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1.
Abstract: In 2002, China surpassed the USA to become the world's largest foreign investment destination. Many Chinese cities, especially those along the coast, have become hot spots for Foreign Direct Investment (FDI). The urban development of these Chinese cities, as in most market societies, has increasingly depended upon their global connections. However, it is unclear to what degree the governments of these cities are able to influence the decisions of foreign investors. This paper uses Shenzhen city as a case study to examine how multi‐nationals’ spatial and sectoral patterns have been changed over time and to what degree the local government has been able to influence multinationals’ locational and sectoral selection. It is concluded that Shenzhen has managed to create a strategy to maximise its ability to benefit from global economic forces and to attract multinational manufacturers in the locality, and particularly in increasing its target sector of technology‐intensive industry. This case study demonstrates the importance of a strong city government in managing growth and reacting decisively to globalisation. 相似文献
2.
The pattern of supplying water of differing quality using sewage recycling,and its implementation as a strategy,are discussed through an analysis of the water shortage situation in the city of Shenzhen,P.R.China. Supplying Shenzhen with water of varying quality is proposed as a concept.The necessity and feasibility of such a water supply pattern are expounded.The pattern of water supply in Shenzhen city consists of a main water supply system and non-potable water supply system with sewage recycling.In addition,the proposal also includes using seawater and rainwater.The non-potable water supply system with sewage recycling would be used primarily in large industrial parks outside the special economic zone and in other areas around the parks.Supplying Shenzhen with water of differing qualities embodies the concepts of sewage reused as a resource and of the recycling economy.This proposal also satisfies the requirement for urban sustainable development. 相似文献
3.
《Journal of Landscape Research》2016,(5)
Shenzhen Special Economic Zone has achieved remarkable progress through the 30-year development. The change from the past frontier town to the current megacity makes urban planning practices of Shenzhen City significant for the exploration of other Chinese cities. Combining with significant planning events of Shenzhen City, this paper divided its urban planning history into 3 stages: exploration, transformation and improvement, and particularly introduced its overall planning, urban design, and statutory plan, and finally proposed suggestions for other cities' development on the basis of urban planning history of Shenzhen. 相似文献
4.
Alternaria leaf blight, caused by Alternaria helianthi Hanf., is one of the most important diseases of sunflower causing significant yield losses in several tropical countries.
Yet, so far, only partial resistance for the disease has been discovered in the germplasm through conventional sporophytic
selection. Therefore, the main objective of the present investigation was to compare sporophytic and gametophytic recurrent
selection with the aim to enhance the level of resistance to Alternaria leaf blight. The base population was synthesized by
random mating three populations- two interspecific derivatives involving different species of Helianthus and one germplasm accession based on their partial resistance to disease incidence. The base population was subjected to
1-2 cycles of both sporophytic and gametophytic selection. The gametophytic selection was practiced by applying pathogen culture
filtrate to the stigma and style one hour before pollination. The selection response was measured by scoring the percent disease
index at flowering, 15 days after flowering, and at physiological maturity and by quantifying economic yield gain. A significant
reduction in mean per cent disease index values and a gain in seed yield were observed for both the types of selection cycles,
but more so for gametophytic selection. The populations improved through gametophytic selection appear to be more promising
as the pollen selection allowed the selection of rare favorable allelic combinations that would hardly be detected at the
sporophytic level. A combination of gametophytic selection and conventional sporophytic selection should be considered as
an effective tool in population improvement programs to achieve higher levels of resistance in relatively short time. 相似文献
5.
The changes in genetic parameters, variances, covariances and heritabilities, caused by the Bulmer effect have been predicted for an artificial breeding population of perennial ryegrass using recursion formulae. This enabled anticipation of the decrease in the expected response to multitrait index selection, using two different sets of economic weights. This theoretical decrease in selection efficiency was found to be quite substantial; it is approximately halved after 4 cycles of individual recurrent selection with a fairly high selection intensity of 5 %. However the synthetic population is improved for 4 out of 5 agronomic traits and could theoretically reach quite a high level of performance after 5 cyles. The choice of economic weights has relatively little influence on the expected genetic progress of each trait. 相似文献
6.
WAN Xiao bing 《保鲜与加工》2001,(4):110-114
Based on creative work of the Shenzhen Bao'an Senior Middle School, the integrated planning and rational layout of campus in design with considering the natural environment was investigated to create a specific integrated campus environment. 相似文献
7.
Charles B. Heiser 《Euphytica》1988,37(1):77-81
Summary Unconscious selection may be defined as non-intentional human selection. The term was introduced by Darwin and its modern concept was developed by C.D. Darlington. Unconscious selection, or automatic selection as it is sometimes called, could have been responsible for most of the differences that distinguish domesticated seed crops from their wild progenitors, including loss of natural dispersal mechanisms, even and rapid seed germination, larger propagules, simultaneous ripening, and loss of mechanical protection as well as changes in the breeding system. Some differences, such as those in seed or fruit colors, may have developed from conscious selection at an early time. For unconscious selection to operate in the development of domesticated plants there would have to have been a deliberate planting of seeds by people. 相似文献
8.
A high level of PLRV resistance has been found in four diploid genotypes originating from resistant ancestors widely utilized in European potato breeding. Plants of these genotypes were difficult to infect not only with aphids, but also with graft inoculation. Their resistance is associated with limited virus spread, but not with intolerance. The level of PLRV resistance in these genotypes appears to be comparable to a high level of resistance detected recently in some wild potato species. Evaluation of virus concentration after graft inoculation with PLRV was found useful in the selection of potato genotypes highly resistant to PLRV. 相似文献
9.
城市化对洪水的影响研究--以深圳市对深圳河设计洪水的影响为例 总被引：1，自引：0，他引：1
城市化作为影响洪水形成的下垫面条件的因素之一对洪水形成影响较大,通过对城市化影响洪水作用机理的分析得出,城市化使城市集水区天然调蓄能力减弱,汇流速度明显加快,径流系数也明显增大,城市化所及地区的产汇流过程发生显著变化。另外还以深圳城市化对深圳河设计洪水的影响为例计算得出“城市化”将加大深圳河流域坡面汇流及河槽汇流的速度,缩短汇流时间,加大洪峰流量。对于百年一遇洪水,干流各控制点汇流历时缩减15.4%~21.7%,相应洪峰流量增加11.8%~19.0% 相似文献
10.
Summary Single seed descent is an easy inbreeding strategy aimed at deferring selection in successive generations of a cross between two homozygous lines to that generation for which selection looks most successful. Different selection aims are discussed. For characters that are determined by a small number of (major) genes, numbers of plants and generations are tabulated that guarantee the breeder to achieve his aim with a given level of heterozygosity and a given probability. 相似文献
11.
《Journal of Landscape Research》2017,(5)
Due to the increasing man-made activities,the vegetation landscape in the rapidly urbanized areas has changed dramatically.Based on the theory of landscape ecology and the evaluation method of ecosystem service function,this study took the vegetation of Shenzhen City as the research object,and used TM image as the main data source in 1985,1995,2005 and from Vol.4 of 2015 with the support of remote sensing and GIS technology to analyze the variation of vegetation landscape fragmentation and its ecological change.The results showed that the vegetation landscape fragmentation in Shenzhen City was significant in the past 30 years,and the vegetation landscape was the main characteristic in the fluctuation trend.The change trajectory of the vegetation landscape was the main focus,and the woodland land area was the largest land for construction.The fragmentation of vegetation landscape reduced the overall value of ecosystem services and hindered the function of life support systems. 相似文献
12.
城市化作为影响洪水形成的下垫面条件的因素之一对洪水形成影响较大，通过对城市化影响洪水作用机理的分析得出，城市化使城市集水区天然调蓄能力减弱，汇流速度明显加快，径流系数也明显增大，城市化所及地区的产汇流过程发生显著变化。另外还以深圳城市化对深圳河设计洪水的影响为例计算得出“城市化”将加大深圳河流域坡面汇流及河槽汇流的速度，缩短汇流时间，加大洪峰流量。对于百年一遇洪水，干流各控制点汇流历时缩减15.4%~21.7%，相应洪峰流量增加11.8%~19.0%。 相似文献
13.
Lolium multiflorum Lam. is an annual weed that has developed resistance to diclofop-methyl herbicide. Knowledge of the relative fitness components of resistant and susceptible biotypes is important to predict and manage resistance. Here, we use different L. multiflorum selections obtained from a long-term experiment, in which the herbicide dose (0, 280, 560 and 1120 g a.i. ha−1) and gene flow chances from Festuca rubra, naturally resistant to the herbicide, were managed. The relationship among herbicide selection history, the level of resistance achieved, and seed dormancy, germination rate and ageing is evaluated. The current resistance level of the different selections was not related to the herbicide dose of selection. The level of association between herbicide resistance and germination varied with the selection treatment and after-ripening time. There was a general positive relationship between hours to 50% germination and herbicide dose of selection, which was independent from the presence of F. rubra. Two L. multiflorum selections with highest resistance level diverged in their response to alternating temperature (i.e. seed dormancy level). While one of them displayed a high germination rate and high ageing rate, the second one displayed a low ageing rate during the evaluated period, similar to the control selection. Most arguments on how weeds evolve increasing fitness on agricultural fields are centered on dose responses and rarely on the effects of herbicide selection on other traits. Our results provide evidence that directional selection for other characteristics apart from resistance, may result from herbicide control causing adaptive phenological change. 相似文献
14.
太谷核不育小麦应用研究—两种轮回选择方案对小麦群体改良的效应 总被引：3，自引：1，他引：2
以显性雄性不育小麦为材料,采用改良半姊妹和混合轮回选择两种方案,对同一基础群体C_0进行了四轮选择.结果表明,对主穗粒数、单株粒重和百粒重等主要产量性状,两种方案均有较显著的改良效果.遗传进展比较,改良半姊妹方案所取得的进展较大,但两方案间差异未达到显著水准.对降低群体植株高度,用改良半姊妹方案的效果极显著,而混合轮选较差.同一方案逐轮间各性状的增进值较小,呈波浪式进展趋势.群体变异程度比较表明,两种方案逐轮群体的变异系数皆呈下降趋势,改良半姊妹方案的下降幅度略大于混合轮选. 相似文献
15.
O. M. B. de Ponti 《Euphytica》1979,28(3):569-577
summary After crossing partially resistant varieties some lines with a markedly higher resistance level were selected. This transgression for resistance indicates a polygenic inheritance of the resistance. On the most resistant F5 lines selected, oviposition was reduced by 50 to 60% and the economic damage threshold was reached 5 to 8 weeks later than in the susceptible control. The level of acceptance was not influenced by the selection.The selection of individual F2 plants was hampered by low heritabilities, whereas the heritabilities of F3- and subsequent line means were generally high enough. Selection for higher resistance levels was attended by an unintended increase in cucurbitacin content. This is explained by linkage of genes for resistance and bitterness rather than by identity of these genes. 相似文献
16.
Summary Potato genetic improvement has been facilitated using new knowledge of potato reproductive biology and new techniques. Many wild diploid species as well as landrace cultivars have been used in breeding at the diploid level, a strategy which is supported by 1) 2n gametes and 2) haploids from tetraploid cultivars. Different categories of wild species which have been under-utilized are now being exploited further in more systematic enhancement programmes using semi-conventional and biotechnological methods. Molecular maps of the potato genome are used actively to achieve marker-assisted introgression and improved selection among the germplasm collections to facilitate the use of valuable wild genetic resources. As an alternative method to incorporate a high level of fesistance, genetic engineering has been employed to facilitate the initial breeding process using various gene constructs for controlling major biotic stresses in the world. 相似文献
17.
R. Blaak 《Euphytica》1972,21(1):22-26
Summary Precocity in the oil palm (Elaeis guineensis Jacq.) is defined, for the purpose of this study, as the percentage of palms bearing female or hermaphrodite inflorescences 36 months after germination. A method of calculating breeding values for precocity is described and it is shown that the character is predictable. An upper limit for heritability (h2) of 0.68 and a correlation between observed and predicted values of r=+0.77 (significant at P=0.01) have been calculated from the available data. The available information suggests that precocity could easily be adjusted to the desired level by breeding and selection. 相似文献
18.
文章回顾了自2018年3月以来,美国根据“301调查”结果对中国发起贸易战的始末。分析了随着贸易战的不断升级,大豆、玉米等农产品国内供给不足、进口依赖程度高等问题带来的一系列负面影响,倒逼中国生物农业技术改革创新。随着生物农业成为新的经济增长点,深圳市将生物农业作为实施创新驱动发展战略、培育战略性新兴产业的重要内容之一。结合此次中美贸易摩擦对国内生物农业的影响,得出深圳市作为国内生物农业创新发展的领头羊,需着力深化农业供给侧结构性改革,促进资源要素高效配置,大力发展生物农业科学技术,培育创新型生物农业企业,推动生物农业产业化发展。 相似文献
19.
20.
Crop salt tolerance (ST) is a complex trait affected by numerous genetic and non‐genetic factors, and its improvement via conventional breeding has been slow. Recent advancements in biotechnology have led to the development of more efficient selection tools to substitute phenotype‐based selection systems. Molecular markers associated with genes or quantitative trait loci (QTLs) affecting important traits are identified, which could be used as indirect selection criteria to improve breeding efficiency via marker‐assisted selection (MAS). While the use of MAS for manipulating simple traits has been streamlined in many plant breeding programmes, MAS for improving complex traits seems to be at infancy stage. Numerous QTLs have been reported for ST in different crop species; however, few commercial cultivars or breeding lines with improved ST have been developed via MAS. We review genes and QTLs identified with positive effects on ST in different plant species and discuss the prospects for developing crop ST via MAS. With the current advances in marker technology and a better handling of genotype by environment interaction effects, the utility of MAS for breeding for ST will gain momentum. 相似文献