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Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

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    Beroep op zadenbank op Spitsbergen
    Visser, B. - \ 2015
    zaden - opslag van zaden - genetische bronnen van plantensoorten - syrië - seeds - seed storage - plant genetic resources - syria
    Voor het eerst sinds de opening in 2008 maakt een land aanspraak op zaden uit de Svalbard Global Seed Vault, de wereldwijde ondergrondse kluis voor landbouwzaden op Spitsbergen. Syrië heeft een deel van haar ingeleverde zaden nodig, omdat de eigen zadenbank bij Aleppo in de oorlog zwaar beschadigd is, en veel van de daar opgeslagen gewassen vervangen moeten worden. Bert Visser, directeur van het Centrum voor Genetische Bronnen Nederland, in deze uitzending.
    Impact of grazing on range plant community components under arid Mediterranean climate in northern Syria
    Niane, A.A. - \ 2013
    Wageningen University. Promotor(en): Paul Struik, co-promotor(en): Z. Bishaw. - Wageningen : Wageningen UR - ISBN 9789461734143 - 209
    extensieve weiden - begrazing - droge graslanden - rotatiebeweiding - botanische samenstelling - biodiversiteitsbepaling - zaadlevensduur - syrië - rangelands - grazing - arid grasslands - rotational grazing - botanical composition - biodiversity assessment - seed longevity - syria

    Keywords: Rotational grazing, full protection, continuous grazing species richness,

    species diversity, soil seed bank, Bayesian methods, Salsola vermiculata, seed

    longevity, rangeland management, Syria.

    Rangelands represent 70% of the semi-arid and arid Mediterranean land mass. It is a

    natural habitat for millions of people whose livelihood depends on animal husbandry.

    The revolutionary developments in the animal husbandry and veterinary medicines

    resulted in exponential increases in human and livestock population living on and from

    dry lands. To respond to population growth, urbanization and transportation means

    and expanded road networks, land reform and rural development policies forced

    nomads to adopt semi to fully sedentary lifestyles with disintegrated traditional

    community structures and organizational frameworks. Under these demographic

    changes coupled with national and international border crossing restrictions, there was

    an escalation in opportunistic cultivation, and excessive exploitation of the scarce and

    slowly renewable vegetation cover resulting in a steep decline in the primary

    production components of the rangeland ecosystems. In an attempt to stop and reverse

    the degradation process, large-scale re-vegetation programs based on transplanting and

    reseeding with perennial shrubs, resting and grazing management systems were

    devised and implemented. This study aimed to evaluate the impacts of the

    rehabilitation programs on the above-ground vegetation cover and soil seed bank

    replenishment in the Syrian rangelands. The underlying assumption of the

    rehabilitation program is that with a well-established perennial plant cover and proper

    grazing management, top soil is stabilized, soil moisture, nutrients and seed bank are

    replenished, organic matter is accumulated and microorganisms’ activity is promoted

    resulting in greater abundance, species richness and diversity of annuals. To test the

    above hypothesis, field and controlled environment based studies were carried out with

    quantitative data collection and processing on plant species abundance, richness and

    diversity of above-ground vegetation and soil seed bank for fully protected rotationally

    and continuously grazed areas of 10 rangeland sites in northern Syria for three

    consecutive seasons.

    In addition to the use of frequentist statistical approaches for species diversity

    estimation in the studies, the Bayesian method was explored. Moreover, the crucial

    issues of seed quality in re-vegetation were tackled through a study on seed viability

    and longevity in Salsola vermiculata L., which is a highly palatable, well adapted and

    widely used species in the arid Mediterranean rangeland rehabilitation programs.

    The major findings are indicated below.

    Above ground vegetation cover

    The vegetation cover data analysis using ANOVA showed that overall plant density

    consistently declined from full protection to rotational and then continuous grazing in

    9 out of the 10 sites studied, whereas the trends of change in species richness and

    diversity were not consistent.

    Pair-wise comparison showed that plant density, species richness and diversity

    were lowest for the overall plant population under rotational grazing in which plant

    density of perennial grasses was highest. This suggests that rotational grazing has

    reshaped the composition of the plant communities under the study areas by promoting

    the perennial grasses that are more arid rangeland adapted and ecosystem significant.

    Higher plant density under rotational grazing and similarity in species diversity under

    the three grazing treatments for perennial grasses imply that a longer period of

    rehabilitation and/or probably incorporating inter-seasonal rotational grazing and

    variation in herbivore types into the current intra-seasonal rotational grazing system

    will be required to cross the line of no return in plant community composition

    optimization through the prevalent arid Mediterranean rangelands rehabilitation


    Soil seed bank assessment

    The soil seed bank data analysis using ANOVA showed no significant differences in

    the overall physical and germinable soil seed bank size and diversity along the grazing

    gradient. However, there was a significant grazing-by-site interaction for both and a

    significant grazing-by-year interaction for germinable seed bank size showing that the

    change in seed bank size is moderated by physical and environmental characteristics

    and human-induced disturbances. Continuous grazing treatments for some sites were

    located near agglomerations of people and animals, main roads and water points.

    Under such conditions the more disturbance-adapted ephemerons and non-palatable

    plants with limited constraints for seed setting dominated and this resulted in a larger

    soil seed bank under continuous compared to rotational and full protection grazing

    treatments. For the more human-induced disturbance distanced sites, the soil seed bank

    was at larger or similar under full and/or rotational compared to continuous grazing.

    Results from pair-wise comparisons showed a simultaneous decline and surge in

    physical and germinable soil seed bank size of annuals and those of perennials under

    the grazing treatments over sites. This suggests relative differences in root competition

    and gap exploitation characteristics among plant functional groups; these differences

    could be considered indicative to rangeland status and a guide to vary herbivores in

    order to maintain optimum plant species diversity in the target rangelands.

    Soil seed banks with no seeds of perennial grasses generated 208 seedlings m-2 of

    germinable soil seed bank under continuous grazing. This is probably due to seed

    setting failure resulting from overgrazing compensated by vegetative reproduction.

    The widely used phanerophytes in the rangeland rehabilitation program had a physical

    soil seed bank of 59.7 to 119 seed m-2 and a zero germinable one. This shows high

    complementarity between physical and germinable seed testing methods for rangeland


    Similarity indices

    High Morisita-Horn and Sørensen similarities were recorded between the quadrat and

    point intercept measurements of the above ground vegetation and with each of

    physical and germinable soil seed banks. However, the similarity indices of the above

    ground vegetation measurements were higher with the germinable soil seed bank than

    with the physical soil seed bank. This suggests that the germinable soil seed bank is

    more suitable for monitoring arid Mediterranean rangeland than the physical soil seed


    Correlation coefficients

    Based on the coefficients of determination (CDs), the variation in plant density and

    seed bank size accounted for a significant portion of the variations in spcies richness

    but not of the diversity indices. However, plant density and species diversity

    consistently and significantly declined during the season with the lowest mean annual

    precipitation showing the crucial role of precipitation in the dynamics of the yet active

    soil seed banks of the study areas. The CDs for the germinable soil seed bank size

    tested under optimum soil moisture with species richness were also significant

    throughout the grazing treatments reflecting the dependence of seed bank dynamics on

    soil moisture.

    For the physical soil seed bank (PSSB), CDs of its size with species richness

    were only significant under rotational grazing implying positive impacts of grazing

    management on soil seed bank replenishment. Morover, the CDs of PSSB richness

    with the diversity indices were only significant for Singletons but not for Shannon and

    Simpson. This is attributable to the fact that the Singleton index is more sensitive to

    rare species than Shannon and Simpson. The non-significant correlations between

    plant density and species diversity reflect a need to incorporate inter-seasonal

    rotational grazing and herbivore variation to the current intra-seasonal rotational

    grazing for greater plant community integrity.

    Phytogeographic analysis

    Using two above and two underground vegetation data collection methods, a total of

    137 species, including 102 annuals and 35 perennials from 36 families of 11

    chorotypes, were recorded. The number of species recorded were 56, 66, 68 and 98

    from physical seed extraction, point intercept, quadrat and grow out test, respectively.

    These results showed the superiority of the growing out test over the three other

    methods. With its easiness and relative flexibility of application in terms of time and

    space, the grow out test seems to be the best method for arid Mediterranean rangelands

    monitoring and assessment of rehabilitation impacts in which the frequency of good

    rainy season is one out of four years.


     The rotational grazing component of the rangeland rehabilitation program resulted

    in a change in plant community composition shown by an increase in low

    proportional abundance perennial grasses with greater arid Mediterranean

    rangeland adaptation.

     Continuous grazing reduced plant density but not richness and diversity, indicating

    that maximum diversity is not a sign of rangeland health and integrity. This also

    suggests that inter-seasonal rotational grazing and herbivore variation could

    probably improve the shaping effects of grazing on the arid rangeland

    rehabilitation programs.

     Capturing more species and higher similarity indices with the above ground

    measurements, the simple and flexible, germinable soil seed bank test seems to be

    a good monitoring and evaluation method for arid Mediterranean rangelands.

    However, results from the tedious and less accurate physical seed extraction

    method could be crucial to capture the species with long seed dormancy.

     Larger Bayesian estimates of diversity, smaller standard errors, lower p-values and

    more significance of differences in diversity between grazing treatments compared

    to the frequentist approaches were observed, thus indicating clear merits for the

    approach in estimating diversity.

     The seed longevity study showed that under relatively higher seed moisture

    content, longevity increased suggesting that desiccation susceptibility is probably

    the cause of short seed longevity of Salsola vermiculata L. Moreover, drying and

    packaging alone increased longevity, thus providing a simple, cost-effective and

    environmentally friendly method for rangeland rehabilitation programs.

    The empowerment of women farmers in the context of participatory plant breeding in Syria: towards equitable development for food security
    Galie, A. - \ 2013
    Wageningen University. Promotor(en): Paul Struik; J.L.S. Jiggins, co-promotor(en): S. Ceccarelli. - [S.l. : S.n. - ISBN 9789461730077 - 234
    plantenveredeling - syrië - vrouwen - participatie - voedselzekerheid - empowerment - plattelandsvrouwen - plant breeding - syria - women - participation - food security - empowerment - rural women
    Wheat and barley seed systems in Ethiopia and Syria
    Bishaw, Z. - \ 2004
    Wageningen University. Promotor(en): Paul Struik, co-promotor(en): A.J.G. van Gastel. - [S.l.] : S.n. - ISBN 9789085040354 - 383
    triticum aestivum - hordeum vulgare - tarwe - gerst - zaaizaadindustrie - kwaliteit - ethiopië - syrië - triticum aestivum - hordeum vulgare - wheat - barley - seed industry - quality - ethiopia - syria
    Keywords: Wheat,Triticumspp., Barley,Hordeumvulgare L., Seed Systems, Formal Seed Sector, Informal Seed Sector, National Seed Program, Seed Source, Seed Selection, Seed Management, Seed Quality, Genetic Diversity, Ethiopia, Syria

    InEthiopiaandSyria, wheat and barley are the two most important principal cereal crops grown since ancient times.Manygenerations of natural and human selection led into highly adapted and diverse populations of local landraces. For most of the history of agriculture, plant improvement and seed selection were farmer-based activities carried out as an integral part of crop production. Withthe development of commercial agriculture, plant breeding and seed production evolved into different disciplines.Thewheat and barley seedsystemswere studied in Ethiopia and Syria to obtain an insight into the functioning of formal and informal seed systems with emphasis on understanding: the flow of information on new agricultural technologies;farmers' perception, criteria and adoption of modern varieties; farmers' seed sources and indigenous knowledge in seed management practices; quality of seed planted by farmers and its constraints;and on-farm wheat and barley diversity.

    Farmers use multiple sources of information such as the formal (extension services, development agencies, research institutions, media broadcast) or the informal (own experience, relatives, neighbors, other farmers, local traders) sources to acquire knowledge on varieties and/or agronomic packages for crop production. Most wheat growers (over 90%) are aware of and have information on modern varieties, agrochemical inputs (fertilizers, herbicides, etc.) and agronomic packages.In Ethiopia, the formal extension service was the main source of information for new technologies generated by research through its recently introduced agricultural package program, comparatively more so than in Syria where fellow farmers (relatives, neighbors and other farmers) accounted as the major source of information. Neighbors and other farmers were the second most important informal sources of information particularly for modern varieties partly due to the lateralvarietaldiffusion through traditional seed exchanges.

    Farmers grow three broad categories of wheat varieties, i.e. recommended, 'obsolete' or landraces. An extensive use of modern wheat varieties and production packages was found among wheat growers in both countries. InEthiopia, the majority of farmers grew modern bread wheat varieties (76% recommended and 10% obsolete varieties), and applied fertilizers (96.7%) and herbicides (63.5%) to their wheat crop. Similarly, wheat farmers inSyriaused modern varieties on the recommended list (97%), fertilizers (99.5%), herbicides (92.7%), storage pesticides (40.8%), and seed treatment chemicals (90.3%). However, the use of modern varieties and associated technologies was negligible for barley growers inSyriaexcept for the use of fertilizers (56%). Although seven modern barley varieties were released none of them were widely adopted because of farmers' preferences or lack ofvarietaladaptability. The entire barley area (99%) was planted with a local landraceArabiAswadin northeasternSyria. Developing crop varieties with high yield and yield stability foragroecologicallydiverse durum wheat growing environments inEthiopiaor agro-climatically variable marginal environments typical to barley production areas in northeasternSyriastill remains a challenging task.

    About 26 technological and socio-economic criteria were identified by farmers for adopting new modern wheat and barley varieties or for evaluating those currently grown on their farm. Grain yield, grain color, grain size, marketability and food quality (feed quality for barley), appeared most important in both crops and transcended all regions. Ethiopian farmers also consider tolerance to pests very important given their awareness of the susceptibility of the existing wheat varieties to major rust diseases. In Syria, non-lodging, frost tolerance or drought tolerance are additional agronomic characteristics farmers seeking from new wheat varieties. Some wheat local landraces were highly preferred by farmers because of their unique adaptation to diverseagroecologicalzones, stable yield, grain quality, marketability and for traditional food preparation. Most farmers in Syria had positive perceptions of the barley local landrace where one third saw no disadvantage in growing it.

    Farmers' seed acquisition from external sources is dynamic reflecting their response to specifictechnical and socio-economic factorsassociated with farming. Farmers used four main sources of seed for planting: (a) own saved seed from the previous years' harvest; (b) seed obtained from relatives, neighbors or other farmers; (c) seed purchased through local markets or grain traders; and (d) seed purchased from the formal sector. The informal farmer-to-farmer seed exchange is the major initial source of wheat and barley varieties as well as for seed used for planting each year. InEthiopia, the informal sector accounted as an initial source of modern varieties for 58% of the wheat farmers and as a source of seed for planting for 92% of farmers in 1997/98 crop season.InSyriathe formal sector was the main initial seed source of modern wheat varieties where it accounted for nearly 60%, but provided wheat seed for only 24% among sample farmers in 1998/99 crop season.Almost all barley farmers (87%) as expected initially sourced their current seed stock from informal sources (relatives, other farmers, neighbors or local markets).Farmers had a positive perception of seed both from formal and informal sources and were generally satisfied with the quality of seed obtained from different sources. Farmers purchase seed from the formal sector because of likely perception of high physical purity, chemical treatment, or as a strategy to acquire new varieties. Moreover, most farmers were also satisfied with the quality of own saved seed or that obtained from other informal sources due to its timely availability, less or no transaction costs or lack of credit facilities, adaptable varieties and certified seed.

    Farmers' perception of seed influenced them topractisedifferent on-farm seed management approaches to maintain the quality of their wheat and barley seed through selection (46-67%), cleaning (83-90%), treatment (4-90%), separate storage (64-76%) or informal assessment of physiological quality (3-34%). Almost all wheat and barley growers recognized the difference between grain and seed and attributed these to physical purity, absence of weeds, big kernel size,goodgermination, free of insect damage. The responsibility for on-farm seed management was shared between men and women, who had a distinctive role to play.

    In Ethiopia, the mean physical purity and germination of wheat seed was 98.92 and 96%, respectively and the majority of samples reached the minimum purity and germination standards. In Syria, mean physical purity and germination for wheat was 97.59% and 86%, respectively whereas for barley the average analytical purity was 95.47% and germination was 86%. However, the quality of wheat seed samples was higher than that of barley seed samples where most of the samples (90 and 28% for purity and germination, respectively) failed to meet the minimum official seed standards. Highly significant differences in seed quality were observed for seed samples collected from different regions and districts for wheat and barley crops in both countries. However, there was limited significant difference in physiological quality of seed samples obtained from different sources, but not in physical quality.

    Several seed-borne fungi such asDrechslerasativum,Septorianodorum andFusariumgraminearum, F. poae, F. avenaceum, and F. nivale including storage fungi were recorded across samples from different wheat growing region ofEthiopia. Among fungal pathogens isolated from wheat seed, 83.6% of samples were infected with D.sativum (average infection rate of 1.85%) and 74% of the samples withFusariumgraminearum (average infection rate of 1.54%). Infection with loose smut (Ustilagotritici) , common bunt (Tilletiaspp.) and seed gall nematode (Anguinatritici ) was low where only 11.2, 2.3 and 8.6% of the samples were infected, respectively. InSyria, 68 and 14% of wheat seed samples were infected with common bunt and loose smut, respectively. The average loose smut infection was 0.8%. The majority of barley seed samples were also infected with covered smut (Ustilagohordei =85%) and loose smut (83%) in varying proportion. The average loose smut infection for barley was 18%. Seed health quality of wheat was better than of barley in terms of the frequency (number of samples) and intensity of infection (% infection).

    On-farmvarietaldiversity in terms of the number of varieties/landraces grown and area coverage were quite low both for wheat and barley. Farm level surveys showed low spatial diversity where few dominant wheat varieties occupy a large proportion of area. These few wheat varieties were also grown by the majority of farmers threatening the diversity of local landraces. InEthiopia, the five top wheat varieties were grown by 56% of the sample farmers and these varieties were planted on 80% of the total wheat area whereas forSyriait was 78 and 81%, respectively in the same order. In case of barley one single local landrace was grown in the entire survey area. The weighted average age of wheat varietieswas13.8 years for bread wheat inEthiopiaand 10.8 years for wheat inSyriashowing lowvarietalreplacement by farmers, an indicator of low temporal diversity. The coefficient of parentage analysis showed that the average and weighted diversity for bread wheat was 0.76 and 0.66, respectively inEthiopiaand for bread wheat (0.73/0.42) and durum wheat (0.85/0.73) inSyria. The field experiments showed significant variations for desirable agronomic and phenotypic traits diversity such as plant height, grain yield, and yield components (spike length,spikeletsspike -1 , kernels per spike -1 , seed weight) among wheat and barley varieties and/or local landraces. This study combined farmer surveys, laboratory analysis and field experiments to better understand farmer's perception and adoption of modern varieties (and associated technologies) and to investigate on-farm genetic diversity and seed quality suggesting alternative ways for improving and strengthening the national seed system. Moreover, the study used extensive secondary data to draw a synthesis on the future direction of the national seed sector in developing countries in general and of the Ethiopian and Syrian seed industry in particular.

    Verslag van een studiereis naar Syrie
    Alphen, J.G. van - \ 1966
    Wageningen : ILRI - 9
    kalkrijke gronden - irrigatie - syrië - calcareous soils - irrigation - syria
    Contribution a l'etude de la vegetation dans le Baer-Bassit et le Djebel Alaouite de Syrie
    Nahal, I. - \ 1962
    Wageningen University. Promotor(en): H.J. Venema. - Firenze : L'Impronta - 165
    plantenecologie - bosbouw - synecologie - flora - plantengeografie - syrië - plant ecology - forestry - synecology - flora - phytogeography - syria
    The Baer-Bassit and Alaouite Mountains are in north-west Syria. The Jebel Alaouite is composed of Jurassic and Cretaceous calcareous rocks, running north-south and culminating on 1580 m. The Baer-Bassit is hilly country with green rocks.

    The climate is of Mediterranean type. Soil genesis and classification and degradation by the action of man were studied. Nahal. related soil characteristics to the vegetation. The flora already showed its most prominent traits in the Pliocene. The pluvial periods during the Quaternary influenced its distribution; their effect was still visible.

    Directions were worked out for the rational management and exploitation of the forests of Pinus brutia Ten., still in good condition, and the re-establishment of remnant forests of Abies cilicica (Ant. et Ky.) and Cedrus libani A. Rich.

    The work closed with a synsystematic and synecological study of the most important tree association of Syria, the Pistacieto-Quercetum calliprini. The importance of the progressive and regressive phases of photodynamic successions for the forester was pointed out.

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