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The Fundamentals of Horticulture
Abstract
Cambridge Core - Natural Resource Management, Agriculture, Horticulture and forestry - The Fundamentals of Horticulture - edited by Chris Bird
... Plants 2020, 9, 13 2 of 21 contribute towards food security and social stability. Within this scope, applied research on innovative horticultural practices can make effective use of dynamic crop growth models [4] under conditions optimal for plant growth and for eliciting plant response to abiotic stresses [5], therefore, allowing a more rational use of resources, such as water and nutrients [4]. ...
In this study, five allometric models were used to estimate the single leaf area of three well-known medicinal and aromatic plants (MAPs) species, namely basil (Ocimum basilicum L.), mint (Mentha spp.), and sage (Salvia spp.). MAPs world production is expected to rise up to 5 trillion US$ by 2050 and, therefore, there is a high interest in developing research related to this horticultural sector. Calibration of the models was obtained separately for three selected species by analyzing (a) the cultivar variability-i.e., 5 cultivars of basil (1094 leaves), 4 of mint (901 leaves), and 5 of sage (1103 leaves)-in the main two traits related to leaf size (leaf length, L, and leaf width, W) and (b) the relationship between these traits and single leaf area (LA). Validation of the chosen models was obtained for each species using an independent dataset, i.e., 487, 441, and 418 leaves, respectively, for basil (cv. 'Lettuce Leaf'), mint (cv. 'Comune'), and sage (cv. 'Comune'). Model calibration based on fast-track methodologies, such as those using one measured parameter (one-regressor models: L, W, L 2 , and W 2) or on more accurate two-regressors models (L × W), allowed to achieve different levels of accuracy. This approach highlighted the importance of considering intra-specific variability before applying any models to a certain cultivar to predict single LA. Eventually, during the validation phase, although modeling of single LA based on W 2 showed a good fitting (R 2 basil = 0.948; R 2 mint = 0.963; R 2 sage = 0.925), the distribution of the residuals was always unsatisfactory. On the other hand, two-regressor models (based on the product L × W) provided the best fitting and accuracy for basil (R 2 = 0.992; RMSE = 0.327 cm 2), mint (R 2 = 0.998; RMSE = 0.222 cm 2), and sage (R 2 = 0.998; RMSE = 0.426 cm 2).
Plant tolerance against a combination of abiotic stresses is a complex phenomenon, which involves various mechanisms. Physiological and biochemical analyses of salinity (NaCl) and nickel (Ni) tolerance in two contrasting tomato genotypes were performed in a hydroponics experiment. The tomato genotypes selected were proved to be tolerant (Naqeeb) and sensitive (Nadir) to both salinity and Ni stress in our previous experiment. The tomato genotypes were exposed to combinations of NaCl (0, 75 and 150 mM) and Ni (0, 15, and 20 mg L‐1) for 28 days. The results revealed that the tolerant and sensitive tomato genotypes showed similar response to NaCl and Ni stress, however the level of response was significantly different in both genotypes. The tolerant tomato genotype showed less reduction in growth than the sensitive genotype against both NaCl and Ni stress. Root and shoot ionic analysis showed a decrease in Na and increase in K concentration by increasing Ni levels in the growth medium. Moreover, accumulation of Na and Ni in tissues showed a decrease in membrane stability index and an increase in malondialdehyde contents. The activity of superoxide dismutase, catalase, peroxidase and glutathione reductase under NaCl and Ni stress was significantly higher in the tolerant compared to the sensitive genotype. Enhanced activity of many antioxidant enzymes in Naqeeb under stress conditions is among the other mechanisms that enabled the genotype to better detoxify reactive oxygen species and therefore Naqeeb tolerated the stresses better than Nadir.
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El Jardín Botánico de Lourizán (Pontevedra, España) empezó a adquirir su fisionomía actual en la década de 1880, aprovechando la morfología irregular del terreno. Desde entonces, sobre el modelo establecido en su momento, se han añadido algunas zonas nuevas y se ha plantado un gran número de ejemplares, de los que actualmente quedan representación de más de 850 taxones, en su mayoría árboles y arbustos. Entre los árboles existentes, los ejemplares Cedrus libani, Corylus avellana, Cryptomeria japonica, Metasequoia glyptostroboides, Styphnolobium japonicum (=Sophora japonica) ´Pendulum´, Sequoia sempervirens y la colección de Castanea sp. pl. están incluidos en el Catálogo Galego de Árbores Senlleiras. Además de los anteriores, hay otros ejemplares o formaciones que, por sus características dendrométricas, biológicas, estéticas o históricas, consideramos merecen ser incluidas en el citado Catálogo. Un ejemplar de Camellia japonica, en el llamado Parque de las Rías, destaca por ser el más alto del Mundo (20,5 m) y data de la época de creación del Parque (1887). También el ejemplar de Tetraclinis articulata, plantado en 1993 en el Parque de las Autonomías, que con una altura de 15,5 m es una rareza en el Noroeste Ibérico; el Eucalyptetum, iniciado en 1955, es único en la Península Ibérica por el número de taxones (88) y el tamaño de los especímenes, muchos de los cuales sobrepasan los 50 m de altura y algunos llegan a ser los mayores en el Mundo, Europa o España de la especie; también los ejemplares de Alnus cordata, Angophora floribunda, Casuarina cunninghamiana o Pawlonia fortumei son también singulares. Como formaciones, destacamos la alineación de Platanus x hispanica, que rodea el Parque de las Rías, tiene una altura media de casi 40 m y un porte de candelabro, plantados en la época creación del Parque (1887); la colección de Coníferas, comprende 36 géneros y 160 taxones, que abarca los géneros Pinus (51 taxones), Abies (13), Picea (13), Afrocarpus, Agathis, Araucaria, Austrocedrus, Calocedrus, Callitris, Callitropsis, Cedrus, Cephalotaxus, Chamaecyparis, Cryptomeria, Cunninghamia, Cupressus, Dacridium, Dacrycarpus, Hesperocyparis, Hesperotropsis, Juniperus, Larix, Libocedrus, Metasequoia, Nageia, Platycladus, Podocarpus, Pseudotsuga, Scyadopitys, Sequoia, Sequoiadendron, Taiwania, Taxodium, Tetraclinis, Thuja y Tsuga, que en conjunto representa la mejor colección del grupo en la Península Ibérica. Además de por su rareza o número, destacan muchos de los especímenes citados por su valor histórico e interés científico.
A germplasm assembly of 128 finger millet genotypes from 18 countries was evaluated for seedling-stage phosphorus (P) responses by growing them in P sufficient (Psuf) and P deficient (Pdef) treatments. Majority of the genotypes showed adaptive responses to low P condition. Based on phenotype behaviour using the best linear unbiased predictors for each trait, genotypes were classified into, P responsive, low P tolerant and P non-responsive types. Based on the overall phenotype performance under Pdef, 10 genotypes were identified as low P tolerants. The low P tolerant genotypes were characterised by increased shoot and root length and increased root hair induction with longer root hairs under Pdef, than under Psuf. Association mapping of P response traits using mixed linear models revealed four quantitative trait loci (QTLs). Two QTLs (qLRDW.1 and qLRDW.2) for low P response affecting root dry weight explained over 10% phenotypic variation. In silico synteny analysis across grass genomes for these QTLs identified putative candidate genes such as Ser-Thr kinase and transcription factors such as WRKY and basic helix-loop-helix (bHLH). The QTLs for response under Psuf were mapped for traits such as shoot dry weight (qHSDW.1) and root length (qHRL.1). Putative associations of these QTLs over the syntenous regions on the grass genomes revealed proximity to cytochrome P450, phosphate transporter and pectin methylesterase inhibitor (PMEI) genes. This is the first report of the extent of phenotypic variability for P response in finger millet genotypes during seedling-stage, along with the QTLs and putative candidate genes associated with P starvation tolerance. © 2017 Ramakrishnan et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
In this paper, we summarize the international situation with respect to environmental risk assessment for biological control
agents. Next, we apply a recently designed, comprehensive risk evaluation method consisting of a stepwise procedure to evaluate
the environmental risks of Harmonia axyridis in Northwest Europe. This resulted in the very clear conclusion that H. axyridis is a potentially risky species for Northwest Europe, because it is able to establish, it has a very wide host range including
species from other insect orders and even beyond the class of Insecta, it may feed on plant materials, it can cover large
distances (>50km per year), it does move into non-target areas, it may attack many non-target species including beneficial
insects and insects of conservation concern, its activities have resulted in the reduction of populations of native predators
in North America, it is known as a nuisance in North America and recently also in Northwest Europe, and it may develop as
a pest of fruit in North America. Considering the H. axyridis case, current knowledge would lead to the conclusion that, although the predator is capable to effectively control several
pest species, its risks are manifold and it should, thus, not have been released in Northwest Europe. At the time of the first
releases in Nortwest Europe in 1995, the available scientific literature made clear that H. axyridis is a large sized polyphagous predator and has a great reproductive capacity in comparison with other ladybird beetles, and
that there was a need to study non-target effects because of its polyphagous behaviour. In retrospect, this information should
have been sufficient to reject import and release of this species, but it was apparently ignored by those who considered release
of this predator in Northwest Europe. The case of Harmonia releases in Northwest Europe underlines that there is an urgent need for harmonized, world-wide regulation of biological
control agents, including an information system on risky natural enemy species.
Keywords
Harmonia
axyridis
-Environmental risk assessment-Host range-Dispersal-Establishment-Non-target effects-Quick scan risk evaluation-Comprehensive risk evaluation
The literature on effects of habitat fragmentation on biodiversity is huge. It is also very diverse, with different authors measuring fragmentation in different ways and, as a consequence, drawing different conclusions regarding both the magnitude and direction of its effects. Habitat fragmentation is usually defined as a landscape-scale process involving both habitat loss and the breaking apart of habitat. Results of empirical studies of habitat fragmentation are often difficult to interpret because (a) many researchers measure fragmentation at the patch scale, not the landscape scale and (b) most researchers measure fragmentation in ways that do not distinguish between habitat loss and habitat fragmentation per se, i.e., the breaking apart of habitat after controlling for habitat loss. Empirical studies to date suggest that habitat loss has large, consistently negative effects on biodiversity. Habitat fragmentation per se has much weaker effects on biodiversity that are at least as likely to be positive as negative. Therefore, to correctly interpret the influence of habitat fragmentation on biodiversity, the effects of these two components of fragmentation must be measured independently. More studies of the independent effects of habitat loss and fragmentation per se are needed to determine the factors that lead to positive versus negative effects of fragmentation per se. I suggest that the term "fragmentation" should be reserved for the breaking apart of habitat, independent of habitat loss.
More than 5000 introductions of about 2000 species of exotic arthropod agents for control of arthropod pests in 196 countries or islands during the past 120 years rarely have resulted in negative environmental effects. Yet, risks of environmental effects caused by releases of exotics are of growing concern. Twenty countries have implemented regulations for release of biological control agents. Soon, the International Standard for Phytosanitary Measures (ISPM3) will become the standard for all biological control introductions worldwide, but this standard does not provide methods by which to assess environmental risks. This review summarizes documented nontarget effects and discusses the development and application of comprehensive and quick-scan environmental risk assessment methods.
Push-pull strategies involve the behavioral manipulation of insect pests and their natural enemies via the integration of stimuli that act to make the protected resource unattractive or unsuitable to the pests (push) while luring them toward an attractive source (pull) from where the pests are subsequently removed. The push and pull components are generally nontoxic. Therefore, the strategies are usually integrated with methods for population reduction, preferably biological control. Push-pull strategies maximize efficacy of behavior-manipulating stimuli through the additive and synergistic effects of integrating their use. By orchestrating a predictable distribution of pests, efficiency of population-reducing components can also be increased. The strategy is a useful tool for integrated pest management programs reducing pesticide input. We describe the principles of the strategy, list the potential components, and present case studies reviewing work on the development and use of push-pull strategies in each of the major areas of pest control.
The dominant late twentieth century model of land use segregated agricultural production from areas managed for biodiversity conservation. This module is no longer adequate in much of the world. The Millennium Ecosystem Assessment confirmed that agriculture has dramatically increased its ecological footprint. Rural communities depend on key components of biodiversity and ecosystem services that are found in non-domestic habitats. Fortunately, agricultural landscapes can be designed and managed to host wild biodiversity of many types, with neutral or even positive effects on agricultural production and livelihoods. Innovative practitioners, scientists and indigenous land managers are adapting, designing and managing diverse types of 'ecoagriculture' landscapes to generate positive co-benefits for production, biodiversity and local people. We assess the potentials and limitations for successful conservation of biodiversity in productive agricultural landscapes, the feasibility of making such approaches financially viable, and the organizational, governance and policy frameworks needed to enable ecoagriculture planning and implementation at a globally significant scale. We conclude that effectively conserving wild biodiversity in agricultural landscapes will require increased research, policy coordination and strategic support to agricultural communities and conservationists.
Most conventional gardening books concentrate on how and when to carry out horticultural tasks such as pruning, seed sowing and taking cuttings. Science and the Garden, Third Edition is unique in explaining in straightforward terms some of the science that underlies these practices. It is principally a book of 'Why' ? Why are plants green? Why do some plants only flower in the autumn? Why do lateral buds begin to grow when the terminal bud is removed by pruning? Why are some plants successful as weeds? Why does climate variability and change mean change for gardeners? But it also goes on to deal with the 'How', providing rationale behind the practical advice. The coverage is wide-ranging and comprehensive and includes: the diversity, structure, functioning and reproduction of garden plants; nomenclature and classification; genetics and plant breeding; soil properties and soil management; environmental factors affecting growth and development; methods of propagation; size and form; colour, scent and sound; climate; environmental change; protected cultivation; pest, disease and weed diversity and control; post-harvest management and storage; garden ecology and conservation; sustainable horticulture; gardens and human health and wellbeing; and gardens for science. This expanded and fully updated Third Edition of Science and the Garden includes two completely new chapters on important topics: Climate and Other Environmental Changes; Health, Wellbeing and Socio-cultural Benefits. Many of the other chapters have been completely re-written or extensively revised and expanded, often with new authors and/or illustrators, and the remainder have all been carefully updated and re-edited. Published in collaboration with the Royal Horticultural Society, reproduced in full colour throughout, carefully edited and beautifully produced, this new edition remains a key text for students of horticulture and will also appeal to amateur and professional gardeners wishing to know more about the fascinating science behind the plants and practices that are the everyday currency of gardening.
Weeds play an important role in human affairs over much of the earth. The major characteristics of weeds are their unwanted occurrence, undesirable features and ability to adopt to a disturbed environment (Combellack, 1992). Despite measures adopted for their control, weeds are estimated to reduce world food supplies by about 11.5% annually ((Combellack, 1992Parker and Fryer, 1975). Many of our problem weeds are of exotic origin, having been introduced accidentally or deliberately as ornamental plants, etc. They flourish in the new environment as they have escaped from the natural enemies, which suppress their vigour and aggressiveness in their native lands.
The potential for using “augmentative” biological control (or “augmentation”) for suppressing arthropod pests has been recognized for many years. Nevertheless, augmentation is applied commercially in relatively few agricultural systems, particularly in the US. To address why this might be the case, we reviewed the literature on augmentative biological control and critically evaluate three questions. First, does augmentative biological control effectively suppress agricultural pests? Second, is augmentation cost effective? Third, what ecological factors limit the effectiveness of augmentation? We evaluated the effectiveness of augmentation by assessing whether pest densities were suppressed to specified target levels and by reviewing studies that explicitly compared augmentation with pesticide applications. Augmentation achieved target densities in about 15% of case studies and failed 64% of the time. Augmentation was also usually less effective than pesticide applications, though not always. In the evaluation of economics, augmentative releases were frequently more expensive than pesticides, although there were cases where augmentation was cost effective. Finally, 12 ecological factors were implicated as potential limits on the efficacy of augmentation. Unfavorable environmental conditions, compensatory mortality, enemy dispersal, host refuges from released natural enemies, and predation of released agents were most often suggested as ecological limits. Future research should seek to counteract ecological limits by combining different natural enemy species and/or by combining augmentative releases with low-risk pesticides. Use of low-risk insecticides and organic agricultural practices in particular provides new opportunities for augmentative biological control.
ABSTRACT All pesticides used in United Kingdom glasshouse lettuce production (six fungicides, four insecticides, and one herbicide) were evaluated for their effects on Coniothyrium minitans mycelial growth and spore germination in vitro agar plate tests. Only the fungicides had a significant effect with all three strains of C. minitans tested, being highly sensitive to iprodione (50% effective concentration [EC(50)] 7 to 18 mug a.i. ml(-1)), moderately sensitive to thiram (EC(50) 52 to 106 mug a.i. ml(-1)), but less sensitive to the remaining fungicides (EC(50) over 200 mug a.i. ml(-1)). Subsequently, all pesticides were assessed for their effect on the ability of C. minitans applied as a solid substrate inoculum to infect sclerotia of Sclerotinia sclerotiorum in soil tray tests. Despite weekly applications of pesticides at twice their recommended concentrations, C. minitans survived in the soil and infected sclerotia equally in all pesticide-treated and untreated control soil trays. This demonstrated the importance of assessing pesticide compatibility in environmentally relevant tests. Based on these results, solid substrate inoculum of a standard and an iprodione-tolerant strain of C. minitans were applied individually to S. sclerotiorum-infested soil in a glasshouse before planting lettuce crops. The effect of a single spray application of iprodione on disease control in the C. minitans treatments was assessed. Disease caused by S. sclerotiorum was significantly reduced by C. minitans and was enhanced by a single application of iprodione, regardless of whether the biocontrol agent was iprodione-tolerant. In a second experiment, disease control achieved by a combination of C. minitans and a single application of iprodione was shown to be equivalent to that of prophylactic sprays with iprodione every 2 weeks. The fungicide did not affect the ability of C. minitans to spread into plots where only the fungicide was applied and to infect sclerotia. These results indicate that integrated control of S. sclerotiorum with soil applications of C. minitans and reduced foliar iprodione applications was feasible, did not require a fungicide tolerant isolate, and that suppression of Sclerotinia disease by C. minitans under existing chemical control regimes has credence.
How to Start Your Own Gardening Business: an Insider Guide to Setting Yourself up as a Professional Gardener, revised edn
- P Power
A review of spring 2010
- R Smithers
- S Sparks
The biology and control of mites in pot and bedding plants
- J Buxton
Guidelines for integrated production of pome fruits in Europe
- J V Cross
Plant Propagation. Principles and Practices, 6th edn
- H Hartmann
- D E Koster
- F T Davies
- Geneve
Biological Control of Weeds Handbook
- A K Watson
Integrated Pest and Disease Management in Greenhouse Crops
- R Albajes
- M L Gullimo
- Van Lenteren
Silenoidae) as a reservoir and a hibernation site for predatory mites (Acari: Phytoseiidae). Integrated control in protected crops, temperate climate
- Caryophyllaceae