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.

    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.

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Nitrogen use efficiency in potato : an integrated agronomic, physiological and genetic approach
Ospina Nieto, C.A. - \ 2016
University. Promotor(en): Paul Struik; Edith Lammerts van Bueren, co-promotor(en): Gerard van der Linden. - Wageningen : Wageningen University - ISBN 9789462576469 - 177 p.
solanum tuberosum - potatoes - nitrogen - nutrient use efficiency - plant breeding - crop physiology - plant physiology - quantitative trait loci - cultivars - aardappelen - stikstof - nutriëntengebruiksefficiëntie - plantenveredeling - gewasfysiologie - plantenfysiologie - loci voor kwantitatief kenmerk

Nitrogen (N) fertilizers increased food production over the last 60 years, but also contributed significantly to the use of fossil energy and the total amount of reactive N in the environment. Agriculture needs to reduce N input and increase nitrogen use efficiency (NUE). Legislation like the Nitrate Directive (91/767/EEC) and the Water Framework Directive (2000/60/EC) forces a reduction in N supply in crop production. The effects of this constraint on yield and quality of potato are expected to be significant since N plays an important role in the vegetative development and production of potato. Considerable amounts of N are needed as N recovery is notoriously low due to the small and shallow roots. The overall aim of this thesis is to improve the nitrogen use efficiency of potato under low nitrogen supply. Specific aims are i) to understand the N effects on potato performance, especially under low N input, ii) to quantify the genotypic variation under contrasting N inputs, iii) to identify quantitative trait loci associated with the crop’s response to nitrogen. We used ecophysiological models to dissect the canopy development into biological meaningful parameters as phenotyping tools. Two potato populations (a set of tetraploid cultivars and a biparental diploid population) were phenotyped in the field under two contrasting N levels. Additionally, a set of 6 cultivars from three maturity groups (early, middle and late) were phenotyped in more detail under 5 nitrogen conditions combining two input levels and two fertilizers types plus a control without nitrogen fertilisation. The curve-fit parameters were, together with other agronomical traits, used in the agronomic and genetic analysis. Our approach using the ecophysiological models captured the phenotypic response to N, enhancing the interpretation of the nitrogen effects and of the differences among maturity types. The nitrogen effects on canopy development resulted in large differences in light interception, tuber yield, tuber size distribution and nitrogen uptake. There were differences in the response to nitrogen between the diploid biparental population and the set of tetraploid cultivars. In general, in the diploid population, having less vigour and therefore less potential to respond to the extra nitrogen, the time required to complete each phase of the canopy development was longer than in the set of tetraploids. In the set of cultivars the rate of early vegetative growth was higher, the onset of the phase with maximum canopy cover was earlier, and the duration of maximum canopy was longer than for the diploid population. However, in both the diploid and the tetraploid population maturity was the major factor accounting for genetic variation in canopy development and tuber development traits. The genotypic differences were reflected in quantitative trait loci that were either N dependent or N independent, with pleiotropic regions affecting most of the maturity-related traits. Few traits showed quantitative trait loci on common regions that were not maturity related like those on chromosomes 2 and 6 (association mapping) or linkage groups ma_VI, pa_VIII pa_XI. Maturity obscures other genotype-dependent physiological traits; therefore it is imperative to find traits that are responsible for genotypic variation, but not related to maturity type. Moreover the results showed that nitrogen use efficiency under low nitrogen input is higher than under high nitrogen input, and higher for late cultivars than for early cultivars. Therefore, breeding for nitrogen use efficiency under low input requires direct selection combined with good response to extra nitrogen and should be done within each maturity group. Finally in a broader context we discussed the need of high-throughput phenotyping in breeding for complex traits, like those involving efficiency, to make the most of the large amount of genetic data, all possible based on advances in technology in remote sensing and images analysis.

Keywords: Association mapping, Breeding for low input, Canopy development, Maturity type, Nitrogen use efficiency, Potato, Solanum tuberosum, Quantitative trait loci.

Inzicht en Zichtbaar Weerbaar: meetmethoden nodig voor teelt-zeker weerbaar telen
Wurff, A.W.G. van der; Streminska, M.A. ; Boer, F.A. de; Cuesta Arenas, Y. ; Janse, J. - \ 2015
Wageningen UR
cropping systems - horticulture - plant protection - hydroponics - greenhouse horticulture - conferences - chrysanthemum - soilless culture - substrates - measurement - interactions - markers - plant development - climate - cultivars - tuinbouw - glastuinbouw - teeltsystemen - cultuur zonder grond - substraten - meting - interacties - merkers - plantenontwikkeling - klimaat
Aandacht wordt geschonken aan: voedingswater, micro-leven, rasverschillen, en oud stekmateriaal. Poster van PlantgezondheidEvent 12 maart 2015.
Adaptation of the brown planthopper, Nilaparvata lugens (Sta°l), to resistant rice varieties
Ferrater, J.B. - \ 2015
University. Promotor(en): Marcel Dicke, co-promotor(en): F.G. Horgan; Peter de Jong. - Wageningen : Wageningen University - ISBN 9789462575592 - 200
insectenplagen - nilaparvata lugens - adaptatie - oryza sativa - rijst - cultivars - plaagresistentie - symbionten - gisten - endosymbionten - insect pests - adaptation - rice - pest resistance - symbionts - yeasts - endosymbionts

This thesis examines the three-way interaction between yeast-like symbionts, an insect herbivore [Nilaparvata lugens (Stål)] and its rice (Oryza sativa L.) host, during adaptation of the herbivore to resistant rice varieties. A long-term selection study (20 generations of continuous rearing, ca. 24 months) was conducted with N. lugens populations on four rice varieties (IR22, a susceptible variety and IR65482, IR62, and PTB33, three resistant varieties). Planthopper performance and the abundance of yeast-like symbionts (YLS) were monitored throughout the selection process. N. lugens populations adapted to the resistant varieties as noted by increasing body size and increased egglaying. Xylem feeding was observed as a possible behavioural adaptation of N. lugens: planthoppers on resistant plants had relatively high levels of xylem feeding compared with planthoppers on susceptible plants. Planthoppers selected on resistant varieties, had clear differences in YLS densities that were not related to fitness on the varieties and, therefore, did not support a YLS density-mediated adaptation hypothesis.

Furthermore, this study examined whether YLS density affected the capacity of planthoppers to switch between hosts on which they have been selected for several generations (natal plant) to new varieties (exposed plants) under normal YLS densities (symbiotic) and after reduction of YLS densities by heat treatment (aposymbiotic). The results suggested that YLS do not mediate host plant switching in planthoppers as removal of symbionts influenced body weight but not the relative capacity of nymphs to feed on different plants. This study also tested if virulence is acquired by shared feeding sites with virulent and avirulent planthoppers. In the study, planthoppers with varying levels of virulence affected the host plants differently: The most virulent hoppers appeared to suppress rice defences to a greater extent than non-virulent planthoppers. Planthoppers attained highest weights on those plants on which virulent planthoppers had previously fed which suggests that feeding by the virulent planthoppers facilitated subsequent planthopper feeding on the same plant. Our preliminary results indicate that feeding by mixed virulent-avirulent populations could potentially accelerate adaptation by N. lugens to resistant rice varieties.

The capacity of virulent and avirulent planthoppers to feed on a range of 24 resistant rice varieties was examined using a series of bioassays. Planthoppers were observed to feed and lay eggs on all the varieties tested, many of which have never been widely deployed in the field. Furthermore, planthoppers selected on resistant varieties often had increased fitness on other resistant varieties, even when these possess different resistance genes. However, there was no strong evidence that once planthoppers have adapted to a resistant variety, they will exhibit fitness costs on other varieties with dissimilar genes. The mechanisms underlying insect virulence are complex and further research on planthopper adaptation is necessary to help conserve genetic resources and prolong the durability of available resistant varieties.

Estimation of the in situ degradation of the washout fraction of starch by using a modified in situ protocol and in vitro measurements
Jonge, L.H. de; Laar, H. van; Dijkstra, J. - \ 2015
Animal 9 (2015)9. - ISSN 1751-7311 - p. 1465 - 1472.
dairy-cows - digestion - rumen - gas - degradability - barley - vivo - digestibility - feedstuff - cultivars
The in situ degradation of the washout fraction of starch in six feed ingredients (i.e. barley, faba beans, maize, oats, peas and wheat) was studied by using a modified in situ protocol and in vitro measurements. In comparison with the washing machine method, the modified protocol comprises a milder rinsing method to reduce particulate loss during rinsing. The modified method markedly reduced the average washout fraction of starch in these products from 0.333 to 0.042 g/g. Applying the modified rinsing method, the fractional degradation rate (k d ) of starch in barley, oats and wheat decreased from on average 0.327 to 0.144 h-1 whereas for faba beans, peas and maize no differences in k d were observed compared with the traditional washing machine rinsing. For barley, maize and wheat, the difference in non-fermented starch in the residue between both rinsing methods during the first 4 h of incubation increased, which indicates secondary particle loss. The average effective degradation of starch decreased from 0.761 to 0.572 g/g when using the new rinsing method and to 0.494 g/g when applying a correction for particulate matter loss during incubation. The in vitro k d of starch in the non-washout fraction did not differ from that in the total product. The calculated ratio between the k d of starch in the washout and non-washout fraction was on average 1.59 and varied between 0.96 for oats and 2.39 for maize. The fractional rate of gas production was significantly different between the total product and the non-washout fraction. For all products, except oats, this rate of gas production was larger for the total product compared with the non-washout fraction whereas for oats the opposite was observed. The rate of increase in gas production was, especially for grains, strongly correlated with the in vitro k d of starch. The results of the present study do not support the assumption used in several feed evaluation systems that the degradation of the washout fraction of starch in the rumen is much faster than that of the non-washout fraction.
QTL mapping of pomological traits in peach and related species breeding germplasm
Fresnedo-Ramírez, J. ; Bink, M.C.A.M. ; Weg, W.E. van de; Famula, T.R. ; Crisosto, C.H. ; Frett, T. ; Gasic, K. ; Peace, C.P. ; Gradziel, T.M. - \ 2015
Molecular Breeding 35 (2015). - ISSN 1380-3743 - 19 p.
persica l. batsch - prunus-persica - linkage disequilibrium - fruit size - population-structure - candidate genes - genome database - sweet cherry - almond - cultivars
Peach is an economically important fruit tree crop that exhibits high phenotypic variability yet suffers from diversity-limited gene pool. Genetic introgression of novel alleles from related species is being pursued to expand genetic diversity. This process is, however, challenging and requires the incorporation of innovative genomic and statistical tools to facilitate efficient transfer of these exotic alleles across the multiple generations required for introgression. In this study, pedigree-based analysis (PBA) in a Bayesian QTL mapping framework was applied to a diverse peach pedigree introgressed with almond and other related Prunus species. The aim was to investigate the genetic control of eight commercially important fruit productivity and fruit quality traits over two subsequent years. Fifty-two QTLs with at least positive evidence explaining up to 98 % of the phenotypic variance across all trait/year combinations were mapped separately per trait and year. Several QTLs exhibited variable association with traits between years. By using the peach genome sequence as a reference, the intrachromosomal positions for several QTLs were shown to differ from those previously reported in peach. The inclusion of introgressed germplasm and the explicit declaration of the genetic structure of the pedigree as covariate in PBA enhanced the mapping and interpretation of QTLs. This study serves as a model study for PBA in a diverse peach breeding program, and the results highlight the ability of this strategy to identify genomic resources for direct utilization in marker-assisted breeding.
Simulation of the phenological development of wheat and maize at the global scale
Bussel, L.G.J. van; Stehfest, E. ; Siebert, S. ; Müller, C. ; Ewert, F. - \ 2015
Global Ecology and Biogeography 24 (2015)9. - ISSN 1466-822X - p. 1018 - 1029.
climate-change - winter-wheat - annual crops - photoperiod sensitivity - geographical variation - temperature - responses - adaptation - cultivars - model
To derive location-specific parameters that reflect the geographic differences among cultivars in vernalization requirements, sensitivity to day length (photoperiod) and temperature, which can be used to simulate the phenological development of wheat and maize at the global scale. Location: Global. Methods: Based on crop calendar observations and literature describing the large-scale patterns of phenological characteristics of cultivars, we developed algorithms to compute location-specific parameters to represent this large-scale pattern. Vernalization requirements were related to the duration and coldness of winter, sensitivity to day length was assumed to be represented by the minimum and maximum day lengths occurring at a location, and sensitivity to temperature was related to temperature conditions during the vegetative development phase of the crop. Results: Application of the derived location-specific parameters resulted in high agreement between simulated and observed lengths of the cropping period. Agreement was especially high for wheat, with mean absolute errors of less than 3 weeks. In the main maize cropping regions, cropping periods were over- and underestimated by 0.5-1.5 months. We also found that interannual variability in simulated wheat harvest dates was more realistic when accounting for photoperiod effects. Main conclusions: The methodology presented here provides a good basis for modelling the phenological characteristics of cultivars at the global scale. We show that current global patterns of growing season length as described in cropping calendars can be largely reproduced by phenology models if location-specific parameters are derived from temperature and day length indicators. Growing seasons can be modelled more accurately for wheat than for maize, especially in warm regions. Our method for computing parameters for phenology models from temperature and day length offers opportunities to improve the simulation of crop productivity by crop simulation models developed for large spatial areas and for long-term climate impact projections that account for adaptation in the selection of varieties.
Nieuwe mogelijkheden voor de bestrijding van wittevlieg in de sierteelt onder glas : onderzoek aan omnivore roofwantsen en gedragsbeïnvloedende geuren
Messelink, G.J. ; Kruidhof, H.M. ; Elfferich, C. ; Leman, A. - \ 2015
Bleiswijk : Wageningen UR Glastuinbouw (Rapport GTB 1350)
glastuinbouw - sierteelt - organismen ingezet bij biologische bestrijding - reduviidae - thrips - effecten - schade - gerbera - cultivars - limoneen - geurstoffen - greenhouse horticulture - ornamental horticulture - biological control agents - effects - damage - limonene - odours
This study explored new possibilities to control whiteflies in greenhouse ornamental crops with omnivorous predatory bugs and volatiles. Besides the well-known Macrolophus pygmaeus, we tested 4 new species of predatory bugs: Dicyphus errans, Dicyphus eckerleini, Dicyphus maroccanus and Dicyphus tamaninii. We assessed both their potential to control whiteflies and their possible plant damaging effects through plant feeding. The best control of whiteflies was achieved by the species M. pygmaeus, D. tamaninii and D. maroccanus. Significant flower damage was only observed for the predator M. pygmaeus. The degree of flower damage depended strongly on the gerbera cultivar, but damage was observed for both large-flowered and small-flowered types. All 5 species of predatory bugs were able to establish in a winter crop of 2 gerbera cultivars and the exotic plant Lantana camara. The most promising candidate predatory bug for biological control in gerbera is D. maroccanus. This species established well on the 2 tested gerbera cultivars, gave in all cases an excellent control of pests and no significant plant damage was observed. The predatory bugs gave, besides whiteflies, a good control of Echinothrips and in some cases a suppression of aphids and western flower thrips. The volatile limonene showed no significant effect on the oviposition of tobacco and greenhouse whiteflies. Neither did they repel adults of these whiteflies. The mixture of (E)-2-hexenal and 3-hexen-1-ol did not induce a significant attraction response of the adult whiteflies.
Damage thresholds and population dynamics of Meloidogyne chitwoodi on carrot (Daucus carota) at different seed densities
Heve, W.K. ; Been, T.H. ; Schomaker, C.H. ; Teklu, M.G. - \ 2015
Nematology 17 (2015)5. - ISSN 1388-5545 - p. 501 - 514.
plant-parasitic nematodes - root-knot nematode - partial resistance - potato - cultivars - increase - hapla
Yield loss of carrot (Daucus carota) cv. Nerac caused by Meloidogyne chitwoodi and population dynamics of this nematode were studied using a range of 13 nematode densities at three seed densities (2, 4, 18 seeds pot-1) in a climate-controlled glasshouse. Yield and quality data were fitted to Seinhorst’s yield models. Final population densities were fitted to the population dynamic models for sedentary and free-living nematodes. The tolerance limits for yield loss were 0.34, 0.62 and 0.50, while that of quality were 0.012, 0.142 and 0.813 second-stage juveniles (J2) (g dry soil)-1 at increasing seed densities, respectively. The minimum yield (m), increased with seed density: 0.25, 0.30 and 0.50; the minimum quality yield was 0.10, 0.08 and 0.15 J2 (g dry soil)-1 at increasing seed densities, respectively. Both maximum multiplication rates and maximum population densities increased with increasing seed density but were generally low. Carrot cv. Nerac can be considered a bad host for M. chitwoodi.
Onderzoek stuurlicht Freesia winter 2013-2014 : praktijkonderzoek met lage intensiteit LED belichting tijdens de donkerperiode
Kromwijk, J.A.M. ; Echtelt, E. van; Akerboom, T. ; Pronk, H. - \ 2015
Bleiswijk : Wageningen UR Glastuinbouw (Rapport GTB 1346) - 28
glastuinbouw - freesia - cultivars - cultuurmethoden - energiebesparing - belichting - led lampen - verrood licht - temperatuur - gewasproductie - greenhouse horticulture - cultural methods - energy saving - illumination - led lamps - far red light - temperature - crop production
The use of low intensity red or far-red LED light during the dark period was tested in a commercial greenhouse at Akerboom Freesia. The use of red or far-red light in the dark period had no clear effect in Freesia. The production of the variety ‘Ambiance’ increased 6% at 8 μmol.m-2.s-1 red LED light during the dark period, but there was no increase in production for the variety ‘PinkPassion’. Low intensity far-red during the night period did not give an increase in production. It was shown that it is possible to realise a good Freesia production in a greenhouse with a lower intensity assimilation lighting. This was in combination with a lower temperature which resulted in a longer growing period compared to the cultivation of Freesia in a greenhouse with a higher intensity assimilation lighting and higher temperature.
Onderzoek stuurlicht Freesia winter 2012-2013 : praktijkonderzoek met lage intensiteit LED belichting tijdens de donkerperiode
Kromwijk, J.A.M. ; Echteld, E. van; Akerboom, T. ; Pronk, H. - \ 2015
Bleiswijk : Wageningen UR Glastuinbouw (Rapport GTB 1347) - 24
glastuinbouw - freesia - cultivars - belichting - led lampen - verrood licht - plantenontwikkeling - cultuurmethoden - effecten - greenhouse horticulture - illumination - led lamps - far red light - plant development - cultural methods - effects
Low intensity red or far-red LED light (4 µmol.m-2.s-1) during the dark period was tested in a commercial greenhouse (Akerboom Freesia). During the day assimilation lighting was used. The trial showed no clear effect on production. At the first planting date, plants showed symptoms of virus, so no production counts were carried out. At the second planting date, only small differences in production were observed (max. 6% difference in production) and there was no clear correlation with the treatments. This might be a result of low intensities of red and far-red light reaching the control plots and/or the variety used in this experiment (Ambassador). The production increase varied from 5% for the variety Albatros to 22% for the variety Red Beauty in a previous experiment with red and far-red LED light on Freesia. Ambassador maybe less sensitive to low intensity LED light during the dark period than the other cultivars.
Kwaliteit roos: relaties vaasleven en kasklimaat
Benninga, J. ; Barendse, J. ; Vermeulen, C. ; Garcia Victoria, N. ; Raaphorst, M.G.M. ; Hofland-Zijlstra, J.D. - \ 2015
snijbloemen - rozen - rassen (planten) - vaasleven - duurzaamheid (durability) - proeven - cultivars - relatieve vochtigheid - cut flowers - roses - varieties - vase life - durability - trials - relative humidity
Kwaliteit is het sterke punt van Nederlandse ten opzichte van buitenlandse rozen. Vanuit de markt bestaat een toenemende vraag naar kwaliteit garanties. Gebleken is dat, vooral in de periode vanaf half december tot half februari, veel partijen Nederlandse rozen niet kunnen voldoen aan de verwachting van zeven dagen vaasleven, zo blijkt uit het project “vaasleven getest” van FloraHolland, waar 60% van de Nederlandse aanvoerders om de week aan deelnemen. Om het vaasleven in de kritische periode (winter) te verbeteren is in de winters 2012/2013 en 2013/2014 een onderzoek uitgevoerd bij acht rozenteeltbedrijven: 4 teelden het ras Red Naomi! en 4 het ras Avalanche+.
Energiezuinige belichting bij chrysant
Meinen, E. ; Kempkes, F.L.K. ; Raaphorst, M.G.M. ; Dueck, T.A. - \ 2015
Wageningen UR Glastuinbouw (Rapport GTB 1341) - 101
glastuinbouw - energiebesparing - teelt onder bescherming - chrysanten - belichting - led lampen - landbouwkundig onderzoek - rassen (planten) - cultivars - greenhouse horticulture - energy saving - protected cultivation - chrysanthemums - illumination - led lamps - agricultural research - varieties
The effect of three different lighting systems was investigated on chrysanthemum, i.e. HPS, hybrid lighting (50% HPS and 50% LED), and LED lighting. The study looked at the effect of exposure on rooting, on the morphology in the long-day period, and for a whole crop in spring and autumn. Then also looked at post-harvest quality and shelf life. The spring crop showed that production was highest under hybrid lighting with end-of-day far red. A test with young chrysanthemum cuttings (cv. Baltica) revealed that end-of-day far red did not have a positive influence on light interception or leaf area. Spectral composition also affected rooting: only blue or red light led to fewer roots than spectra where far red was added. In an autumn crop 14 varieties were grown under HPS, hybrid and LED lighting. Production, quality and light use efficiency was highest under HPS, but the energy consumption in this treatment was the highest as well. Cultivating under LEDs cost 20% less electricity (for lighting), but the production and quality were less than under HPS lighting
In search of compact pot plants without chemicals : control possible by manipulating DIF and DROP
Heuvelink, E. ; Kierkels, T. - \ 2015
In Greenhouses : the international magazine for greenhouse growers 4 (2015)1. - ISSN 2215-0633 - p. 40 - 41.
glastuinbouw - potplanten - teelt - cultuurmethoden - cultivars - plantenontwikkeling - groeivertraging - groeiremmers - plantengroeiregulatoren - temperatuur - lichtregiem - greenhouse horticulture - pot plants - cultivation - cultural methods - plant development - growth retardation - growth inhibitors - plant growth regulators - temperature - light regime
Alternatives to growth inhibitors for pot plants are welcome. Scientific research points to cultivation practises that can inhibit growth. These offer possibilities where breeding fails to provide a solution.
Host plant resistance towards the cabbage whitefly in Brassica oleracea and its wild relatives
Pelgrom, K.T.B. ; Broekgaarden, C. ; Voorrips, R.E. ; Bas, N. ; Visser, R.G.F. ; Vosman, B.J. - \ 2015
Euphytica 202 (2015)2. - ISSN 0014-2336 - p. 297 - 306.
aleyrodes-proletella homoptera - glucosinolate polymorphism - insect-resistance - cultivars - populations - fruticulosa - tomato - tabaci
The cabbage whitefly (Aleyrodes proletella) is a phloem-feeding insect that is a serious problem in Brassica oleracea crops like Brussels sprouts, kale and savoy cabbage. In order to develop whitefly-resistant varieties it is essential to identify effective sources of resistance. In this study, we screened a large collection of 432 accessions, including wild material and landraces of Brassica oleracea as well as crop wild relatives, to determine whitefly performance in a no-choice field experiment. Putatively resistant accessions were further tested under greenhouse conditions. Resistant accessions were identified among B. oleracea var. capitata (cabbage) landraces and in the species B. villosa, B. incana and B. montana. Whereas resistance in cabbage is only expressed in plants of at least 12 weeks old, some wild relatives were already starting to express resistance at 6 weeks. This could open up possibilities for breeding cabbages that are resistant at a young(er) plant age. Our research also shows again the importance of crop wild relatives for finding pest resistances.
Various ways for successful Cultivar introduction in the market
Nuijten, H.A.C.P. ; Zeelenberg, A. ; Janmaat, L. ; Lammerts Van Bueren, E. - \ 2015
Louis Bolk Instituut
marketing - marketingkanalen - appels - gevalsanalyse - cultivars - ziekteresistentie - fruitteelt - agro-industriële ketens - verbetering - biologische productie - biologische landbouw - marketing channels - apples - case studies - disease resistance - fruit growing - agro-industrial chains - improvement - biological production - organic farming
In this brochure key obstacles and opportunities for market introduction of disease-resistant cultivars of apple and potato are described. Various solution pathways have been compared. The comparison focuses strongly on apple because many experiences have been gained with the introduction of scab resistant cultivars. Four solution pathways are described with four case studies.
Get a taste of new talented Robust potato cultivars
Lammerts Van Bueren, E. ; Janmaat, L. - \ 2015
Louis Bolk Instituut
marketing - aardappelen - consumptieaardappelen - verbetering - ziekteresistentie - biologische landbouw - phytophthora - cultivars - akkerbouw - potatoes - table potatoes - improvement - disease resistance - organic farming - arable farming
In the potato breeding programme Bioimpuls, the Louis Bolk Institute and Wageningen UR are working together with breeding companies and farmer-breeders to develop robust cultivars that are resistant to Phytophthora. Thanks to these new cultivars, organic growers now have more chance of yield security. The next step is to collaborate with organic wholesalers and retailers to make sure that the new cultivars reach the shop shelves and consumers’ plates. In the Netherlands, the organic market has already accepted new cultivars such as Bionica, Sarpo Mira and Carolus, but other cultivars are still relatively unknown, and additional promising cultivars will become available for the European market in the near future. Together, these cultivars will offer a complete assortment of boiling, baking and multi-purpose potatoes in various colours and shapes. The new talents are presented in this brochure.
Essentaksterfte, bosbouwkundig beheersbaar?
Kopinga, J. ; Vries, S.M.G. de - \ 2015
Bosberichten 2015 (2015)1. - ISSN 1574-6046 - p. 1 - 4.
bomen - schimmelziekten - fraxinus excelsior - plantenziekten - rassen (planten) - cultivars - resistentie van variëteiten - trees - fungal diseases - plant diseases - varieties - varietal resistance
Vanaf ca. 2010 slaat de essentaksterfte in Nederland op grote schaal toe. Tot dusver vooral in bossen en wat minder in laanbeplantingen. Hoe het zich verder ontwikkelt, is nog onduidelijk, maar het einde lijkt nog niet in zicht. In sommige regio’s is binnen enkele jaren de conditie van bomen zwaar achteruit gegaan of zijn bomen geheel afgestorven. Voor bosbeheerders en boseigenaren een ware ramp. Gedane investeringen ‘verdampen’. Sommigen vrezen zelfs dat de es geheel uit het Nederlandse bosbeeld zal verdwijnen. Echter, met gerichte bosbouwkundige maatregelen, lijken er mogelijkheden de es te behouden. In deze bijdrage van gastauteurs Jitze Kopinga en Sven de Vries wordt aangegeven welke strategieën daarbij denkbaar zijn en wordt aangegeven welke de meest kansrijke lijken te zijn.
Delving deeper into technological innovations to understand differences in rice quality
Calingacion, M.N. ; Fang, L. ; Quiatchon-Baeza, L. ; Mumm, R. ; Riedel, A. ; Hall, R.D. ; Fitzgerald, M.A. - \ 2015
Rice 8 (2015). - ISSN 1939-8433 - 10 p.
odor-active compounds - oryza-sativa l. - stage drought stress - grain-yield - genetic backgrounds - mass-spectrometry - direct selection - scented rice - cultivars - varieties
Increasing demand for better quality rice varieties, which are also more suited to growth under sub-optimal cultivation conditions, is driving innovation in rice research. Here we have used a multi-disciplinary approach, involving SNP-based genotyping together with phenotyping based on yield analysis, metabolomic analysis of grain volatiles, and sensory panel analysis to determine differences between two contrasting rice varieties, Apo and IR64. Plants were grown under standard and drought-induced conditions. Results revealed important differences between the volatile profiles of the two rice varieties and we relate these differences to those perceived by the sensory panel. Apo, which is the more drought tolerant variety, was less affected by the drought condition concerning both sensory profile and yield; IR64, which has higher quality but is drought sensitive, showed greater differences in these characteristics in response to the two growth conditions. Metabolomics analyses using GCxGC-MS, followed by multivariate statistical analyses of the data, revealed a number of discriminatory compounds between the varieties, but also effects of the difference in cultivation conditions. Results indicate the complexity of rice volatile profile, even of non-aromatic varieties, and how metabolomics can be used to help link changes in aroma profile with the sensory phenotype. Our outcomes also suggest valuable multi-disciplinary approaches which can be used to help define the aroma profile in rice, and its underlying genetic background, in order to support breeders in the generation of improved rice varieties combining high yield with high quality, and tolerance of both these traits to climate change.
Empowering breeding programs with new approaches to overcome constraints for selecting superior quality traits of rice
Calingacion, M.N. - \ 2015
University. Promotor(en): Robert Hall; M.A. Fitzgerald, co-promotor(en): Roland Mumm. - Wageningen : Wageningen University - ISBN 9789462572188 - 198
oryza sativa - rijst - rassen (planten) - cultivars - genetische diversiteit - gewaskwaliteit - aroma - geur en smaak - consumentenvoorkeuren - plantenveredeling - veredelingsprogramma's - rice - varieties - genetic diversity - crop quality - flavour - consumer preferences - plant breeding - breeding programmes

Empowering breeding programs with new approaches to overcome constraints for selecting superior quality traits of rice

Mariafe N. Calingacion

Most rice breeding programs have focused on improving agronomic traits such as yield, while enhancing grain quality traits such as flavour and aroma, especially of non-fragrant rices, has not been given high priority. In this study, we utilised a multi-disciplinary approach to understand better quality traits of aroma and flavour in rice grains, and to determine whether good flavour in the grain could be combined with stress tolerant genotypes.

To understand what factors drive rice preferences, an extensive survey among members of the International Network for Quality Rice who are local experts in grain quality evaluation programs in 25 countries was conducted (Chapter 2). The objective was to identify the grain quality characteristics of the popular rice varieties in each region. Eighteen combinations of size and shape of the grain, amylose content (AC), gelatinisation temperature (GT) and fragrance were identified. These trait combinations reveal the complexity of consumer preferences. The two most popular combinations both have long and slender grains, while one has low amylose, low GT and is aromatic, and the other has intermediate AC and intermediate GT and is non-aromatic. Further evaluation of varieties having the same combination of grain quality traits showed that consumers readily identify differences between these varieties. For example, BRS Primavera and IR64 that are popular in Brazil and in the Philippines, respectively, have the same combination of all 18 traits, however, panellists of sensory evaluation can easily perceive differences in aroma and flavour of BRS Primavera and IR64. This emphasises that the current tools we have available to assess rice quality are unable to capture all the quality traits consumers are looking for in rice.

In Chapter 3, a novel multiplatform metabolomic and ionomic approach with genome-wide genotyping was utilised to investigate the effect of different nitrogen fertiliser regimes on the biochemical profile of three premium waxy rice varieties, Hom Nang Nouane (HNN), Kai Noi Leuanag (KNL) and Tha Sa No (TSN) from Lao PDR. The current tools used to phenotype grain quality such as GT, values from viscosity curves, and hardness and stickiness, were unable to differentiate between HNN, KNL and TSN either on the basis of nitrogen treatment nor genotype. However, metabolite profiling of metabolites and minerals followed by multivariate statistical methods readily separated the genotypes on each platform, and discriminatory compounds that were identified were relevant to consumers in terms of flavour, taste and nutrition. However, despite yield differences, nitrogen treatment did not significantly affect the overall metabolite and mineral profiles of the samples. Using 1536 single nucleotide polymorphism (SNP) loci, the Euclidean distance between each variety was calculated and compared to the distance between each variety for each metabolomic platform. Procrustes analysis was used to rotate and scale the variety mean scores on the metabolite principal components to give the best fit to the genetic principal coordinates. Comparing the triangles whereby each vertex of the triangle is a variety and the length of each side is equal to the scaled Euclidean distance, mineral elements, polar metabolites and volatile compounds all associate very well with the genetic distance between each variety. This study highlights that multiple metabolomic platforms are potential phenotyping tools to characterise rice quality in a comprehensive and efficient way, and in a way that provides data that is relevant to consumers.

To gain insights on the influence of water availability to the metabolomic profile of drought tolerant rice, two contrasting varieties, Apo and IR64, and a mapping population derived from them were extensively characterised in Chapters 4 and 5. Apo is drought tolerant but has unacceptable grain quality while IR64 is drought susceptible with premium grain quality. Apo and IR64 were grown under irrigated and drought conditions. Yield of Apo from both water conditions was higher than yield of IR64 under the same conditions. Moreover, metabolite profiling and sensory analysis showed that grains of Apo were not affected by drought conditions i.e. panellists perceived no difference in the aroma of Apo from both conditions and Principal Components Analysis (PCA) of the volatiles showed one cluster of Apo from both conditions. However, grains of IR64 formed two clusters based on water condition in the PCA and panellists were able to perceive ‘water-like metallic’ aroma in IR64 that was grown under drought conditions but this was not detected in grains from the irrigated treatment. This suggests that response to water stress in the metabolomic profile of the grain is variety dependent.

In Chapter 5, a mapping population derived from Apo and IR64 was grown, with the parents, under irrigated and drought conditions. The yield of more than half of the population was higher than the yield of Apo and IR64 under both irrigated and drought conditions; this indicates significant transgressive segregation. Using a dense linkage map based on genotyping by sequencing data, quantitative trait loci (QTL) analysis of drought stress identified one major QTL on chromosome 3 that is likely to be qDTY3.1 which was previously detected in a population derived from Apo as the drought tolerant parent. All the lines of the population carrying this QTL showed significantly higher yield under drought than those without it, indicating the potential importance of this QTL in drought tolerance.

Metabolite profiling and sensory analysis were also conducted in the grains of the population. More than a hundred volatiles were detected in the headspace of rice samples and PC1 and PC2 explained 55.6% of the variation in the metabolite profiles with many of the lines clustering in between the Apo and IR64 parent values. Six novel metabolite QTLs for volatile compounds were identified - 1 QTL was detected in chromosome 1 for 3,7-dimethyl-octen-1-ol, 1 QTL for hexanol in chromosome 2, and 4 QTLs for pentanol, hexanol, hexanal, and heptanone in chromosome 3. Interestingly, three lines were observed by the panellists to have similar aroma as IR64 while four lines were observed to have similar aroma as that perceived in Apo. Lines 20, 164 and 28 were perceived by the panellists to have high levels of corn, dairy and sweet aromatic features. Moreover, the yield of these 3 lines under both irrigated and drought conditions was similar to that of the Apo parent under the same conditions with Line 28 yielding the highest under drought and has the QTL associated with yield under drought on chromosome 3.

Finally, the potential of metabolomics as a phenotyping tool in characterising grain quality is further highlighted in Chapter 6. Combining metabolomics with high throughput genotyping and sensory analysis offers new breadth of approach in understanding grain quality of rice. Three lines identified that carry IR64 quality along with high yield in both irrigation and drought, are recommended to enter a rice breeding program at the stage of advanced replicated and multi-location testing. By using advanced tools of phenotyping and genotyping, with validation by sensory panels, these three advanced lines have been selected in just three years.

Rassenbulletin ultravroege snijmais 2015
Groten, J.A.M. - \ 2014
zea mays - maïs - rassenlijsten - rassen (planten) - rassenproeven - cultivars - akkerbouw - krachtvoeding - nederland - maize - descriptive list of varieties - varieties - variety trials - arable farming - force feeding - netherlands
Rassenonderzoek ultravroege snijmaïs/kortseizoen krachtvoer maïs (KKM) 2014 :Gemiddelde resultaten over 2011 t/m 2014
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