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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    Toxicity of Pyrrolizidine Alkaloids to Spodoptera exigua Using Insect Cell Lines and Injection Bioassays
    Nuringtyas, T.R. ; Verpoorte, R. ; Klinkhamer, P.G.L. ; Oers, M.M. van; Leiss, K.A. - \ 2014
    Journal of Chemical Ecology 40 (2014)6. - ISSN 0098-0331 - p. 609 - 616.
    tertiary amine - n-oxides - performance - herbivores - resistance - asteraceae - vulgaris - hybrids - plants
    Pyrrolizidine alkaloids (PAs) are feeding deterrents and toxic compounds to generalist herbivores. Among the PAs of Jacobaea vulgaris Gaertn, jacobine and erucifoline are the most effective against insect herbivores as indicated by correlative studies. Because little is known about the effect of jacobine and erucifoline as individual PAs, we isolated these compounds from their respective Jacobaea chemotypes. These PAs and other commercially available senecionine-like PAs, including senecionine, seneciphylline, retrorsine, and senkirkine, were tested as free base and N-oxide forms at a range of 0–70 ppm. Feeding bioassays using live insects are closer to the natural pattern but require relatively large amounts of test compounds. We, therefore, compared the toxicity of PAs using both Spodoptera exigua cell line and larval injection bioassays. Both bioassays led to similar results in the order of PA toxicity, indicating that the cell lines are a valuable tool for a first toxicity screen. Testing individual PAs, jacobine and erucifoline were the most toxic PAs, suggesting their major role in plant defense against generalist herbivores. Senkirkine and seneciphylline were less toxic than jacobine and erucifoline but more toxic than retrorsine. Senecionine was not toxic at the tested concentrations. For all toxic PAs, the free base form was more toxic than the N-oxide form. Our results demonstrate that structural variation of PAs influences their effectiveness in plant defense.
    A Stringent and Broad Screen of Solanum spp. tolerance Against Erwinia Bacteria Using a Petiole Test
    Rietman, H. ; Finkers, H.J. ; Evers, L. ; Zouwen, P.S. van der; Wolf, J.M. van der; Visser, R.G.F. - \ 2014
    American Journal of Potato Research 91 (2014)2. - ISSN 1099-209X - p. 204 - 214.
    carotovora subsp atroseptica - soft-rot erwinias - tuber-bearing solanum - potato clones - stem rot - cultivated potato - ssp atroseptica - section petota - resistance - hybrids
    Blackleg and stem rot caused by coliform bacteria belonging to Dickeya spp. and Pectobacterium spp. (both referred to as Erwinia in this paper) are a problem for potato growers worldwide and no sources of high tolerance are currently present in the cultivated S. tuberosum gene pool. To find sources of tolerance, 532 genotypes from 340 accessions, covering most of the known potato species, were assayed with P. wasabiae, P. carotovorum and D. ‘solani’ species in a petiole test. This petiole test was optimized later on using well responding genotypes from the broad screen. Based on the obtained data, the best developmental stage for cell wall degradation tests was identified to be the 4th-6th youngest leaf. Under the stringent biotic and climatic screening conditions used, only three genotypes were regarded as tolerant against all tested Erwinia species. These genotypes all belonged to the series Yungasensa, this series can be readily crossed with cultivated potato and is considered as a genetic source to upgrade the Erwinia tolerance level of cultivated potato
    Cross-sectoral conflicts for water under climate change: the need to include water quality impacts
    Vliet, M.T.H. van; Ludwig, F. ; Kabat, P. - \ 2013
    planten - polyploïdie - hybriden - hybridisatie - genomica - evolutie - drosophila - plants - polyploidy - hybrids - hybridization - genomics - evolution - drosophila
    Climate change is expected to increase pressures on water use between different sectors (e.g. agriculture, energy, industry, domestic uses) and ecosystems. While climate change impacts on water availability have been studied widely, less work has been done to assess impacts on water quality. This study proposes a modelling framework to incorporate water quality in analyses of cross-sectoral conflicts for water between human uses and ecosystems under climate change and socio-economic changes. We illustrate this with an example that shows that increasing river temperatures and declines in summer low flow under climate change are likely to increase environmental restrictions on cooling water use, with substantial reductions in power plant capacities in Europe and the US. Hence, conflicts between environmental objectives and electricity supply are expected to increase due to both changes in water availability and water quality (water temperature) under climate change. A new impact modelling framework is proposed, which integrates relations between water availability, water quality and cross-sectoral water uses, including water requirements for ecosystems. This could provide improved understanding of how climate change and socioeconomic developments will affect the ‘water-energy-food-ecosystem nexus’. Index Terms—river flow, water temperature, water quality, climate change, socio-economic developments, human water use, ecosystems
    A molecular cytogenetic analysis of chromosome behavior in Lilium hybrids
    Xie, S.L. - \ 2012
    Wageningen University. Promotor(en): Richard Visser; Jaap van Tuyl, co-promotor(en): Paul Arens. - S.l. : s.n. - ISBN 9789461732248 - 115
    lilium - cytogenetica - moleculaire genetica - genetische analyse - hybriden - chromosomen - recombinatie - soortkruising - meiose - lilium - cytogenetics - molecular genetics - genetic analysis - hybrids - chromosomes - recombination - interspecific hybridization - meiosis

    Lily (Lilium) has become one of the top bulbous crops for the cut flower industry in the past two decades. The genus Lilium comprises of approximately 80 species, which have been classified into seven sections. Each section possesses distinctive phenotypic characters, such as flower color, flower shape and resistances to diseases and pests. Crosses between species in the same section are relatively easy and the resulting hybrids are in general fertile, while interspecific crosses between species from different sections are rather difficult and the resulting hybrids are in general sterile. As a result, different hybrid groups have been bred in the 20th century. Within these different hybrid groups, Longiflorum (L), Asiatic (A) and Oriental (O), which are derived from the section Leucolirion, Sinomartagon and Archelirion respectively, are of commercial importance and hence, are the most widely cultivated lilies worldwide.

    Lily hybrids provide an ideal model for molecular cytogenetic research. With the development of techniques of overcoming pre- and post- crossing barriers of interspecific crosses, as well as the application of asexual and sexual polyploidization to restore the fertility of F1 lily hybrids, combining of desirable traits from different hybrid groups has become feasible. As a result, interspecific hybridization and polyploidization have been widely used in the breeding of new cultivars of lily. These cultivars, as well as other breeding materials from interspecific crosses, facilitate the application of molecular cytogenetic analysis due to three reasons: 1) the chromosomes of lily are large enough for cytological observations; 2) genomes of different hybrid groups are homoeologous; and 3) these homoeologous genomes can be simultaneously distinguished by DNA in situ hybridization. Using these lily hybrids combined with genomic in situ hybridization (GISH) and florescence in situ hybridization (FISH), the interaction of homoeologous genomes can be studied though meiotic observation of the F1 hybrids. Meanwhile, chromosome sequential variation with relevance to crossover and chromosome rearrangements can also be observed.

    For this purpose, interspecific crosses between the Lilium longiflorum cultivar ‘White Fox’ and the Asiatic cultivar ‘Connecticut King’ were made, and some of these F1 hybrids, which show a relatively high fertility with the production of unreduced gametes, were backcrossed with an Asiatic cultivar . The meiosis of the interspecific hybrids, as well as the sexual polyploidized progenies, were analysed by GISH and FISH. In addition, one population of sexual polyploidized AOA hybrids was also analysed for the genome composition. Results showed that there was no evidence that lily allopolyploids possess any noticeable chromosome rearrangements. The equal segregation of reciprocal and non-reciprocal recombinant product showed that the intergenomic recombination in the sexual polyploidized progenies was indeed from a natural process-chiasmata formation and crossovers and hence, should not be considered as translocations as was suggested in literature for intergenomic recombination. This conclusion was further confirmed by meiotic observation of the interspecific F1 hybrids.

    Detailed meiotic observations were carried out in interspecific hybrids between Longiflorum × Asiatic groups of lilies (Lilium) which were used as parents to generate sexual polyploids with intergenomic recombination. Bivalents involving two homoeologous chromosomes, as well as unpaired univalents were the main configurations at metaphase I. However, in two genotypes, multivalents and bivalents both involving non-homologous pairing of two Asiatic chromosomes were observed. This indicated the presence of a duplication which was common to two non-homologous chromosomes in the hybrids. It is deduced that there was a reciprocal translocation in the Asiatic parent cv. ‘Connecticut King’ and these two genotypes resulted from duplication-deficiency gametes. Results from Anaphase I showed that chiasma formation involving non-sister chromatids gave rise to two strand single, two strand double, three strand double, four strand double and multiple exchanges. It is also noticeable that there was a high frequency of multiple crossovers in the genotypes with duplication, indicating a reduced crossover interference in multivalents. Beside the normal crossovers, also chromosome bridges at anaphase I of meiosis were observed. GISH and FISH painting showed that these bridges involve not only non-sister chromatids but also sister-chromatids. The bridges, without any differentiation along their length, were always accompanied by fragments with a variable size. These results indicated that the bridges, together with the accompanying fragments, were derived from U-type exchanges. Other than homologous recombination (HR), nonhomologous end joining (NHEJ) probably led to the production of bridges when repairing the double strand breaks (DSBs) during meiosis.

    Progenies from unilateral polyploidization of crosses between LA hybrids and Asiatic cultivars were predominant triploids. However, three exceptional plants, which possessed 35 normal chromosomes and a small aberrant chromosome instead of the expected normal number of 36, were observed. In all three cases the small aberrant chromosomes were isochromosomes which had obviously originated during the first backcross generation, and the length of the arms of these aberrant chromosomes were always related with the length of the short arm of the missing chromosome. Furthermore, one of these three chromosomes possessed 45S rDNA hybridization sites in the proximal positions, which resembles the short arm of the missing chromosome (chromosome 4 of L genome). Combined with the results of chromosome breakage during meiosis, centric breakage and fusion is a putative mechanism of the production of these isochromosomes. Meanwhile, two small, supernumerary or B chromosomes were detected as extra chromosomes in a tetraploid plant derived from chromosome doubling of an intersectional hybrid (2n=2x=24) between a cultivar of the Longiflorum (L) and the Trumpet (T) group. When this tetraploid LLTT hybrid was crossed with a triploid LLO hybrid (O=Oriental), the B chromosome was transmitted to 73.4% of the progenies. Based on GISH and FISH characterization it was shown that the B chromosome found consisted of two identical arms, with 5S rDNA hybridizing to the majority of it, which were flanked by normal telomeres, suggesting that this is an isochromosome.

    The results of current investigations are of practical implication for a number of reasons. Firstly, the behavior of homoeologous chromosomes during meiotic processes in lily hybrids was studied in detail, and it can be used to explain the profound genetic changes in the early generations during hybrid speciation. Secondly, some problems that go unnoticed in genetic mapping can be predicted and well explained by the occurrence of chromosome rearrangements in the parents which are used to produce the segregation population and thirdly, the discovery of U-type exchanges during meiosis and de novo isochromosomes in the backcross progenies supplies an alternative mechanism for the origin of B chromosomes.

    A Bayesian analysis of gene flow from crops to their wild relatives: cultivated (Lactuca sativa L.) and prickly lettuce (L. serriola L.) and the recent expansion of L. serriola in Europe
    Uwimana, B. ; Andrea, L. D'; Felber, F. ; Hooftman, D.A.P. ; Nijs, H.C.M. den; Smulders, M.J.M. ; Visser, R.G.F. ; Wiel, C.C.M. van de - \ 2012
    Molecular Ecology 21 (2012)11. - ISSN 0962-1083 - p. 2640 - 2654.
    genetically-modified crops - multilocus genotype data - populus-nigra l. - population-structure - sect lactuca - situ conservation - hybridization - asteraceae - hybrids - spp.
    Interspecific gene flow can lead to the formation of hybrid populations that have a competitive advantage over the parental populations, even for hybrids from a cross between crops and wild relatives. Wild prickly lettuce (Lactuca serriola) has recently expanded in Europe and hybridization with the related crop species (cultivated lettuce, L. sativa) has been hypothesized as one of the mechanisms behind this expansion. In a basically selfing species, such as lettuce, assessing hybridization in natural populations may not be straightforward. Therefore, we analysed a uniquely large data set of plants genotyped with SSR (simple sequence repeat) markers with two programs for Bayesian population genetic analysis, STRUCTURE and NewHybrids. The data set comprised 7738 plants, including a complete genebank collection, which provided a wide coverage of cultivated germplasm and a fair coverage of wild accessions, and a set of wild populations recently sampled across Europe. STRUCTURE analysis inferred the occurrence of hybrids at a level of 7% across Europe. NewHybrids indicated these hybrids to be advanced selfed generations of a hybridization event or of one backcross after such an event, which is according to expectations for a basically selfing species. These advanced selfed generations could not be detected effectively with crop-specific alleles. In the northern part of Europe, where the expansion of L. serriola took place, the fewest putative hybrids were found. Therefore, we conclude that other mechanisms than crop/wild gene flow, such as an increase in disturbed habitats and/or climate warming, are more likely explanations for this expansion.
    Buddleja davidii en hybriden : sortimentonderzoek en keuringsrapport
    Hop, M.E.C.M. - \ 2011
    Dendroflora 2011 (2011)48. - ISSN 0374-7247 - p. 34 - 67.
    buddleja davidii - houtachtige planten als sierplanten - rassen (planten) - cultivars - hybriden - winterhardheid - gebruikswaarde - buddleja davidii - ornamental woody plants - varieties - cultivars - hybrids - winter hardiness - use value
    In Buddleja davidii zijn de afgelopen jaren veel ontwikkelingen geweest. Om het kaf van het koren te scheiden is eerst een proef in Boskoop gedaan, die later ook nog in Europees verband is opgepakt. De keuringsresultaten worden hier gepresenteerd. Tevens volgt een overzicht van wereldwijd beschikbare Buddleja's waaronder meerdere veelbelovende nieuwigheden.
    Towards F1 Hybrid Seed Potato Breeding
    Lindhout, P. ; Meijer, D.A. ; Schotte, T. ; Hutten, R.C.B. ; Visser, R.G.F. ; Eck, H.J. van - \ 2011
    Potato Research 54 (2011)4. - ISSN 0014-3065 - p. 301 - 312.
    plantenveredeling - plantenveredelingsmethoden - hybridisatie - hybriden - diploïdie - zelfincompatibiliteit - aardappelen - plant breeding - plant breeding methods - hybridization - hybrids - diploidy - self incompatibility - potatoes - species solanum-chacoense - inhibitor sli gene - self-compatibility - quantitative trait - diploid potatoes - yield - heterosis - sequence - markers - tomato
    Compared to other major food crops, progress in potato yield as the result of breeding efforts is very slow. Genetic gains cannot be fixed in potato due to obligatory out-breeding. Overcoming inbreeding depression using diploid self-compatible clones should enable to replace the current method of out-breeding and clonal propagation into an F1 hybrid system with true seeds. This idea is not new, but has long been considered unrealistic. Severe inbreeding depression and self-incompatibility in diploid germplasm have hitherto blocked the development of inbred lines. Back-crossing with a homozygous progenitor with the Sli gene which inhibits gametophytic self-incompatibility gave self-compatible offspring from elite material from our diploid breeding programme. We demonstrate that homozygous fixation of donor alleles is possible, with simultaneous improvement of tuber shape and tuber size grading of the recipient inbred line. These results provide proof of principle for F1 hybrid potato breeding. The technical and economic perspectives are unprecedented as these will enable the development of new products with combinations of useful traits for all stakeholders in the potato chain. In addition, the hybrid’s seeds are produced by crossings, rendering the production and voluminous transport of potato seed tubers redundant as it can be replaced by direct sowing or the use of healthy mini-tubers, raised in greenhouses.
    Invloed lagere nachttemperatuur tijdens opkweek Phalaenopsis
    Kromwijk, J.A.M. ; Campen, J.B. - \ 2011
    Bleiswijk : Wageningen UR Glastuinbouw (Rapporten GTB 1115) - 80
    phalaenopsis - hybriden - cultivars - luchttemperatuur - orchidaceae - bloei-inductie - teelt - energiebesparing - nederland - glastuinbouw - sierteelt - phalaenopsis - hybrids - cultivars - air temperature - orchidaceae - flower induction - cultivation - energy saving - netherlands - greenhouse horticulture - ornamental horticulture
    In Amerika bleven twee Phalaenopsiscultivars geteeld bij een hoge dag- en lage nachttemperatuur (29/23 oC en 29/17 oC) volledig vegetatief. In Nederlands onderzoek, gefinancierd door het ministerie van EL&I en het Productschap Tuinbouw in het kader van het programma Kas als Energiebron, bleek dat het tegenhouden van de bloei door middel van een dagtemperatuur van 29°C en een lage nachttemperatuur sterk afhankelijk is van de cultivar. Bij de cultivars ‘Boston’, ‘Bristol’ en ‘Lennestadt’ werd de bloemtakvorming gedurende de eerste 23 weken van de opkweek wel voldoende tegen gehouden, maar bij de andere 5 cultivars (‘Chalk Dust’, ‘Fire Fly’, ‘Liverpool’, ‘Precious’ en ‘Vivaldi’) werden al meer of minder snel voortakken gevormd. Ondanks het achterblijven van de bladafsplitsing en de weggeknipte voortakken na een opkweek bij een hoge dag- en lage nachttemperatuur, was het percentage meertakkers (=planten met minimaal 2 bloemtakken) in het veilingrijpe stadium maar 5 tot 8% lager dan na een gangbare opkweek bij een constante temperatuur van 28 oC. Voor toepassing van een lagere nachttemperatuur onder gangbare praktijkomstandigheden is een energiebesparing berekend van 8%.
    Praktijkervaringen lelies koken met voor- en nawarmte
    Kok, B.J. ; Aanholt, J.T.M. van - \ 2010
    BloembollenVisie 2010 (2010)184. - ISSN 1571-5558 - p. 22 - 23.
    bloembollen - lelies - cultivars - hybriden - heetwaterbehandeling - warmtebehandeling - steriliseren - mijten - dood - ornamental bulbs - lilies - cultivars - hybrids - hot water treatment - heat treatment - sterilizing - mites - death
    In 2009 hebben 10 lelietelers de nieuwe kookbehandeling bij 41°C in combinatie met voor- en nawarmte in 27 leliecultivars uit de groep van de Oriëntals en de LA-hybriden. De resultaten waren positief
    Genetic composition of cultured and wild mussels Mytilus from The Netherlands and transfers from Ireland and Great Britain
    Kijewski, T. ; Wijsman, J.W.M. ; Hummel, H. ; Wenne, R. - \ 2009
    Aquaculture 287 (2009)3-4. - ISSN 0044-8486 - p. 292 - 296.
    galloprovincialis - populations - edulis - trossulus - coast - selection - markers - protein - hybrids - zone
    The genetic composition of wild and cultured mussel populations from the Oosterschelde, The Netherlands, is compared to representative samples of mussel shipments from culture sites in Ireland and Great Britain. A total of 2272 mussels from 27 samples were assayed for the nuclear DNA markers Me 15116, EFbis and M7. The three markers showed similar patterns of taxonomic consistency across the mussel samples. However, some variation between markers was observed. While, all samples were almost "pure" Mytilus edulis, nevertheless Dutch wild populations Were more admixed with M. galloprovincialis and M. trossulus alleles than those from eastern Ireland, Wales and southern England. The mixed allele genotypes (hybrids) indicate the pre-existing occurrence of non-indigenous Mytilus taxa or natural introgression into Oosterschelde. Our results demonstrated that at the genetic level. there is no immediate threat from the introduction of nonindigenous Mytilus taxa through import from the studied sites in Ireland and Great Britain into the Oosterschelde. However, it is possible that with the import of mussels, M. galloprovincialis will be translocated, especially in the face of expected climate changes in the future.
    Broei en afzet van biologische lelies
    Kok, B.J. ; Kool, S.A.M. de - \ 2009
    Lisse : Praktijkonderzoek Plant & Omgeving, Bloembollen (PPO 721) - 34
    biologische landbouw - bloementeelt - forceren van planten - lelies - liliaceae - lilium longiflorum - hybriden - organic farming - floriculture - forcing - lilies - liliaceae - lilium longiflorum - hybrids
    Jaarrond levering van biologische bloemen is nog niet goed mogelijk. Vooral in het voorjaar en najaar is er een tekort aan bloemen die een substantieel deel kunnen uitmaken van biologische boeketten. In dit project werd onderzocht of het mogelijk is om in genoemde periodes biologische lelies te broeien. Het uitgangspunt daarbij is dat de lelies zonder of met minimale belichting in bloei worden getrokken. Uit een inventarisatie onder lelieveredelaars is naar voren gekomen dat lelies uit de groep van de LA-hybriden het meest geschikt zijn om zonder licht te broeien. Ook lelies uit de groep van de Longiflorums zouden geschikt zijn om zonder licht in bloei te trekken maar de verwachting is dat de trekduur erg lang zal zijn. Leliebollen uit de groep van de orientals zijn te duur als uitgangsmateriaal voor de biologische broeierij. Er werden 5 cultivars uit de groep van de LA-hybriden getest en 1 cultivar uit de groep van de Longiflorums. De roze bloeiende LA-hybride Brindisi en de rood bloeiende LA-hybride California bleken geschikt te zijn om in de winter zonder belichting in bloei te trekken. Met minimale belichting was ook Salmon Classic bij alle geteste plantdata in bloei te trekken
    A molecular cytogenetic study of intergenomic recombination and introgression of chromosomal segments in lilies (Lilium)
    Nadeem Khan, M. - \ 2009
    Wageningen University. Promotor(en): Richard Visser; Jaap van Tuyl. - [S.l. : S.n. - ISBN 9789085853800 - 121
    lilium - cytogenetica - recombinatie - genomen - introgressie - hybridisatie - hybriden - genetische kartering - polyploïdie - koppelingskartering - lilium - cytogenetics - recombination - genomes - introgression - hybridization - hybrids - genetic mapping - polyploidy - linkage mapping
    Lilies (Lilium L.) are one of the most important ornamental bulbous crops for cut flower industry
    grown extensively in The Netherlands for last few decades. The genus Lilium consists of seven
    different sections with about 80 species. The species within genus Lilium (2n = 2x = 24)
    comprise a range of desirable and complementary characters. Besides being an important
    horticultural crop, lily (Lilium) also serves as an interesting model plant for molecular
    cytogenetic research and introgression breeding for several reasons like, i). Lily is a model crop
    for interspecific hybridization and it includes plants of different taxonomic species each of which
    possess valuable horticultural traits that need to be combined in the new cultivars. ii) Through
    careful selection n and 2n gametes can be obtained in interspecific hybrids. iii) The genomes of
    different species are so well differentiated genetically that the parental chromosomes can be
    clearly identified in the F1 hybrids as well as in the progenies through DNA in situ hybridization
    techniques. iv) The chromosomes are large enough and the number and position of
    homoeologous recombination sites can be clearly detected. v) The large and easily identified
    chromosomes in different lily species could be a potential source for the cytological mapping of
    the Lilium genomes. Taking advantage of these favourable attributes of lily, a molecular
    cytogenetic investigation was conducted to evaluate the amount of recombination and
    introgression of characters between Longiflorum - Asiatic (LA) and Oriental - Asiatic (OA)
    hybrids through the use of n and 2n gametes.
    For this purpose different F1 Longiflorum × Asiatic (LA) and Oriental × Asiatic (OA)
    hybrids were backcrossed with different Asiatic cultivars. Ovule and embryo rescue techniques
    were employed to get backcross (BC) progenies. Most of the F1 LA appeared to be sterile but
    some hybrids were able to produce only 2n gametes in considerable frequencies. However, in
    rare occasions it was also found that normal meiosis took place in few of the LA hybrids which
    resulted into the formation of normal n gametes. Ploidy level and intergenomic recombination
    was studied in LA interspecific hybrids in order to assess the possibility of functional n gametes
    and their potential use in introgression at diploid level in lily. A total of 104 BC1 LA
    interspecific lily hybrids were obtained, 27 diploids (2n = 2x = 24), 73 triploids (2n = 2x = 36)
    and 4 aneuploids (2x – 1, 2x + 2 or 2x + 3). Similarly, triploid BC1 (LAA) plants were
    backcrossed to diploid Asiatic parents. As a result 14 diploid BC2 progenies were produced. The
    intergenomic recombination and amount of introgression of respective genome (L and A) was
    assessed in these diploid genotypes through GISH (Genomic in situ Hybridization). Extensive
    intergenomic recombination was found among the chromosomes in LA hybrids. A large of
    amount of L- genome was transmitted from F1 LA hybrids to their subsequent BC1 progenies.
    However, very few segments of L- genome were introgressed from the BC1 diploid and triploid
    (LAA) plants to the BC2 progenies (Chapter 2). GISH identifies a considerable amount of
    recombination events amongst different interspecific lily hybrids (LA and OA) obtained from
    functional 2n gametes. Based on recombination sites on different chromosomes identified by
    GISH, cytological maps of three genomes of Lilium were constructed. For this purpose, BC
    progenies of two diploid interspecific hybrids of lily, viz., Longiflorum × Asiatic (LA) and
    Oriental × Asiatic (OA) were used. The BC progenies of LA hybrids consisted of both triploid
    (2n = 3x = 36) and diploid (2n = 2x = 24) with some aneuploid genotypes and those of OA
    hybrids mostly consisted of triploid (2n = 3x = 36) and some aneuploid genotypes. In LA
    hybrids 248 recombination sites were cytologically localized on 12 different chromosomes of
    each genomes (i.e., L and A). Similarly, 116 recombinant sites were marked on 12 chromosomes
    each from the BC progenies of OA hybrids (O and A genomes). The distances of the
    recombination sites from the centromeres are measured (in micrometres). Based on these
    recombination sites four cytological maps were constructed. Since an Asiatic parent was
    involved in both hybrids, viz., LA and OA, two maps were constructed for A genome which
    were indicated as Asiatic (L) and Asiatic (O) and one each for Longiflorum (A) and Oriental (A)
    genomes (Chapter 3).
    With a view to generate genetic variation via homoeologous recombination in BC
    progenies of LA and OA hybrids the most logical approach was the use of 2n gametes. 63 BC1
    LA (LA × AA or AA × LA) and 53 OA (AA × OA) progeny plants were obtained after unilateral
    sexual polyploidization. 16 genotypes from F2 LA populations were obtained after bilateral
    sexual polyploidization through sib-mating of F1 LA hybrids. GISH was employed for the
    identification of the parental genomes, mode of origin of these progenies and measurement of the
    introgression in different interspecific lily hybrids. Most of the BC1 progeny plants (LA and OA)
    had originated through 2n gametes by First Division Restitution (FDR) mechanism. However,
    there were 12 genotypes in LA hybrids and four genotypes in OA hybrids that originated through
    2n gametes formation as the result of Indeterminate Meiotic Restitution (IMR). A higher amount
    of recombination was found in LA hybrids as compared to OA hybrids. Intergenomic
    recombination was also determined in the sib-mated F2 LA population. In this case both parents
    had contributed gametes with the somatic number of chromosomes (i.e., 2n-2n) thus confirming
    the event of bilateral sexual polyploidization in interspecific LA hybrids. Based on these results,
    the relevance of interspecific lily hybrids obtained from uni- and bilateral sexual
    polyploidization leading to allotriploid and allotetraploid formation in interspecific lily hybrids is
    discussed in the context of introgression and mapping (Chapter 4). Molecular markers are an important tool for the construction of genetic linkage maps, as the first step in the genetic
    dissection of the required traits leading to crop improvement followed by the marker assisted
    breeding in different plants. Lilium has one of the largest genome in plant kingdom and genetic
    mapping in lilies is constrained by its large genome. DArT (Diversity Array Technology), a
    molecular marker technique can detect and type DNA variation at several hundred genomic loci
    in parallel without relying on genome sequence information. The DArT technique was developed
    for Longiflorum × Asiatic (LA) lily hybrids to enable an efficient and effective genetic mapping
    with the production of a large numbers of markers in microarrays-based assay. The restriction
    enzyme PstI + TaqI combination generated the largest frequency of polymorphic genomic
    representations for a genotyping array. Genomic representations from 88 F1 LA plants were used
    to assemble a DArT genotyping microarray. A total of 687 DArT markers were developed and
    382 polymorphic markers were mapped on 14 main linkage groups which is two more then the
    haploid chromosome number (i.e. n = 12). The resulting linkage map with 382 DArT markers
    spanned 1329 cM (3.5 cM/marker on average). The results highlighted the potential of DArT as
    a genetic technique for genome profiling in the context of molecular breeding and genomics,
    especially in crops with large genome sizes where other techniques proved to be less useful
    (Chapter 5).
    The results of the present investigation are of practical implication. These results show
    the advantages of the n gametes and their subsequent progenies which opened a new approach of
    lily breeding ‘the analytic breeding’ in the allopolyploids. It also shows the possibility of using
    certain triploid hybrids for further breeding. A comparison has been made between different
    types of interspecific crosses, the amount of intergenomic recombination and introgressions of
    chromosomal segments obtained after unilateral sexual polyploidization. Furthermore, bilateral
    sexually polyploidization via sib-mated F1 hybrids producing 2n gametes has been proven. The
    use of allotetraploids obtained from bilateral sexual polyploidization could be a novel approach
    in the breeding of LA-hybrids. These allotetraploid with recombinant chromosomal segment
    may be a potential source to generate genetic variation in subsequent progenies. The molecular
    cytogenetic GISH and FISH techniques proved to be a powerful tool useful for the construction
    of cytogenetic maps in interspecific crosses in crops with large genomes sizes like lily. These
    techniques are also used for the identification and integration of genetic maps with chromosome
    maps. FISH also helps to monitor the introgressed chromosome segment or marker of interest in
    the subsequent progenies. Application of the DArT technique proved to be an effective method
    to construct genetic linkage maps especially crops (like Lilium) with large genome sizes where
    other techniques might be less useful.

    The Potential Of High-Resolution BAC-FISH In Banana Breeding
    Capdeville, G. De; Souza, M.T. ; Szinay, D. ; Eugenio Cardamone Diniz, L. ; Wijnker, T.G. ; Swennen, R. ; Kema, G.H.J. ; Jong, J.H.S.G.M. de - \ 2009
    Euphytica 166 (2009)3. - ISSN 0014-2336 - p. 431 - 443.
    artificial chromosome library - in-situ hybridization - musa-acuminata - diploid bananas - genome structure - dna - hybrids - gene - construction - balbisiana
    Abstract The genetic complexity in the genus Musa has been subject of study in many breeding programs worldwide. Parthenocarpy, female sterility, polyploidy in different cultivars and limited amount of genetic and genomic information make the production of new banana cultivars difficult and time consuming. In addition, it is known that part of the cultivars and related wild species in the genus contain numerous chromosomal rearrangements. In order to produce new cultivars more effectively breeders must better understand the genetic differences of the potential crossing parents for introgression hybridization, but extensive genetic information is lacking. As an alternative to achieve information on genetic collinearity we make use of modern chromosome map technology known as high-resolution fluorescent in situ hybridization (FISH). This article presents the technical aspects and applications of such a technology in Musa species. The technique deals with BAC clone positioning on pachytene chromosomes of Calcutta 4 (Musa acuminata ssp. burmanicoides, A genome group, section Eumusa) and M. velutina (section Rodochlamys). Pollen mother cells digestion with pectolytic enzymes and maceration with acetic acid were optimized for making cell spread preparations appropriate for FISH. As an example of this approach we chose BAC clones that contain markers to known resistance genes and hybridize them for establishing their relative positions on the two species. Technical challenges for adapting existing protocols to the banana cells are presented. We also discuss how this technique can be instrumental for validating collinearity between potential crossing parents and how the method can be helpful in future mapping initiatives, and how this method allows identification of chromosomal rearrangements between related Musa species and cultivars
    Stem characteristics of two forage maize (Zea mays L.) cultivars varying in whole plant digestibility. III. Intra-stem variability in anatomy, chemical composition and in vitro rumen fermentation
    Boon, E.J.M.C. ; Struik, P.C. ; Tamminga, S. ; Engels, F.M. ; Cone, J.W. - \ 2008
    NJAS Wageningen Journal of Life Sciences 56 (2008)1/2. - ISSN 1573-5214 - p. 101 - 122.
    cell-wall digestibility - gas-production - genetic-variation - surface-area - silage maize - hybrids - degradation - kinetics - traits
    The internodes of forage maize (Zea mays L.) stems were studied at anthesis for variation in anatomy and chemical composition in relation to digestibility. The study was carried out with a short (Vitaro) and a tall (Volens) cultivar differing in whole-plant digestibility, both of which were grown in the field in the growing seasons of 1999 and 2000. Internode diameter increased from the top to the base of the stem and Vitaro had shorter and thicker internodes than Volens. The cell walls of the sclerenchyma tissue in the rind were thicker and the numbers of sclerenchyma layers around vascular bundles in the rind higher in lower than in upper internodes. The neutral detergent fibre content (NDF%) of the internodes increased from the top to the base of the stems of both cultivars, but was very high for the peduncle. NDF% was lower for Vitaro than for Volens in all internodes. The sugar content of the dry matter was highest for Internode 12, i.e., the internode near the position of the ear, and was very low for the peduncle. Vitaro always had a higher sugar content than Volens. When subjected to fermentation tests with rumen fluid in an automated gas production system, gas production values after 3, 20 or 72 h of incubation were higher for internodes from the top than for internodes from the base of the stem, and were lower for the peduncle than for Internode 14. The values were consistently higher for Vitaro than for Volens internodes; in general, this difference was most apparent for Internode 10. The differences in gas production amongst internodes and between cultivars were in line with differences expressed by in vitro digestibility measurements. Fermentation results of cross sections suggest that the cell walls in lower internodes disappeared faster and to a greater extent than the cell walls in upper internodes, except for Volens in 1999, and with the exception of the peduncle. The rate of cell wall disappearance was higher for Volens than for Vitaro, but ultimately similar amounts of cell wall material disappeared
    Low Dietary Energy Concentration, High Nonstarch Polysaccharide Concentration, and Coarse Particle Sizes of Nonstarch Polysaccharides Affect the Behavior of Feather-Pecking-Prone Laying Hens
    Krimpen, M.M. van; Kwakkel, R.P. ; Peet-Schwering, C.M.C. van der; Hartog, L.A. den; Verstegen, M.W.A. - \ 2008
    Poultry Science 87 (2008). - ISSN 0032-5791 - p. 485 - 496.
    egg-production - performance - protein - strains - plumage - hybrids - layers - fiber - whole
    An experiment was conducted with 504 non-cage-housed ISA Brown laying hens from 18 to 40 wk of age to investigate the separate effects of dietary energy concentration, nonstarch polysaccharide (NSP) concentration, and particle sizes of added NSP source on the eating behavior, feather-pecking behavior, and hen performance of laying hens. Hens were allotted to 1 of 6 dietary treatments according to a 2 x 3 factorial arrangement, with 7 replicates per treatment. The factors were control and low energy concentration (2,825 vs. 2,540 kcal/kg), control and high NSP concentration (133 vs. 195 g/kg), and fine vs. coarse particle size of the added NSP source in the high-NSP diets. We hypothesized that eating time would be increased by feeding low-energy diets or coarsely ground, high-NSP diets, or both, resulting in reduced feather-pecking behavior, without negatively affecting hen performance. Energy reduction, NSP addition, and coarse grinding of NSP increased eating time by 14.2% (P = 0.001), 17.2% (P <0.001), and 7.9% (P = 0.075), respectively, compared with the control level of these factors. Addition of NSP decreased eating rate (g/min) by 21.0% (P = 0.010). Layers already performed gentle feather-pecking behavior during the fifth week of the rearing period. Dietary treatments did not affect the maximal level of feather condition scores, but arise of feather damage was delayed by 10 wk in hens fed low-energy, coarsely ground, NSP-rich diets compared with hens fed control diets. Hens fed the control NSP diets showed reduced culling rates, because of less cannibalistic pecking, when energy concentration was decreased (44.1 vs. 13.1%), whereas in the high-NSP diets, culling rate decreased slightly when hens were fed the low-energy diets (31.6 vs. 28.6%; P = 0.071). Hens that were fed the low-energy diets compensated for the 10% reduction in energy concentration by a 9.3% higher maximal feed intake (143.0 vs. 130.8 g/d). Hen performance and BW gain of the hens were not affected by dietary treatments. We concluded that hens that were fed low-energy or high (coarsely ground)-NSP diets spend more time on feed intake, compared with hens that were fed the control diets. As a result, hens in some treatments showed less feather-pecking behavior.
    Hoever staat het met de OA-hybriden?
    Tuyl, J.M. van; Silfhout, A.A. van - \ 2007
    BloembollenVisie 1 (2007)107. - ISSN 1571-5558 - p. 24 - 25.
    lilium - bloembollen - plantenveredeling - rassen (planten) - hybriden - laboratoriumproeven - lilium - ornamental bulbs - plant breeding - varieties - hybrids - laboratory tests
    In de ontwikkeling van het leliesortiment spelen niet alleen veredelingsbedrijven zelf een belangrijke rol. Ook in Wageningen vormen allerlei lastige kruisingen onderwerp van studie. Al veertien jaar is de kruising tussen Oriëntal en Aziaat een project dat voor twaalf veredelingsbedrijven wordt uitgevoerd door PlantBreeding van WUR. In dit artikel de stand van zaken in dat project
    A study of the process of synchronisation and micronucleation in Beta vulgaris and the monitoring of an isolation procedure for micro-nuclei and micro-protoplasts by confocal laser scanning microscopy and flow cytometry
    Famelaer, I. ; Verhoeven, H.A. ; Dijkhuis, P. ; Ramulu, K.S. - \ 2007
    Plant Cell, Tissue and Organ Culture: an international journal on in vitro culture of higher plants 90 (2007)2. - ISSN 0167-6857 - p. 169 - 179.
    partial genome transfer - cell-suspension cultures - nicotiana-plumbaginifolia - gametic microprotoplasts - hybridization - hybrids - fusion - plants - regeneration - chromosomes
    The process of synchronization and micro-nuclei induction in a suspension culture of Beta vulgaris, was induced by the sequential treatment with the DNA-synthesis inhibitor aphidicolin (30 mu M, 24 h) and the spindle-toxin amiprophos-methyl (32 mu M, 24 h). Mitotic arrest of divisions, spreading of G2-metaphase chromosomes, re-grouping of chromosomes, formation of a nuclear cell wall around single and re-grouped chromosomes and restitution of nuclei with a doubled DNA content was observed. The process of micro-nucleation was induced much less efficiently in Beta vulgaris than in Nicotiana plumbaginifolia. Cytological observations and monitoring of the process with flow cytometry and confocal laser scanning microscopy, was essential to follow up the course of events and to monitor the development of an efficient procedure for micro-protoplast isolation. Micro-nucleated protoplasts were fractioned by iso-osmotic Percoll gradient centrifugation to obtain heterogeneous micro-protoplast populations with cytoplasts and micro-protoplasts of different size. An enriched fraction with small sub-diploid micro-protoplasts was obtained with the equivalent DNA content of 1-4 chromosomes, as revealed by confocal laser scanning microscopy and flow cytometry. Sub-diploid micro-protoplasts with DNA amounts equivalent to 1-4 chromosomes were predominantly observed in the size classes of 1.8-10.2 mu m at a frequency of 34.2-34.5%. The DNA measurements of micro-nuclei and micro-protoplasts, confirmed the hypothesis that the process of micro-nucleation followed the same course of cellular events as observed in N. plumbaginifolia. The correlation between DNA content and size of micro-nuclei and micro-protoplasts was not linear and affected by the degree of DNA condensation, total amount of DNA, and the presence of cytoplasm.
    Fusarium ear rot and how to screen for resistance in open pollinated maize in the Andean regions
    Silva, E. ; Mora, E.A. ; Medina, A. ; Vasquez, J. ; Valdez, D. ; Danial, D.L. ; Parlevliet, J.E. - \ 2007
    Euphytica 153 (2007)3. - ISSN 0014-2336 - p. 329 - 337.
    graminearum infection - corn - moniliforme - genotype - colonization - fumonisins - mycotoxins - hybrids - fungal
    Ears infected with ear rot were collected from five provinces in Ecuador. Of the 44 samples analysed 26 carried Fusarium verticillioides, 11 F. subglutinans, two F. graminearum and five carried fungi different from Fusarium. The pathogenicity of ten isolates, seven of F. verticillioides and three of F. subglutinans, were tested. Per isolate 30 ears of the susceptible cultivar Mishca were inoculated by pricking a steel pin, dipped into a spore suspension, through the husks in the central part of the ear 14 days after mid-silk. Ears inoculated with sterile water and ears without any treatment, natural infection, served as controls. The disease severity (DS) of the ears ranged from 14 to 58% ear rot, the range being similar for both species. The DS of the water control, 19%, was much higher than that of the natural control of 2%. Five strains gave a DS of over 40%, significantly higher than the water control. The DS of the others were similar to the water control. In a series of experiments the effect of various methods of applying Fusarium spores through the husks into young ears were compared. All tested methods resulted in DSs significantly higher than those of the two controls. Inoculation with tooth picks and steel pins dipped in a spore suspension gave similar ear rot percentages. Inoculations at 7 to 14 days after mid-silk produced the highest DS¿s. There was no significant effect of spore concentration on the DS. Cultivars differed considerably, the range being from around 20% to over 50%. Surprisingly, only wounding the husks, the sterile water control, resulted in a fairly high DS, much higher than that of the natural control. As the ranking order of the cultivars after wounding only and after inoculation did not seem to be different from the ranking order of the natural control it is suggested to use in areas with high inoculum pressures like the Andes only wounding by means of a steel pin for screening for resistance to maize ear rot.
    Distribution, diversity and environmental adaptation of highland papaya (Vasconcellea spp.) in tropical and subtropical America
    Scheldeman, X. ; Willemen, L. ; Coppens D'eeckenbrugge, G. ; Romeijn-Peeters, E. ; Restrepo, M.T. ; Romero Motoche, J. ; Jimenez, D. ; Lobo, M. ; Medina, C.I. ; Reyes, C. ; Rodriguez, D. ; Ocampo, J.A. ; Damme, P. van; Goetghebeur, P. - \ 2007
    Biodiversity and Conservation 16 (2007)6. - ISSN 0960-3115 - p. 1867 - 1884.
    wild crop germplasm - ex-situ collections - interspecific hybridization - biodiversity exploration - conservation priorities - geographic information - carica-cauliflora - pentagona - ecuador - hybrids
    Vasconcellea species, often referred to as highland papayas, consist of a group of fruit species that are closely related to the common papaya (Carica papaya). The genus deserves special attention as a number of species show potential as raw material in the tropical fruit industry, fresh or in processed products, or as genetic resources in papaya breeding programs. Some species show a very restricted distribution and are included in the IUCN Red List. This study on Vasconcellea distribution and diversity compiled collection data from five Vasconcellea projects and retrieved data from 62 herbaria, resulting in a total of 1,553 georeferenced collection sites, in 16 countries, including all 21 currently known Vasconcellea species. Spatial analysis of species richness clearly shows that Ecuador, Colombia and Peru are areas of high Vasconcellea diversity. Combination of species occurrence data with climatic data delimitates the potential distribution of each species and allows the modeling of potential richness at continent level. Based on these modeled richness maps, Ecuador appears to be the country with the highest potential Vasconcellea diversity. Despite differences in sampling densities, its neighboring countries, Peru and Colombia, possess high modeled species richness as well. A combination of observed richness maps and modeled potential richness maps makes it possible to identify important collection gaps. A Principal Component Analysis (PCA) of climate data at the collection sites allows us to define climatic preferences and adaptability of the different Vasconcellea species and to compare them with those of the common papaya.
    Red de iep
    Hiemstra, J.A. ; Kopinga, J. ; Buiteveld, J. - \ 2007
    De Boomkwekerij 20 (2007)5. - ISSN 0923-2443 - p. 18 - 19.
    ulmus - ulmaceae - ulmus laevis - ulmus glabra - ulmus minor - hybriden - rassen (planten) - ophiostoma ulmi - ziekteresistentie - ulmus - ulmaceae - ulmus laevis - ulmus glabra - ulmus minor - hybrids - varieties - ophiostoma ulmi - disease resistance
    Het gebruik van de iep - ook resistente iepen - is in de afgelopen decennia dan ook sterk afgenomen. Hierdoor verdwijnt de iep steeds meer uit het Nederlandse landschap. De onvrede van groenbeheerders en boomkwekers leidde in de afgelopen jaren tot een aantal discussiebijeenkomsten over de toekomst van de iep. De conclusie hiervan was dat de iep in Nederland niet kan worden gegemist. Het nieuwe iepenproject van PPO en Alterra is onderzoek doen naar de groei- en gebruikseigenschappen van het huidige iepensortiment. Om de rassen onderling goed te kunnen vergelijken worden proefbeplantingen aangelegd waar rassen naast elkaar worden uitgeplant. De eerste twee grote beplantingen worden door de gemeente Amsterdam aangelegd in IJburg en het Westpoortgebied.
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