| 1. |
- Abouhatab, Assem, et al.
(författare)
-
Determinants of import demand for Egyptian potatoes in Germany and the United Kingdom
- 2016
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1132, s. 39-48
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The European Union (EU) is the major import market for Egyptian fresh potatoes. Germany and the United Kingdom (UK) jointly imported about 44% of Egyptian potato exports to the EU during the period 1994-2012. This study sought to identify the determinants of import demand for Egyptian potatoes in these two countries. A general differentiated demand system approach was used to estimate conditional potato import demand per country. For each country, it was assumed that the system of conditional import demand equations for potatoes is specified according to the sources of origin and also depends on all imported potato prices and total import potato expenditure. When estimated econometrically, this import demand model allows conditional price and expenditure elasticities to be derived. The econometric results indicated that with an estimated elasticity of 1.95, Egyptian potato exports responded significantly to total expenditure on imported potatoes by Germany. On the other hand, Egyptian potato exports to Germany did not exhibit significant price responses. In all cases but one, estimated conditional uncompensated price elasticities were not statistically different from zero. However, more interesting results were obtained concerning the price responses of Egyptian potato exports to the UK, whereby the conditional (uncompensated) direct elasticity of potato imports from Egypt to the UK (-0.71) showed an inelastic response to its own price. Furthermore, Egyptian potato exports seemed to compete on the UK market with potatoes originating from Israel and France, while they displayed complementarity with Dutch imports.
|
|
| 2. |
- Abouhatab, Assem, et al.
(författare)
-
Exchange rate uncertainty and Egyptian exports of horticultural commodities into the EU
- 2019
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1258, s. 11-18
-
Konferensbidrag (refereegranskat)abstract
- This paper investigates the impact of exchange rate volatility on Egyptian exports of fresh fruit and vegetables (FFVs) to their major importing markets in the EU. Using quarterly data covering the period 1994-2016, we examine the determinants of Egypt’s exports of FFVs to the EU, and then derive the long-term effects of exchange rate volatility on the FFV exports. The empirical results show that exchange rate volatility has a long-run significant effect on Egypt’s FFV exports to the EU. Overall, the findings highlight the importance of exchange rate volatility in understanding the behavior of Egyptian exports of FFVs to the EU. Thus, the design and implementation of exchange rate policies and export promotion programs in Egypt should take into consideration the stability and level of the real exchange rate.
|
|
| 3. |
- Ahmadi Afzadi, Masoud, et al.
(författare)
-
Genetics of resistance to blue mould in apple: inoculation-based screening, transcriptomics and biochemistry
- 2016
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1127, s. 55-60
-
Konferensbidrag (refereegranskat)abstract
- Blue mould caused by Penicillium expansum is a major contributor to loss of marketable fruit during storage. Damage is also aggravated by the prohibition of postharvest fungicides in many countries, and in organic production everywhere. Robust data on levels of resistance to this disease are crucial for further research and for breeding of improved cultivars. Inoculation of fruit with fungal spores and estimation of the diameter of resulting lesions after cold storage demonstrated significant variation among cultivars. In addition, cultivars with high firmness at harvest and little softening, i.e., loss of firmness during storage, had less susceptibility, as also did late-ripening cultivars. In another part of the study, a possible association between lesion diameter and chemical contents in fruit flesh and fruit peel of 23 cultivars was investigated. Content of different quercetins and procyanidin B2 was positively associated with the level of tolerance. Samples taken after inoculation showed stronger association with the chemical contents than did samples of control fruit, suggesting that disease development had triggered a defence reaction. In a third part of the study, gene regulation in apple fruit after inoculation was evaluated in two relatively resistant and two relatively susceptible cultivars using an AryANE chip covering 60K apple transcripts. Validation of the most highly up-and down-regulated genes was undertaken using qPCR. Some genes related to disease resistance, biosynthesis of flavonoids and to cell-wall structure were identified as most likely to be responsible for differences in susceptibility to blue mould. These results will be used to search for candidate genes that can be used in marker-assisted selection in apple breeding.
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Alsanius, Beatrix
(författare)
-
Vision of COST BioGreenhouse
- 2017
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1164, s. 1-8
-
Konferensbidrag (refereegranskat)abstract
- Good food is the basis of a healthy, active life. Horticulture provides fresh commodities rich in minerals, fibres and bioactive compounds, and thereby contributes to a healthy diet. Integrated and organic horticultural production, either indoors or outdoors, contribute to food provisioning. For food and nutrition security, food must be: 1) present in sufficient quantities, 2) physically, economically and socially accessible and affordable, 3) nutritious, with a quality that meets dietary needs and preferences, 4) safe and 5) supported by an adequate environment regarding sanitation, health service and care. To pursue the ambition of developing organic horticulture in greenhouses and high tunnels into an active player within the food system and foodservice, a shift in paradigm is needed - organic protected horticulture needs to redefine itself from being a resource provider/supplier, mainly focusing on production systems and environment, to being an active player in the arena of grand global challenges and human health-integrating societal aspects, e.g., well-being. Organic greenhouse horticulture not only addresses, but also delivers, key solutions in some areas of conflicts, such as land, water and energy use and recycling of resources. In addition, it offers opportunities for empowerment of rural and urban areas. Most research on organic horticulture considers organic greenhouse production systems and production environments. The BioGreenhouse vision considers interactivities between the environmental and societal sphere of food. Innovative organic approaches are a critical precondition for improvement. The potential of organic greenhouse horticulture needs to be brought to the awareness of policy makers. Research to explore the multilevel and multidisciplinary as well as multistakeholder interactions of organic production in greenhouses and high tunnels must be encouraged, by all necessary means.
|
|
| 7. |
|
|
| 8. |
- Bergstrand, Karl-Johan, et al.
(författare)
-
Growth control of ornamental and bedding plants by manipulation of photoperiod and light quality
- 2016
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1134, s. 33-39
-
Konferensbidrag (refereegranskat)abstract
- Altering the light regime is a sound and non-polluting way of controlling the growth of greenhouse-grown pot and bedding plants, and a promising way of eliminating the use of chemical plant growth regulators (PGRs), which are now becoming less available and more questioned by consumers. Modern greenhouses often have blackout screens, originally installed for flower regulation purposes but which can also be used for growth regulation. Modern light emitting diode (LED) light sources can be designed to provide narrow-band light (NBL), which can affect growth and elongation of plants if given in addition to natural sunlight, or as daylight extension (end-of-day or pre-day treatments). Two different approaches were used: short photoperiods in combination with pre-day and end-of-day NBL treatments, and short photoperiods combined with simultaneous addition of NBL and natural light. The plants used were Calibrachoa, Pelargonium, Euphorbia, and Chrysanthemum. A light regime with 620 nm light given before the period of natural light and 525 nm light given at the end of the natural light effectively controlled elongation in both Calibrachoa and Pelargonium. Supplementation of natural sunlight with a small portion of 660 nm light significantly reduced plant height in Euphorbia, but not in Chrysanthemum. It was concluded that management of photoperiod and light quality is very promising for replacing PGRs within greenhouse production of ornamental and bedding plants.
|
|
| 9. |
|
|
| 10. |
|
|
| 11. |
- Båth, Birgitta
(författare)
-
Soil fertility management in organic greenhouse: an analysis of the European context
- 2017
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1164, s. 113-126
-
Konferensbidrag (refereegranskat)abstract
- Soil fertility management systems in organic greenhouses are quite diversified within Europe. The challenge is to identify and implement strategies which are in agreement with the organic principles stated by (EC) Reg. 834/2007 and (EC) Reg. 889/2008 as well as environmentally, socially and economically sustainable. In this paper, written by a group of scientists of different geographical origin and with different background, the state of the art of the sector and the main characteristics of the European greenhouse cropping systems are described. The main bottlenecks and constraints are discussed with a particular reference to the regulatory framework in force. The more relevant issues that may influence the enforcement and future development of the sector have been identified as specific knowledge gaps. For each of them, the appropriate research needs were elaborated in a multidisciplinary perspective as forthcoming challenges for the whole sector. Far to be exhaustive, given the wide heterogeneity of the implemented systems, this paper is able, for the first time, to give a structured outlook, on soil fertility in protected organic condition at an European scale.
|
|
| 12. |
- Ekelund Axelson, Lena, et al.
(författare)
-
Climate labelling and the importance of increased vegetable consumption
- 2016
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1132, s. 191-197
-
Konferensbidrag (refereegranskat)abstract
- Nearly a third of the climate change impacts attributed to human consumption are believed to be caused by food and drink. Climate communication and marketing efforts have been the focus of an interdisciplinary research exploring how food retailers, in their unique intermediary role between producers and consumers, could guide consumers’ food choices in a more climate-friendly direction, with examples mainly from Sweden. Consumers are not aware of what actions are the most important from a climate point of view. A guide to more climate friendly protein choices (meat guide) was created within the project, with the aim of developing a way of informing about the environmental impacts of meat and other sources of protein. While food waste was considered an important issue, climate effects of transportation and packaging was of greater concern to the consumers in the study, who found it more important to buy local and seasonal food, and organic products, than to choose vegetarian alternatives. Observational studies in European stores, as well as interviews with representatives of Swedish supermarkets, revealed that direct climate messages were scarce. A recommendation to supermarkets is to promote vegetarian choices in store and develop the fruit and vegetable department. A novel suggestion is to encourage retailers to build on ambiguous categories and indirect messages, in particular local, seasonal and organic, in communicating climate mitigating behaviour and promote an increase in consumption of vegetables.
|
|
| 13. |
- Fernqvist, Fredrik
(författare)
-
Strategic options for a potato market in decline-lessons from two Swedish studies
- 2015
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1103, s. 125-131
-
Konferensbidrag (refereegranskat)abstract
- In recent decades, the consumption of fresh potatoes in Europe and North America has been declining, possibly due to health concerns, changing income and labour structures and convenience. However, prepared potato products, such as crisps are gaining market share, so convenience is probably a stronger driver for changes in consumption than negative health claims associated with the low carb-high fat, Atkins or Montignac diets. Changing consumption patterns raise questions about the future of the fresh potato market and how a rather bulky product can be differentiated and re-marketed to beat increasing competition, not least from substitute products such as pasta and rice. This study undertook focus group interviews related to consumption and a quantitative consumer survey on attitudes to various product-related attributes in a shopping situation. The focus group results indicated that convenience is one of the strongest drivers behind changing consumption patterns and revealed some significant choice-related factors. The survey results showed that sensory properties (taste and texture), origin and named varieties were among the more important attributes, indicating that these could be relevant marketing arguments. Overall, these results indicate that rather than focusing on bulk and low cost, a strategic option for the fresh potato industry could be to differentiate into convenience and underline consumers' positive associations with potatoes.
|
|
| 14. |
|
|
| 15. |
- Ghasemkhani, Marjan, et al.
(författare)
-
Screening for Partial Resistance to Fruit Tree Canker in Apple Cultivars
- 2015
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1099, s. 687-690
-
Konferensbidrag (refereegranskat)abstract
- Fruit tree canker in apple, caused by the fungus Neonectria ditissima, is considered as a serious economic problem in apple orchards, especially in northwestern Europe. This fungus produces cankers on the wood of branches and trunks, and severe attacks can result in the loss of limbs or whole trees. The fungus produces conidia and ascospores, both of which are dispersed and cause infection during prolonged periods of rainy weather. Apple cultivars show variable levels of partial resistance to the fungus, whereas complete resistance has not yet been reported. Therefore, apple genotypes with high levels of genetically determined resistance should be identified for use in apple breeding. In this study, ten apple cultivars were screened for resistance to N. ditissima. For each cultivar, both potted trees and cut-off shoots in glass bottles were inoculated in a greenhouse. The resulting lesions were measured and disease progression curves were calculated; AUC (area under curve) was used for comparisons of infection severity. Significant differences between cultivars were observed in both experiments. The cultivar 'Rodluvan' showed the highest degree of resistance in both experiments, while the most susceptible were 'Jonathan'(cut shoots) and 'Akero' (potted trees).
|
|
| 16. |
- Grudén, Maria, et al.
(författare)
-
Processing of green leaf produce: microorganisms associated with process water and produce
- 2016
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1141, s. 373-379
-
Konferensbidrag (refereegranskat)abstract
- Bacterial colonisation of a green leaf product (rocket) was studied before processing and after packing and raw and process water quality at different stages during processing under commercial conditions was analysed. “Raw water” denotes fresh water of potable water quality used to fill the washing line, whereas “process water” describes water sampled from the prewash and the main wash unit in the washing line. Samples were collected on four events, with three replicates per event. Leaf and water samples were both analysed for heterotrophic plate counts (HPC) at 22 °C, slow-growing bacteria (SGB), total coliform bacteria (TC), Escherichia coli (EC), intestinal enterococci (IE), Listeria monocytogenes (LM), Salmonella spp. and Campylobacter spp. The bacterial load in the process water increased substantially after produce came in contact with raw water. HPC exceeded 300,000 CFU mL-1 and SGB 50,000 CFU mL-1. IE were also very abundant, but not TC and EC. The microbial reduction rate was log 0.5. From these specimens, microorganisms were grown on semi-selective media (0.1x Tryptic Soy Agar, King agar B, Enterococci agar and Violet Red Bile Dextrose Agar) and five randomly selected colonies were identified using Biolog GenIII panels. Various Pseudomonas species and Pantoea agglomerans were frequent in the process water. The phyllosphere microbiota before washing was also dominated by P. agglomerans. After washing, P. agglomerans, Rahnella aquatilis and Pseudomonas spp. were abundant. Pseudomonas fluorescens and Enterobacter cloacae resisted washing procedures in the washing line and under laboratory conditions.
|
|
| 17. |
- Gunnarsson, Allan, et al.
(författare)
-
The Valls Hage arboretum in Sweden as a knowledge-source and a renewal project
- 2017
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1189, s. 303-310
-
Konferensbidrag (refereegranskat)abstract
- A restoration of the arboretum Valls Hage about 170 km north of Stockholm in Sweden is to be realized. The arboretum has got a strict focus on the variation within the woody flora of Sweden. The rich variety within some of the genera and species makes the collection to a very important gene resource for future. In this paper we highlight some of the most valuable cultivars and clones found, as well as some of the possible new introductions. In the discussion about the future, questions about the focus of the arboretum, as well as the geographical limits for the origin of introduced plants are raised. A direction is pointed out changing the focus from forestry towards ecology, horticulture, ethno-botany and outdoor learning to attract and activate a broader public. In the renewal work a successful propagation of valuable trees and shrubs is crucial not to lose parts of the present gene pool. Therefore the shortage of practical propagation knowledge and skill in Sweden is a problem to handle.
|
|
| 18. |
- Gustavsson, Larisa, et al.
(författare)
-
Approaches for evaluation of resistance to European canker (Neonectria ditissima) in apple
- 2016
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1127, s. 75-81
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- European canker is caused by the fungus Neonectria ditissima (Neonectria galligena, formerly Nectria galligena). The disease causes significant losses to apple production in Sweden and many other countries with a temperate wet climate. Application of fungicides and good horticultural practices do not prevent canker damage in nurseries and orchards. Disease outbreaks damage and even completely destroy trees. To date, complete resistance to N. ditissima is not known in apple, but cultivars differ considerably in their level of partial resistance. To be able to conduct breeding for resistance to European canker, reliable plant tests are urgently needed. Differences in resistance to N. ditissima (colonization rate; CR) in apple cultivars were evaluated by wound inoculations with a standardized number of conidia on cut shoots from mature trees placed in a climate chamber and on potted trees in an unheated greenhouse. Infection percentage (Inf%) was assessed by 'natural' inoculations in leaf scars under high infection pressure in the field. All the experiments were carried out over 2 years. Lengths of lesions were measured at regular time intervals on five occasions for shoots and seven occasions for trees. Considerable differences in CR and Inf% were found among the cultivars. The relative levels of resistance obtained are consistent with previous reports for most cultivars. Assessment of CR (area under curve) and Inf% thus proved to be useful tools for evaluation of resistance to European canker. Also, some potentially new sources of resistance were identified.
|
|
| 19. |
- Khalil, Sammar, et al.
(författare)
-
Biological control of root pathogens in strawberry cultivation in tunnel
- 2017
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1156, s. 811-815
-
Konferensbidrag (refereegranskat)abstract
- Cultivation of strawberries in tunnels has been of interest in the last few years as a mean to expand the cultivation season and increase yield. The need to move the tunnels due to soil depletion is a disadvantage for production in tunnels. By shifting to a substrate cultivation, the tunnels could be stationary and open up for the possibility to expand the cultivation season and increase yield. However, a lot of factors must be optimized when cultivation of strawberries in substrate is considered. Among these factors is the spread of root pathogens belonging to fungal genera Phytophthora, Pythium, Fusarium and Verticillium that are the underlying cause for crow, rot and wilt diseases. In the current study a sustainable and secure strawberry production approach against root diseases using the biocontrol agent Binab T with Trichoderma isolates as active ingredients is evaluated. Investigations were carried out in tunnel on three different strawberry cultivars. The fungal pathogens Phytophthora cactorum and Verticillium dahlia were used as model pathogens and investigated with and without the presence of Binab T. The effect of Binab T on the investigated root pathogens varied depending on the plants cultivar and the type of pathogen present in the cultivation system. The best biocontrol against both pathogens was obtained with the strawberry cultivar 'Rumba'. Variations in this effect were observed when 'Honeoye' and 'Sonata' cultivars were used.
|
|
| 20. |
- Lindfors, Lauri
(författare)
-
Silver birch ability to refill fully embolised xylem conduits under tension
- 2018
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1222, s. 67-73
-
Konferensbidrag (refereegranskat)abstract
- Whether trees have the ability to refill embolised xylem conduits and possibly to do it under tension, i.e., in a physiologically active state, has been a topic of research and debate for many years. However, direct experimental evidence for embolism refilling remains scarce. Combining traditional tree hydraulic methods (e.g., hydraulic conductance measurements on excised stems), new approaches (cut end of a branch placed in contact with water held in an agar matrix), and newer technology (X-ray microtomography), we tested the potential of silver birch branches to refill embolised xylem conduits even under negative water potential. The hydraulic method suggests that refilling of embolised xylem can occur even under negative pressure. The successful ability of birch to refill xylem was confirmed by X-ray microtomography. Furthermore, our results suggest that refilling is unlikely to be driven osmotically given the small difference measured between sap and the osmolality of the source water (tap water, agar). Finally, our results have direct influence on the method of choice when studying the vulnerability of silver birch to cavitation.
|
|
| 21. |
- Lv, Yanrong, et al.
(författare)
-
Changes in the Triterpene Content during Storage of Three Apple Cultivars
- 2015
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1071, s. 365-368
-
Konferensbidrag (refereegranskat)abstract
- The triterpenes, oleanolic acid, OA and its isomer, ursolic acid, UA are important phytochemicals in apple fruit. In order to investigate the influence of cold storage and cultivar differences on the content of major triterpenes in apple peel, the total content of oleanolic acid and ursolic acid were analyzed by HPLC. It was found that the late ripening cultivar ‘Gloster' had higher triterpene content as compared with the early ripening cultivar ‘Discovery' and the middle ripening cultivar ‘Aroma'. The short-term cold storage did not show any significant influence on the triterpene content in any of the three cultivars.
|
|
| 22. |
- Lv, Yanrong, et al.
(författare)
-
Influence of rootstock, harvest time, and storage conditions on triterpene content of apple peel
- 2016
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1120, s. 405-408
-
Konferensbidrag (refereegranskat)abstract
- Triterpenoids are a large group belonging to the isoprenoid group of compounds. The oleanolic acid (OA) and ursolic acid (UA) are two major triterpenic compounds in apple. Many studies have identified the pharmacological effects of triterpenoids and their derivatives in preventing different cancers and immune disease. However, the pre-harvest and postharvest factors associated with the content of triterpenes remain unclear. In the present study, the triterpene contents (OA and UA) were determined in order to identify the effect of different factors at harvest time and after cold and ultra lower oxygen (ULO) storages. The analyses were performed using high performance liquid chromatography (HPLC). The largest differences in triterpene content were found between rootstocks. The results showed that both at harvest time, and after cold storage except the first harvest time samples, the apples from rootstock MM106 had significantly higher triterpene content compared with those from M9; after ULO storage, the differences were found on first and third harvest time samples. The harvest time and storage had limited impact on triterpene content. Selecting suitable rootstock might increase the triterpene content in apple peel in practice production.
|
|
| 23. |
- Mogren, Lars
(författare)
-
Assessment of the vitamin C content in selected baby leafy species over the season
- 2018
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1209, s. 27-33
-
Konferensbidrag (refereegranskat)abstract
- Baby leaf vegetables have naturally high levels of vitamin C, of which the major part is found as ascorbic acid (AsA). A higher level of AsA at harvest may prolong the shelf life of this perishable vegetable commodity. Temperature has been shown to be one of the factors that affect AsA synthesis in plants, as well as light and day length, and all these factors vary over the season. This study compared different baby leaf species, different baby leaf spinach cultivars and variation in vitamin C content in commercially grown baby leaf spinach over the season. AsA levels as well as dehydro ascorbic acid (DHA) levels on both fresh and dry weight basis were analyzed. These preliminary results indicate that vitamin C content varies greatly between baby leaf species and that exactly the same type of bag of baby leaf spinach from the same super market can contain leaves with a vitamin C content varying between 50-350 mg kg(-1) fw over the season.
|
|
| 24. |
- Mogren, Lars
(författare)
-
Hot water treatment after harvest preserves nutritional quality of spinach during storage
- 2018
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1209, s. 123-127
-
Konferensbidrag (refereegranskat)abstract
- The concentration of antioxidants in fresh produce is important in terms of human nutrition. The main antioxidants, found in relatively high concentrations in leafy vegetables, are ascorbic acid (AsA), carotenoids and flavonoids. There is an increasing interest in finding ways to improve the nutritional quality of vegetables by increasing or maintaining antioxidant content during storage. This study has investigated the effect of postharvest high temperature treatments on nutritional quality changes in spinach during subsequent storage. Ascorbic acid was determined by HPLC during storage. The hot water (40 degrees C) pre-treatment reduced AsA loss during storage of spinach. However, the treatment was only effective in the case of spinach leaves subsequently stored at 0 degrees C, while in spinach leaves stored at 6 degrees C this effect was lost. In conclusion, hot water (40 degrees C) treatment can potentially be used for nutritional quality preservation in spinach leaves. Physiological processes induced by hot water treatment require further investigation.
|
|
| 25. |
- Mogren, Lars
(författare)
-
Potential for Controlled Abiotic Stress as a Quality Enhancer of Baby Leaf Spinach
- 2015
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1099, s. 407-412
-
Konferensbidrag (refereegranskat)abstract
- Applying abiotic stress in a controlled fashion during growth, preharvest, to leafy vegetables has been suggested as a strategy that may increase levels of bioactive compounds, and in some cases, increase shelf life potential. In a two-year project, change in ascorbic acid (AA) content in baby leaf spinach (Spinacia oleracea L.) was studied in response to a wide range of preharvest abiotic stress factors. AA is one of the main antioxidants found in leafy vegetables and the total amount and proportion of the oxidised form dehydroascorbic acid (DHA), could potentially be a parameter giving an indication of the stress level of the leaves. The assumption is that the higher the content of AA and the lower the proportion of DHA, the better the shelf life potential. AA and DHA concentrations were determined by HPLC. The analyzed leaves were grown under green house conditions. Foliar application of water solutions of common salts resulted in higher AA levels, but the leaves were damaged with necrotic spots and brown edges. Both cold treatment (10°C day/5°C night) of whole plants a few days prior to harvest as well as heat treatment (40°C) a few hours prior to harvest increased the AA levels. This approach needs further technical development to be commercially applicable. Restricted water supply leading to mild drought stress, a few days prior to harvest turned out to be the most promising preharvest treatment leading to increased AA content without any visual quality differences compared to full watered treatments. The extent of drought stress as well as timing of the treatment in the growth cycle needs further investigation.
|
|
| 26. |
|
|
| 27. |
- Mårtensson, Anna, et al.
(författare)
-
Impact of organic N on corky root in organically cultivated greenhouse tomatoes
- 2017
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1164, s. 327-332
-
Konferensbidrag (refereegranskat)abstract
- Corky root of tomato caused by Pyrenochaeta lycopersici, is a major soil-borne disease in Swedish organic greenhouse production where tomatoes are grown in soil-based substrate. The corky root attacks the roots of the tomatoes and results in a suberisation of the roots reducing the plants ability to take up water and nutrients. Currently, for most producers, corky root resistant grafted plants is a presumption for the production but apprehensions are that this will affect the taste and may result in a build-up of resistance. Other methods for controlling the disease are urgently needed. A way to decrease the problem is to replace the substrate but this is very expensive. In the present study we tested the hypothesis that a proper N fertilization regime decreases disease severity. A greenhouse study was conducted using ungrafted tomato plants which were grown in a substrate naturally infected with corky root at three levels of additions of organic N, combined with three different pH levels. A high N addition increased the yields whereas a high pH reduced the yields. We conclude that tomatoes can resist corky root better at low pH. The reduced tomato yield at high pH cannot be explained by a calcium deficiency due to calcium immobilization at high pH. For organic tomato growers, a substrate with a low pH and a proper N fertilization is recommended.
|
|
| 28. |
- Naznin, Most Tahera
(författare)
-
Different Ratios of Red and Blue LEDs Light Affect on Coriander Productivity and Antioxidant Properties
- 2016
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1134, s. 223-229
-
Konferensbidrag (refereegranskat)abstract
- Light emitting diodes (LEDs) can be selected to target the wavelengths absorbed by plants, enabling the users to customize the wavelengths of light required for maximum production. The purpose of this study was to evaluate the growth and antioxidant accumulation in coriander plants cultured under various ratios of red to blue LEDs. Four light treatments including: red LEDs (100%) and three ratios of red (661 nm) to blue (449 nm) LEDs light (5:1, 10:1 and 19:1) at 120 mu mol m(-2) s(-1), were applied for this study. Coriander plants were cultured under different ratios of red to blue LEDs and were found to have an increase in the leaf and shoot number and fresh and dry mass than those plants cultured under 100% red LEDs. The highest fresh and dry mass accumulation were observed in plants cultured under the 10:1 ratio of red to blue LEDs but were not significantly different from the 19:1 ratio of red to blue LEDs. The coriander plants cultured under 100% red LEDs showed a significant decrease in antioxidant properties. This research will allow for improved selection of red to blue ratios of LEDs lighting for antioxidant rich leafy vegetables or spice production.
|
|
| 29. |
- Nilsson, Ulf, et al.
(författare)
-
The potential of trap crops as a pest management strategy against the carrot psyllid (Trioza apicalis) - an initial investigation of plant material for use as a trap crop
- 2017
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1153, s. 219-223
-
Konferensbidrag (refereegranskat)abstract
- The carrot psyllid (Trioza apicalis, Forster (Homoptera: Psylloidea: Triozidae)) is a serious phloem-feeding pest of carrots in Scandinavian countries. Carrot fields attacked at a sensitive growth stage can be completely destroyed. A damaged plant typically develops curled leaves and shows stunted growth. In an ongoing scientific project, a pest management strategy is being studied in which a carrot trap crop is used to lure the psyllid away from the main crop. The trap crop is then destroyed before the carrot psyllid has completed its life cycle. Within the scope of this project, the aim was to find cultivars that have the ability to grow quickly during the early growth stages and could be used as a trap crop. A total of 11 carrot cultivars were screened in a greenhouse trial. The time to reach three different development stages cotyledon, one-true-leaf and two-true-leaf - differed significantly between cultivars. Bolero and Calibra were among the fastest growing cultivars throughout the experiment and therefore appeared appropriate for use as a trap crop in upcoming large-scale field trials.
|
|
| 30. |
- Nordmark, Lotta, et al.
(författare)
-
The Nordic Light Terroir
- 2016
-
Ingår i: 29th International Horticultural Congress on Horticulture: Sustaining Lives, Livelihoods and Landscapes (IHC 2014): 4th International Symposium on Tropical Wines and International Symposium on Grape and Wine Production in Diverse Regions. - 0567-7572 .- 2406-6168. - 9789462611108 ; 1115, s. 189-193
-
Bokkapitel (refereegranskat)abstract
- Grapes are culturally a new crop in the Swedish landscape, which demands an introduction period concerning development of knowledge about how to grow the wine. Climate changes together with the development of "cross breeding" in Vitis vinifera open up new possibilities with new grapes, that previously were not possible to grow commercially and that suits the Swedish consumers. Wine production is of great interest among growers, producers and consumers. Experiences from regions with the same climate as Sweden show that production of quality wines is possible. Sweden was appointed as EU official wine country in 1999. There is a lack of tradition and experience of commercial cultivation of grapes, but Sweden has 300 vineyards including 15 to 25 vineyards approved by the authorities. A project started in the winter 2013 with the aim to increase the knowledge about grapevine growing and wine production with the Swedish and Nordic Light Terroir as background. A study where researchers from disciplines like agriculture, chemistry, yeast/microbiology, process engineering, sensorial analysis and market analysis collaborates. We have started to study the micro climate at Hällåkra vineyard and different types of grapes/crops and vineyards management that suits the Swedish and Nordic Light Terroir. A sensory analysis was made of Swedish white wines trying to identify The Nordic Light Terroir attributes. The Sensory profile of white wine from Solaris grown in Sweden is as we found a wine with a fresh, citrus and flowery aroma and a fresh, citrus and green apple taste. The wine's body will grow with increased knowledge of the entire chain; from soil to bottle based on the knowledge-building the new beverage platform will assist with.
|
|
| 31. |
- Nybom, Hilde, et al.
(författare)
-
Beauty Is as Beauty Does - Culinary and Medicinal Use of Rosehips
- 2015
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1064, s. 137-150
-
Konferensbidrag (refereegranskat)abstract
- The ornamental value of the rose flower is well-known, but rose plants have long been appreciated also for their fruits, the rosehips. These rosehips are sometimes harvested from cultivated or, more commonly, wild or naturalized stands to produce juice, dessert soup, jelly and other tasty products. Rosehips of especially the dogroses, i.e., Rosa sect. Caninae, have recently enjoyed a renewed interest due to their very high levels of antioxidant compounds, mainly polyphenols, but also carotenoids and vitamins B, C and E. Other important rosehip-producing species are found in sections Rosa and Gallicanae, as well as R. roxburghii in subgenus Platyrhodon. Medicinal preparations are presently produced and marketed for the treatment of, e.g., osteoarthritis and various stomach problems. The seeds contain high contents of unsaturated fatty acids, which are used for production of oils for skin treatment and as cosmetics. The amount and composition of bioactive compounds in rosehips vary greatly with genotype and environment. Breeding of improved dogrose genotypes or of intersectional hybrids is, however, complicated by the unique canina meiosis, resulting in widely different offspring in reciprocal crosses, and occasionally also producing offspring by apomixis.
|
|
| 32. |
|
|
| 33. |
- Nybom, Hilde, et al.
(författare)
-
Pre-breeding for future challenges in Nordic apples: susceptibility to fruit tree canker and storage diseases
- 2016
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1127, s. 117-124
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Apple production has a long history in the Nordic countries, but high labour costs and challenging climatic conditions result in production costs that are not competitive on the international market. In addition, access to permitted pre‐harvest chemicals in the orchards has been severely restricted in recent years, and post‐ harvest applications are completely banned. Moreover, grower economy would benefit from being able to forego chemical fungicides altogether, as there is an increasing demand for locally produced, organic fruit. Consequently, climate adaptation and disease resistance/tolerance are major issues for apple breeding programmes in Norway, Sweden and Finland. A public‐private partnership project initiated by the Nordic Council of Ministers and administered by NordGen started in 2012 with the aim of producing and disseminating knowledge concerning levels of susceptibility against some of the most devastating apple diseases in the Nordic countries, namely fruit tree canker (Neonectria ditissima) and storage diseases (Neofabraea spp. and Penicillium expansum), in apple cultivars of potential interest for plant breeding and cultivar development in the Nordic countries. Inoculation of fruit of 81 different apple cultivars with blue mould, P. expansum, has been carried out in Norway and Sweden, whereas evaluation of spontaneous infections of various fungi during storage has been carried out in Finland using fruit of organically produced, local apple cultivars. For fruit tree canker, inoculations have been carried out on detached shoots of 50 different apple cultivars in Norway and Sweden. For both apple canker and blue mould, reproducibility among years and sites was sufficiently high to enable an approximate determination of the level of susceptibility of the studied cultivars.
|
|
| 34. |
- Nybom, Hilde
(författare)
-
Towards the Rose Genome Sequence and Its Use in Research and Breeding
- 2015
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1064, s. 167-175
-
Konferensbidrag (refereegranskat)abstract
- Rose is one of the most economically important ornamental crops worldwide. Rosa sp. can become a model for woody ornamentals. Its genome size is relatively small (560 Mb), its genetic history with ploidy events is well documented, and rose has a short life for a woody plant. Furthermore, different tools are available, including transcriptomic tools, genetic maps and genetic transformation protocols. Rose represents an original model for studying some ornamental traits that cannot be addressed in other model plant species such as Arabidopsis. Some of these traits, such recurrent blooming, flower morphogenesis or scent production and emission, are of economic interest. Different groups involved in rose genetics and genomics gathered to form the 'Rose Genome Sequence Initiative'. Our objective is to obtain a high quality rose genome sequence of the diploid R. chinensis 'Old Blush'. One important issue is the high level of heterozygosity of roses. To tackle this issue, different strategies are proposed: production of a haploid and development a high density genetic map to anchor the genome. This genetic map will be developed from a cross between 'Old Blush' and R. wichurana. The genotype R. chinensis 'Old Blush' will be sequenced using NGS technologies. The data will be assembled and arranged using the high-density map. In order to increase ESTs and to facilitate genome annotation, we have recently produced ESTs from various tissues of 'Old Blush' under different conditions. Digital expression (RNA Seq) was obtained from the different tissues and data are available on the following web site (https://iant.toulouse.inra.fr/plants/rosa/FATAL/). The rose genome sequence will be a great step to help identifying the molecular basis of ornamental traits and also to study genetic diversity and genome evolution in the genus Rosa and in the Rosaceae family.
|
|
| 35. |
- Olausson, Inger, 1969-
(författare)
-
Market gardens in Sweden 1900-1950 with four case studies from Stockholm County
- 2015
-
Ingår i: ISHS Acta Horticulturae 1108XXIX International Horticultural Congress on Horticulture: Sustaining Lives, Livelihoods and Landscapes (IHC2014): V International Conference on Landscape and Urban Horticulture and International Symposium on Sustainable Management in the Urban Forest. - : International Society for Horticultural Science. - 9789462611023 ; 1108, s. 123-129
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The links between market gardens and cities were symbiotic until the mid-1900s. In my thesis about market gardens in Sweden 1900-1950, four market gardens in Stockholm County are investigated, trying to find out how different resources and strategies contributed to the businesses competitiveness. Two of the market gardens belonged to mansions with all the staff employed. The other two were established as family businesses by entrepreneurs without employees. Garden products are sensitive to bumps, heat, low temperatures, etc. Due to this, the access to a nearby market was necessary at that time. The development of the trade with garden products was linked to a fast-growing population in the cities, the growing demand for garden products, and the development of the transport sector. From the growing city, gardeners bought horse manure, garbage, or anything that produced heat to the hotbeds when it decomposed. Most of the market gardens were small family businesses situated on small plots. In the 1930s and 1940s in 75% of the businesses a maximum of three people were engaged. The production was both resource-demanding and labour-intensive. The use of hotbeds and greenhouses extended the growing season and made it possible to grow all year around. The gardenerRSQUOs dependence on merchandises increased like an avalanche to beat the growing competition on the market. The import, often of high quality products, was growing very fast and affected the interest for garden products. It forced the domestic horticulture industry to increase the quality and effectiveness of the production.
|
|
| 36. |
|
|
| 37. |
|
|
| 38. |
|
|
| 39. |
- Sehic, Jasna, et al.
(författare)
-
DNA marker-assisted identification of Prunus accessions
- 2015
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1101, s. 153-158
-
Konferensbidrag (refereegranskat)abstract
- Considerable efforts have been made to provide gene bank accessions with DNA-based identification profiles, especially for expensive collections that are maintained in the field like fruit trees. We have recently genotyped 52 cherry accessions and 73 plum accessions with SSR markers. Several synonyms were found among the plum accessions, many of which had been collected in the countryside in Norway without any documentation of genetic origin. By contrast, the cherry samples had been obtained from established gene bank collections. Nevertheless, less than 60% of the investigated cherry trees were correctly labeled. The highest proportion of suspected mislabelings was found among the sweet cherries. For both the plums and the cherries, parentage could be verified in some cases where both parent and offspring cultivars were analyzed.
|
|
| 40. |
- Sehic, Jasna
(författare)
-
Genetic diversity of Prunus domestica selected from ten countries across Europe
- 2019
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1260, s. 159-162
-
Konferensbidrag (refereegranskat)abstract
- A DNA marker-based study in European plum was performed within the project "Identification of a representative set of Prunus domestica accessions of European origin, well documented and characterized, to be included into the AEGIS system (PRUNDOC)" funded by Bioversity International under the European Cooperative Programme for Plant Genetic Resources (ECPGR) programme. A total of 46 local plum accessions from 10 European countries (Belgium, France, Germany, Greece, Italy, Latvia, Norway, Serbia, Slovakia and Sweden) were analysed using simple sequence repeat (SSR) loci. In addition, seven reference cultivars ('Bistrica', 'Hanita', 'Mirabelle de Nancy', 'Reine Claude Violette', 'Stanley', 'Valor' and 'Victoria') were analysed for standardization of allele sizes. The following nine primers were used: PacA33 is an EST-SSR developed in apricot, BPPCT039, BPPCT007, BPPCT014, BPPCT034, BPPCT040, UDP96 and UDP98 were developed from genomic peach DNA, while CPSCT026 was developed from genomic DNA of Japanese plum, Prunus salicina. None of the investigated local plum accessions were identical, nor were any of them identical to any of the reference cultivars. Genetic similarity among accessions was examined using Jaccard's similarity coefficients. The dendrogram obtained showed that the plum accessions did not group in a pattern corresponding to their country of origin.
|
|
| 41. |
|
|
| 42. |
- Svensson, Birgitta
(författare)
-
Organic production of raspberries in high tunnels in Sweden, 2008-2014
- 2016
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1133, s. 211-216
-
Konferensbidrag (refereegranskat)abstract
- Organic raspberry cultivation places heavy demands on climate and environment to achieve sufficiently profitable production in the Nordic countries. High plastic tunnels provide excellent opportunities for safe production of high quality berries. A project with multiannual production of floricane and primocane raspberries was established in 2008 at Ranna Experimental Station, Skovde, Sweden (58 degrees 27'1 '' N, 13 degrees 49'51 '' E). During part one of the project, treatments comprising three cultivars of each raspberry type, growing floricanes in soil or pots, two levels of nitrogen and single or double crops of primocanes were compared in field trials. A need for crop protection measures suitable for organic raspberry production became apparent and part two of the project focused on control of raspberry leaf and bud mite (Phyllocoptes gracilis) and small raspberry aphid (Aphis idaei). The results of part one revealed two very good cultivars for organic production in tunnels, the floricane 'Glen Ample' and the primocane 'Polka'. Maintaining a sustainable substrate and organic fertilisation in pot culture of raspberries for more than one season proved difficult and the best yield and quality were achieved by growing in soil. The optimal level of nitrogen was found to be 12-17 g organic nitrogen per plant and season. Fertiliser needed to be applied during the growing season. A double crop of primocanes was achieved only when lower-positioned lateral shoots did not emerge in the previous autumn. In part two of the project, acceptable control of raspberry leaf and bud mite was achieved with biweekly rapeseed oil and soap treatment, in combination with late autumn treatments. Small raspberry aphid was sufficiently controlled by early spraying with a pyrethrum product (Raptol) at bud burst and a second spraying two weeks later. Botrytis cinerea was not observed on fruits during the six harvesting years of the project. Raspberry cane diseases such as Didymella applanata and Botrytis cinerea occurred to some extent during the project period, but did not require any control measures. Overall, the project results demonstrate profitable organic production of high-quality floricane and primocane raspberries with adequate control of common pests.
|
|
| 43. |
- Tahir, Ibrahim, et al.
(författare)
-
Control of storage diseases of apples by plant volatile compounds and hot water
- 2019
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1261, s. 251-258
-
Konferensbidrag (refereegranskat)abstract
- The antifungal effect of four plant volatile compounds (thymol from Thymus vulgaris, eugenol from Syzygium aromaticum, cinnamon oil from Cinnamomum zeylanicum and lemongrass oil from Cymbopogon citrullus) and of hot water (48, 51, 54, and 57°C) against two postharvest diseases in apples, caused by Neofabraea perennans and Penicillium expansum, was tested in vitro and in vivo. Lemongrass oil or a mixture of thymol (60 mg L-1) and eugenol (3 g L-1) reduced infection with N. perennans and P. expansum by 40-46% and 41-45%, respectively, in artificially inoculated apples (‘Amorosa’) compared with non-treated apples. Hot water (48-54°C) decreased infection with P. expansum and N. perennans by 33 and 41%, respectively, while the hot water 57°C treatment had a negative effect. A combination of thymol (60 mg L-1) and eugenol (3 g L-1) inhibited mycelial growth of both pathogens by 75-80%. Cinnamon oil and lemongrass oil also showed strong inhibition of mycelial growth of N. perennans, but not of P. expansum. Hot water treatment for 1 min decreased mycelial growth of N. perennans by more than 80% and of P. expansum by 35-55%. No significant differences were found between the different temperatures of the hot water for N. perennans, while hot water at 54°C had the greatest effect on P. expansum. Viability of N. perennans conidia was inhibited by 73 and 54%, respectively, after treatment with a combination of thymol (60 mg L-1) and eugenol (3 g L-1), or lemongrass oil. Conidia of P. expansum lost approximately 60% of their viability when treated with the thymol-eugenol mixture.
|
|
| 44. |
- Tahir, Ibrahim
(författare)
-
Determination of optimum harvest maturity for five apple cultivars using the chlorophyll absorbance index
- 2019
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1261, s. 219-223
-
Konferensbidrag (refereegranskat)abstract
- Prediction of the optimum harvest date and storability of apples is an important concern for the fruit industry in Scandinavia. Streif index, firmness or only starch conversion are commonly used methods. To replace these with a more practical and non-destructive method, a portable spectrometer (DA meter, chlorophyll absorbance index (IAD)) was used to determine the optimum harvest date and storage potential for five apple cultivars grown in a cool climate. There was a very strong negative correlation between harvest date and IAD value in all cultivars. IAD values also showed a strong negative correlation with fruit respiration. However, the relationship was stronger in ‘Discovery’, ‘Rubinola’ and ‘Santana’ than in ‘Aroma’ and ‘Karin Schneider’. Streif index values showed very close relationships with IAD in all five apple cultivars. Apples harvested with IAD values of 0.8-1.8 had Streif index values of 0.14-0.20, which corresponds to an adequate threshold for harvesting apples for long-term storage. After four months in cold storage, fruits with higher IAD value at harvest showed higher firmness in all cultivars except ‘Rubinola’, and slower softening in ‘Aroma’, ‘Rubinola’ and ‘Santana’. Only in ‘Aroma’ and ‘Karin Schneider’ did IAD show a negative correlation, with a decline in soluble solids content during storage. Negative correlations were also found between IAD values at harvest or after storage and the occurrence of fungal decay. Since fruit respiration rate increases with advanced maturity while Streif index decreases, determination of IAD can be a very promising technique to predict the storage potential of apples and to identify high-quality fruit.
|
|
| 45. |
- Tasin, Marco
(författare)
-
Control of the grapevine moth Lobesia botrana through genetic engineering manipulation of host-plant volatiles
- 2019
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 1248, s. 201-206
-
Konferensbidrag (refereegranskat)abstract
- The European grapevine moth, Lobesia botrana, is one of the most important pests of grape. Feeding activity by caterpillars leads to direct damage to reproductive plant tissues (flower buds and berries), and also to indirect damage by promoting secondary infections by microorganisms. Current control systems are based either on the use of insecticides or on mating disruption: while the first is not environmentally friendly, the second is not particularly suitable for non-delimited areas or areas where the pest population is high. Previous studies have shown that a synthetic blend of the three terpenoids (E)-beta-caryophyllene, (E)-beta-farnesene and (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) was as attractive for the moth as the complete grape odour profile under laboratory conditions. The same studies also showed that the specific ratio of these compounds in the grape bouquet was crucial, because small variations in the proportion of any of the three volatiles resulted in almost complete inhibition of the blend's attractiveness. Here, we report on the creation of stable grapevine transgenic lines with modified (E)-beta-caryophyllene and (E)-beta-farnesene emission and thus with an altered ratio compared with the original plants. When headspace collections from these plants were tested in wind-tunnel behavioural assays, they were less attractive than control extracts. This result was confirmed by testing synthetic blends that imitated the ratios found in natural and transformed plants, as well as by testing the plants themselves. With this evidence, we suggest that a strategy based on volatile ratio modification may also interfere with the host-finding behaviour of L. botrana in the field, paving the way for new pest-control methods.
|
|
| 46. |
- Vagiri, Michael, et al.
(författare)
-
Quality traits in black currant (Ribes nigrum L.) as affected by genotype and location
- 2016
-
Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; 117, s. 207-211
-
Konferensbidrag (refereegranskat)abstract
- Black currants are favoured for their tasty juice, rich colour and intense flavour and they are also rich sources of different phytochemicals with health promoting properties. In the present study ascorbic acid, total phenols, total anthocyanins, soluble solids and titratable acidity were quantified in five black currant genotypes grown in the north and south of Sweden over a three-year period. Remarkable variation between the genotypes for the different traits was revealed. For ascorbic acid, a 3-fold difference and for total phenols, a 2-fold difference, were observed. Although, the content of ascorbic acid and soluble solids were found to be genetically determined, growing location influenced cultivars 'Ben Finlay', 'Poesia' and 'Titania', with higher levels recorded in the south as compared to the same genotypes grown in the north. Also for total phenols and titratable acidity genotypic effects were more pronounced than that of location and year, whereas location was most important for the total anthocyanin content.
|
|
| 47. |
- Ahlman, Linnéa, 1987, et al.
(författare)
-
LED spectrum optimisation using steady-state fluorescence gains
- 2016
-
Ingår i: Acta Horticulturae. - 0567-7572. - 9789462611092 ; 1134, s. 367-374
-
Tidskriftsartikel (refereegranskat)abstract
- The use of light emitting diodes (LEDs) in greenhouses entails the possibility to control the light in a better way, since both spectrum and light intensity can be adjusted. We aim at developing a method to automatically find the optimal spectrum in terms of energy consumption and plant growth. Previous work shows that chlorophyll fluorescence (ChlF) at 740 nm strongly correlates with the photosynthetic rate (carbon dioxide uptake rate) and that the net efficiency of a LED group therefore is coupled to the fluorescence gain w.r.t. energy consumption, i.e., the slope of a curve depicting steady-state ChlF versus applied power to the LED group. In the present work we compare the fluorescence gains for six different LED types (wavelength peaks from 400 to 660 nm) and six different species: tomato, cucumber, basil, lettuce (two species) and dill. We also compare two different kinds of experiments: steadystate experiments, waiting for the fluorescence to reach a steady state at a few incident light intensities, and ramp experiments, where the light intensity is increased slowly. The ramp experiment gives essentially the same information as the steady-state experiment, but was found to slightly overestimate the gains of the blue LEDs. Being aware of this, it should be possible to initially use the faster (ramp) method in order to find the right light composition, possibly using steady-state experiments for a few LED colours to fine tune the lamp. The relative order of the fluorescence gains among the tested LED groups is similar, but not identical, for all species tested. LED660 has the highest fluorescence gain w.r.t. incident photon flux density, and LED400 and/or LED530 have the lowest. However, the important quantity is in fact the fluorescence gain w.r.t. applied electrical power. If the individual electrical efficiencies of the LEDs change the most efficient power split on the different LEDs might change.
|
|
| 48. |
- Campolo, Orlando, et al.
(författare)
-
Efficacy of Selected Insecticides for the Control of the California Red Scale in Southern Italy
- 2015
-
Ingår i: Acta Horticulturae. - : INT SOC HORTICULTURAL SCIENCE. - 0567-7572. ; 1065, s. 1149-1156
-
Tidskriftsartikel (refereegranskat)abstract
- The California red scale (CRS), Aonidiella aurantii (Maskell), is considered one of the most important pests of citrus in the Mediterranean basin as well as in other citrus growing areas worldwide. In Southern Italy, citrus is the most widely cultivated crop and the control of the CRS relies mainly on the application of synthetic insecticides. During 2009 and 2010, selected insecticides (spirotetramat, chlorpyriphos and pyriproxyfen) were evaluated against this pest in two calabrian citrus orchards (southern Italy) under integrated pest management. Treatments were performed according to the dosage reported on the label of the commercial products. Two treatments, at 15-day interval, were performed. Control plots were sprayed with water only. Efficacy was assessed 7, 14, 21, and 28 days after the first treatment and at the harvest. In both trials, spirotetramat showed the highest levels of efficacy against CRS and other citrus pests (citrus leafminer, and aphids) that were adequately controlled until the harvest.
|
|
| 49. |
- Carstensen, Anna-Maria, 1982, et al.
(författare)
-
Exploring the dynamics of remotely detected fluorescence transients from basil as a potential feedback for lighting control in greenhouses
- 2016
-
Ingår i: Acta Horticulturae. - 0567-7572. - 9789462611092 ; 1134, s. 375-383
-
Tidskriftsartikel (refereegranskat)abstract
- Optimizing artificial lighting control in industrial scale greenhouses has a potential for increased crop yields, energy savings and production timing. One possible component in controlling greenhouse lighting is continuous and accurate measurement of plant photosynthetic performance. A widely used tool for measuring photosynthetic performance non-invasively is chlorophyll fluorescence. For the purpose of automatic control, remote sensing of fluorescence is favourable, since it provides an aggregated measure for a large canopy area. However, adaptation of traditional fluorescence methodologies to remote sensing is problematic since they are based on the analysis of fluorescence intensities and therefore sensitive to distance and morphology. Other problems with using traditional methods remotely in a greenhouse are a need for dark adaption and use of saturating light. This paper presents a novel concept for the detection of photosynthetic performance based on the dynamics of remotely sensed light induced fluorescence signals. The dynamics of the fluorescence signal is insensitive to distance and morphology and hence provide a good basis for remote detection of photosynthetic performance. Through experiments we have explored how the dynamics of the time-varying fluorescence signal from basil plants was affected by light intensity, light acclimation and light induced stress. This was done by first identifying a dynamic model by transient analysis and then applying frequency analysis on the model. We conclude that the capacity of basil plants to use a certain light intensity was reflected by how fast and how complex the dynamics are. These results show that an identified resonance peak frequency is a potential indicator of plants' ability to adapt to light, which could be a valuable feedback signal for lighting control in greenhouses.
|
|
| 50. |
- Khan, M.A.M., et al.
(författare)
-
Contribution of native fruits to alleviation of poverty and malnutrition in rural areas in Mozambique
- 2016
-
Ingår i: Acta Horticulturae. - 0567-7572. - 9789462611412 ; 1128, s. 73-78
-
Konferensbidrag (refereegranskat)abstract
- In Mozambique, 80% of the population depend on agriculture for their livelihoods, and 64% are food insecure. Malnutrition is the major health problem in some rural areas, and this is related to micro- and macronutrient deficiency. Irregular food availability throughout the year caused by seasonality and critical events contributes to this situation. The main cause of malnutrition, particularly in women and children, is insufficient intake of foods rich in micronutrients. During the dry season, native fruits play an important and crucial role in ensuring food security and, in many cases, are becoming the only way of survival for rural families. This study examined the potential use of native fruits as an alternative source of nutrients for alleviating malnutrition in Mozambique. Two key native fruits, Strychnos spinosa and Strychnos madagascariensis, were identified, and their chemical and nutritional Ipotential determined. The results showed that both products are rich in sugar and fiber, as well as in vitamins A and C. The fat content of S. spinosa pulp (0.15%) was much lower than that of S. madagascariensis (64%). Protein content was relatively low in both products. Mineral content analysis showed that both of these fruits are highly nutritional, being rich in K, Na, Mg, and Ca, and also in the essential microelements Cu, Zn, and Fe. For these reasons, they may contribute in a significant way to alleviation of poverty and malnutrition in Mozambique.
|
|
