Aggarwal P.K.,Indian Agricultural Research Institute |
Baethegan W.E.,IRI Inc |
Cooper P.,International Crops Research Institute for Semi Arid Tropics ICRISAT |
Gommes R.,Food and Agricultural Organization FAO |
And 3 more authors.
Procedia Environmental Sciences | Year: 2010
This paper discusses the key information needs to reduce the negative impacts of weather variability and climate change on land degradation and food security, and identifies the opportunities and barriers between the information and services needed. It suggests that vulnerability assessments based on a livelihood concept that includes climate information and key socio-economic variables can overcome the narrow focus of common one-dimensional vulnerability studies. Both current and future climatic risks can be managed better if there is appropriate policy and institutional support together with technological interventions to address the complexities of multiple risks that agriculture has to face. This would require effective partnerships among agencies dealing with meteorological and hydrological services, agricultural research, land degradation and food security issues. In addition a state-of-the-art infrastructure to measure, record, store and disseminate data on weather variables, and access to weather and seasonal climate forecasts at desired spatial and temporal scales would be needed. © 2010 Published by Elsevier.
Haileselassie B.,Tigray Agricultural Research Institute |
Haileselassie B.,Wageningen University |
Stomph T.-J.,Center for Crop Systems Analysis |
Hoffland E.,Wageningen University
Soil Science and Plant Nutrition | Year: 2011
Teff (Eragrostis tef (Zucc.) Trotter) is a major food crop in Ethiopia and Eritrea. It is well adapted to Vertisols. Yields are low (around 1000 kg ha -1) despite fertilization with urea and diammonium phosphate. The objectives of this study were to understand farmers' perception on teff production constraints and to evaluate on-farm yield response of teff to zinc (Zn) fertilization. We conducted a farm survey and a participatory fertilization experiment in three teff-based sites (peasant associations) on Vertisols in the mid highland and lowland agroecological zones in Ethiopia. Per site 10 farmers participated in the survey and on-farm experiment. Poor soil fertility in the mid highland and moisture deficit in the lowland agroecological zones were mentioned by farmers as major teff production constraints, respectively. On-farm application of Zn fertilizer at a rate of 8 kg Zn ha -1 increased teff grain and straw yields by 14% and 15% on average, respectively, which could be economically profitable. Not all plots showed a positive response, however, indicating the necessity for enhanced insight in indicators for soil Zn bioavailability as a yield-limiting factor. Our study indicates the importance of Zn in teff production on Vertisols. We propose further research on management options to prepare for effective interventions based on the farm survey and on-farm experiment. © 2011 Japanese Society of Soil Science and Plant Nutrition.
Yan J.,China Agricultural University |
Yan J.,Center for Crop Systems Analysis |
Yu J.,China Agricultural University |
Tao G.C.,China Agricultural University |
And 4 more authors.
Field Crops Research | Year: 2010
Water shortage in the Huai River Basin prompts farmers to adopt water-saving technologies such as direct-seeded nonflooded or aerobic rice. Different cultivation practices impact on tiller growth and development. Improved insight into tiller dynamics is needed to increase yield in these production systems. We conducted field experiments with four direct-seeded rice varieties under flooded and nonflooded conditions in Mengcheng county, Anhui province, in 2005-2006. The soil water content in the nonflooded treatment varied between saturation and field capacity. Yields in nonflooded soil ranged from 3.6 to 4.7 t ha-1, and did not differ significantly from yields in flooded soil that ranged from 3.6 to 5.1 t ha-1. Variety had a significant effect on biomass, yield, panicle number, spikelet number, grain weight, and grain filling percentage. Panicle number was the main factor limiting yield, resulting from a low tiller emergence frequency and a low fraction of productive tillers in both the flooded and the nonflooded soils. On average, the panicle number was 159-232 m-2, including 34-167 productive tillers per m2 for all the varieties under the two water regimes. The contribution of productive tillers to yield varied between 7% and 47%. There were two peaks of tillers that contributed to yield, one at the low (4th or 5th) and one at the high (10th or 11th) phytomer orders. Frequencies of tiller emergence at most phytomer orders were higher in the flooded soil than in the nonflooded soil. There were no significant differences in frequencies of productive tiller emergence and contributions to yield from tillers between the soil water regimes for three of the four tested varieties. To increase yield in direct-seeded nonflooded rice production systems, both the tiller emergence frequency and the fraction of productive tillers should increase through breeding, improved crop management, or a combination. © 2010 Elsevier B.V. All rights reserved.
Burema B.S.,Center for Crop Systems Analysis |
Buck-Sorlin G.H.,Center for Crop Systems Analysis |
Damen T.,Center for Crop Systems Analysis |
Vos J.,Center for Crop Systems Analysis |
And 2 more authors.
Acta Horticulturae | Year: 2010
Growing in lower planting density, rose plants produce more assimilates, which can be used to produce more and/or heavier flowering shoots. The effect of planting density was investigated during a period including the first five flowering flushes of a young crop. In a heated greenhouse two cut-rose cultivars were grown under bent canopy management. Akito on own-roots and Ilios on Natal Briar rootstock were planted with densities of 8 and 4 plants per m2. Starting at the end of June 2007, flowering shoots were harvested over a time span of eight months. Based on flowering flushes, times of high harvest rate, the harvesting time span could be divided into five consecutive periods, each including one flush. The cultivars showed contrasting responses to planting density. In the first three periods the response in Ilios was extraordinary, because at low density plants did not produce more flowering shoots, as would be expected. However, the response in shoot fresh weight was larger for Ilios than for Akito, 35% compared to 21% over the entire study period. The results imply that there was a genetic difference in the effect of assimilate availability and/or local light environment. During the first three periods, these factors can not have influenced shoot number in Ilios, while they did in Akito. It is suggested that decreases of assimilate availability in winter caused the shoot number response to emerge for Ilios later on.
Mafakheri A.,University of Kurdistan |
Siosemardeh A.,University of Kurdistan |
Bahramnejad B.,University of Kurdistan |
Struik P.C.,Center for Crop Systems Analysis |
Sohrabi E.,University of Kurdistan
Australian Journal of Crop Science | Year: 2010
Drought stress is one of the major abiotic stresses in agriculture worldwide. This study was carried out to investigate the effect of drought stress on proline content, chlorophyll content, photosynthesis and transpiration, stomatal conductance and yield characteristics in three fgave the highest yield whereas the drought sensitive variety 'Pirouz' gave the lowest yield. Drought was carried out in a randomized complete block design with three replications. Treatments included control (no drought), drought stress imposed during the vegetative phase, drought stress imposed during anthesis and drought stress during the vegetative phase and during anthesis. All physiological parameters were affected by drought stress. Drought stress imposed during vegetative growth or anthesis significantly decreased chlorophyll a, chlorophyll b and total chlorophyll content. Proline accumulation was higher in 'ILC482' than in 'Pirouz' both under control and drought stress conditions. Photosynthesis, transpiration, stomatal conductance and yield were higher but sub-stomatal CO2 concentration was lower under drought stress conditions than under control conditions. The results showed that mesophyll resistance is the basic determinate of rate of phototosynthesis under drought stress conditions. Under drought conditions the drought tolerant variety 'Bivaniej' gave the highest yield whereas the drought sensitive variety 'Pirouz' gave the lowest yield. Drought stress at anthesis phase reduced seed yield more severe than that on vegetative stage.
Maaike Wubs A.,Wageningen University |
Maaike Wubs A.,Center for Crop Systems Analysis |
Heuvelink E.,Wageningen University |
Marcelis L.F.M.,Wageningen University |
And 7 more authors.
Journal of the American Society for Horticultural Science | Year: 2013
When flower-bearing shoots in cut-rose (Rosa ×hybrida) are harvested (removed), a varying number of repressed axillary buds on the shoot remainder start to grow into new shoots (budbreak). Besides removing withinshoot correlative inhibition, it is hypothesized that shoot removal leads to 1) increased light intensity lower in the crop canopy; 2) changes in the light spectrum (particularly red:far-red ratio); and 3) changed source:sink ratio (i.e., the ratio between supply and demand of assimilates). As a fourth hypothesis it is proposed that the degree of budbreak on a shoot remainder is also influenced by the correlative inhibition exerted by other shoots on the plant. It is the goal of this work to determine which of these four hypotheses is most important for budbreak in a cut-rose crop. Four experiments were conducted, in which these factors were varied by leaf removal, removal of mature shoots, varying the number of young shoots, shading of the crop, and application of direct light on the buds. Increase in source:sink ratio was not consistently associated with higher budbreak. If source:sink ratio was decreased by removal of leaves or a mature shoot, budbreak showed even a tendency to increase. Budbreak was subject to correlative inhibition exerted by other shoots on the plant. Treatments where more light reached the bud (as a result of less shoots, no shading of the crop, application of local light) increased budbreak. Increased red:farred ratio had the same result as more light reaching the bud but was often interrelated with light intensity. It was concluded that after removal of the flower-bearing shoot, among the factors tested, light intensity on the buds was an important and consistent factor explaining budbreak on the shoot remainder, whereas the effect of light spectrum should be further investigated.
Stem characteristics of two forage maize (Zea mays L.) cultivars varying in whole plant digestibility. IV. Changes during the growing season in anatomy and chemical composition in relation to fermentation characteristics of a lower internode
Boon E.J.M.C.,Center for Crop Systems Analysis |
Boon E.J.M.C.,Wageningen University |
Struik P.C.,Center for Crop Systems Analysis |
Engels F.M.,Center for Crop Systems Analysis |
Cone J.W.,Wageningen University
NJAS - Wageningen Journal of Life Sciences | Year: 2012
Improving digestibility of forage maize (Zea mays L.) through breeding is important to optimize the efficiency of ruminant's rations. It can partly be achieved by improving the digestibility of stem tissue, a genetically complex and diverse trait changing drastically during the growing season. We tried to gain insight into this trait by analysing the changes during the growing season in the anatomy, chemical composition and fermentation characteristics of a lower internode (internode 7) of two forage maize cultivars differing in whole plant digestibility. These two cultivars, known to differ in digestibility, were grown in the Netherlands for two growing seasons. Cell wall thickness of the sclerenchyma tissue in the rind of internode 7 increased linearly with the temperature sum until reaching final cell wall thickness several days before anthesis. Volens, the less digestible cultivar, had a higher final cell wall thickness than Vitaro, the cultivar with a better digestibility. Chemical analyses included determination of NDF, ADF, ADL, crude protein, sugar content, and ash. Lignin content increased until shortly after anthesis in both cultivars, in both years. Lignin content was higher for Volens than for Vitaro and higher in 2000 than in 1999. Crude protein content decreased from 15-21% in early July to 2-5% in late September with no clear differences between cultivars or years. Fermentation characteristics showed that maximum gas production of cell wall components was highest immediately before anthesis and subsequently decreased. At all stages of development, Vitaro had a higher maximum gas production than Volens. The cultivar differences in digestibility could not be confirmed by differences in rate of cell wall disappearance. Seasonal changes showed an increase in fermentable cell wall material until anthesis; thereafter fermentability decreased. Differences in cell wall thickness and in lignin content reflected the changes in digestibility during the growing season best; the differences between the two contrasting cultivars were best reflected by the differences in cell wall thickness, lignin content and the decline of the potential digestibility in the period before anthesis. © 2011 Royal Netherlands Society for Agricultural Sciences.
Wubs A.M.,Wageningen University |
Wubs A.M.,Center for Crop Systems Analysis |
Heuvelink E.,Wageningen University |
Heuvelink E.,Agrocampus Ouest |
And 3 more authors.
Journal of the American Society for Horticultural Science | Year: 2014
When flower-bearing shoots in cut rose (Rosa ×hybrida) are harvested, a varying number of repressed axillary buds on the shoot remainder start to grow into new shoots (budbreak). Earlier experiments indicated that light reaching the bud affected the number of budbreaks. In all these studies, whole plants were illuminated with different light intensities or light spectra. The aim of this article is to disentangle the effects of light intensity and light spectrum, in this case red:far-red ratio, at the level of the buds on budbreak in a rose crop. Three experiments were conducted in which light intensity and red:far-red ratio at the level of the buds were independently varied, whereas intensity and red:far-red ratio of incident light on the crop were not changed. Light intensity and red:far-red ratio at the position of the buds were quantified and related to budbreak on the shoot remainders. Removal of vertical shoots increased light intensity and red:far-red ratio as well as budbreak (1.9 budbreaks per shoot remainder compared with 0.4 budbreaks when five vertical shoots were present). No vertical shoots and red light-absorbing shading paper over the plant base mimicked the effect of vertical shoots with respect to light intensity and red:far-red ratio, but budbreak (1.0 budbreaks) was intermediate compared with treatments with and without shoots. This suggested that the presence of shoots exerts an inhibiting effect on budbreak through both effects on light at the bud and correlative inhibition. When plants had no vertical shoots and light intensity and red:far-red ratio at bud level were changed by neutral and red light-absorbing shading paper, there was a positive effect of light intensity on budbreak (0.3 more budbreaks per shoot remainder) and no effect of red:far-red ratio. Combinations of high and low light intensity with high and low red:far-red ratio on axillary buds showed that there was a positive effect of light intensity on budbreak (0.5 more budbreaks per shoot remainder) and no effect of red:far-red ratio. Our study reveals that when light intensity and red:far-red ratio received by the plant are similar but differ at bud level, budbreak was affected by light intensity and not by red:far-red ratio.
Agency: Narcis | Branch: Project | Program: Completed | Phase: Agriculture | Award Amount: | Year: 2007
PubMed | Center for Crop Systems Analysis
Type: | Journal: Frontiers in plant science | Year: 2013
Modern lettuce cultivars underperform under conditions of variable temporal and spatial resource availability, common in organic or low-input production systems. Information is scarce on the impact of below-ground traits on such resource acquisition and performance of field-grown lettuce; exploring genetic variation in such traits might contribute to strategies to select for robust cultivars, i.e., cultivars that perform well in the field, even under stress.To investigate the impact of below-ground (root development and resource capture) on above-ground (shoot weight, leaf area) traits, different combinations of shoot and root growth were created using transplants of different sizes in three field experiments. Genetic variation in morphological and physiological below- and above-ground responses to different types of transplant shocks was assessed using four cultivars.Transplanting over-developed seedlings did not affect final yield of any of the four cultivars. Small transplant size persistently impacted growth and delayed maturity. The cultivars with overall larger root weights and rooting depth, Matilda and Pronto, displayed a slightly higher growth rate in the linear phase leading to better yields than Mariska which had a smaller root system and a slower linear growth despite a higher maximal exponential growth rate. Nadine, which had the highest physiological nitrogen-use efficiency (g dry matter produced per g N accumulated in the head) among the four cultivars used in these trials, gave most stable yields over seasons and trial locations.Robustness was conferred by a large root system exploring deep soil layers. Additional root proliferation generally correlates with improved nitrate capture in a soil layer and cultivars with a larger root system may therefore perform better in harsh environmental conditions; increased nitrogen use efficiency can also confer robustness at low cost for the plant, and secure stable yields under a wide range of growing conditions.