Staff Publications

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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    Microspore embryogenesis: reprogramming cell fate from pollen to embryo development
    Hui Li, - \ 2014
    Wageningen University. Promotor(en): Gerco Angenent, co-promotor(en): Kim Boutilier. - Wageningen : Wageningen University - ISBN 9789462570702 - 224
    stuifmeel - embryogenese - embryonale ontwikkeling - biologische ontwikkeling - plantenontwikkeling - in vitro kweek - plantenembryo's - brassica napus - pollen - embryogenesis - embryonic development - biological development - plant development - in vitro culture - plant embryos - brassica napus

    Microspore embryogenesis is an expression of plant cell totipotency that leads to the production of haploid embryos. Besides being a widely exploited plant breeding tool, microspore embryogenesis is also a fascinating system that can be used to obtain a deeper mechanistic understanding of plant totipotency. This thesis aims to provide more insight into the process of microspore embryogenesis, from the formation of embryogenic cells to the outgrowth of differentiated embryos.

    In Chapter 1 background information is provided on the various aspects of Brassica napus microspore culture and plant development that intersect with the topics that are studied in this thesis. Emphasis is placed on the basic requirements and limitations for successful microspore embryo culture, as well as on the roles of the plant hormone auxin and epigenetic regulation in the development of plant embryos, during both zygotic and in vitro embryo development.

    Chapter 2 reviews the recent advances that have been made in understanding the developmental and molecular changes that take place during microspore embryogenesis in model systems. The commonly reported cellular changes associated with the establishment of embryo cell fate are summarized and evaluated. The subsequent differentiation of the embryo is also discussed, specifically, what is known about the establishment of polarity, with emphasis on the importance of exine rupture as a positional clue, and the processes that influence meristem maintenance during culture. Finally, the studies on the molecular changes during microspore embryo induction are put into context of male gametophytic development. Overall, the current perspective on microspore embryo initiation presents a landscape in which several routes can lead to the same final destination.

    Stress treatments are widely applied to induce embryogenic growth in microspore culture. Chapter 3 explores the role of histone acetylation status in stress-induced microspore embryogenesis in Brassica napus. Inhibition of histone deactylases (HDACs) using the HDAC inhibitor trichostatin A (TSA), phenocopies the heat stress treatment that is normally used to induce embryogenic cell proliferation in B. napus microspore culture. Arabidopsis is recalcitrant for haploid embryogenesis, yet treatment with TSA also induced embryogenic cell divisions in this model species. Our observations suggest that the totipotency of the male gametophyte is kept in check by an HDAC-dependent mechanism and that the stress treatments used to induce haploid embryo development in culture impinge on this HDAC-dependent pathway. The repression of HDACs or HDAC-mediated pathways by stress and the accompanying changes in histone acetylation status could provide a single, common regulation point for the induction of haploid embryogenesis.

    Chapter 4 builds on the knowledge developed in Chapter 3 on the role of HDAC proteins in plant totipotency. A wide variety of chemically distinct HDAC inhibitors was evaluated and additional inhibitors that enhance embryogenic cell induction and/or embryo yield were identified. One surprising observation was made during the course of this study: the initial donor microspore/pollen stage affects the quality of the embryo that is formed. In control cultures, embryos from progressively older stages of donor microspores/pollen became progressively compromised in their basal (axis region) region, characterized by a shift from normal embryos with apical (cotyledons) and basal (root) polarity to abnormal embryos with a reduced basal pole and ball-shaped embryos. These abnormal phenotypes could be partially complemented by treatment with HDAC inhibitors, which promoted growth of the basal region of the embryo. Progressive enhancement of embryo basal identity was accompanied by enhanced and broadened expression of the DR5 auxin response reporter. The embryo phenotypes observed in control and HDAC inhibitor treated microspore cultures are similar to the phenotypes induced by altered expression of the Arabidopsis TOPLESS (TPL)/HDAC19/BODENLOS (BDL) repressor complex, which acts to restrict expression of the AUXIN RESPONSE FACTOR ARF5/MONOPTEROS (MP) to the basal region of the embryo during zygotic embryo development.

    To understand why most embryogenic callus failed to develop further, we examined the transcriptome of globular-shaped embryos that have started to histodifferentiate and compared it with embryogenic callus. The transcriptome analysis showed that the expression of many genes that regulate (auxin-related) embryo patterning were downregulated in embryogenic callus compared to globular stage embryos. This result may simply reflect the lack of patterning in these embryos or might indicate a role of auxin-signalling in embryogenic callus formation.

    Chapter 5 examines how embryo identity and patterning is established in two B. napus microspore embryo pathways, a zygotic-like pathway, characterized by suspensor and then embryo proper formation, and a pathway characterized by initially unorganized structures that lack a suspensor. We specifically asked the question: how can embryo patterning be established in the absence of an initial asymmetric division and in the absence of a suspensor, two key events in zygotic embryo development. Analysis of embryo fate (GRP) and auxin (PIN1, PIN7 and DR5) markers showed that embryo fate was established prior to cell division, and independent of subsequent division pattern. The suspensorless embryo program was marked by a transient auxin maximum, followed by establishment of the apical and basal poles at the globular stage, coincident with release of the embryo from the pollen exine. Unlike zygotic embryo development, polar auxin transport (PAT) was not required for embryo initiation or polarity establishment in this system. Suspensor embryos developed in a similar fashion as zygotic embryos, PAT was required for specification of the embryo proper from the suspensor. Haploid embryogenesis therefore follows at least two programs, a PAT-dependent program that requires embryo proper specification from the suspensor, and an alternative PAT-independent program marked by an initial auxin maximum.

    In the final chapter, Chapter 6, the work presented in this thesis is put in context of the broader plant development field. The epigenetic regulation of developmental transitions that respond to stress and during pollen development are highlighted. A model is provided that histone acetylation levels mediated by HAT and HDAC regulate pollen fate.

    Koolzaad - Brassica Napus / Eiwit en oliepad
    PPO Akkerbouw, Groene Ruimte en Vollegrondsgroente, - \ 2012
    brassica napus - koolzaad - olieleverende planten - brandstofgewassen - planten met oliehoudende zaden - gewassen - akkerbouw - biobased economy - brassica napus - rape - oil plants - fuel crops - oilseed plants - crops - arable farming - biobased economy
    Factsheet van het Eiwit en Oliepad met korte informatie over het gewas Koolzaad. Met het project Eiwit & Oliepad wil Innovatief Platteland samen met de gemeente Venray en andere partners het publiek de gelegenheid geven zich een beeld te vormen van de enorme multifunctionaliteit en de nog steeds verder te ontdekken mogelijkheden van in Europa te telen gewassen als grondstof voor de biobased economie
    Teelthandleiding groenbemesters : bladkool (Brassica napus)
    Timmer, R.D. ; Korthals, G.W. ; Molendijk, L.P.G. - \ 2011
    Kennisakker.nl 2004 (2011)1 mei.
    groenbemesters - brassica napus - teeltsystemen - zaaien - plantenziekten - plagen - onkruiden - nematoda - akkerbouw - teelthandleidingen - green manures - cropping systems - sowing - plant diseases - pests - weeds - arable farming - cultivation manuals
    Bladkool is een speciaal op snelheid van beginontwikkeling en bladproductie geselecteerde vorm van winterkoolzaad. Het is vanouds een gewaardeerde groenbemester. Hoewel de beworteling van de bouwvoor niet intensief is geeft het een betere beworteling dan bladrammenas en gele mosterd. Daar staat tegenover dat bladkool niet geschikt is voor late zaai. De gebruiksmogelijkheden zijn beperkt, omdat bladkool een waardplant is voor zowel het bietencysteaaltje als knolvoet. Het is een lang en zeer bladrijk gewas en kan een grote massa vormen. Het bovengrondse deel is erg smakelijk voor dieren en wordt vaak bestemd voor veevoer. Geteeld als groenbemester (stoppelgewas) komt bladkool niet in bloei. Het is op de meeste gronden goed te verbouwen. Veengrond is hierop een uitzondering, terwijl lichte gronden alleen geschikt zijn als er voldoende kalk en magnesium in de bodem aanwezig is. De pH(-KCl) op deze grond moet minimaal 4,5 zijn
    Ziektewering van bodemgebonden pathogenen en functionele diversiteit van de bodemmicroflora
    Schilder, M.T. ; Postma, J. - \ 2009
    Gewasbescherming 40 (2009)1. - ISSN 0166-6495 - p. 23 - 23.
    gewasbescherming - bodembiologie - thanatephorus cucumeris - streptomyces - verticillium - streptomyces scabiei - suikerbieten - raphanus - brassica napus - bodemweerbaarheid - bodempathogenen - bodemmicrobiologie - plant protection - soil biology - thanatephorus cucumeris - streptomyces - verticillium - streptomyces scabiei - sugarbeet - raphanus - brassica napus - soil suppressiveness - soilborne pathogens - soil microbiology
    Dit onderzoek richt zich op het vinden van micro-organismen of hun eigenschappen die correleren met ziektewering op verschillende bedrijfstypen en grondsoorten.
    Cover crop-based ecological weed management: exploration and optimization
    Kruidhof, H.M. - \ 2008
    Wageningen University. Promotor(en): Martin Kropff, co-promotor(en): Lammert Bastiaans. - [S.l. : S.n. - ISBN 9789085049357 - 156
    gewassen - onkruiden - onkruidbestrijding - gewas onkruid concurrentie - dekgewassen - plantenecologie - biologische landbouw - groenbemesters - allelopathie - secale - brassica napus - medicago sativa - oogstresten - allelochemicaliën - zaailingen - onkruidkunde - agro-ecologie - crops - weeds - weed control - crop weed competition - cover crops - plant ecology - organic farming - green manures - allelopathy - secale - brassica napus - medicago sativa - crop residues - allelochemicals - seedlings - weed science - agroecology
    Keywords: organic farming, ecologically-based weed management, cover crops, green manure, allelopathy, Secale cereale, Brassica napus, Medicago sativa

    Cover crop-based ecological weed management: exploration and optimization. In organic farming systems, weed control is recognized as one of the main production-related bottlenecks. System-oriented approaches for ecological weed management are needed and cover crops may form an important component of such an approach. Inclusion of cover crops in crop rotations introduces two important mechanisms through which the development of weed populations may be hampered. In late summer and autumn the successful introduction of cover crops can prevent growth and seed production of weeds through competition. In springtime, cover crop residues incorporated in the upper layer of the soil may suppress or retard weed development and growth due to, among others, allelopathic effects. The main focus of research was put on the weed suppressive effect of cover crop residue material in spring and particularly on identifying management options to maximize this effect. To better appreciate the potential of cover crop residue material the investigations were focused on three aspects, namely allelochemicals in the cover crop, the residence time of the residue-mediated inhibitory potential in the soil and the variability in inhibitory effects on receptor plants. The study was conducted with representatives of three plant families: Secale cereale L. (winter rye), Brassica napus L. (winter oilseed rape) and Medicago sativa L. (lucerne). Mechanical injuring of field grown cover crops enhanced the allelopathic activity per unit biomass. However, this increase was often just sufficient to compensate for loss of plant material resulting from damaging, implying the limited practical significance of damaging. Different options for pre-treatment and incorporation of cover crop residue material were compared and these were found to influence the size and persistence of an inhibitory effect on seedling emergence. Results were found to be cover crop specific. With regard to species’ sensitivity our results suggest that for inhibition of a receptor plant not just seed size is important. Only if the time course of sensitivity of the receptor plant matches with the time course of residue-mediated inhibitory potential, significant reductions in seedling establishment can be expected. In light of this, it was postulated that variation in synchronicity of receptor species’ sensitivity and potential residue effects may well explain the large degree of variation often noted in field studies of allelopathy.

    Breder herbicidenpakket in koolzaad
    Zeeland, M.G. van; Hoek, J. - \ 2007
    Boerderij/Akkerbouw 93 (2007)1. - ISSN 0169-0116 - p. 1 - 1.
    koolzaad - brassica napus - herbiciden - gewasbescherming - rape - herbicides - plant protection
    Het middelenaanbod voor de onkruidbestrijding in winterkoolzaad beperkt. Enkele herbiciden blijken perspectiefvol, blijkt uit PPO-onderzoek
    Teeltonderzoek aan koolzaad voor biobrandstof 2003-2006 : verslag veldproeven Ebelsheerd en Vredepeel
    Geel, W.C.A. van; Borm, G.E.L. ; Beers, T.G. van; Floot, H. ; Meuffels, G.J.H.M. ; Mheen, H.J.C.J. van der; Verstegen, H.A.G. - \ 2007
    Wageningen : PPO AGV (Rapport / PPO-AGV ) - 60
    koolzaad - brassica napus - bio-energie - brandstofgewassen - rentabiliteit - cultuurmethoden - veldproeven - biobrandstoffen - biobased economy - akkerbouw - rape - brassica napus - bioenergy - fuel crops - profitability - cultural methods - field tests - biofuels - biobased economy - arable farming
    In diverse delen van Nederland zijn initiatieven ontwikkeld om een productiekolom op te zetten voor de winning van biobrandstof uit koolzaad. In opdracht van het Hoofdproductschap Akkerbouw heeft PPO van 2003 t/m 2006 teeltonderzoek uitgevoerd in koolzaad. Het onderzoek richtte zich op de mogelijkheden om de rendabiliteit van de teelt te verhogen en op het verkennen van de koolzaadteelt op zandgrond. Naast de traditionele teelt van winterkoolzaad kregen de teelt en opbrengstpotentie van zomerkoolzaad aandacht, door middel van rassenonderzoek.
    Peptide signalling in plant development: functional analysis of CLE ligands in Arabidopsis
    Fiers, M.A. - \ 2007
    Wageningen University. Promotor(en): W.J. Stiekema, co-promotor(en): C.M. Liu. - [S.l.] : S.n. - ISBN 9789085045793 - 144
    plantenontwikkeling - liganden - signaalpeptide - arabidopsis - brassica napus - signaaltransductie - genen - plant development - ligands - signal peptide - arabidopsis - brassica napus - signal transduction - genes

    In multicellular organisms, cell to cell communication is essential for coordinating growth and differentiation. In plants most known intercellular communication is mediated by phytohormones such as auxin, cytokinin, GA, ABA, ethylene and brassinosteroids. However, in recent years, several putative peptide ligands have been identified in plants and were shown to mediate signalling events. One of these ligands is CLAVATA3 (CLV3) which is a peptide ligand in Arabidopsis and is involved in stem cell maintenance.

    CLV3 is part of the CLV3/ESR (CLE) gene family which consists of 31 members in Arabidopsis. These genes encode small proteins which contain a putative secretion signal at their N-termini and a conserved CLE-motif at or near their C-termini. Recently the mature CLV3 was identified and shown to consist of 12 amino acids comprising the CLE motif with two hydroxylated prolines.

    This thesis aims to better understand signalling by the CLE gene family and in particular CLE19 and CLV3. This research started with the characterization of one of the CLE members namely CLE19 in Brassica napus embryos. This was followed by a small proteomic study of the secretome of Brassica microspore embryos to identify differences in low and high yielding embryo cultures and concludes with a newly developed peptide based approach to better understand CLE signalling in shoot and root meristems.

    Chapter 1 is an introduction on CLE signalling in Arabidopsis. This chapter combines all the data that is published related to the CLE gene family. The Arabidopsis CLE family was used as a starting point for making a genomic survey of the rice genome to identify rice CLE genes. This survey resulted in the identification of33 putative rice CLE genes. All rice CLEs were compared to the ones from Arabidopsis in order to find orthologues based on the amino acid sequence of the complete protein or only the CLE domain. The comparison, based on the complete protein did not result in the identification of CLE orthologues between rice and Arabidopsis. Comparing the 14 amino acid CLE domains resulted in the identification of some putative orthologues but most similar CLE domains were within the Arabidopsis or rice gene family. The CLE domain is probably too short to identify any orthologues between the In multicellular organisms, cell to cell communication is essential for coordinating growth and differentiation. In plants most known intercellular communication is mediated by phytohormones such as auxin, cytokinin, GA, ABA, ethylene and brassinosteroids. However, in recent years, several putative peptide ligands have been identified in plants and were shown to mediate signalling events. One of these ligands is CLAVATA3 (CLV3) which is a peptide ligand in Arabidopsis and is involved in stem cell maintenance.

    CLV3 is part of the CLV3/ESR (CLE) gene family which consists of 31 members in Arabidopsis. These genes encode small proteins which contain a putative secretion signal at their N-termini and a conserved CLE-motif at or near their C-termini. Recently the mature CLV3 was identified and shown to consist of 12 amino acids comprising the CLE motif with two hydroxylated prolines.

    This thesis aims to better understand signalling by the CLE gene family and in particular CLE19 and CLV3. This research started with the characterization of one of the CLE members namely CLE19 in Brassica napus embryos. This was followed by a small proteomic study of the secretome of Brassica microspore embryos to identify differences in low and high yielding embryo cultures and concludes with a newly developed peptide based approach to better understand CLE signalling in shoot and root meristems.

    Chapter 1 is an introduction on CLE signalling m Arabidopsis. This chapter combines all the data that is published related to the CLE gene family. The Arabidopsis CLE family was used as a starting point for making a genomic survey of the rice genome to identify rice CLE genes. This survey resulted in the identification of 33 putative rice CLE genes. All rice CLEs were compared to the ones from Arabidopsis in order to find orthologues based on the amino acid sequence of the complete protein or only the CLE domain. The comparison, based on the complete protein did not result in the identification of CLE orthologues between rice and Arabidopsis. Comparing the 14 amino acid CLE domains resulted in the identification of some putative orthologues but most similar CLE domains were within the Arabidopsis or rice gene family. The CLE domain is probably too short to identify any orthologues between the monocotyledon (rice) and dicotyledon (Arabidopsis) but can be used as a starting point for further research. This chapter is concluded with an outline of this thesis. In Chapter 2 a short survey on the biochemical aspects of haploid embryogenesis is described and in particular the identification of extra cellular signalling molecules in microspore embryo development of Brassica napus. Differences were examined in protein profiles present in the medium from high-yielding microspore derived embryos cultures and low-yielding that did not produce any embryos. Several proteins were isolated and identified by de-novo protein sequencing including some unknown proteins with no obvious orthologue in the Arabidopsis genome.

    Chapter 3 describes DD3-12, one of the genes that were isolated in a screen to identify markers for embryo development in Brassica napus. DD3-J2 encodes BnCLE19, a small 74 amino acid secreted protein that belongs to the CLE like family of proteins. With the use of northerns, a pBnCLE19:;GUS construct and RT-PCR analysis the expression pattern of CLE19 was established in Brassica and Arabidopsis. interestingly CLE19 is expressed in the LI andL2 layers of the periphery of shoot and inflorescence meristems as compared to CLV3 which is expressed in the first three layers in the top of the meristem. But also in embryos CLE19 expression was observed from globular stage onwards in the epidermal cells covering the developing cotyledons. BnCLE19 and CLE19, its orthologue in Arabidopsis, were over expressed in Arabidopsis which resulted, among other phenotypes, in the consumption of the root meristem. Interestingly this consumption of the root meristem was also observed upon over expression of other members of the CLE family, namely CLV3 and CLE40. The only conserved domain among all CLE proteins, beside the secretion signal, is a 14 amino acid CLE domain at or near the C-terminus. To test if this domain is the functional part of the CLE proteins and if this domain can act independently from the rest of the protein an in-vitro system was developed using chemically synthesized 14 amino acid CLE peptides.

    Chapter 4 describes the research aimed at the analysis of the functional domain of CLE proteins. We show that the CLE peptides can cause an over-expression phenotype in the roots of Arabidopsis, namely termination of the root meristem, as previously shown in chapter 3 upon over expression ofCLE19. Already after 4 days of growth in CLE peptide containing media the first signs of a general miscommunication between cells and cell layers were observed. In early root development the CLE peptides caused a misspecification in the pericycle, endodermis and cortex cell layers and a premature differentiation of the cortical daughter cells. In the search for receptors involved in the perception of the CLE ligands we challenged the clv mutants with several CLE peptides. Only the clv2 mutant, when incubated with CLE peptides, resulted in normal root development with no defects in the meristematic tissue. This result was revealing a CLV-like signalling pathway in the roots with CLV2 as one of the receptors which was involved in the perception of the CLE peptides during root development.

    Chapter 5 pictures the functional analysis of the CLV3 peptide in shoot apical meristem (SAM) development of the clv3 mutant which results in the reduction of the enlarged SAM to wild type (WT) proportions. Different CLE peptides were used to determine the redundancy between different CLE genes in SAM development. The functional analysis of different CLE peptides in clv3 resulted in a variable degree of complementation. The CLE40p and CLV3p peptides caused an almost complete restoration of the SAM to WT while CLE19p and CLE5p resulted in a partial complementation. This in contrast with CLE22p which was not able to replace CLV3 resulting m a greatly enlarged meristem as seen in clv3. These results clearly showed that not all CLE ligands were freely interchangeable and a certain degree of sequence specificity is required which was also shown with a mutated and several truncated peptides. The in-vitro peptide approach is combined with a deletion analysis of the CLV3 gene to proof that the CLE domain, beside the secretion signal, is essential and sufficient in rescuing the clv3 mutant.

    This thesis finishes with some concluding remarks and future prospectives in Chapter 6. This chapter describes the future of research in the field of CLE signalling with a particular interest in understanding ligand-receptor signalling and the pitfalls and drawbacks in identifying the receptors involved in the perception of the CLE ligands.

    Factors affecting the density of Brassica napus seeds
    Young, L. ; Jalink, H. ; Denkert, R. ; Reaney, M. - \ 2006
    Seed Science and Technology 34 (2006)3. - ISSN 0251-0952 - p. 633 - 645.
    brassica napus - zaadproductie - oliezaden - kwaliteit - brassica napus - seed production - oilseeds - quality - protein-concentration - chlorophyll fluorescence - oilseed rape - degradation - selection
    Brassica napus seed is composed of low density oil (0.92 g.cm(-3)) and higher density solids (1.3-1.45 g.cm(-3)). Seed buoyant density may potentially be used to determine seed oil content and to separate seeds with different oil contents, however, we have found that seeds with the lowest buoyant density had lower than expected oil contents. It is proposed that the low oil content observed in the lowest density seed is a function of air gaps or pockets within the seed coat with sufficient volume to disrupt the linear relationship between oil content and density. The air gaps make density-based selection of seeds for oil content more difficult. Seed solid and liquid components are essentially incompressible with increased hydrostatic pressure but air gaps in seeds may be compressed or filled if density sorting is conducted in a pressurised apparatus. Experimental evidence shows that compression of air pockets with hydrostatic pressure or filling of air pockets with solvent simplifies the relationship between seed density and oil Content. In spite of applied pressure it was observed that pressure was not sufficient to eliminate the buoyancy of all seeds with air pockets. Seeds containing air pockets may have been immature or improperly filled during maturation. Interrupted maturation, premature maturation or desiccation may potentially interrupt storage compound accumulation and lead to morphological changes. Chlorophyll fluorescence was used in this study as an indicator of seed maturity. An inverse relationship between chlorophyll content and oil content was observed, but was not observed for chlorophyll content and density. This relationship between oil content, chlorophyll content and density suggests that the lowest and highest density seed groups were enriched in immature seed.
    Innovations in microspore embryogenesis in Indonesian hot pepper (Capsicum annuum L.) and Brassica napus L.
    Supena, E.D.J. - \ 2004
    Wageningen University. Promotor(en): Evert Jacobsen, co-promotor(en): J.B.M. Custers. - [S.I.] : S.n. - ISBN 9789085041337 - 131
    capsicum annuum - spaanse pepers - brassica napus - microvermeerdering - embryogenese - antherencultuur - haploïdie - kiemcellen - plantenveredeling - capsicum annuum - chillies - brassica napus - micropropagation - embryogenesis - anther culture - haploidy - germ cells - plant breeding
    Hot pepper (Capsicum annuumL.) is the most important vegetable inIndonesia, but the yield is low, and the breeding programs are confined to the conventional methods and not efficient. To improve the efficiency of the breeding programs by speeding up the production of homozygous lines, studies were aimed at the introduction of haploid technology, which includes the regeneration and the production of doubled haploid plants from gametes. This technique is well developed in the model speciesBrassica napusL. via microspore culture. The results of various investigations involving both applied and fundamental aspects on microspore embryogenesis are presented in this thesis. The main results of the applied part deal with the development of an efficient shed-microspore culture protocol for the production of doubled haploid plants in Indonesian hot pepper (C. annuum), and its implementation under the local conditions of Indonesia. With regard to the more fundamental part, we presented for the first time an entirely new developmental pathway of embryogenesis including suspensor formation in microspore culture ofB. napuscv. Topas that mimics zygotic embryogenesis from early stages of development onwards. These results will have significant impact for practical application in hot pepper breeding programs as well as for further fundamental research on unraveling of early plant embryogenesis.
    Teelthandleiding koolzaad - onkruidbestrijding
    Bernelot Moens, H.L. ; Wolfert, J.E. ; PPO Akkerbouw, Groene Ruimte en Vollegrondsgroente, - \ 2003
    Kennisakker.nl 2003 (2003)1 juli.
    brassica napus - koolzaad - onkruidbestrijding - cultuurmethoden - teelt - akkerbouw - teelthandleidingen - brassica napus - rape - weed control - cultural methods - cultivation - arable farming - cultivation manuals
    In dit hoofdstuk van de teelthandleiding koolzaad wordt ingegaan op de bestrijding van onkruid in koolzaad.
    Teelthandleiding koolzaad : nieuwe ontwikkelingen
    Bernelot Moens, H.L. ; Wolfert, J.E. ; PPO Akkerbouw, Groene Ruimte en Vollegrondsgroente, - \ 2003
    Kennisakker.nl 2003 (2003)1 juli.
    brassica napus - koolzaad - teelt - cultuurmethoden - olieleverende planten - zaadoliën - brandstofgewassen - plantaardige oliën - akkerbouw - toepassingen - biobased economy - teelthandleidingen - brassica napus - rape - cultivation - cultural methods - oil plants - seed oils - fuel crops - plant oils - arable farming - applications - biobased economy - cultivation manuals
    In deze teelthandleiding wordt ingegaan op plantaardige olie, biologisch afbreekbare smeermiddelen en brandstof uit koolzaad voor de toekomst.
    Teelthandleiding koolzaad : ziekten en plagen
    Bernelot Moens, H.L. ; Wolfert, J.E. ; PPO Akkerbouw, Groene Ruimte en Vollegrondsgroente, - \ 2003
    Kennisakker.nl 2003 (2003)1 juli.
    brassica napus - koolzaad - teelt - cultuurmethoden - gewasbescherming - plagen - plantenziektebestrijding - akkerbouw - teelthandleidingen - brassica napus - rape - cultivation - cultural methods - plant protection - pests - plant disease control - arable farming - cultivation manuals
    Er zijn veel organismen die koolzaad in meer of mindere mate kunnen beschadigen en daardoor de zaadopbrengst in ongunstige zin kunnen beïnvloeden. In het onderstaande wordt een opsomming met een korte beschrijving van de meest voorkomende beschadigers gegeven, terwijl van de belangrijkste tevens de bestrijdingswijze zal worden aangegeven
    Teelthandleiding koolzaad
    Bernelot Moens, H.L. ; Wolfert, J.E. ; PPO Akkerbouw, Groene Ruimte en Vollegrondsgroente, - \ 2003
    Kennisakker.nl 2003 (2003)1 juli.
    koolzaad - brassica napus - teelt - teelthandleidingen - cultuurmethoden - akkerbouw - olieleverende planten - biobased economy - rape - brassica napus - cultivation - cultivation manuals - cultural methods - arable farming - oil plants - biobased economy
    In de teelthandleiding koolzaad vindt u informatie over de teelt, oogst en bewaring van koolzaad.
    Teelthandleiding koolzaad - botanische gegevens
    Bernelot Moens, H.L. ; Wolfert, J.E. ; PPO Akkerbouw, Groene Ruimte en Vollegrondsgroente, - \ 2003
    Kennisakker.nl 2003 (2003)1 juli.
    brassica napus - koolzaad - teelt - cultuurmethoden - brassicaceae - akkerbouw - teelthandleidingen - brassica napus - rape - cultivation - cultural methods - brassicaceae - arable farming - cultivation manuals
    Koolzaad en raapzaad behoren met diverse kool soorten, knol of raap, koolraap, mosterdsoorten, radijs, rammenas, tuinkers en nog vele andere gewassen tot de familie van de Cruciferae (Kruisbloemigen). Deze familie ontleent haar naam aan het feit dat de vier bloem, kroonbladeren duidelijk in een kruis staan.
    Teelthandleiding koolzaad - teeltvoorwaarden en grondbewerking
    Bernelot Moens, H.L. ; Wolfert, J.E. ; PPO Akkerbouw, Groene Ruimte en Vollegrondsgroente, - \ 2003
    Kennisakker.nl 2003 (2003)1 juli.
    brassica napus - koolzaad - teelt - cultuurmethoden - grondbewerking - akkerbouw - teelthandleidingen - brassica napus - rape - cultivation - cultural methods - tillage - arable farming - cultivation manuals
    In deze teelthandleiding wordt ingegaan op teeltvoorwaarden, grondsoort, vruchtopvolging, grondbewerking en zaaibed bij koolzaad.
    Teelthandleiding koolzaad - zaad en zaaien
    Bernelot Moens, H.L. ; Wolfert, J.E. ; PPO Akkerbouw, Groene Ruimte en Vollegrondsgroente, - \ 2003
    Kennisakker.nl 2003 (2003)1 juli.
    brassica napus - koolzaad - teelt - cultuurmethoden - zaaien - zaden - akkerbouw - teelthandleidingen - brassica napus - rape - cultivation - cultural methods - sowing - seeds - arable farming - cultivation manuals
    In deze teelthandleiding wordt ingegaan op rassenkeuze, zaaizaadontsmetting en zaadbehandeling, zaaizaadhoeveelheid en standdichtheid, zaaitijd, zaaitechniek en zaaien zonder grondbewerking bij koolzaad.
    Teelthandleiding koolzaad - bemesting
    Bernelot Moens, H.L. ; Wolfert, J.E. ; PPO Akkerbouw, Groene Ruimte en Vollegrondsgroente, - \ 2003
    Kennisakker.nl 2003 (2003)1 juli.
    brassica napus - koolzaad - teelt - cultuurmethoden - kunstmeststoffen - stikstofmeststoffen - bemesting - akkerbouw - teelthandleidingen - brassica napus - rape - cultivation - cultural methods - fertilizers - nitrogen fertilizers - fertilizer application - arable farming - cultivation manuals
    Het doel van de bemesting van koolzaad is een aanvulling aan de bodemvoorraad te geven, zodat het gewas steeds over voldoende voedingsstoffen kan beschikken en zo een ongestoorde groei kan geven. Ingegaan wordt op bemesting met fosfaat, kali, stikstof en overige mineralen.
    Teelthandleiding koolzaad - oogst en bewaring
    Bernelot Moens, H.L. ; Wolfert, J.E. ; PPO Akkerbouw, Groene Ruimte en Vollegrondsgroente, - \ 2003
    Kennisakker.nl 2003 (2003)1 juli.
    brassica napus - koolzaad - teelt - oogsten - opslag (planten) - oogsttijdstip - zwadmaaien - maaidorsen - akkerbouw - teelthandleidingen - brassica napus - rape - cultivation - harvesting - volunteer plants - harvesting date - windrowing - combine harvesting - arable farming - cultivation manuals
    In de praktijk wordt winterkoolzaad voor het grootste gedeelte eerst gezwadmaaid en na een velddroogperiode uit het zwad gedorst. Daarnaast wordt ook van stam gedorst. De oogsttijd, de oogstmethode en de droging en bewaring van het zaad hebben grote invloed op opbrengst en kwaliteit van koolzaad.
    Teelthandleiding koolzaad - producten uit koolzaad
    Bernelot Moens, H.L. ; Wolfert, J.E. ; PPO Akkerbouw, Groene Ruimte en Vollegrondsgroente, - \ 2003
    Kennisakker.nl 2003 (2003)1 juli.
    brassica napus - koolzaad - teelt - cultuurmethoden - landbouwproducten - akkerbouw - teelthandleidingen - brassica napus - rape - cultivation - cultural methods - agricultural products - arable farming - cultivation manuals
    In deze teelthandleiding worden de producten genoemd die uit koolzaad worden verkregen. Koolzaad word geteeld vanwege oliewinning, het wordt gebruikt voor dierlijke en menselijke consumptie en er zijn technische en industriële toepassingen.
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