Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    '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.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

    We have a manual that explains all the features 

    Current refinement(s):

    Records 1 - 20 / 38

    • help
    • print

      Print search results

    • export

      Export search results

    Check title to add to marked list
    How plant–soil feedbacks influence the next generation of plants
    Long, Jonathan R. De; Heinen, Robin ; Jongen, Renske ; Hannula, S.E. ; Huberty, Martine ; Kielak, Anna M. ; Steinauer, Katja ; Bezemer, T.M. - \ 2020
    Ecological Research (2020). - ISSN 0912-3814
    grassland - maternal effect - plant–soil feedback - seed quality - soil legacies

    In response to environmental conditions, plants can alter the performance of the next generation through maternal effects. Since plant–soil feedbacks (PSFs) influence soil conditions, PSFs likely create such intergenerational effects. We grew monocultures of three grass and three forb species in outdoor mesocosms. We then grew one of the six species, Hypochaeris radicata, in the conditioned soils and collected their seeds. We measured seed weight, carbon and nitrogen concentration, germination and seedling performance when grown on a common soil. We did not detect functional group intergenerational effects, but soils conditioned by different plant species affected H. radicata seed C to N ratios. There was a relationship between parent biomass in the differently conditioned soils and the germination rates of the offspring. However, these effects did not change offspring performance on a common soil. Our findings show that PSF effects changed seed quality and initial performance in a common grassland forb. We discuss the implications of our findings for multi-generational plant–soil interactions, and highlight the need to further explore how PSF effects shape plant community dynamics over different generations and across a broad range of species and functional groups.

    Detection of QTLs for genotype × environment interactions in tomato seeds and seedlings
    Geshnizjani, Nafiseh ; Snoek, Basten L. ; Willems, Leo A.J. ; Rienstra, Juriaan A. ; Nijveen, Harm ; Hilhorst, Henk W.M. ; Ligterink, Wilco - \ 2020
    Plant, Cell & Environment 43 (2020)8. - ISSN 0140-7791 - p. 1973 - 1988.
    high phosphate - low nitrogen - maternal environment - QTL × E - seed quality - seedling establishment - tomato

    Seed quality and seedling establishment are the most important factors affecting successful crop development. They depend on the genetic background and are acquired during seed maturation and therefor, affected by the maternal environment under which the seeds develop. There is little knowledge about the genetic and environmental factors that affect seed quality and seedling establishment. The aim of this study is to identify the loci and possible molecular mechanisms involved in acquisition of seed quality and how these are controlled by adverse maternal conditions. For this, we used a tomato recombinant inbred line (RIL) population consisting of 100 lines which were grown under two different nutritional environmental conditions, high phosphate and low nitrate. Most of the seed germination traits such as maximum germination percentage (Gmax), germination rate (t50) and uniformity (U8416) showed ample variation between genotypes and under different germination conditions. This phenotypic variation leads to identification of quantitative trait loci (QTLs) which were dependent on genetic factors, but also on the interaction with the maternal environment (QTL × E). Further studies of these QTLs may ultimately help to predict the effect of different maternal environmental conditions on seed quality and seedling establishment which will be very useful to improve the production of high-performance seeds.

    The interaction between genotype and maternal nutritional environments affects tomato seed and seedling quality
    Geshnizjani, Nafiseh ; Sarikhani Khorami, Saadat ; Willems, Leo A.J. ; Snoek, Basten L. ; Hilhorst, Henk W.M. ; Ligterink, Wilco - \ 2019
    Journal of Experimental Botany 70 (2019)10. - ISSN 0022-0957 - p. 2905 - 2918.
    Solanum lycopersicum - Solanum pimpinellifolium - Genotype by environment interaction (G×E) - maternal environment - metabolites - seed quality - seedling quality

    Seed and seedling traits are affected by the conditions of the maternal environment, such as light, temperature, and nutrient availability. In this study, we have investigated whether different maternally applied nitrate and phosphate concentrations affect the seed and seedling performance of two closely related tomato species: Solanum lycopersicum cv. Money maker and Solanum pimpinellifolium accession CGN14498. We observed large differences for seed and seedling traits between the two species. Additionally, we have shown that for nitrate most of the seed and seedling traits were significantly affected by genotype-environment interactions (G×E). The effect of the maternal environment was clearly visible in the primary metabolites of the dry seeds. For example, we could show that the amount of γ-aminobutyric acid (GABA) in Money maker seeds was affected by the differences in the maternal environments and was positively correlated with seed germination under high temperature. Overall, compared with phosphate, nitrate had a larger effect on seed and seedling performance in tomato. In general, the different responses to the maternal environments of the two tomato species showed a major role for G×E in shaping seed and seedling traits.

    Uganda Early Generation Seed Study : Unlocking Pathways for Sustainable Provision of EGS for Food Crops in Uganda
    Mastenbroek, A. ; Ntare, Bonny - \ 2016
    Centre for Development Innovation (Report CDI-16-030 ) - 120
    seeds - seed quality - food crops - sustainability - farmers - uganda - zaden - zaadkwaliteit - voedselgewassen - duurzaamheid (sustainability) - boeren - uganda
    One of the major bottlenecks limiting farmers’ access to good quality seed for food crops in Uganda is the shortage of early generation seed (EGS - breeder and foundation) to produce sufficient quantities of certified and/or quality declared) to satisfy the needs of farmers. A national study was conducted between October 2015 to March 2016 to analyse pathways for promoting commercial and sustainable production and delivery of EGS. Five crops (hybrid maize, rice, beans, sesame and finger millet) were selected. The analysis provides real examples of potential business models that could scale in a commercially sustainable manner. For areas that are best suited to public sector investment, opportunities for public-private collaboration and increased efficiencies in the sector are outlined. Generalizable principles and recommendations to guide key stakeholders as they pursue policies, investments, and interventions are proposed.
    Adaptation and acclimation of seed performance
    Souza Vidigal, D. De - \ 2015
    Wageningen University. Promotor(en): Harro Bouwmeester, co-promotor(en): Leonie Bentsink; Henk Hilhorst. - Wageningen University - ISBN 9789462575943 - 156
    zaden - zaadkwaliteit - zaadkieming - klimaatverandering - adaptatie - arabidopsis - kiemrust - klimaatadaptatie - seeds - seed quality - seed germination - climatic change - adaptation - arabidopsis - seed dormancy - climate adaptation
    Manuel - L’entrepreneuriat semencier
    Burg, H. van den; Roo, N. de; Barikore, C. ; Haizuru Zamu, G. ; Ndyanabo, E. ; Simbashizubwoba, C. - \ 2015
    Wageningen : Centre for Development Innovation, Wageningen UR (CDI Guide manuel ) - 128
    businesses - small businesses - seeds - seed quality - seed certification - certification - markets - storage - africa - bedrijven - kleine bedrijven - zaden - zaadkwaliteit - zaadkeuring - certificering - markten - opslag - afrika
    A systems genetics study of seed quality and seedling vigour in Brassica rapa
    Basnet, R.K. - \ 2015
    Wageningen University. Promotor(en): Richard Visser, co-promotor(en): Guusje Bonnema; Chris Maliepaard. - Wageningen : Wageningen University - ISBN 9789462574250 - 177
    brassica campestris - zaadkwaliteit - groeikracht - zaden - zaadontwikkeling - zaadkieming - zaailingen - plantengenetica - genomica - brassica campestris - seed quality - vigour - seeds - seed development - seed germination - seedlings - plant genetics - genomics

    Summary

    Seed is the basic and most critical input for seed propagated agricultural crops: seed quality and seedling vigour determine plant establishment, growth and development in both natural and agricultural ecosystems. Seed quality and seedling vigour are mainly determined by the interactions of the following three components: genetic background, physiological quality and the environmental conditions during seed set, seed ripening, storage, seed germination and early seedling development. In the past, many efforts have been made to improve seed germination and seedling vigour by optimizing physiological and environmental factors (non-genetic factors); however, the paradigm has shifted to investigate genetic factors and to use these to improve crop performance by plant breeding. The aim of this thesis is to unravel the genetics of seed germination and seedling vigour under different conditions in Brassica rapa, using a systems genetics approach. Studies in many crop species have reported that seed germination and seedling vigour traits are governed by many genes and are strongly affected by environmental conditions. As salinity stress is becoming one of the most important abiotic stresses affecting crop growth and yield, we studied the genetics of seed germination and seedling vigour under neutral and salt stress conditions. For a number of crops, it has been established that larger seed size and higher seed weight indicate more reserve food and contribute positively to seedling establishment. Therefore, our hypothesis for this thesis is that transcriptional regulation of genes during seed development determines the composition and content of seed reserves, and that these seed reserves play a major role in seed germination and seedling growth, especially at the heterotrophic stage under optimal and sub-optimal conditions.

    B. rapa is an extremely diverse Brassica species which includes, besides many diverse leafy vegetable types and turnips, also oilseed crops. Brassica seeds are of high economic importance for several reasons. They are the starting point of the life cycle of the crop, but also they are directly used as sources of vegetable oil or condiments. At present, B. napus is the most important source of vegetable oil worldwide, but B. rapa is often used for introgression breeding to broaden its narrow genetic base resulting in genetic improvements. Therefore, the acquired knowledge is also useful for the scientific community and plant breeders working in B. napus and other Brassica species.

    In Chapter 2 we evaluated the genetic diversity of a B. rapa core collection of 168 accessions representing different crop types and geographic origins. Using the Bayesian cluster analysis software STRUCTURE, we identified four subpopulations: subpopulation 1 with accessions of Indian origin, spring oil, yellow sarson and rapid cycling; subpopulation 2 consisting of several types from Asian origins: pak choi, winter oil, mizuna, mibuna, komasuna, turnip green, oil rape and Asian turnip; subpopulation 3, which included mainly accessions of Chinese cabbage and subpopulation 4 with mostly vegetable turnip, fodder turnip and brocoletto accessions from European origin. The geographical distribution of the accessions was very much congruent with genetic, metabolic and morphological diversity. This initial study was followed by association studies for secondary metabolites from the tocopherol and carotenoids pathways, using the population structure of these four subpopulations as a correction term to control for spurious marker-trait associations (Chapter 2). Additionally, we used a machine learning approach, Random Forest (RF) regression, to find marker-trait associations. We chose the RF approach as it can handle large numbers of variables (markers, metabolites, transcript abundance) in combination with relatively small sample sets of accessions, to show its perspectives for application to the increasing amounts of data available through the different ~omics technologies. In our analysis, the markers showing significant association with metabolites identified by the RF approach overlapped with markers obtained from association mapping. Those markers could potentially be used for marker-assisted selection (MAS) in breeding for these secondary metabolites in different morphotypes or sub-populations. Knowledge of genetic distance as evaluated in this chapter allowed the choice of parents to create a segregating population for QTL analyses by maximizing genetic variation between the parents.

    In Chapter 4, a doubled haploid (DH) population from a cross of genetically diverse morphotypes of B. rapa, an oil-type yellow sarson (YS143) and a vegetable pak choi (PC175) (Chapter 2), was used to evaluate the genetic basis of seed germination and seedling vigour traits under both non-stress and salt stress conditions. The yellow sarson parent had larger seed size and higher thousand-seed weight than the pak choi parent, and displayed earlier onset, higher uniformity in germination, faster germination and maximum germination, and higher root- and shoot- lengths and biomass under both non-stress and salt stress conditions. Positive correlations of thousand-seed weight with earliness, speed and uniformity of germination and maximum germination percentage, supports that larger seeds germinate earlier, faster, more uniformly and to a higher maximum germination percentage than smaller seeds. Thus, we conclude that yellow sarson had higher seed quality and seedling vigour than pak choi. However yellow sarson also contributed negative alleles to seed germination, as illustrated by its allele of the QTL at A05 which decreases the uniformity of seed germination. In addition we also observed that yellow sarson seedling growth was more affected by salt stress than pak choi. All traits were scored over the DH population, and this clearly showed transgressive variation for most traits. Eight QTL hotspots were identified for seed weight, seed germination, and root and shoot lengths. A QTL hotspot for seed germination on A02 co-located with a homologue of the FLOWERING LOCUS C (BrFLC2) genes and its cis-acting expression QTL (cis-eQTL). FLC2 (BrFLC2 in B. rapa) is an important repressor of flowering time in both A. thaliana and B. rapa and recently, FLC2 was reported for its pleiotropic effect on seed germination in A. thaliana. A QTL hotspot on A05 with salt stress specific QTL co-located with the FATTY ACID DESATURASE 2 (BrFAD2) gene and its cis-eQTL. Besides the role of FAD2 in fatty acid desaturation, the up-regulation of this gene was associated with enhanced seed germination and hypocotyl elongation under salinity in B. napus (BnFAD2) and A. thaliana (FAD2). We observed epistatic interactions between the QTL hotspots at the BrFLC2 and BrFAD2 loci, and between other QTL hotspots.

    Seed development is regulated by many dynamic metabolic processes controlled by complex networks of spatially and temporally expressed genes. Therefore, morphological characteristics and the transcriptional signatures of developing seeds from yellow- and brown/black-seeded genotypes were studied to get to know the timing of key metabolic processes, to explore the major transcriptional differences and to identify the optimum stage for a genetical genomics study for B. rapa seed traits (Chapter 3). This is the first study of genome-wide profiling of transcript abundance during seed development in B. rapa. Most transcriptional changes occurred between 25 and 35 days after pollination (between the bent-cotyledon stage and the stage when the embryo fully fills the seed), which is later than in the related species B. napus. A weighted gene co-expression network analysis (WGCNA) identified 47 gene modules with different co-expression patterns, of which 17 showed a genotype effect, 4 modules a time effect during seed development and 6 modules both genotype and time effects. Based on the number of genes in gene modules, the predominant variation in gene expression was according to developmental stages rather than morphotype differences. We identified 17 putative cis-regulatory elements (motifs) for four co-regulated gene clusters of genes related to lipid metabolism. The identification of key physiological events, major expression patterns, and putative cis-regulatory elements provides useful information to construct gene regulatory networks in B. rapa developing seeds and provides a starting point for a genetical genomics study of fatty acid composition and additional seed traits in Chapter 5.

    Since Brassica seeds are sources of vegetable oil, genetic studies of the gene regulatory mechanisms underlying lipid metabolism is of high importance, not only in relation to seed and seedling vigour, but also for Brassica oilseed breeding. In Chapter 5, an integrative approach of QTL mapping for fatty acids composition and for transcript abundance (eQTL) of genes related to lipid metabolism, together with gene co-expression networks was used to unravel the genetic regulation of seed fatty acid composition in the DH population of B. rapa. In this study, a confounding effect of flowering time variation was observed on fatty acid QTLs (metabolite level) at linkage group A02 and of seed colour variation on eQTLs (transcript level) at linkage group A09. At A02, fatty acid QTLs from 2009 seeds co-locate with the genetic position of a gene-targeted marker for BrFLC2, its cis-QTL, and a major flowering time QTL. Flowering time variation is very obvious in this DH population and the BrFLC2 gene at A02 (16.7 cM) is the major regulator of flowering time, with a non-functional allele in the yellow sarson parent. When QTL analysis was performed on seeds from 2011, from DH lines that flowered synchronously due to staggered sowing, this fatty acid QTL hotspot disappeared. The 2011 seed lot was used for further analysis combining fatty acid QTLs with eQTLs in this study. On A09, a large trans-eQTL hotspot was co-localized with a major seed colour QTL, in the region where the causal gene, the bHLH transcription factor BrTT8, was cloned. The role of this gene in seed colour development was functionally proven in B. rapa. As the yellow sarson and pak choi parents of this population have contrasting seed coat colour (Chapter 3) the DH lines segregated for seed colour. When seed colour variation was used as a co-variate in our statistical model, we could exclude its confounding effect on eQTL mapping. We compared the fatty acid QTL and eQTL results from the analyses before and after seed colour correction and later discuss the results from the analysis after correction. The distribution of major QTLs for fatty acids showed a relationship with the types of fatty acids: linkage group A03 contained major QTLs for monounsaturated fatty acids (MUFAs), A04 for saturated fatty acids (SFAs) and A05 for polyunsaturated fatty acids (PUFAs). Using a genetical genomics approach, eQTL hotspots were found at major fatty acid QTLs on A03, A04 and A05 and on A09. Finally, an eQTL-guided gene co-expression network of lipid metabolism related genes showed major hubs at the genes BrPLA2-ALPHA, BrWD-40, a number of seed storage protein genes and a transcription factor BrMD-2, suggesting essential roles of these genes in lipid metabolism. Several genes, such as BrFAE1, BrTAG1, BrFAD2, BrFAD5, BrFAD7, which were reported as important genes for fatty acid composition in seeds in other studies of related species, had relatively lower degrees of connection in the networks. However their cis-eQTLs co-localized with specific fatty acid QTLs, making them candidate genes for the observed variation. We hypothesize that these play a role in modifying fatty acid content or composition across genotypes, rather than playing essential roles in the pathway itself. These results suggest the need of a global study of lipid metabolism rather than a strict focus on the fatty acid biosynthesis pathway per se. This study gives a starting point for understanding the genetic regulation of lipid metabolism, by identification of a number of key regulatory genes, identified as major hub genes, and candidate genes for fatty acid QTLs.

    In the final chapter (Chapter 6) we summarize and critically discuss the relationships among phenotypic traits, metabolites and expression variation as well as the co-localization of QTLs from these different levels. In this thesis, we developed methodology to integrate transcriptomics and metabolomics data sets and to construct gene regulatory networks related to major fatty acids, and found a set of (possible) candidate genes involved in lipid metabolism. In the future, we recommend to integrate the genome-wide transcriptome data set with all major seed metabolites and phenotypic data on seed and seedling vigour to directly link all three components: transcriptome, metabolome and phenotypic traits, and ultimately expand the knowledge on the genetic regulation of seed metabolites, seed quality and seedling vigour in B. rapa to other Brassica species.

    Supporting Local Seed Businesses : A Training Manual for ISSD Uganda
    Mastenbroek, A. ; Chebet, A. ; Muwanika, C.T. ; Adong, C.J. ; Okot, F. ; Otim, G. ; Birungi, J. ; Kansiime, M. ; Oyee, P. ; Ninsiima, P. - \ 2015
    Wageningen : Centre for Development Innovation, Wageningen UR - 273
    seed production - seed development - seed quality - rural development - farming - markets - businesses - small businesses - regional development - training courses - training - agricultural development - uganda - west africa - africa - zaadproductie - zaadontwikkeling - zaadkwaliteit - plattelandsontwikkeling - landbouw bedrijven - markten - bedrijven - kleine bedrijven - regionale ontwikkeling - scholingscursussen - opleiding - landbouwontwikkeling - uganda - west-afrika - afrika
    The training manual is developed in Uganda to train partner organisations in coaching farmer groups to become sustainable local seed businesses. It introduces the Integrated Seed Sector Development Programme in Uganda and the concept of local seed businesses (LSBs). The manual has 5 modules covering selection, monitoring and sustaining local seed businesses; technically equipping local seed businesses, professionally organising LSBs; orienting LSBs to the market and strategically linking them to service providers.
    Progress Report China Potato GAP project; Late blight control, seed quality, storage facilities and sustainability studies in Heilongjiang province and communications
    Kempenaar, C. ; Kessel, G.J.T. ; Wustman, R. ; Pronk, A.A. ; Haverkort, A.J. ; Ruijter, F.J. de; Lyu, D. ; Wan, S. ; Fan, G. ; Bai, Y. ; Min, F. ; Guo, M. ; Zhang, S. ; Yang, S. ; Gao, Y. - \ 2015
    Wageningen : Plant Research International (Report / Plant Research International 608) - 73
    potatoes - seed potatoes - solanum tuberosum - good practices - phytophthora infestans - disease resistance - decision support systems - seed quality - land use - water use efficiency - storage - storage equipment - china - aardappelen - pootaardappelen - solanum tuberosum - good practices - phytophthora infestans - ziekteresistentie - beslissingsondersteunende systemen - zaadkwaliteit - landgebruik - watergebruiksrendement - opslag - voorzieningen voor de opslag - china
    In this report we describe the mid-term results of the R&D program of the PPS Potato GAP China. The aim of the Potato GAP China PPS is to exchange information on GAP in potato production and storage, and to set up experiments and demonstration farms in China with Dutch technology and know-how. This last objective, the setup of Centres of Dutch potato Expertise in China, has not been achieved yet, but still has high priority in 2015. In this report, we describe the results of experiments, investigations and communications within the PPS in 2013 and 2014. The R&D topics are potato late blight disease monitoring and control, potato seed quality evaluation, potato storage investigation and sustainability evaluation of potato production.
    Beter zaad voor Afrika
    Boo, M. de; Thijssen, M.H. - \ 2014
    WageningenWorld (2014)4. - ISSN 2210-7908 - p. 28 - 31.
    kwaliteit - zaden - plantenvermeerdering - rassen (planten) - zaadproductie - zaadkwaliteit - overheid - afrika - tuinbouw - plantenveredeling - pootknollen - geografische rassen - quality - seeds - propagation - varieties - seed production - seed quality - public authorities - africa - horticulture - plant breeding - seed tubers - geographical races
    Veel Afrikaanse boeren blijven verstoken van goed zaai- en pootgoed. Nationale overheden en bedrijven kunnen niet aan de vraag voldoen. Het Centre for Development Innovation in Wageningen werkt met boerengroepen om lokaal beter zaaizaad op de markt te brengen.
    Genetic and physiological quality of tomato seed and seedlings
    Khan, N. - \ 2013
    Wageningen University. Promotor(en): Harro Bouwmeester, co-promotor(en): Henk Hilhorst; Wilco Ligterink. - S.l. : s.n. - ISBN 9789461736475 - 249
    solanum lycopersicum - tomaten - zaden - zaailingen - zaadkwaliteit - genetische analyse - zaadfysiologie - kieming - solanum lycopersicum - tomatoes - seeds - seedlings - seed quality - genetic analysis - seed physiology - germination
    Seed quality in informal seed systems
    Biemond, P.C. - \ 2013
    Wageningen University. Promotor(en): Paul Struik, co-promotor(en): Tjeerd-Jan Stomph. - S.l. : s.n. - ISBN 9789461736420 - 120
    zaadkwaliteit - zaadfysiologie - vigna unguiculata - vignabonen - zaadkieming - zaadpathologie - mycotoxinen - zea mays - nigeria - seed quality - seed physiology - vigna unguiculata - cowpeas - seed germination - seed pathology - mycotoxins - zea mays - nigeria

    Keywords: informal seed systems, seed recycling, seed quality, germination, seed pathology, seed health, seed-borne diseases, mycotoxigenic fungi, Fusarium verticillioides, mycotoxins, Vigna unguiculata, Zea mays, Nigeria.

    Seed is a crucial input for agricultural production. Approximately 80% of the smallholder farmers in Africa depend for their seed on the informal seed system, consisting of farmers involved in selection, production and dissemination of seed. The lack of overhead, distribution and seed testing costs enables seed-producing farmers to offer seed for low prices, but seed quality is not always good. Seed-producing farmers multiply their seed on-farm without frequent seed renewal, referred to as seed recycling, which may lead to low seed quality. This research analysed the effect of seed recycling on physiological quality and seed health of cowpea and maize, and compared seed quality of the formal and informal seed system.

    We tested the physical and physiological quality of cowpea seeds produced by the formal and informal seed system. Five out of six foundation seed samples, 79 out of 81 samples of farmers’ seed, and six out of six seed company samples failed to meet standards for foundation and certified seeds of the National Agriculture Seed Council (NASC), the seed industry regulatory agency in Nigeria. No evidence was found for a negative effect of seed recycling on physiological quality of cowpea seeds. We analysed 45,500 cowpea seeds for seed-borne bacteria and fungi to compare the performance of formal and informal seed systems. All samples were heavily infected with seed-borne pathogens, including Fusarium oxysporum (69% of the samples) and Macrophomina phaseolina (76%). No evidence was found that seed recycling in the informal seed system did lead to increased levels of seed-borne pathogens. We also analysed seed quality of farmer-produced maize seed to compare it with the formal seed system. The seed company samples had significantly higher germination (99.3%) than farmer-produced seed (97.7%), but not a single sample passed the requirements for certified seed of the NASC. Twelve seed-borne pathogens were identified including Bipolaris maydis (found in 45% of the farmer-produced samples), Botryodiplodia theobromae (97%) and Fusarium verticillioides (100%). Seed recycling had no negative effect on the physiological quality or seed health of maize seed. We analysed formal and informal seed systems to assess the opportunities to prevent mycotoxigenic fungi infection in maize seeds. A range of control methods to avoid fungal infection and mycotoxin production is discussed in relation to three criteria for sustainable implementation in developing countries. An integrated approach is recommended, with special attention towards the local seed system. As an overall conclusion of the work it can be stated that the informal seed system did not underperform compared to the formal seed system for cowpea, but did underperform in relation to seed company samples of maize. There was no evidence that seed recycling reduces seed quality of cowpea and maize seed samples, so frequent seed renewal will not improve seed quality of the informal seed system. We recommend a new quality assurance system for the informal seed system based on seed quality testing by farmers themselves, without interference by government or external laboratories. Farmers publish their seed testing results on the bag, while buyers can retest the seed to verify the quality. Further research is required to develop and implement this system in different countries, agro-ecologies and crops, and to develop methods that enable farmers to test seed health quality themselves.

    Economic and agronomic analysis of the seed potato supply chain in Ethiopia
    Tufa, A.H. - \ 2013
    Wageningen University. Promotor(en): Alfons Oude Lansink; Paul Struik, co-promotor(en): Miranda Meuwissen; Willemien Lommen. - S.l. : s.n. - ISBN 9789461735430 - 170
    pootaardappelen - zaadkwaliteit - verbetering - voedselketens - ketenmanagement - houding van boeren - voedselzekerheid - productie - solanum tuberosum - aardappelen - economische analyse - prestatieniveau - ethiopië - seed potatoes - seed quality - improvement - food chains - supply chain management - farmers' attitudes - food security - production - solanum tuberosum - potatoes - economic analysis - performance - ethiopia
    Production and productivity of potato in Ethiopia are very low because of poor quality seed tubers and unavailability of seed tubers of improved varieties. These poor quality seed tubers and unavailability of seed tubers of improved varieties are caused by economic and agronomic factors. This thesis deals with economic and agronomic aspects that affect quality and availability of seed potatoes in Ethiopia. It encompasses analysis of strengths and weaknesses of seed potato systems currently operating in Ethiopia, elicitation of farmers’ opinions on management attributes that they believed to affect yield and quality of potato, cost-effective seed potato production plans for farmers in Ethiopia, and analysis of performance of existing and potential seed potato supply chains. The results of this thesis indicate that seed quality and availability can be improved by improving economic and agronomic aspects of the seed systems in general and seed supply chains in particular.
    Genes for seed quality : integrating physiology and genetical genomics to mine for seed quality genes in tomato
    Kazmi, R.H. - \ 2013
    Wageningen University. Promotor(en): Harro Bouwmeester, co-promotor(en): Henk Hilhorst; Wilco Ligterink. - S.l. : s.n. - ISBN 9789461735201 - 243
    solanum lycopersicum - solanum pimpinellifolium - tomaten - zaadkwaliteit - genen - plantenfysiologie - genomica - fenotypen - metabolomica - solanum lycopersicum - solanum pimpinellifolium - tomatoes - seed quality - genes - plant physiology - genomics - phenotypes - metabolomics

    Seed quality in tomato is associated with many complex physiological and genetical traits. The performance of seeds is determined by three interlinked and interactive components that constitute a performance triangle of genetics, physiological quality and the environment. So far, there has been little or no discussion about the genetic analysis of seed and seedling traits in tomato at a systems level. To the best of our knowledge, the present study is the first systemic analysis of the genetics of seed and seedling traits, adding to a growing body of information on tomato seed quality. With the aim of improving the production of high-quality tomato seeds, a multidisciplinary study (physiology, genetics and genomics) was undertaken to develop and evaluate methods for improving the percentage, rate and uniformity of germination and early seedling development, and for increasing the range of environmental conditions for germination. Primarily, we explored the natural variation present in a Solanum lycopersicum x Solanum pimpinellifolium RIL population to dissect the molecular-genetic mechanisms controlling seed quality. Although previous solutions to issues associated with seed quality phenotypes seemed promising, none have utilized the integration of genomic, phenotypic and metabolic datasets to understand seed quality in tomato.Thus, the integration of metabolic and genomic analysis contributed to a comprehensive biological understanding of observed phenotypic differences between RILs of S. lycopersicumx S. pimpinellifolium. Here we describe, for the first time, the use of a generalized genetical genomics (GGG) model in tomato seeds that incorporates genetics, as well as environmental effects, and we applied this approach to map traditional quantitative trait loci (Genetic QTLs) and QTLs that are the result of interaction between the genetics and environmental changes (Genetic x Environmental QTLs). This model uses chosen environmental perturbations (different seed developmental stages, i.e. dry and 6h imbibed seeds) in combination with the analysis of genetic variation present in the RIL population, to study the change of metabolites over the multiple environments and to identify genotype-by-environment interactions. This thesis gives an account of the integration of genotyping, phenotyping and a molecular phenotype using metabolomics in generating a novel understanding of seed phenotypes and their interaction with the environment. In summary, the integration of phenotypic and metabolomics data has facilitated the identification of potential biomarkers for better understanding of the complex nature of tomato seed quality.

    Razendsnel én nauwkeurig
    Zedde, Rick van de - \ 2013
    nurseries - seedlings - planting stock - sorters - innovations - quality controls - labour - seed quality
    Betere test voor houdbaarheid zaad
    Groot, S.P.C. - \ 2011
    Kennis Online 2011 (2011)14 juni. - p. 9 - 9.
    zaadkwaliteit - houdbaarheid (kwaliteit) - opslag van zaden - vermeerderingsmateriaal - seed quality - keeping quality - seed storage - propagation materials
    Een nieuwe test maakt het mogelijk de houdbaarheid van zaaizaad nauwkeuriger vast te stellen. Dat geeft meer zekerheid bij bewaring en kan ook helpen bij de veredeling op houdbaarheid van zaad.
    Seed quality in genetic resources conservation : a case study at the Centre for Genetic Resources, the Netherlands
    Groot, S.P.C. ; Groot, E.C. de - \ 2008
    Wageningen : Centre for genetic resources (CGN) (Report / Centre for Genetic Resources 2008/11) - 47
    zaden - kiemrust - zaadlevensduur - zaadkieming - zaadkwaliteit - zaadveroudering - zaadleeftijd - genenbanken - gewassen - zaad verzamelen - aardappelen - uien - spinazie - slasoorten - erwten - vicia faba - bonen - meloenen - komkommers - tomaten - vlas - graansoorten - akkerbouw - zaadproductie - ex-situ conservering - opslag van zaden - seeds - seed dormancy - seed longevity - seed germination - seed quality - seed aging - seed age - gene banks - crops - seed collection - potatoes - onions - spinach - lettuces - peas - vicia faba - beans - melons - cucumbers - tomatoes - flax - cereals - arable farming - seed production - ex situ conservation - seed storage
    This report describes an analysis of the impact of workflow and storage conditions at the Centre for Genetic Resources the Netherlands (CGN) on the quality of seed samples in their genebank collection which is maintained under low temperature and low relative humidity conditions. Emphasis is placed on seed longevity and health.
    Meten van zaadkwaliteit m.b.v. Nabij InfraRood Spectroscopie
    Brakel, R.P. van; Zedde, H.J. van de - \ 2007
    zaadkwaliteit - infraroodspectroscopie - meting - analyse - nabij infrarood spectroscopie - seed quality - infrared spectroscopy - measurement - analysis - near infrared spectroscopy
    Nabij InfraRood Spectroscopie (NIR) is één van de analysetechnieken waarmee kwaliteitsparameters kunnen worden bepaald. Het gaat daarbij niet alleen om concentratie-metingen maar ook om indirecte kwaliteitskenmerken die in het te meten product aanwezig zijn
    Vloeistofscheiden rekent af met slechte zaden
    Derkx, M.P.M. - \ 2007
    De Boomkwekerij 2007 (2007)1. - ISSN 0923-2443 - p. 14 - 15.
    zaadkwaliteit - zaden - dichtheid - selectie - scheiding - boomkwekerijen - seed quality - seeds - density - selection - separation - forest nurseries
    Men kan slechte zaden onderscheiden van goede zaden door middel van de dichtheid, hoe lager de dichtheid hoe slechter het zaad. Zaden kunnen zo worden gescheiden van elkaar met behulp van vloeistoffen van verschillende dichtheden. Zaad kan zo veel efficienter worden gebruikt en de kwaliteit worden verhoogd door alleen de beste kwaliteit te gebruiken.
    High Tech Kleurensorteerder voor Zaden : Een nieuwe technologie voor opwaardering van zaadpartijen
    Jalink, H. ; Schoor, R. van der - \ 2006
    fusarium - tarwe - zaadproductie - zaadkwaliteit - sorteren - kwalitatieve technieken - spectrometrie - fusarium - wheat - seed production - seed quality - sorting - qualitative techniques - spectrometry
    Een nieuwe methode voor sorteren van tarwezaad op besmetting met Fusarium is ontwikkeld. De methode is gebaseerd op het nauwkeurig meten van kleurverschillen van het zaad, zowel verschillen in het zichtbare als ook in het nabij infrarood gebied.
    Check title to add to marked list
    << previous | next >>

    Show 20 50 100 records per page

     
    Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.