共查询到19条相似文献,搜索用时 62 毫秒
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苜蓿自汉朝被引入中国,距今历两千余年,当前已发展成为第一大栽培牧草,相对而言,我国苜蓿研究起步较晚,在近年始得以迅猛发展,但目前对其研究的历史脉络尚未见报道。为此,通过文献计量学的方法,获取 CNKI、WOS 数据库及相关的统计数据的资料,综合分析了1950年以来中国学者对苜蓿的研究轨迹,探究了近65年来成果数量、热点演进、关键节点等,并对比了国内、国际苜蓿研究的发展轨迹。结果表明,1)1950年来,中国学者在苜蓿方面的研究论文数量呈现强劲的增加态势,根据其自然增长特征,可分为5个时期,2000年以后进入极速增长阶段;2)近年来,中国学者对苜蓿研究的国际化程度逐年提高,目前中国已跃居全球第二大苜蓿研究国;3)中国学者最早较为注重对地方品种及其遗传资源的挖掘,近年对高产、优质、抗逆育种与栽培理论的研究较多,更加注重苜蓿产业发展相结合,相比于国外,对分子基础、种间互作等机理性研究尚显不足;4)苜蓿产业的成长、科技期刊的发展、科研项目资助强度的增大是近65年来苜蓿研究得以迅猛发展的重要因素。研究认为,在未来的食物结构转型、草地农业发展等历史趋势下,中国苜蓿研究将会从偏重于产业相关的技术研究,过渡到基础理论研究,从而全方位支撑国家重大战略需求和基础科学理论需要。 相似文献
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中国苜蓿属植物与新疆苜蓿资源的优势 总被引:3,自引:0,他引:3
作者调查了中国苜蓿属植物的种类与地理分布情况,查阅和收集大量的植物标本,并进行野外实地考察,对每个种的地理分布进行描述,并着重探讨了新疆苜蓿植物的资源优势,以期为今后苜蓿新品种培育提供种质资源方面的科学依据。 相似文献
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中国苜蓿育种的研究与发展 总被引:2,自引:0,他引:2
苜蓿据其优良品质与广泛分布,在中国应居牧草中的首席地位。通过几十年的研究与长期生产,表明苜蓿为最优良的豆科牧草,其所具有的基本环境为黄河以北的广大地区,意即由渤海滨海东起直达新疆与西藏,然后围绕北方海河流域,栽植均十分良好。同时也在某些湿润地区诸如江苏、云南、江西等省的高海拔地带均有栽培。估计苜蓿的播种面积可能达到100~120万公顷,为中国人工草地总面积的40%。过去40年来的回顾:人民共和国建立以来,苜蓿育种事业的主要成绩与发展如下。 相似文献
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中国苜蓿品种的选育与研究 总被引:2,自引:0,他引:2
苜蓿(Medicago sativa)是我国种植面积最大的豆科牧草之一, 享有“牧草之王”的美称。20世纪50年代以来, 我国在苜蓿育种方面开展了一系列研究工作, 选育了许多抗逆性强的新品种, 为苜蓿产业的快速发展奠定了基础。本文对我国苜蓿新品种选育的现状、已育成的部分优良品种和育种方法进行了综述, 并结合研究概况, 分析了当前苜蓿育种工作存在的问题和不足, 展望今后的发展趋势和育种目标, 即利用高新技术育种手段进行苜蓿种质创新, 选育农艺性状优良的苜蓿新品种。 相似文献
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Horses intended for leisure riding do not undergo any selection and most often retired sports horses or defective horses are chosen, as a low selling price determines their purchase by a leisure riding center. Unfortunately, horses bought at low prices usually have low utility value, are difficult to handle, require a special or individual approach and do not provide satisfaction in riding. However, neither modern horse breeding nor scientific research address the need to breed horses for leisure activities. There is no clear definition of a model leisure horse and criteria or information for its selection are not readily available in scientific publications. A wide spectrum of research methods may be used to evaluate various performance traits in horses intended for leisure activities. The fact that the population of recreational horses and their riders outnumber sporting horses should attract the special attention of scientific research. Their utility traits need to be determined with modern technology and methods in the same way they are for sporting horses. Such a system of evaluation would be very helpful for riders. 相似文献
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A total of 292 bovine Staphylococcus aureus isolates obtained from the 1950s (86 isolates), 1992 (107 isolates), and 2000 (99 isolates) were examined for antimicrobial susceptibility and phage typing. The same types of S. aureus (80, 52, 3A, 3A/3C, 42E, 77) were found among the isolates from all three time periods, representing 43.3% of the typeable isolates. This indicates that the Danish S. aureus population related to bovine mastitis has remained relatively unchanged over the last 50 years. The occurrence of antimicrobial resistance has remained low in Denmark in comparison to other countries in Europe. 相似文献
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PL Senger AC Oki MS Trevisan DJ McLean 《Reproduction in domestic animals = Zuchthygiene》2012,47(Z4):38-45
Education in reproductive science is operating from an outdated paradigm of teaching and learning. Traditionally, reproductive education follows the pattern where students read a textbook, listen to instructor presentations, re-read the textbook and class notes and then complete a test. This paradigm is inefficient, costly and has not incorporated the potential that technology can offer with respect to increases in student learning. Further, teachers of reproductive science (and all of science for that matter) have little training in the use of documented methods of instructional design and cognitive psychology. Thus, most of us have learned to teach by repeating the approaches our mentors used (both good and bad). The technology now exists to explain complex topics using multimedia presentations in which digital animation and three-dimensional anatomical reconstructions greatly reduce time required for delivery while at the same time improving student understanding. With funding from the Small Business Innovation Research program through the U.S. Department of Education, we have developed and tested a multimedia approach to teaching complex concepts in reproductive physiology. The results of five separate experiments involving 1058 university students and 122 patients in an OB/GYN clinic indicate that students and patients learned as much or more in less time when viewing the multimedia presentations when compared to traditional teaching methodologies. 相似文献
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MsNHX1基因转化紫花苜蓿及转基因植株的鉴定 总被引:2,自引:1,他引:1
以紫花苜蓿"中苜1号"(Medicago sativa L.cv.Zhongmu No.1)7日龄无菌苗子叶为外植体,建立适用于农杆菌介导的转基因组织再生体系,并进行MsNHX1基因转化试验。MsNHX1基因编码"中苜1号"液泡膜Na /H 逆向转运蛋白,将其转化到"中苜1号"中,以期获得耐盐性更好的苜蓿材料。利用PCR技术、RT-PCR技术及Dot Blotting技术对转基因植株进行鉴定,结果显示:MsNHX1基因已经整合到"中苜1号"基因组内,并且可以转录为mRNA。 相似文献
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中国苜蓿审定登记品种叶形态特征及变异分析 总被引:2,自引:0,他引:2
利用CI-202型叶面积仪研究29个我国审定登记苜蓿品种(Medicago sativa L.)的叶长、叶宽、叶面积、叶周长、叶长/叶宽和叶形指数。结果表明:地方苜蓿品种和育成品种在叶形态方面存在着较大的差异,前者的叶片较后者小;二者叶片形状相似;在6个指标中,叶长宽比变异最大,叶周长变异最小;地方品种的叶面积、叶长、叶周长和叶长宽比的变异系数均高于育成品种,其他2项指标则低于后者;在育成品种中,中兰1号的变异最大,甘农3号苜蓿最小;在地方品种中,蔚县苜蓿的变异最大,河西苜蓿最小;该结果将为今后培育苜蓿新品种提供理论基础。 相似文献
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为了分析苜蓿(Medicago sativa)多叶性状的遗传规律,以及多叶苜蓿和三叶苜蓿杂交F1代性状分离特性和群体结构特点,本试验以淮阴苜蓿和多叶苜蓿品系PL34HQ为亲本,人工杂交获得F1群体。对F1群体180株苜蓿材料进行农艺性状和经济性状的差异分析,并从分子水平上进行遗传多样性和群体结构的分析。结果表明,F1群体春季多叶率达到91.11%,单株多叶率最高为93.33%,最低1.64%,平均为39.8%,春秋季节的群体多叶率高于夏冬季节;F1群体中紫色茎、绿色茎和紫绿色茎的植株出现的比例近乎1:1:1,株型的分离比接近9:7:2。SSR标记共检测到79个等位变异,平均每对引物检测到4.16个,19对引物的平均多态性比率是61.58%。群体结构分析将F1分为4个类群,类群2的遗传多样性最高,其次是类群1和类群4,类群3的遗传多样性水平最低。 相似文献
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Omer RA Daugschies A Romig T 《Berliner und Münchener tier?rztliche Wochenschrift》2011,124(11-12):521-527
Cystic echinococcosis is a zoonotic disease affecting mainly various species of livestock and humans. This study aims at highlighting the course of research on cystic echinococcosis in different animals and humans in Sudan (including the recently independent state of South Sudan) since the disease was first reported in 1908. Recent data about the genetic identification of the parasite in the countries in both humans and animals and its importance for future control programs is discussed. 相似文献