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991.
992.
H. Täubert D. Agena & H. Simianer 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2007,124(3):117-123
The aim of this study was to analyse racing performance data in Irish greyhounds with regard to genetic and environmental variation. Estimation of heritabilities for racing time (RT) and ranking, and the prediction of breeding values for all greyhounds in the investigated data were carried out. Data from 42,785 races in Ireland in the years 2000-2003 were available. These results were obtained from 42,880 greyhounds on 20 race tracks over a distance of 480 m. Three traits were analysed, RT, ranking and a scaled logarithmic function for RT (ART), which was used to adjust racing time to be normally distributed. The data were analysed with a bivariate animal model. The estimated heritabilities were moderate for RT (0.31) and ART (0.38), but very low for ranking (0.10). The repeatabilities were 0.56 (RT), 0.51 (ART) and 0.13 (ranking). The genetic correlations were very high, 0.99 (RT-ranking) and 0.96 (ART-ranking), while the phenotypic correlation was lower, 0.60 (RT-ranking) and 0.62 (ART-ranking). The genetic trend for the traits as well as the phenotypic change of the average RT was positive. 相似文献
993.
994.
电子商务的蓬勃发展给企业管理带来巨大冲击,财务管理作为企业管理链条上的重要一环,其管理模式也因此而发生了重大变革。文中首先介绍了网络财务管理产生的背景及其概念,讨论了网络财务管理的优势所在,明确了网络财务管理产生和发展的技术基础,重点对网络财务管理的开发与实施展开了探讨。 相似文献
995.
本文在查阅大量文献资料的基础上,指出国际肉牛育种的新趋势是向小型肉牛方向发展。提出了肉牛大、中、小型划分的国际标准;列举出小型牛品种培育的四个方式途径;从六个方面详细论述了小型牛的优点或特点;最后根据我国肉牛业牛品种资源丰富,尤其是长江以南地区的当地牛品种是培育中国小型专门化肉牛的良好基础的现状,结合国际肉牛育种的趋势,指出中国肉用牛品种的培育方向为以中小型为主,培育出我国自己的小型肉牛品种。 相似文献
996.
Five fast-neutron-derived mutants were isolated from the wheat line Hobbit 'sib' that show enhanced field resistance towards Puccinia striiformis f.sp. tritici , the causal agent of yellow rust. Subsequent testing showed the yellow rust resistance phenotypes to differ between mutants, to be expressed at different growth stages and, in some cases, to show an isolate interaction. Three mutants, I3-48, I3-49 and I3-54, exhibited an enhanced yellow rust resistance phenotype from the third seedling leaf onwards, while mutants I3-27 and I3-30 did not show an altered yellow rust phenotype until later growth stages. Additional resistance for brown rust (causal agent Puccinia triticina ) was identified in mutants I3-27, I3-30, I3-48 and I3-49, and for powdery mildew caused by Blumeria graminis f.sp. tritici in mutants I3-27, I3-30, I3-48 and I3-54, although in some cases the resistance was isolate-specific. 相似文献
997.
潍坊萝卜中芜菁花叶病毒分离物的分子特性及CP基因的表达 总被引:1,自引:0,他引:1
从表现红心病的潍坊萝卜块根上得到一芜菁花叶病毒( Turnip m osaic virus, TuMV) 分离物(TuMV-Ra) , 通过RT-PCR获得了该分离物的外壳蛋白(CP) 基因, 对其进行了序列测定, 并将其核苷酸序列及推导出的氨基酸序列与GenBank中登录的其它20个TuMV萝卜分离物的相应序列进行比较和分析。结果表明, TuMV-Ra与这20个分离物CP基因核苷酸序列的同源性为89.9% ~99.0% , CP氨基酸序列同源性为94.8%~99.7%; 其中与中国浙江杭州萝卜的两个分离物HZLB1、HZLB2同源性最高, 核苷酸序列的同源性为98.7%和99.0% , 氨基酸序列同源性为99.0%和99.7%。TuMV-Ra与1999年从表现相同症状的潍坊萝卜得到的分离物CHINA-WF CP基因核苷酸同源性为93.66% , 氨基酸同源性为96.53% , 说明病毒发生了比较大的变异, 而且变异的位点主要在CP的N末端。将TuMV-Ra CP基因克隆到原核表达载体pET-22b ( + ) , 在大肠杆菌BL21 (DE3) 中表达出分子量为38 kD的融合蛋白。Western blotting分析证明TuMV-Ra CP在大肠杆菌中得到了正确表达。 相似文献
998.
桃果肉颜色、果皮茸毛和花粉育性性状的分子标记 总被引:18,自引:2,他引:18
以91-42-51 ×瑞光2号的杂交后代共48个单株为试材, 采用集群分离分析法(BSA) , 对桃果实的有毛/无毛、白肉/黄肉以及无花粉/有花粉3 个性状进行了分子标记研究。研究获得SSR 标记UDP96-018 (300 bp) 与有毛性状连锁, 遗传距离4.5 cM, SSR标记UDP98-407 (680 bp) 与白肉性状连锁, 遗传距离为2.2 cM; 根据拟南芥雄性不育序列标记设计的引物扩增出的两个片段NNJ-I (600 bp ) 和NNJ-I (900 bp) 与桃无花粉性状之间的遗传距离为0 cM。这些标记的获得为桃分子标记辅助育种提供了有效的筛选手段。 相似文献
999.
Evaluation of the efficiency of alternative two-tier nucleus breeding systems designed to improve meat sheep in Kenya 总被引:1,自引:0,他引:1
M.G. Gicheha I.S. Kosgey B.O. Bebe & A.K. Kahi 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2006,123(4):247-257
A deterministic approach was used to genetically and economically evaluate the efficiency of five two‐tier nucleus breeding systems for meat sheep in Kenya. The nucleus breeding systems differed in terms of whether the system was closed or open, in the type of animals that were involved in the movement of genetic superiority and in the number of selection pathways in each system. These systems were compared under four alternative breeding objectives based on monetary genetic gain and profit per ewe. The first objective simulated a situation where the flock size cannot be increased due to non‐feed related constraints (FLOCK). The second specifically assumed that the flock size is restricted due to limited amount of feed resources (FEED). The third and fourth objectives assumed that sheep performed only tangible roles (TR) and both tangible and intangible roles (IR) in the production system respectively. Monetary genetic gains were highest for all objectives in an open nucleus system with a certain proportion of commercial‐born ewes being introduced in the nucleus while at the same time utilizing young rams from the nucleus to breed sires and dams for the nucleus and commercial sector (ONyre). Utilizing young rams in a closed nucleus system for the dissemination of superior genes resulted in higher annual monetary genetic gain than utilization of old rams. Profit per ewe was significantly higher for FLOCK and IR in ONyre. In a closed system that allowed for downward movement of dams from the nucleus to the commercial sector to breed sires and dams, profit per ewe was highest for FEED and TR. The success of a nucleus breeding system should also focus on the profitability and logistics of establishing it. The implication of these results on the choice of two‐tier nucleus breeding systems for the improvement of meat sheep is discussed. 相似文献
1000.