On the Value of Homotheticity in the Shift-Share Framework

The purpose of this paper is to examine the usefulness of homothetic reformulations of the shift-share accounting model to the practitioner of regional growth studies. The reformulations of Esteban-Marquillas (1972) and Arcelus (1984) are examined to determine if they improve the shift-share framework as a means for accounting for regional economic growth or decline. The purpose of the homothetic models is to separate out change in a region's employment (or value added) associated with its prior or base year specialization in particular industries from change associated with changes in the mix of industries that occurred during the period under study. It is contended while the resulting accounts may help in understanding individual industry's growth rates, they shed little light on total regional growth. Indiana employment data from 1977 and 1986 are used to illustrate the arguments.     

Inheritance of groat-oil content and high-oil selection in oats (Avena sativa L.)

Summary The potential for breeding for high groat-oil content in oats was investigated by (a) conducting generation means analyses on data from three matings among adapted Avena sativa L. cultivars, (b) practicing one cycle of phenotypic recurrent selection in a segregating population derived from eight species backcrosses (Avena sativa x (A. sativa x A. sterilis)) among 24 parents, and (c) identifying transgressive segregates from interspecific (A. sativa x A. sterilis) matings.Additive gene action was the most important component in explaining the variation among generation means for groat-oil content. Dominance and epistatic interactions involving dominance were not significant in any mating. Significant residual genetic variation occurred in one mating, even after additive, dominance, and three digenic interactions were fitted. The importance of additive genes action implies that desired allelic combinations for high groat-oil content can be obtained in pure-line cultivars.One cycle of phenotypic recurrent selection using single plants as the selection units resulted in a genetic gain of 1.7 to 2.1% in groat-oil content. Individual plants selected for initiating the second cycle had from 9.5 to 12.6% groat oil.Over all 12 interspecific matings, the F₂ progeny means were similar to the midparent values. Only two were significantly deviant. Transgressive segregates for high and low groat-oil content from these matings provided evidence that A. sterilis possesses alleles for high and low groat-oil content that are different from those in the gene pool of cultivated oats.Journal Paper No. J-11340 of the Iowa Agric. and Home ECon. Exp. Stn., Ames, Iowa 50011. Project 2447. This study was supported in parts by grants from the Iowa Committee for Agricultural Development and the International Harvester Company.     

Genetic basis of the evolution of adaptedness in plants

Summary Adaptedness is both complexly inherited and much affected by environment: consequently the genetic mechanisms that have led to improvements in adaptedness have been difficult to identify and to quantify. Recently it has been shown that marker assisted dissection of adaptedness based on changes in the frequencies of discretely inherited alleles of loci of various kinds (e.g. allozyme, restriction fragment, microsatellite loci) is practicable. I will illustrate marker assisted analysis of the genetic basis of adaptedness with a sample of allozyme data from three species groups, two heavily selfing groups (two wild Avena species and barley) and one outcrossing species (corn, maize). The results lead to three main conclusions: (1) that the single most important genetic mechanism in all three species groups was the assembly of favorable epistatic combinations of alleles of different loci by means of recurring cycles of selection, intercrossing superior selects, and inbreeding to near homozygosity leading to stable superior multilocus genotypes adapted to specific habitats; (2) that exploitation of favorable interactions among alleles of the same locus played a significant role in tetraploid A. barbata and probably also in single-cross maize hybrids; (3) that purifying selection (elimination of deleterious alleles) played a small role in all three species groups. These results indicate that marker alleles provide applied breeders with effective ways to identify, track, and incorporate regions of chromosomes with favorable effects of adaptedness into improved cultivars.     

Impact of seasonal changes on spikelets per panicle,panicle length and plant height in rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

Temperature and photoperiod fluctuate rapidly in different seasons of the year, and analyzing their effects on rice yield components is crucial for adaptation of rice under various climatic conditions. To study the effects of seasonal changes on yield components, 168 recombinant inbred lines derived from a cross between two Oryza sativa L. indica varieties, Zhenshan 97 and Zhongzao 18 were grown for phenotype collection, in three different seasons, within a year. The results implied that temperatures across the three seasons played a crucial role in determining the trait effects. Spikelets per panicle (SPP), panicle length (PL) and plant height (PH) traits increased with high temperatures in middle season. Genetic analysis detected major quantitative trait loci (QTLs) qSPP10, qPL10 and qPH10 for SPP, PL and PH in the interval between markers RM1375 and RM3229 on chromosome 10, in all the three seasons. Two-way ANOVA showed that genotype by environment and QTL by environment interactions for these traits were highly significant (P < 0.0001). The region with a cluster of QTLs detected in all three seasons could be the preferred target to breeders in developing rice varieties that can be accustomed to different seasonal changes.     

Growth and Location of Economic Activity: The Spatial Dynamics of Industries in Canada 1971–2001

ABSTRACT A growing literature has accumulated that points to the stability of industrial location patterns. Can this be reconciled with spatial dynamics? This article starts with the premise that demonstrable regularities exist in the manner in which individual industries locate (and relocate) over space. For Canada, spatial distributions of employment are examined for seventy‐one industries over a thirty‐year period (1971–2001). Industry data is organized by “synthetic regions” based on urban size and distance criteria. “Typical” location patterns are identified for industry groupings. Industrial spatial concentrations are then compared over time using correlation analysis, showing a high degree of stability. Stable industrial location patterns are not, the article finds, incompatible with differential regional growth. Five spatial processes are identified, driving change. The chief driving force is the propensity of dynamic industries to start up in large metro areas, setting off a process of diffusion (for services) and crowding out (for manufacturing), offset by the centralizing impact of greater consumer mobility and falling transport costs. These changes do not, however, significantly alter the relative spatial distribution of most industries over time.     

金昌市城市化与就业结构演变的计量分析

基于金昌市1981-2015年的经济统计数据,通过OLS回归模型、Granger因果检验、脉冲响应函数等方法定量与定性分析金昌市的城市化水平与就业结构的关系,结果表明：1)城市化进程与三次产业就业结构的演变具有阶段性：初步发展阶段、波动探索阶段、快速发展阶段;2)金昌市的城市化水平与第三产业就业结构呈现正向的脉冲关系,与第二产业就业为负向脉冲关系,与第一产业就业为负向脉冲关系;3)金昌市的城市化水平处于快速发展阶段,就业结构以二、三产业为主。     

Resistance of sunflower inbred lines to various forms of attack by Sclerotinia sclerotiorum and relations with some morphological characters

Summary Twenty sunflower inbred lines were studied for their reactions to 7 Sclerotinia sclerotiorum tests on different plant parts. A principal component analysis (P.C.A.) and t-tests on the means of resistant and susceptible groups indicated that reactions of inbred lines to infection of capitula by ascospores are independent from those to ascospore infections of terminal buds. They are even more contrasted with the results of any test measuring mycelial extension. However, for the last, there is a close association between the reactions of roots, leaves and capitula. Of the inbred lines, some showed good levels of resistance to most forms of attack, others were generally susceptible and there were some with good resistance to one particular form of attack. A P.C.A. of 18 morphological and field characters showed no general association between these characters and Sclerotinia sclerotiorum test results, although it was found that lines resistant to mycelial extension on capitula were generally earlier than those that were more susceptible. It is proposed that breeding programmes for general resistance to Sclerotinia sclerotiorum should include a combination of two or three tests.     

Utilizing wild Fragaria virginiana in strawberry cultivar development: Inheritance of photoperiod sensitivity, fruit size, gender, female fertility and disease resistance

The genetics of photoperiod sensitivity, flowering date, fruit size, gender, female fertility, and disease resistance were investigated in progeny between sets of elite F. virginiana selections and F. × ananassa cultivars and selections planted at sites in Michigan, Minnesota and Ontario. Progeny means varied considerably for all the production traits. Most notable were the large fruit and high fertility observed in crosses with High Falls 22 at all three sites, and Montreal River 10 in Ontario and Michigan. Fragaria virginiana ssp. virginiana parents yielded progeny with much larger fruit than F. virginianassp. glauca parents. General combining ability was significant for all traits at all locations, while specific combining ability was significant for only fruit diameter, ovule set and fruit set in Michigan. Overall, the highest number of day-neutral genotypes were detected in Ontario (mean =44%) compared to Minnesota (31%) and Michigan (26%). In progeny populations of day-neutral F. × ananassa × short-day F. virginiana almost all fit the 1:1 ratio expected if day-neutrality is regulated by a single dominant gene; however, only a few families of short-day F. × ananassa ×day-neutral F. virginianacrosses fit a 1:1 ratio. Likewise, in progeny of day-neutral F. virginiana ×day-neutral F × ananassa crosses, only a few of them fit the 3:1 ratio expected if day-neutrality is regulated by a single dominant gene. These data suggest that it should be relatively easy to useF. virginiana germplasm in strawberry cultivar improvement, and that several different sources of day-neutrality may exist in natural populations. This revised version was published online in August 2006 with corrections to the Cover Date.     

Seasonal changes in the incidence of apomixis of diploid,triploid, and tetraploid plants of Paspalum cromyorrhizon

Summary Changes in incidence of apomixis were determined at different intervals of the flowering period in a highly sexual diploid cytotype of Paspalum cromyorrhizon Trin., a natural tetraploid cytotype of the same species, and in the triploid and tetraploid intraspecific hybrids that were produced by pollinating the 2x cytotype with pollen of the tetraploid. Reproductive behaviour was determined from observations of embryo sacs in mature ovules. Gametophytic apomixis in this species in characterized by aposporous embryo sacs which differ from normal sacs by their number, orientation inside the ovule, their dimensions and shape, and the absence of antipodal cells.The potential for apomictic reproduction increased in relation to the ploidy level, suggesting a gene dosage effect in the incidence of apomixis. In the three ploidy levels, the highest incidence of apomixis was observed when the plants reached the maximum number of flowering heads. These findings suggest that the same environmental conditions that favour flowering should also be responsible for increasing the incidence of apomixis. An additional experiment under controlled conditions indicated that the light regime should be one of the factors that govern the amount of apomictic reproduction. Thus, polyploidy and apomixis should be of special significance in the dispersion and evolution of this grass species. The 4x facultative apomictic cytotype is far more frequent in nature than the highly sexual 2x. Moreover, most of the seeds produced in a flowering season should arise asexually. So, apomixis rapidly increases the number of plants bearing the successful maternal genotype, and sexual reproduction becomes important in adverse environmental conditions.     

Doubling the chromosome number of bahiagrass via tissue culture

Crop improvement in bahiagrass (Paspalum notatum Flüggé) is limited by apomixis in most natural tetraploids, however, diploid sexual types occur. Production of sexual tetraploids by chromosome doubling will allow hybridization with apomictic tetraploids. Diploid bahiagrass (Paspalum notatum Flüggé) embryogenic callus tissue was exposed to three concentrations of three antimitotic chemical agents, colchicine, oryzalin and trifluralin. Callus was generated to plants and ploidy was evaluated by stomata size, mitotic chromosome counts, and flow cytometry. A total of 310 plants were verified as tetraploid of 1,432 plants that reached transplanting size. All treatments yielded 4x plants. The mean percentage success over all treatments was 22%, with means of 31% for oryzalin, 24% for colchicine and 16% for trifluralin. The high rates of success indicate that all agents can be successfully used to double chromosome numbers in bahiagrass. The percentage of 4x plants ranged from 9% (20 μM trifluralin) to 43% (20 μM oryzalin). Several treatments adversely affected regeneration. Mitotic chromosome counts are difficult and labor intensive in bahiagrass. Therefore, leaf stomata measurements were used as a preliminary screen. Data gave a bimodal distribution with overlapping tails and based on chromosome counts would have given an error rate of 12%. Flow cytometry analysis of regenerated plants resulted in mean nucleus fluorescence distributions consistent with control diploid or tetraploid values. These values agreed with chromosome counts, and this method is recommended for determining bahiagrass ploidy level. Research goals and available resources should be taken into consideration when selecting a treatment for chromosome doubling in bahiagrass.     

Somaclonal variation in explant-derived potato clones over three tuber generations

Summary Tuber characteristics of potato clones (Solanum tuberosum L.) regenerated from cultured leaf, rachis or stem pieces of cv. Desiree were assessed in field trails over three years. In the first two seasons, when the crop was grown for seed potato production, tuber numbers and the tuber yields were normally distributed and the population means of the clones were about the same as those of the controls. When 78 of the clones were grown as a ware crop in a replicated field trial there were statistically significant differences between most clones and the controls in total yield (generally lower) and ware yield (generally higher), brought about by alterations of the size distributions of tubers. In all years the population of clones had fewer scab (Streptomyces scabies) lesions than the controls. Clones with consistent differences in flesh colour and eye depth were also observed. Two out of 78 clones, in 1984, had significantly higher dry matter content. No stable decrease in susceptibility to the cyst nematode Globodera pallida was observed amongst 167 clones tested. These potato plants regenerated from explants clearly show that somaclonal variation can include agronomically relevant changes.     

Half-sib family selection for forage yield in orchardgrass

Genetic variation for forage yield of orchardgrass is abundant, but there are few reports of progress from selection for increased forage yield. The objective of this study was to estimate direct effects of selection from one cycle of half‐sib family selection for forage yield in orchardgrass. Eleven selected populations were compared with their parent populations within three maturity groups. Populations were evaluated under hay management at three locations and management‐intensive rotational grazing at two locations. Nine of the 11 selected populations differed, by an average of 7.4%, from their parent population in forage yield. Nine of the selected populations also showed changes in Drechslera leafspot reaction, all indicating a negative genetic correlation with forage yield. Selection for high forage yield tended to result in greater ground cover and later relative maturity. However, changes in net herbage accumulation (NHA) under rotational grazing were generally not significant and were uncorrelated with changes in forage yield, indicating that forage yield of hay plots is not correlated with the NHA of grazed plots. Although genetic gains in forage yield measured under hay management were very favourable relative to other reports from the literature, the lack of correlated progress under grazing management indicates that directed selection for NHA of orchardgrass should be conducted under grazing management.     

Innovation strategies for smart specialisation (RIS3): Past,present and future research

The recent change in the regional development strategy of the European Union (EU) results in an important need to study the terms of change and their respective implications. This study seeks, through a bibliometric analysis, to ascertain the developments taking place in studies on research and innovation strategies for smart specialisation (RIS3) to identify shortcomings and opportunities for future research. This bibliometric review drew upon the Scopus database with the sample selected containing all the articles containing the keywords “Research and Innovation Strategies for Smart Specialisation” or “RIS3.” This correspondingly reports how some authors maintain that the path the EU should take involves imitative innovation. Meanwhile, others propose that each region should specialise in those industries that are already established there and thus avoid targeting any areas they do not already know/specialise in. Our findings detail six clusters in RIS3 research, which help in contextualising the literature review: (a) business discovery; (b) smart specialisation; (c) innovation; (d) specialisation; (e) regional policies; and (f) regional development. This study furthermore sets out perspectives for future lines of research and correspondingly seeks to convey a vast theoretical basis that may serve as the point of departure for future studies.     

Using data on biomass and fishing mortality in stock production modelling of flatfish

Stock production modelling was used to estimate population parameters such as the carrying capacity (B_∞), as well as management parameters such as maximum sustainable yield (MSY), the instantaneous rate of fishing mortality at MSY (F_MSY) and the sustainable biomass at MSY (B_MSY). The input data were not catch and effort data, which usually require adjustments for changes in catchability, but biomass and catch (or fishing mortality), which are frequently available from cohort analysis or direct surveys. The model does not require the assumption of stock equilibrium for estimating parameters.The model was applied to data from the Alaska plaice, Pleuronectes quadrituberculatus, and yellowfin sole, Limanda aspera stocks in the eastern Bering Sea, and the Pacific halibut, Hippoglossus stenolepis, stock in the Gulf of Alaska and Bering Sea. All three stocks are characterized by separation of nursery area and exploitable population. There are at least five age groups present in nursery areas and ten or more in the exploitable stock so that recruitment levels and exploitable stock sizes are well-buffered.Predictions from the surplus production model provided reasonable fits to the biomass time series for all three stocks examined, given the sources of uncertainty in the biomass estimates available. It appears that the stock dynamics for the three species can be described by a relatively simple density-dependent model assuming instantaneous responses in stock biomass via recruitment and growth.     

The Growing Economic Specialization of Cities: Disentangling Industrial and Functional Dimensions in the Canadian Urban System, 1971–2006

Decreasing spatial transaction and trade costs have given rise to growing economic specialization of cities. While most studies focus on industries as the primary manifestation of urban specialization, a growing body of literature examines occupational functions, i.e., activities and tasks performed within a given industry or firm. This paper explores how the two dimensions (industries and functions) interact across the urban system and their relative importance over time. Is there a trend toward increasing functional specialization in the Canadian urban system? How much of this phenomenon is attributable to spatial shifts in regional industrial structures as opposed to spatial divisions within industries? The paper uses a unique data set drawn from Statistics Canada Census microdata files between 1971 and 2006. Based on the employed population, the data are spatially organized and cross‐tabulated over industries and occupational groups. A decomposition methodology is used to compare the relative weights of industry and regional (functional) effects in accounting for the changing spatial division of functions across Canadian urban areas. Clear patterns of increasing functional specialization are found within the Canadian urban system. Regional effects are generally greater than industry effects, suggesting that spatial divisions of functions (spatial shifts within industries) are progressing more rapidly than regional shifts in industrial structure.     

Characterization of genotype by environment interactions in soybean breeding programmes of southeast Europe

Southeast Europe is Europe's major production area of soybean of maturity groups (MG) 0, I and II, but genotype by environment interaction (GEI) for soybean traits in this region is still not characterized. The objective of this study was to characterize GEI in soybean grown in Croatia for seed yield, protein and oil content. Fourteen soybean cultivars of MG 0 and I were evaluated at 15 environments. In the combined anova , genotypes, environments and GEI were significant. All three seed traits were more affected by year than by location and seed yield and protein content were more sensitive to environmental changes than oil content. Genotype by environment interaction is generally of less importance than effects of genotypes and years, especially for oil content. High‐yielding genotypes had values of regression coefficient (b) close to 1, indicating that they were not responsive to extreme environments, either positive or negative. Means and b values were not correlated for yield and negatively correlated for protein and oil content, probably because of low‐input practice in the region. The absence of recognizable differences in means, b values and principal component scores of ammi analysis between two MGs for all traits indicated that soybean cultivars of MG 0 may be recommended for growing in the region because they responded similarly to environmental changes as do full‐season genotypes of MG I.     

Ever-transient FDI and ever-polarizing regional development: Revisiting conventional theories of regional development in the context of China,Southeast and South Asia

In this new age of globalization, regions attempt to attract foreign direct investment (FDI) in order to achieve regionally balanced development. We revisit existing theories of regional development and FDI by analyzing recent data sets on FDI, employment, and trade in China, Southeast Asia, and South Asia. Using Chinese provincial data in 2004, 2008, and 2013 and applying panel estimations, our econometric results demonstrate that FDI remarkably influenced the concentration of employment in manufacturing, financial, and business services industries within the three Chinese macro-regions. We also find that FDI is ever transient, always moving away from high-cost to low-cost production bases across different regions. This transient nature of FDI is spatially selective and biased, and not able to generate the trickle-down effects to other neighboring regions. That is why FDI recently moved from China to Southeast and South Asia rather than from its coastal to inland regions. Furthermore, we show that this nature of FDI generally leads to polarization development for regions. As a synthesis or extension of the existing theories, we propose a leapfrog polarization pattern and strategy for vast developing countries in considering their regional development strategies.     

A comparison of traditional and haploid-derived breeding populations of oilseed rape (Brassica napus L.) for fatty acid composition of the seed oil

Summary Microspore embryogenesis technology allows plant breeders to efficiently generate homozygous micros-pore-derived breeding populations of oilseed rape (Brassica napus L.) without traditional generations of inbreeding. This study was conducted to compare the frequency distribution of microspore-derived population and single seed descent populations with respect to fatty acids of seed oil. Both microspore-derived populations and single seed descent populations were produced from each of three crosses made between selected parents containing contrasting amount of erucic, oleic, linoleic and linolenic acids. The fatty acid content of F₃ plants derived lines (F₅ seed) developed by single seed descent was compared to that of microspore-derived populations. The means, ranges and distribution pattern of seed fatty acid contents were similar in both populations for each fatty acid studied, although a few heterozygous lines were observed in the single seed descent populations. The results indicated that microspore-derived population form random, homozygous F₁ plant derived gametic arrays for all fatty acids evaluated. Selection for altered fatty acid composition in microspore-derived and single seed descent homozygous populations should be equally efficient, in the absence of linkage of traits investigated.     

Genetic analysis for developmental behavior of some seed quality traits in Upland cotton (Gossypum hirsutum L.)

Analysis of genetic main effects andGE interaction effects for oil index(OID), protein index (PID), and lysineindex (LID) of Upland cotton (Gossypium hirsutum L.) were conducted for2-yr diallel cross data by using a seedgenetic model. Analysis approaches ofunconditional and conditional variances andcorrelations were employed to evaluatedevelopmental behavior of cottonseed. Thephenotypic means were relatively larger forF₂ generation than F₁ generation,and larger for all generations in 1993 thanin 1994. The results of variance analysisindicated that OID, PID, and LID weresimultaneously controlled by seed nuclear,cytoplasm, and maternal nuclear effects.Genetic effects due to maternal nuclearwere relatively more important at wholedevelopmental period. GE interactioneffects were the main contribution to thetotal variation of OID at first two stages,of PID at the forth stage, and of LIDacross all four stages, respectively. Notonly the phenotypic correlationcoefficients but also the coefficients dueto different genetic effects variedsignificantly between traits themselves atvarious stages. Different genetic effectscaused the variation of the correlationshipbetween traits themselves at various stages.     

Fusarium ear rot and how to screen for resistance in open pollinated maize in the Andean regions

Ears infected with ear rot were collected from five provinces in Ecuador. Of the 44 samples analysed 26 carried Fusarium verticillioides, 11 F. subglutinans, two F. graminearum and five carried fungi different from Fusarium. The pathogenicity of ten isolates, seven of F. verticillioides and three of F. subglutinans, were tested. Per isolate 30 ears of the susceptible cultivar Mishca were inoculated by pricking a steel pin, dipped into a spore suspension, through the husks in the central part of the ear 14 days after mid-silk. Ears inoculated with sterile water and ears without any treatment, natural infection, served as controls. The disease severity (DS) of the ears ranged from 14 to 58% ear rot, the range being similar for both species. The DS of the water control, 19%, was much higher than that of the natural control of 2%. Five strains gave a DS of over 40%, significantly higher than the water control. The DS of the others were similar to the water control. In a series of experiments the effect of various methods of applying Fusarium spores through the husks into young ears were compared. All tested methods resulted in DSs significantly higher than those of the two controls. Inoculation with tooth picks and steel pins dipped in a spore suspension gave similar ear rot percentages. Inoculations at 7 to 14 days after mid-silk produced the highest DS’s. There was no significant effect of spore concentration on the DS. Cultivars differed considerably, the range being from around 20% to over 50%. Surprisingly, only wounding the husks, the sterile water control, resulted in a fairly high DS, much higher than that of the natural control. As the ranking order of the cultivars after wounding only and after inoculation did not seem to be different from the ranking order of the natural control it is suggested to use in areas with high inoculum pressures like the Andes only wounding by means of a steel pin for screening for resistance to maize ear rot.