- E.W. Hofstee (1)
- E. Marle-Koster van (1)
- L.H. Nel (1)
- B.H. Perdok (1)
- J.B. Pinxterhuis (1)
- E. Teenstra (1)
- J. Veer de (1)
- A. Willemsen (1)
- D. Yu (1)
- M.J. Zwankhuizen (1)
Genetic diversity and population structure of locally adapted South African chicken lines: Implications for conservation.
Marle-Koster, E. van; Hefer, C.A. ; Nel, L.H. ; Groenen, M.A.M. - \ 2008
South African Journal of Animal Science = Suid-Afrikaanse Tydskrif Vir Veekun 38 (2008)4. - ISSN 0375-1589 - p. 271 - 281.
kippen - inheems vee - rassen (dieren) - differentiatie - genetische variatie - genetische diversiteit - microsatellieten - merkers - bevolkingsstructuur - conservering - zuid-afrika - fowls - native livestock - breeds - differentiation - genetic variation - genetic diversity - microsatellites - markers - population structure - conservation - south africa - domestic-animal diversity - microsatellite markers - linkage map - naked neck - polymorphisms - biodiversity - genome
In this study microsatellite markers were applied to investigate the genetic diversity and population structure of the six local chicken lines kept in the “Fowls for Africa” program, for better clarification of parameters for breed differentiation and genetic conservation of this valuable resource. The lines included the Black Australorp, Potchefstroom Koekoek, New Hampshire, Ovambo, Lebova- Venda and a Naked Neck line. Unbiased estimates for heterozygosity ranged from 50% in the Potchefstroom Koekoek to as high as 65% in the Naked Neck chickens. FIS values varied from as low as 0.16 for the Black Australorp line to as high as 0.35 for the Ovambo chickens. The FST values indicated moderate to high genetic differentiation between the Naked Neck and New Hampshire (0.11); Ovambo and Naked Neck lines (0.12), and Naked Neck and Lebowa- Venda (0.14). A total of 13% of the total genetic variation observed was between the chicken lines and 87% within the lines, supporting moderate genetic differentiation. Population structure was assessed using STRUCTURE where the Black Australorp was genetically best defined. Although six clusters for the different populations could be distinguished, the other lines were not as clearly defined, with individual birds tending to share more than one cluster. Results support a broad classification of these lines and further investigation of unique alleles is recommended for conservation of the lines within the program.
Wheat powdery mildew in Central China : pathogen population structure and host resistance
Yu, D. - \ 2000
Agricultural University. Promotor(en): M.J. Jeger; J.K.M. Brown. - S.l. : S.n. - ISBN 9789058082138 - 134
tarwe - triticum - plantenziekteverwekkende schimmels - ziekteresistentie - bevolkingsstructuur - china - blumeria graminis f.sp. tritici - wheat - plant pathogenic fungi - disease resistance - population structure
<p>Wheat powdery mildew, causal agent <em>Erysiphe graminis</em> f. sp. <em>tritici</em> , has been a serious disease in central China since the late 1970s.</p><p>The wheat growing area in central China can be divided into three zones defined by altitude. Over 800m altitude, <em>E. graminis</em> f. sp. <em>tritici</em> can oversummer as the sexual stage. Cleistothecia are produced which release ascospores infecting wheat volunteers and early emerging seedlings in autumn. At 500-800m altitudes, ascospores transmit the disease across seasons only by infecting volunteers. In the lowlands below 500m, neither cleistothecia nor wheat volunteers survive the summer, and the disease is re-established each year through immigration of the pathogen from the highlands and external sources. A set of differential cultivars was selected from local varieties important in commercial production and monitoring with this differential set revealed regional differences in the pathogen population. Although there were differences between the mid and high altitude zones in oversummering of the pathogen, the population structures were very similar and can therefore be treated as a single epidemiological unit.</p><p>Five known <em>Pm</em> genes, <em>Pm</em> 1 <em>Pm</em> 3b, <em>Pm</em> 3c, <em>Pm</em> 5 and <em>Pm</em> 8, were postulated to be present in the wheat varieties grown along the Yangtze River valley, but in each case, they were associated with unknown resistance factors which differed across varieties. Most varieties tested carried resistance which cannot be identified by the reference differential set used in Europe and North America. <em>Pm</em> 3d, <em>Pm</em> 4b and <em>Pm</em> 1+2+9 had less than a 1% frequency of matching virulences in the pathogen population in central China. This indicates that these genes have value for wheat resistance breeding in central China. Several local varieties also had a very low frequency of matching virulence in the pathogen population and would also be valuable in resistance breeding.</p><p>Wheat varieties grown in central China and some other regions were assessed for partial resistance in field trials and laboratory studies. Five varieties, Hx8541, E28547, Chun1066, Ze88pin6 and Lin5064, showed compatible interactions with a large proportion of the pathogen population, but had low disease severities. Component analysis showed that low germination rate of conidia of the pathogen, low formation of appressorium and haustorium, and small haustorium size contributed to this resistance. The most common and important components were longer latent period, low colony formation and low sporulation. Calculation of the vertical distance from a cultivar data point to a fitted regression line of disease severity against matching virulence frequency was used as a novel method for assessing partial resistance. The method provided a clear evaluation of partial resistance.</p><p>Variation of responses to triadimefon in the pathogen population was high, and covered a 370-fold range of estimated ED50s. This indicates a fall in the performance of triadimefon in controlling wheat powdery mildew in central China.</p>
White clover dynamics in New Zealand pastures
Pinxterhuis, J.B. - \ 2000
Agricultural University. Promotor(en): L. 't Mannetje; D.F. Chapman. - S.l. : S.n. - ISBN 9789058082992 - 153
trifolium repens - weidevlinderbloemigen - weiden - populatiedynamica - bevolkingsstructuur - groei - nieuw-zeeland - pasture legumes - pastures - population dynamics - population structure - growth - new zealand
<p>The study presented in this thesis is based on the overall target of increased herbage production in cooler times of the year, through the use of fertiliser N, while maintaining the benefits of white clover ( <em>Trifolium repens</em> L.) in New Zealand pastures. To help identify management strategies and plant breeding goals to attain this target, seasonal dynamics in cattle grazed pastures of clover population and plant structure and stolon dynamics were studied, including the effects of fertiliser N applications, grazing management and their interactions. The grazing treatments applied were continuous stocking with 4.9 Friesian bulls/ha and rotational grazing with either 4.9 or 7.4 bulls/ha. Fertiliser N (urea) was applied in mid autumn and late winter, at 50 kg N/ha per dressing.</p><p>Average total herbage dry matter accumulation was about 16 tonnes/ha/year. The average efficiency of the applied fertiliser N was 17.5 kg DM/kg N in 1991 and 12.9 kg DM/kg N in 1992. The grazing treatments applied did not result in great differences in herbage accumulation or composition, and clover was maintained under all grazing treatments. Fertiliser N tended to decrease clover DM accumulation by 15% and clover content by 3.6%.</p><p>Stolon growth dynamics and structures of populations and plants showed great seasonal variation. Growth was related positively to average soil temperature at 10 cm depth, which explained the greatest part of the variation for most growth parameters. Rooting was not related to temperature, rainfall, distribution of rainfall nor radiation.</p><p>Continuous stocking during the cooler periods of the year, shifting to rotational grazing when temperatures rise, may help to maintain clover in the sward. Moderate fertiliser N applications in the cooler times of the year increase herbage accumulation and do not compromise clover permanently. However, it remains to be confirmed that the inhibited root production in spring, when N is applied, makes clover plants or branches in grazed swards more susceptible to local or temporal stress, such as drought. Plant breeding should be directed to improved rooting, and maintenance or improvement of N fixation.</p><p><strong>Key words</strong> : biomass allocation; branching; cattle grazing; climate; continuous stocking; fertiliser nitrogen; grassland; population and plant structure; radiation; rainfall; rainfall distribution; rooting; rotational grazing; stolon growth dynamics; temperature; <em>Trifolium repens</em> L.; white clover.</p>
Albanie, land van ...
Teenstra, E. - \ 1999
Praktijkonderzoek Rundvee, Schapen en Paarden. Praktijkonderzoek 12 (1999)5. - ISSN 1386-8470 - p. 32 - 35.
landbouwontwikkeling - ontwikkelingslanden - planning - bevolkingsstructuur - infrastructuur - geografie - albanië - landbouwvoorlichting - agricultural development - developing countries - population structure - infrastructure - geography - albania - agricultural extension
Tja, land van wat eigenlijk? Duizend mogelijkheden, of juist duizend onmogelijkheden? Land van rijkdom, of van armoede? Kussen, of Kalashnikovs? U mag het zeggen. Ik zal proberen u een eindje op weg te helpen.
Potato late blight epidemics and population structure of Phytophthora infestans
Zwankhuizen, M.J. - \ 1998
Agricultural University. Promotor(en): J.C. Zadoks; Francine Govers. - S.l. : Zwankhuizen - ISBN 9789054859581 - 147
aardappelen - solanum tuberosum - tomaten - solanum lycopersicum - phytophthora infestans - plantenziekteverwekkende schimmels - plantenziekteverwekkers - plantenziekten - epidemiologie - bevolkingsstructuur - potatoes - tomatoes - plant pathogenic fungi - plant pathogens - plant diseases - epidemiology - population structure
<p>Potato late blight is caused by the fungus <em>Phytophthora infestans</em> . To study the relative importance of oospores in the epidemiology, and to estimate the relative impact of various infection sources, late blight epidemics in Southern Flevoland (The Netherlands) were studied using epidemiological and DNA fingerprint analyses. Infested refuse piles were the most important infection source for late blight epidemics in 1994 and 1995. Infected seed tubers were of minor importance.</p><p>The results suggest that oospores play a role in the development of late blight in commercial potato crops, although the importance is less pronounced than refuse piles. Infested organic potato crops were important mid-season infection sources in 1994, but not in 1995 and 1996 due to unfavourable weather. In allotment gardens, oospores appeared to be the major inoculum for disease on potatoes and tomatoes in 1995 and 1996. Influx of inoculum from the commercial potato fields was evident in 1994, a year with a major epidemic in the first half of the growing season.</p><p>A long-term study of late blight epidemics in The Netherlands from 1950 through 1996 indicated that the disease level in the previous year and the number of days with precipitation during the growing season were the most important factors determining the current year's disease level. A multi-year pattern was observed. The results described in the thesis suggest that the disease pressure may increase in the future.</p><p>Potato late blight is caused by the fungus <em>Phytophthora infestans</em> . To study the relative importance of oospores in the epidemiology, and to estimate the relative impact of various infection sources, late blight epidemics in Southern Flevoland (The Netherlands) were studied using epidemiological and DNA fingerprint analyses. Infested refuse piles were the most important infection source for late blight epidemics in 1994 and 1995. Infected seed tubers were of minor importance.</p><p>The results suggest that oospores play a role in the development of late blight in commercial potato crops, although the importance is less pronounced than refuse piles. Infested organic potato crops were important mid-season infection sources in 1994, but not in 1995 and 1996 due to unfavourable weather. In allotment gardens, oospores appeared to be the major inoculum for disease on potatoes and tomatoes in 1995 and 1996. Influx of inoculum from the commercial potato fields was evident in 1994, a year with a major epidemic in the first half of the growing season.</p><p>A long-term study of late blight epidemics in The Netherlands from 1950 through 1996 indicated that the disease level in the previous year and the number of days with precipitation during the growing season were the most important factors determining the current year's disease level. A multi-year pattern was observed. The results described in the thesis suggest that the disease pressure may increase in the future.</p>
De waardij van eene vroege opleiding : een onderzoek naar de implicaties van het alfabetisme op het leven van inwoners van Eindhoven en omliggende gemeenten, 1800 - 1920
Boonstra, O.W.A. - \ 1993
Agricultural University. Promotor(en): A.M. van der Woude. - S.l. : Boonstra - 465
onderwijs - samenleving - bevolkingsstructuur - bevolkingsspreiding - statistiek - geschiedenis - migratie - nederland - noord-brabant - cum laude - education - society - population structure - population distribution - statistics - history - migration - netherlands
In this study, research has been done into the way literates and illiterates were able to cope with the modernisation process that took place in the Netherlands during the second half of the nineteenth century. Assuming that people who had learned to read and write were better equipped to face modernisation and more eager to go along with it, the question was raised whether literates would show more signs of modern behaviour than illiterates. Research was concentrated in a region around Eindhoven, situated in the southeastern part of the Netherlands. This region was selected because, at that time, Eindhoven started to change from a small a small market town into a industrial city, while the number of illiterates still was considerably large. The analyses showed that although literates and illiterates experienced a same amount of social mobility , illiterates were forced much more to look for another profession, whereas literates moved more freely. It also became apparent that literates were more willing to migrate long distance in order to find a new job. Finally, literates showed more signs of modern demographic behaviour than illiterates. Therefore, it could be concluded that literacy really was a vehicle towards modern behaviour in a modernising society.
|Kleine kernen in de toekomst: groei of stagnatie?
Groot, J.P. - \ 1982
De Europese gemeente (1982). - ISSN 0166-4743
migratie - nederland - ruimtelijke ordening - bevolkingsspreiding - bevolkingsstructuur - nederzetting - statistiek - steden - migration - netherlands - physical planning - population distribution - population structure - settlement - statistics - towns
Geconcludeerd wordt, dat de kleine kernen ook de komende jaren nog een voortzetting van de groei tegemoet kunnen zien. Veel stedelingen zullen in de toekomst nog de behoefte hebben om in een landelijke omgeving te wonen.
|Aantal werkende mensen in de landbouw in de verschillende EEG-landen, Groot-Brittannie en Oostenrijk
Anonymous, - \ 1971
Wageningen : [s.n.] (Literatuurlijst / Centrum voor landbouwpublikaties en landbouwdocumentatie no. 3293)
bevolkingsstructuur - bevolkingsspreiding - statistiek - arbeidsmarkt - werkgelegenheid - landbouw - bibliografieën - population structure - population distribution - statistics - labour market - employment - agriculture - bibliographies
De toekomstige ontwikkeling van de mannelijke beroepsbevolking en van de werkgelegenheid in de land - en tuinbouw in het Noorden
Perdok, B.H. ; Veer, J. de; Willemsen, A. - \ 1970
Den Haag : [s.n.] (Streekonderzoek, Bedrijfseconomisch onderzoek, Landbouw-economisch instituut LEI Afd. 2-3, no. 1) - 56
bevolkingsstructuur - bevolkingsspreiding - statistiek - arbeidsmarkt - werkgelegenheid - agrarische bedrijfsvoering - landbouw - tuinbouw - productiviteit - bedrijfsvoering - Nederland - population structure - population distribution - statistics - labour market - employment - farm management - agriculture - horticulture - productivity - management - Netherlands
Regionale verscheidenheid in de ontwikkeling van het aantal geboorten in Nederland in de 2e helft van de 19e eeuw
Hofstee, E.W. - \ 1954
In: Akademie-dagen. Koninklijke Nederlandse Akademie van Wetenschappen Amsterdam : - p. 59 - 106.
geschiedenis - nederland - bevolkingsspreiding - bevolkingsstructuur - statistiek - history - netherlands - population distribution - population structure - statistics