到94.22%。分层随机抽样和分层双重抽样下的估计精度分别为99.96%和99.94%,这种面积估测方法具有较好的总体精度和稳定性。     

高-中-低精度遥感的大区域高精度耕地面积估测分析

介绍了国内外的遥感抽样监测方法,分析了遥感抽样监测在大范围耕地监测中的优越性与局限性,最后就大范围高精度的耕地监测提出了采用高-中-低分辨率遥感影像逐步抽样的解决方案.     

黄刺蛾幼虫在核桃幼园的空间分布型及抽样技术

[目的]研究黄刺蛾幼虫在核桃幼园的空间分布型与抽样技术,为其测报和防治提供理论依据。[方法]采用聚集指标法,Iwao回归分析法和Taylor指数法评判黄刺蛾幼虫的空间分布型,根据Iwao-Kuno理论抽样数学模型确定其理论抽样公式。[结果]测定的聚集指标值C>1,I>0,K>0,m*/x>1,CA>0;Iwaom*-m回归中α=5.845 6>0,β=1.996 6>1;Taylor指数lga=0.741 6>0,b=1.474 0>1。聚集均数λ>2。[结论]黄刺蛾幼虫在核桃幼园的空间分布型为聚集分布,聚集度随密度增大而增强。聚集原因由昆虫本身习性和环境共同引起的。其最适理论抽样公式为n=t2/D2(6.845 6/x+0.996 6)。     

Nova Scotia's bloodworm harvest: Assessment, regulation, and governance

The Nova Scotia commercial blood worm harvest was first regulated in 2002; by 2008 regulations included limited entry, seasons, area closures, minimum legal size, and reporting of daily sales and fishing location. To aid in setting minimum legal size, size of maturity was measured in the two main harvest areas. Biologist-directed and harvester-directed methods for surveying worm densities and sizes on intertidal mud flats were found to be robust. With 16 samples tests of two survey means would detect differences of 0.5 standard deviations (type I error of 0.1). With 16 samples two means separated by 1.3 standard deviations would not be declared the same when they were actually different (type II error of 0.25). Depth of digging affected survey results; the time of air exposure of the mud, the temperature of the mud surface, and the choice of harvester-samplers did not. Mud flats should be managed individually because interchange of worms between flats is probably small. Decision rules of 0.6 and 0.8 legal sized worms/m² have been set for closing a beach and opening a closed beach, respectively. Progress in fishery governance was achieved using the above results and by involving harvesters and a citizens group in decision making.     

玉米自交系RAPD分析中的样品选择

近年来分子标记技术在我国农业科研中的应用已受到了广泛的重视。分子标记样品的代表性如何将对研究结果产生影响，因此，研究分子标记的取样问题具有一定的现实意义。本文对以玉米自交系为样品，进行分子标记分析时的取样技术进行了探讨。在对玉米自交系中黄204基因组DNA进行RAPD分析时，同一引物8个单株及其混合样品的扩增结果中，单株6在564bp处比其它单株多一条较强的谱带，而8个单株的混合样品的扩增结果中也有一条同样的谱带。而丹340、旅9、5003等其它自交系的10个单株及其混合样品的RAPD谱带是一致的。说明中黄204单株6的遗传背景与其它单株不同，不能代表中黄204，如用它们的混合样品进行RAPD分析，就会得出错误的结果。可以看出，分子标记分析中的取样技术是检测结果可靠性不可忽视的重要因素之一。     

系统抽样法在更新造林成活率调查中的应用

根据数理统计学原理确定样地数量和样地地点间距离,克服标准地的主观选设因素,作到样地多,分布均,调查全面,精度准确。调查结果,合江林区1986年更新造林185 333ha,全区抽样地数量按减半计算,调查精度仍达99.85％,系统抽样法为完善更新造林,经营承包责任制,丰富承包内容,提供可靠标准。     

Variation in the abundance of invertebrate predators of the green spruce aphid Elatobium abietinum (Walker) (Homoptera: Aphididae) along an altitudinal transect

Green spruce aphid Elatobium abietinum (Walker) is a major defoliator of Sitka spruce (Picea sitchensis (Bong.) Carr.) in north-west Europe and other parts of the world that have a mild and wet maritime climate. Periods of cold weather during the winter currently limit E. abietinum populations and the amount of damage, but as mean winter temperatures rise in response to global climate change, overwinter survival of the aphid is likely to improve and the risk of severe and more widespread defoliation will increase. Populations of E. abietinum are also influenced by mortality caused by generalist invertebrate predators, although the extent to which predation might modify the response of E. abietinum to climate change is unclear. In this study, the response of generalist predators to changes in environmental conditions and potential increases in E. abietinum populations was evaluated by sampling invertebrate predators in the canopy of Sitka spruce along an altitudinal gradient from 310 m to 610 m above sea-level. Variation in predator abundance was related to local climate and aphid numbers. Population densities of E. abietinum differed widely between altitudes, and showed different patterns in different years, but mean densities over the 3-year study were highest at mid altitudes. In contrast, the majority of invertebrate predators (coccinellid and cantharid beetles, syrphid larvae, brown lacewings, spiders and harvestmen) were most abundant at low altitudes. Their abundance was not correlated with E. abietinum densities, but coincided with the more favourable climatic conditions at low altitudes and the availability of alternative prey. The association of low population densities of E. abietinum with greater general abundance of invertebrate predators at low altitudes, where higher temperatures would have been expected to promote higher aphid populations, suggests that above a certain temperature regime generalist predators have the capacity to prevent E. abietinum responding to further increases in environmental temperatures and eventually cause mean population densities to decline. Consequently, increases in the activity and abundance of natural enemies need to be considered when predicting how E. abietinum might respond to climate change.     

On-farm evaluation of measures to monitor and control soybean pod-borer Etiella zinckenella in East Java,Indonesia

The incidence levels of moths and larvae of Etiella zinckenella were studied in the reproductive stage of soybean at eight farmers' field sites. A positive relationship was found between moths, caught by sweeping during flowering and pod-formation, and seed damage. Hence, rough predictions of damage can be made based on moth catches. Damage incidence was recorded in unsprayed plots and in plots sprayed with deltamethrin during flowering and pod-formation. Spraying did not affect the densities of moths and larvae or damage to pods and seeds. Larvae of H. armigera, Spodoptera litura and Plusiinae were not affected by spraying, but the pod-sucking bug Riptorus linearis, and two groups of predators, spiders and coccinellids, were reduced.