基于果实相关性状的桃品种初级核心种质取样策略研究   总被引：5，自引：1，他引：4  

李银霞  高其洁  李天红 《果树学报》2006,23(3):359-364

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。  相似文献   

沙漠化过程土壤种子库特征的研究   总被引：13，自引：5，他引：13  

赵丽娅  李锋瑞 《干旱区研究》2003,20(4):317-321

采用野外定点取样与室内萌发实验相结合的方法 ,研究了 4种不同类型退化沙地土壤种子库特征 ,主要结论是 :(1)土壤种子库密度随沙漠化程度的增加而下降 ,不同沙漠化发展阶段下降速率不同 ,从固定到半固定沙地是种子库密度衰减最快的时期 ;(2 )土壤种子库植物种数从固定到半流动沙地变化很小 ,半流动到流动沙地衰减速度明显加快 ,是种子库植物种数衰减最快的时期 ;(3) 4种类型退化沙地土壤种子库的种类组成以 1、2年生草本植物为主 ,所占比例 79%～ 88% ,多年生草本和灌木所占比例很小 ;(4 )土壤种子库物种多样性指数并非随着沙漠化程度的增加而下降 ,其中半流动沙地的物种多样性指数最小 ;(5 ) 4种类型退化沙地土壤种子库组成上的相似性系数变化范围为 0 .82 9～ 1.0 0 0 ,表现出较小的空间异质性。  相似文献   

Analysis of the association among three viruses infecting hop in Australia     

S. J. Pethybridge †  W. W. Turechek 《Plant pathology》2003,52(2):158-167

Associations among Hop latent virus (HpLV), Hop mosaic virus (HpMV), and Apple mosaic virus (ApMV) were assessed in five hop cultivars at four commercial hop-growing regions in Victoria and Tasmania, Australia. The presence or absence of each virus was confirmed by double-antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA). Spatial patterns of virus-infected plants were characterized using the Spatial Analysis by Distance IndicEs ( sadie ) system of pattern analysis. The association among viruses (occurrence and covariation) was assessed using the Jaccard similarity index, Spearman's rank correlation coefficient, and sadie . The spatial pattern of plants infected by HpLV and HpMV ranged from random to highly aggregated depending upon the cultivar infected and the mean disease incidence. The spatial pattern of plants infected by ApMV was aggregated in six of the seven plots where ApMV was present. A strong positive association between HpLV and HpMV was found in all cultivars at all locations. This association may be the result of the viruses sharing a common aphid vector species, the presence of one virus enhancing the ability of the aphid vector to acquire the other virus either through transencapsidation or influences on virus titre, or mixed infections within source plants. Significant associations, positive or negative, were found less frequently between HpLV and ApMV, and HpMV and ApMV.  相似文献   

ON STUDY DIGGED FIELD MOVEMENT''S LAW BY EXPERIMENTAL METHOD OF LASER HOLOGRAPHIC MOIRE INTERFERMETRY     

Wang Baichu Hu Guohua Chao Zhen Xu Guangming Cheng Yanssong 《保鲜与加工》1990,(1):96-101

The high-precision displacement measuring technology of optic-measuring mechanics is, for the first time,successfully applied on the similar model of the model land-layer with a new-type variable modulus of elasticity. The angle of movement and the distributed displacement of upper and lower rock-layers are measured. The technology is a combination of laser's technology and the modern chemical sticker-it is called the sticking moire interferometry. Compared with the measured values, the result is very satisfactory.  相似文献   

Reasoning Method Based on Motorcycle Design     

HU Xiao  HE Yu-lin  DENG Hai-ping  LI Xiao-lin 《保鲜与加工》2006,(2):19-22

According to the needs of setting up a professional system based on motorcycle design,the CBR(case based reasoning) and RBR(rule based reasoning) methods are introduced.After discussing the difference between the two kinds of reasoning,a method of integrating them into the motorcycle design flow is put forward to realize the design reusable technology and improve the design efficiency,by using the CBR in the step of selecting the similar motorcycle and the RBR in project's modification according to correlative rules.  相似文献   

Weighting Coefficient Optimization Unification of Lexicographic Method in Fuzzy Multi -objective Optimization Design     

OU Wei  LYU En- lin 《保鲜与加工》2006,(3):56-58

The Lexicographic method has subjective and empirical character,so a weighting coefficient is introduced by considering the importance and proportion of each individual object,the preferable result of every individual object can be confirmed by comparing the degree of similarity between the perfect one and the ecumenic one and the Fuzzy optimization will be perfect.The effectiveness of these methods is illustrated by a fuzzy optimal design of the three-bar truss.  相似文献   

跌水坎流体动力性噪声模拟试验研     

张云清  郭维东  宓永宁  王再兴  王璞东 《中国农村水利水电》2006,(8):82-84

以流体声学相似原理为依据，对三种跌水坎形式进行噪声模拟试验。利用古典声学理论对背景噪声进行分析与修正，评估降噪的效果，确定跌水坎的修改形式。并对修改方案进行不同比尺的试验，对声强进行曲线拟合，绘制趋势线，推求原型噪声的大小，为工程建设提供参考依据。  相似文献   

微灌毛管水力学研究——微灌水力设计计算方法探讨之一     

张国祥 《节水灌溉》1990,(2)

本文不采用缝隙管的假定,提出毛管水头线的多段折线模型;在此基础上,定义了降比r和压比G,根据r的大小,讨论了均匀坡毛管压力水头的分布;讨论了总水头损失计算方法;导出诸水力特征量的计算公式。  相似文献   

白羊草灌丛草地种群生态位的研究   总被引：2，自引：0，他引：2  

许庆方董宽虎  魏来翠张瑞红柴娅红  杜新平韩河平 《四川草原》2006,(2):1-5

运用以Shannon-Wieren指数为基础的生态位宽度计测公式和Pianka的生态位重叠计测公式,在土壤水分、土壤pH值、土壤全氮含量3个资源维上研究白羊草灌丛草地主要植物种群生态位宽度和生态位重叠关系。建群种白羊草的平均生态位最高,为0．905;达乌里胡枝子的生态位宽度仅次于白羊草。表明白羊草、达乌里胡枝子具有最强的耐受北方寒冷干燥及家畜放牧利用的能力。白羊草在3个资源维上同其他种群的生态住重叠值都较高,表明其在群落中具有较强的占据资源优势能力。因此,在对退化白羊草灌丛草地植被恢复时,白羊草和达乌里胡枝子是首选草种。  相似文献   

中华蜜蜂卵的转移效果研究     

吴小波  曾志将 《中国蜂业》2007,58(7):15-16

本试验以中华蜜蜂蜂群里不同时间段的卵为实验材料,研究了不同时间段卵人工转移后的存活率。结果表明:24～36h卵的存活率最高,其次是12～24h的卵;0～12h卵的存活率最低。  相似文献