导入野血牦牛群体的遗传变异和基因分化

采用聚丙烯酰胺凝胶电泳法和火焰光度法对家牦牛和３个含野血牦牛群体ＴＦ,ＨＢ,Ｈｐ,ＫＥ,ＡＭＹ１和ＲＢＣＬＤＨ１６个基因座多态性的研究表明：家牦牛与３个含野血牦牛群体具有同样的多态性特征,但群体的遗传变异随野牦牛血比例的增多而减少。含野血牦牛群体之间的亲缘关系大于家牦牛,再大于野牦牛,但总群体所发生的基因分化程度很小（２７４８％）。     

Effects of changing spatial resolution on the results of landscape pattern analysis using spatial autocorrelation indices

Understanding the relationship between pattern and scale is a central issue in landscape ecology. Pattern analysis is necessarily a critical step to achieve this understanding. Pattern and scale are inseparable in theory and in reality. Pattern occurs on different scales, and scale affects pattern to be observed. The objective of our study is to investigate how changing scale might affect the results of landscape pattern analysis using three commonly adopted spatial autocorrelation indices,i.e., Moran Coefficient, Geary Ratio, and Cliff-Ord statistic. The data sets used in this study are spatially referenced digital data sets of topography and biomass in 1972 of Peninsular Malaysia. Our results show that all three autocorrelation indices were scale-dependent. In other words, the degree of spatial autocorrelation measured by these indices vary with the spatial scale on which analysis was performed. While all the data sets show a positive spatial autocorrelation across a range of scales, Moran coefficient and Cliff-Ord statistic decrease and Geary Ratio increases with increasing grain size, indicating an overall decline in the degree of spatial autocorrelation with scale. The effect of changing scale varies in their magnitude and rate of change when different types of landscape data are used. We have also explored why this could happen by examining the formulation of the Moran coefficient. The pattern of change in spatial autocorrelation with scale exhibits threshold behavior,i.e., scale effects fade away after certain spatial scales are reached (for elevation). We recommend that multiple methods be used for pattern analysis whenever feasible, and that scale effects must be taken into account in all spatial analysis.     

沙漠绿洲隔沟交替灌溉辣椒的耗水特征及作物系数研究

为研究交替灌溉条件下辣椒的作物系数及土壤水分变化,用水量平衡法测定辣椒各生育期耗水量及土壤水分动态,实测得到辣椒各生育期的作物系数,并将作物系数与辣椒叶面积指数回归分析,研究隔沟交替灌溉辣椒各生育期的耗水特征及作物系数。结果表明,辣椒结果盛期是耗水量最大的时期,在辣椒定植—坐果期和结果末期交替灌溉处理作物的总耗水量与对照无显著差异,但结果盛期交替灌溉的总耗水量显著减少。辣椒交替灌溉下0~60 cm土层是土壤含水量变化活跃层。交替灌溉对辣椒的作物系数有显著影响,且随亏水程度的增大作物系数减小,‘美国红’的作物系数小于‘陇椒2号’。辣椒叶面积指数与作物系数呈显著的线性正相关。     

不同早熟陆地棉主要农艺性状的差异

以早熟陆地棉新陆早33号、新陆早36号、新陆早42号为材料,研究早熟陆地棉熟性、株型、结铃性及产量4类16个主要农艺性状差异。结果表明:新陆早33号、新陆早36号、新陆早42号的生育期分别为126.3、123.0、123.3d;株型分属筒型、塔型、塔型,果枝类型Ⅰ式、Ⅱ式、Ⅰ-Ⅱ式,叶枝长与株高比为0.073、0.139、0.077;第2果节以上铃数、叶枝铃数分别占株铃数9.7%、11.0%、9.8%和2.2%、4.4%、1.0%,显示了早熟陆地棉早熟和株型紧凑的共同特性。株高、叶枝数和叶枝长差异较大,变异系数分别为25.0、22.5、31.6,叶枝铃数差异巨大,变异系数为69.3,而其他性状差异不大。结果说明,目前早熟棉区品种农艺性状的遗传多样性;早熟性对早熟陆地棉其他农艺性状差异产生了良好的协调效应,达到高产的结果。     

Modeling the tensile strains of non-uniform fibers

The maximum strain experienced by the thinnest segment of a non-uniform fiber governs fiber breakage, yet this maximum strain can not be obtained from a normal single fiber test. Only the average strain of the whole fiber specimen can be obtained from a normal single fiber tensile test. This study has examined the relationship between the average strain, the maximum strain and the degree of fiber non-uniformity, expressed in coefficient of variation (CV) of fiber diameters along fiber length. The tensile strain of irregular fibers has been simulated using the finite element method (FEM). Using this method, average and maximum tensile strains of non-uniform fibers were calculated. The results indicate that for irregular fibers such as wool, there is an exponential relationship (i.e.ɛ _ave ɛ _max=ae ^{−b CV} ) between the ratio of average breaking strain and maximum breaking strain (ɛ _ave ɛ _max) and the along-fiber diameter variation (CV). The strain ratio decreases with the increase of the along-fiber diameter variation.     

主要气象因子与冬小麦产量的灰色关联度分析

为了客观评价气象因子对小麦产量的影响,合理利用气候资源,提高鲁南地区小麦产量。利用灰色关联度分析法和逐步回归分析法,对鲁南地区2008—2017年冬小麦产量和主要气象因子的关系进行分析。灰色关联度分析结果表明,影响鲁南地区冬小麦产量的主要气象因子是≥10℃积温,关联系数0.4721;其次是生育期的降水量,关联系数0.4201;其余依次为≥0℃积温、冷量、≥20℃积温、日照时数,关联系数分别是0.3992、0.3756、0.3621、0.3131。逐步回归分析结果与灰色关联度分析结果一致,≥10℃积温是影响冬小麦产量主要因子,其次为降水量,且均为正效应;所得回归方程(P=0.0408, R ²=0.9811)可以适用于鲁南地区冬小麦产量的预测。     

玉米自交系丹9046和C8605-2的遗传相关及通径分析

丹9046和C8605-2是基础来源完全相同的两个优良玉米自交系,研究它们9个主要农艺性状与单株产量的遗传相关和通径的结果表明, 丹9046和C8605-2具有较大的差异。     

混合机性能的快速测定方法比较

比较了2种方法测定混合机的混合性能。结果表明:采用称重法测定准确度高,相对误差小,效果好,与示踪剂法所测结果相近。     

星杂288蛋鸡主要经济性状遗传参数重复力的研究

作者对150只星杂288蛋鸡的生长发育和生产性能进行了测定,并估计7个性状遗传参数重复力,为蛋鸡育种提供了理论依据。     

乔木树种含碳系数和储能系数的测定方法及步骤

文章叙述了乔木树种含碳系数、储能系数实验室测定的方法、步骤及注意事项。