Thèses sur le sujet « Wild to crop hybridization »
Pour voir les autres types de publications sur ce sujet consultez le lien suivant : Wild to crop hybridization.
Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres
Consultez les 50 meilleures thèses pour votre recherche sur le sujet « Wild to crop hybridization ».
À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.
Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.
Parcourez les thèses sur diverses disciplines et organisez correctement votre bibliographie.
1
Stottlemyer, Amy L. « Investigating Hybridization Potential, Components of Fitness, and Volunteerism in Wild and Cultivated Panicum virgatum L. (switchgrass) ». The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1331060664.
Texte intégral
2
Reagon, Michael. « Mechanisms facilitating and evolutionary consequences of gene flow in two crop-wild hybrid complexes sunflower and rice / ». Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1165602736.
Texte intégral
3
Pace, Brian A. « Maternal effects on multiple generations of Helianthus annuus crop-wild hybrid seed : overwinter germination, dormancy and survival ». The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1354696610.
Texte intégral
4
Spencer, Lawrence J. « Hybridization and introgression in Cucurbita pepo : an examination of the effects of transgenic virus resistance on wild-crop hybrids / ». The Ohio State University, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=osu1486474078048501.
Texte intégral
5
Campbell, Lesley G. « Rapid evolution in a crop-weed complex (Raphanus spp.) ». The Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=osu1166549627.
Texte intégral
6
Fu, Tzu-Yu Richard. « Spontaneous hybridization and introgression from oilseed rape B. napus to wild cabbage B. oleracea and its application for ecological risk evaluation of genetically modified crops ». Thesis, Imperial College London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.508444.
Texte intégral
7
Beddows, Thomas [Verfasser]. « Hybridization and Wild Tomato / Thomas Beddows ». Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2017. http://d-nb.info/114319165X/34.
Texte intégral
8
Beddows, Thomas Ian [Verfasser]. « Hybridization and Wild Tomato / Thomas Beddows ». Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2017. http://d-nb.info/114319165X/34.
Texte intégral
9
Mendis, Merennga Hector. « Interspecific somatic hybridization in Medicago ». Thesis, University of Nottingham, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.276179.
Texte intégral
10
Kost, Matthew. « Maize and Sunflower of North America : Conservation and Utilization of Genetic Diversity ». The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1408642177.
Texte intégral
11
Ellis, Ciaran R. « Valuing wild pollinators for sustainable crop production ». Thesis, University of Stirling, 2014. http://hdl.handle.net/1893/22327.
Texte intégralRésumé :
This thesis looks at the role of wild pollinators in providing services to crops. Two data chapters (2 and 3) are accompanied by a modelling chapter (4) which build on the findings of the field studies. The thesis ends with an overview of the trends in pollinator populations and how these relate to the needs of farmers in the UK (chap-ter 5). It is often assumed that commercial pollinators are appropriate substitutes of wild pollinators on farms; however this view neglects the differing roles that particular pollinator taxa might play in providing pollination services. For example, crops with a long growing system may require multiple pollinators to ensure pollination throughout the season. Strawberries in Scotland have an extremely long growing season, flowering from April to August. Chapter 2 presents a study showing season-al complementarity between different pollinating taxa across strawberry farms in Scotland. Pollinators of strawberries also differed in their responses to weather pa-rameters indicating that preserving multiple pollinator taxa could ensure yields un-der different weather scenarios. The requirements of a long-growing season and ad-verse weather may be specific to strawberry production in Scotland, but the valua-tion of multiple taxa can be generalised to systems with differing needs, and also to different ecosystem services. Wild bees are not only valuable for providing complementary services to commercial pollinators, but are also valuable in the longer term as it is unknown whether com-mercial pollinators will be available in the future. There are threats to the supply of honeybees which have already triggered price rises; such supply shocks could force farmers to leave production or to seek other ways of providing pollination, including supporting wild pollinators. However farm management pressures, in particular pes-ticide use, could threaten the ability of wild pollinators to continue to support crop production. The interplay of pesticides and pollination is discussed in chapter 3 and 4. Chapter 3 presents an experiment undertaken on soft-fruit farms which had and had not used the neonicotinoid, thiacloprid, and shows that nests exposed to thia-cloprid had higher worker mortality, and lower male production than those at con-trol farms. This has implications both for pollination services now, as worker mor-tality will reduce the number of bees visiting farms, and also for the maintenance of future pollination services through decreased reproductive capacity of exposed nests. Chapter 4 uses a theoretical model to link pesticide use and habitat use to pollina-tion services, and shows that the use of commercial pollinators could mask the de-cline in wild populations, making local extinctions more likely. Chapter 5 sets out the status and extent of pollinators in the UK, along with popu-lation trends, trends in habitat and trends in pesticide use to provide an overview of how well pollination services are likely to meet the ongoing needs of crop farmers.
12
Contreras, Toledo Aremi Rebeca. « A crop wild relative conservation strategy for Mexico ». Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8637/.
Texte intégralRésumé :
There is an extensive diversity of crops and their wild relatives in Mexico, which are distributed throughout the country. Crop wild relatives (CWR) play a special role for present and future food security strategies: they represent a potential source of variation for the domesticated species, contributing to the genetic improvement of these crops. However, the effects of climate change, among other threats, are reducing significantly this biodiversity. The purpose of this study was to analyse the diversity of wild relatives of the most important crops in Mexico as a basis for the development and implementation of a national conservation strategy for these genetic resources. The methods involved the identification of priorities and creation of a national CWR inventory, in situ and ex situ gap analyses at taxon and ecogeographic levels, the evaluation of the impacts of climate change, threat assessment and predictive characterisation. Applying these methods, 310 CWR taxa were identified as priorities and recommendations for immediate in situ and ex situ conservation actions were made to ensure their representativeness under current and future climatic conditions. All these components contribute to the systematic active long-term conservation of priority CWR diversity in the country and enhance their sustainable utilisation thus helping mitigate the threats to Mexican agrobiodiversity and global food security.
13
Phillips, Jade. « Development of crop wild relative conservation strategies for Norway ». Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7633/.
Texte intégralRésumé :
Climate change and anthropogenic activities threaten our global food security. One area of research that may help combat a future food crisis is the utilization of the genetic diversity available in wild plants. Crop wild relatives (CWR) are one such resource. They are the wild taxa most closely related to crops and from which diverse traits could be transferred to the crop. This project uses Norway as an example, to contribute towards methodologies to identify those CWR populations that are most important for conservation and use. This involves the creation of a priority list of CWR for Norway, in situ and ex situ diversity analysis of CWR populations, gap analysis and ecogeographic land characterization methodologies, predictive climate change analysis for CWR distributions and genetic diversity studies of taxa using Amplified Fragment Length Polymorphisms (AFLPs). Comprehensive in situ and ex situ national recommendations for the conservation of CWR in Norway are detailed. These include the incorporation of management plans for CWR populations within the Færder national park in Norway, the first instance of such conservation activities in Scandinavia. The scientific methods used and developed will help Norway meet its international obligations for conservation and use of genetic diversity of CWR and will contribute to the regional and global efforts to systematically conserve and utilize the diversity found in CWR.
14
Ward, Andrew Charles William. « Sexual and somatic hybridization between diploid wild species and dihaploid Solanum tuberosum ». Thesis, University of Nottingham, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315025.
Texte intégral
15
Fletcher, Penny Hazel. « The pollination of four wild plants species in crop fields ». Thesis, University of Reading, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.533764.
Texte intégral
16
Castaneda, Alvarez Nora Patricia. « Geographic analysis for supporting conservation strategies of crop wild relatives ». Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/6942/.
Texte intégralRésumé :
Crop wild relatives are important for agriculture due to the genetic richness they possess. They have been used in plant breeding to develop high yielding varieties; varieties with improved resistance to biotic and abiotic stresses, and enhanced nutritional content. Securing their conservation in the long-term is critical to enable the continuous development of crops’ varieties able to respond to future challenges. The work presented in this thesis is a contribution to the effort of understanding the ex situ conservation gaps of crop wild relatives, their expected response to climate change and their needs for conservation. Methods used in this thesis include species distribution modelling, gap analyses, a case study assessing the preliminary IUCN Red List categories, species distribution projections onto future climate change scenarios, and an estimation of the global value of crop wild relatives based on their likelihood of being used in plant breeding, and the contributions of their associated crops to human diets and agricultural production systems. The methods used here can be applied to more crop genepools for global conservation planning, and can also be adapted for analysis at the regional and national level. The results presented here are being used to improve the conservation of the wild relatives of 29 crops.
17
Fedkenheuer, Michael Gerald. « Understanding Plant Pathosystems in Wild Relatives of Cultivated Crop Plants ». Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/81976.
Texte intégralRésumé :
As the global population rises, the demand for food increases which underscores a
need for improvement in food security. Disease pressures are a major concern
surrounding sustainable agriculture. Static crop populations, containing little to no
genetic diversity, are vulnerable to diverse pathogen populations. Wild relatives of crop
plants are a reservoir for new disease resistance traits that can be introgressed into
cultivated crops. The identification of novel disease resistance is of paramount
importance because pathogen co-evolution is not only defeating current resistance genes
(R genes) but chemical controls as well. Phytophthora sojae (P. sojae), the causal agent
of Phytophthora root and stem rot disease, reduces soybean harvests worldwide. We
developed an approach to screen for new R genes that recognize core effectors from P.
sojae. We expect R genes identified by these screens to be durable because P. sojae
requires core effectors for virulence. We utilized effector-based screening to probe
Glycine soja germplasm with core RXLR effectors from P. sojae to search for novel R
genes. We developed segregating populations from crosses of P. sojae resistant G. soja
germplasm with susceptible G. max cultivar Williams to determine inheritance of
potential R genes in germplasm that responded to core effectors. We are using marker
assisted breeding to map disease resistance traits in recombinant inbred (RI) lines. To
better understand pathosystems, we examined host resistance and susceptibility using
bioinformatics. We analyzed the interaction between Arabidopsis thaliana ecotype Col-0
and Hyaloperonospora arabidopsidis isolate Emwa1 using a publicly available RNA
time-course experiment. We describe a new algorithm to sort genes into time-point
specific clusters using activation and repression parameters. Gene ontology annotations
were used to identify defense genes with unique expression profiles, and A. thaliana null
mutants for these genes were significantly more susceptible to Emwa1 than wild-type.
We plan to use these tools to rapidly identify and guide introgression of durable disease
resistance into crop species.Ph. D.
18
D'Utra, Vaz Fernando Berlinck. « Somatic and sexual hybridization in tropical fruit crop species passionfruit and tomato ». Thesis, University of Nottingham, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334766.
Texte intégral
19
Kubis, Sybille Ellen. « Genome organisation of sugar beet (Beta vulgaris) and its wild relatives ». Thesis, De Montfort University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.391543.
Texte intégral
20
Fielder, Hannah Victoria. « Developing methodologies for the genetic conservation of UK crop wild relatives ». Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/6230/.
Texte intégralRésumé :
Modern crop varieties contain limited genetic diversity. Demand from an expanding human population requires crop yields to increase substantially, however, a low capacity for adaptation may leave crops susceptible to environmental change, threatening future food security. Crop wild relatives (CWR) are a valuable, but threatened, genetic resource containing more genetic diversity than their cultivated relatives that can be utilised by plant breeders to improve the resilience of new crop varieties. This thesis researches methodologies to facilitate systematic, active conservation of CWR and their genetic diversity within a national context using the UK and its devolved administrations as an exemplar. Methods involve the development of CWR inventori es, gap analyses, assessment of CWR habitat preferences , a case study seeking to justify the establishment of the first UK CWR genetic reserve on The Lizard Peninsula, Cornwall and finally, exploration of the use of next generation sequencing as a tool for targeting collection of accessions to fill genetic gaps in genebanks. A key success of this research was the involvement of stakeholders, bridging the gap between research and practice. The methods used can now be applied to other countries and can be integrated into European and global conservation planning, contributing to improved future food security.
21
Phelpstead, James St John. « Transformation and somatic hybridization in dihaploid Solanum tuberosum L. and wild Solanum species ». Thesis, University of Nottingham, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335552.
Texte intégral
22
Dhaliwal, Baljinder Kaur. « Physiological basis of competition between spring barley and wild oat (Avena fatua.L) ». Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386984.
Texte intégral
23
Campbell, Lesley Geills. « Rapid evolution in a crop-weed complex (Raphanus spp.) ». Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1166549627.
Texte intégral
24
Vincent, Holly A. « Developing methodologies for the global in situ conservation of crop wild relatives ». Thesis, University of Birmingham, 2016. http://etheses.bham.ac.uk//id/eprint/7126/.
Texte intégralRésumé :
Climate change is predicted to have far-reaching deleterious impacts worldwide; agriculture in particular is expected to be effected by significant loss of suitable land and crop yields in the world’s most populous and poorest regions. Crop wild relatives (CWR) are a rich source of underutilised genetic diversity which could help to mitigate climate change for agriculture through breeding new resilient varieties. However, CWR are under-conserved and threatened in the wild. This thesis researches and develops systematic methodologies to advance knowledge and support action on in situ CWR conservation at the global level. Methods included developing a global inventory of CWR associated with crops important for food security worldwide, species distribution modelling, climate change analysis, in situ gap analysis, reserve planning and prioritisation, and, examining the congruence of CWR distributions with regions of high biodiversity and crop diversity. The methods described here can be applied to CWR at both the national and regional level to ensure robust in situ CWR conservation. A principal success of this research is the global CWR inventory, which has been used in several national strategies and as the basis of a major ex situ germplasm collection mission worldwide.
25
Bassi, Filippo Maria. « Radiation Hybrid Fine Mapping of Two Fertility-Related Genes : Marking the Path to Wheat Hybrids ». Diss., North Dakota State University, 2012. https://hdl.handle.net/10365/26535.
Texte intégralRésumé :
Over one billion people, more than 1/9th of the global population, are undernourished. Feeding the ever increasing population has to be the most important goal of plant sciences. Since cultivated areas are not likely to increase, I will need to produce more with what is available. This can be summarized in one word: yield. Unfortunately, wheat?s yield is expected to increase only 1.13% by 2019, a prediction that if converted into reality will likely indicate that I failed to cope with the world demographic increase. A new strategy to revolutionize wheat production is required, and some believe that this change might be represented by wheat hybrids. Achieving adequate commercial production of wheat hybrids has the potential to nearly double the yield of one of the world?s most important staple food. The first fundamental step toward this goal is to develop feasible methodologies to sterilize the male part of the complete wheat flowers. Two fertility-related genes are the primary target of this study, namely the species cytoplasm specific on chromosome 1D, and the desynaptic locus on chromosome 3B. This dissertation summarizes the important achievements obtained toward the cloning of the two loci by means of radiation hybrid functional analysis. Radiation hybrid is a technique that employs radiation to create genetic diversity along the targeted chromosome. Chapter 1 explains in details how this methodology can be applied to plants. The use of radiation hybrid mapping permitted creating a comprehensive map of wheat chromosome 3B, as discussed in Chapter 2, and then expanded the mapping information to identify the 2 Mb location of the desynaptic locus desw2, as discussed in Chapter 3. A similar approach on chromosome 1D allowed first to pinpoint the location of the species cytoplasm specific gene to a region of 2 Mb, as discussed in Chapter 4, and then ultimately to find a strong candidate for this locus, as discussed in Chapter 5. Now that the molecular locations of these genes have been unraveled by this study, their sequence can be streamlined into transformation to ultimately produce female wheat plants, and consequently hybrids.
26
McKillop, Ian Gordon. « The behaviour of the European wild rabbit Oryctolagus cuniculus L. at electric fences ». Thesis, University of Reading, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.258341.
Texte intégral
27
Lala, Sami. « Developing strategies for the genetic conservation of crop wild relatives in North Africa ». Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8837/.
Texte intégralRésumé :
Agrobiodiversity are threatened due to habitat loss, land reclamation and fragmentation, spread of diseases and pests, genetic uniformity, genetic erosion, and other human activities. Crop wild relatives (CWR) are wild species that are more or less genetically related to crops that can be used to introgress useful genes for improvement of productivity, resistance to biotic and abiotic stresses and quality of cultivated crop. These valuable resources are threatened and untapped for crop improvements. Therefore, their conservation would be valuable and will contribute to maintaining and promoting the sustainability of crop diversity, facilitating agricultural production and supporting the increasing demand for food, feed and natural resources. This thesis tackle for the first time the diversity and conservation status of CWR in North Africa region. In order to achieve this goal, different methods, approaches and techniques were used. These are identifying CWR in the region (CWR checklist), prioritize the checklist, ex situ and in situ gap analyses, species distribution modelling, threat assessment using IUCN Red List categories, climate change assessment and molecular genetic analysis of wild barley (Hordeum vulgare subsp. spontaneum (C. Koch) Thell). The outcomes will assist in lay the foundations for future ex situ and in situ conservation, and subsequent use.
28
Routson, Kanin Josif. « Malus Diversity in Wild and Agricultural Ecosystems ». Diss., The University of Arizona, 2012. http://hdl.handle.net/10150/223381.
Texte intégralRésumé :
Human-induced land degradation and climate change can reduce agricultural productivity and increase susceptibility to food shortages at local and global scales. Planting perennial crop species, such as fruit and nut crops, may be an intervention strategy because of their beneficial contributions to sustainable agriculture and human nutrition. Many perennial temperate fruit and nut species are however, particularly vulnerable to frost events, drought, insufficient chill hours, and disease and insect outbreaks. Modifying these species to yield harvests under a wider range of biotic and abiotic conditions may increase the value and long-term viability of perennials in agroecosystems. This dissertation examines adaptation and ecogeography in temperate perennial fruit crops, using apple (Malus sensu lato) as an example for case studies. The resilience of feral domestic apple trees in abandoned farmstead orchards throughout the southwestern U.S. indicates plasticity in adapting to local environmental conditions. Dendrochronology reveals these trees tend to persist where they have access to supplemental water, either as shallow groundwater or irrigation. While domestic apples are cultivated under a range of growing conditions, wild relatives of agricultural crops may further expand the cultivable range of the species. Crop wild relatives are species closely related to agricultural species, including progenitors that may contribute beneficial traits to crops. Sampling the genetic variation in crop wild relatives may benefit from ecological genetics and GIS theory to reveal genetic structure. The Pacific crabapple is an example of a wild apple relative that may contain genetic variation useful in apple breeding. Species distribution modeling of the Pacific crabapple identifies a narrow climatic window of suitable habitat along the northern Pacific coast, and genetic fingerprinting reveals a highly admixed genetic structure with little evidence of natural or cultural selection. While the moist coastal Pacific Northwest is not necessarily characteristic of many apple-growing regions, the species may have useful adaptations transferable to domestic apples. Genetic resources offer a promising source of raw material for adapting crops to future agricultural environments; their characterization, conservation, and use may offer important contributions to adaptation and use of perennial crops in agro-ecosystems.
29
Thormann, Imke [Verfasser]. « Genetic erosion in crop wild relatives : wild barley, Hordeum vulgare subsp. spontaneum, a case study in Jordan ; [kumulative Dissertation] / Imke Thormann ». Halle, 2017. http://d-nb.info/1131629329/34.
Texte intégral
30
Hibbets, Eric Matthew. « Molecular Characterization of Hybridization Between Magellanic (Spheniscus magellanicus) and Humboldt (Spheniscus humboldti) Penguins in the Wild ». Bowling Green State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1562071641076803.
Texte intégral
31
Scheppler, Hannah B. « Modeling the Climatic Niche of Wild Carica Papaya ». Miami University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=miami157490469591439.
Texte intégral
32
Yamada, Aya. « Ecological studies of wild crop-raiding Japanese macaques : Study on habitat use and ranging pattern ». 京都大学 (Kyoto University), 2010. http://hdl.handle.net/2433/120716.
Texte intégral
33
Pinto, Porcel Milton Víctor. « Analysis of genetic variability of quinoa (Chenopodium quinoa Wild.) germ plasm around Lake Titicaca ». BYU ScholarsArchive, 2002. https://scholarsarchive.byu.edu/etd/5421.
Texte intégralRésumé :
With the goal of analyzing the genetic variability of quinoa (Chenopodium quinoa Willd) germ plasm around Lake Titicaca, which is conserved in the National Bank of High Andean Grains of the PROINPA Altiplano Regional Foundation, the agromorphological behavior of 432 quinoa samples from the surrounding area (both Bolivian and Peruvian) were characterized and evaluated. This activity occurred at agricultural step 99/2000 of Belén Agricultural Station (16°1' South by 68°42' West), with the San Andrés Higher University Faculty of Agronomy, which because of its proximity to the lake represents climate conditions like those of the studied material's origin. In order to determine standards of genetic variation, identify the most discriminating quantitative variables, and classify sample groups of different genetic variability, two multivariate methods were applied using 17 quantitative variables: 5 phenotypic, 10 morphological, yield, and harvest index. The descriptive statistical analysis showed a wide genetic variability regarding the phenologic cycle and the size of the quinoa plants. According to the simple correlation analysis, the most important associations between phenologic variables corresponded to 50% of flowering at the beginning and end of flowering. The morphological variables highlight associations between leaf width with leaf length and stalk length. Likewise, the associations between yield and stem diameter, length of the grain bunch, diameter of the grain bunch, and plant height are statistically significant. All of these are positively associated with the other phenotypic variables. The architecture of the plant, in contrast, negatively influenced the yield and harvest index. The analysis of principle components identified 4 significant components that contributed more than 69% of total variance. The first principal component identified tall plants with thick stems, with large leaves and grain bunches, but with a late phenologic cycle and, as such, with low harvest indexes. The second principal component identified early plants of medium size that tend to develop relatively thick stems, with medium leaves, grain bunches and good-quality grain. Consequently, they produced the best yield. Similarly, the proportion of total variance contributed by each variable over the 4 significant components was determined. It was found that the most important and discriminating variables were 50% flowering, flowering index, and end of flowering, followed by weight of 100 grains, grain diameter, yield, and finally the length of the grain bunch, length of leaves, stem diameter, and leaf width. A non-hierarchical K-medium grouping technique permitted the classification of quinoa samples around Lake Titicaca in two groups. Group 1 consisted of 161 late quinoa plants with tall heights, large grain bunches, and low harvest indexes. Group 2 consisted of 271 early quinoa plants of medium size, leaves, and grain bunches, with small grains that at the same time have high harvest indexes.
34
Conner, Lafe Gerald. « Growing Wild : Crested Wheatgrass and the Landscape of Belonging ». DigitalCommons@USU, 2008. https://digitalcommons.usu.edu/etd/22.
Texte intégralRésumé :
Crested wheatgrass arrived in North America at the turn of the twentieth century through the foreign plant exploration missions sponsored by the United States Department of Agriculture. During the first two decades of the new century, scientists tested the grass at agricultural experiment stations. They determined it was useful for grazing and particularly valuable because it could grow in drought conditions with little or no care and would continue to produce high quality feed even after several years of heavy use. Beginning in the 1930s federally sponsored land utilization and agricultural adjustment programs sponsored the use of crested wheatgrass for soil conservation and weed control. The grass protected the soil on the land that had been entered into the acreage reserves and the conservation reserves programs of the federal soil bank. Also in the late 1930s and through the 1960s, rangeland managers used crested wheatgrass to improve forage productivity on public lands that were used for grazing. By the 1970s somewhere between 12 and 20 million acres of crested wheatgrass grew in North America in eleven western states, and in Saskatchewan and Alberta. By 1980 attitudes about agriculture and wilderness had changed in the United States and land management was focused on multiple uses and on protecting ecosystems and native species. Attitudes about grazing and agricultural landscapes had changed and many preferred nonagricultural landscapes and land uses. As a result, crested wheatgrass went from being considered one of the most valuable plants in North America to being considered an invasive weed, in some quarters. Debates in the last 25 years have tried to determine if, where, and how crested wheatgrass belongs in North America. This thesis explains the discourses, or interest groups, that are participating in the current conversation. One impulse is to use empirical evidence to determine whether or not introduced plants like crested wheatgrass belong, but the main contention of this thesis is that empirical studies alone will always be insufficient measures because belonging is also a subjective and experientially or emotionally derived measure.
35
Reagon, Michael. « Mechanisms facilitating and evolutionary consequences of gene flow in two crop-wild hybrid complexes : sunflower and rice ». The Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=osu1165602736.
Texte intégral
36
Törnqvist, Igelström Cecilia. « Konflikten bakom vildsvinsproblematiken ur ett "Crop-raiding"-perspektiv : med fokus på svenska lantbrukare ». Thesis, Södertörns högskola, Institutionen för naturvetenskap, miljö och teknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:sh:diva-23386.
Texte intégralRésumé :
Vildsvinstammen har ökat snabbt i södra och centrala Sverige sedan några individer rymde ifrån fångenskap på 1970-talet. Vildsvin har aptit för jordbruksgrödor vilket resulterar i en konkurrens om dessa grödor mellan arterna människan och vildsvin i en s.k. interspecifik konkurrens. Detta utgör i sin tur en konflikt mellan jordbrukare och vildsvin. Denna konflikt verkar även förvärras av jägares förvaltningsmetoder som, enligt lantbrukare, innefattar ett bristande jakttryck och utfodring i för stor skala. Mina resultat kunde visa en konflikt mellan jägare och lantbrukare som även verkar förvärras på organisationsnivå, d.v.s. Jägareförbundet respektive Lantbrukarnas riksförbund (LRF). Vildsvin anses som oönskade av flera respondenter och samtliga tycker att jakt är viktigt. Det finns olika sätt att öka lantbrukares toleransnivå för vildsvin i lantbruk vilket i sin tur kan minska konflikten mellan lantbrukare och vildsvin. Icke-dödliga förvaltningsmetoder bör vara anpassade för vildsvinens fysiska förutsättningar för att minska skador på lantbruk. Dödliga förvaltningsmetoder som jakt bör innefatta en snabb död för vildsvinet, vilket kräver god kommunikation mellan jägare samt tränade hundar i syfte att leta reda på det skjutna vildsvinet ifall det första skottet inte var dödligt.Wild boar population has increased rapidly in the south and central parts of Sweden since some individuals escaped from captivity in the 1970s. Wild boars have an appetite for agricultural crops resulting in a competition for these crops between the species man and wild boar, in a so-called interspecific competition. This in turn represents a conflict between farmers and wild boar. Management practices by hunters seem to enlarge the conflict, according to farmers there is a lack of hunting pressure and too much feeding. My results could show a conflict between hunters and farmers, which seems to worsen at an organizational level, Association of Hunters and the Federation of Farmers. Wild boar is considered as undesirable by several respondents and all of them agree that hunting is important. There are various ways to increase farmers' tolerance for wild boar in agriculture, which in turn can reduce the conflict between farmers and wild boar. To have an effect, nonlethal control should be appropriate for the physical conditions of wild boar. Lethal control should include a quick death for the wild boar, which requires good communication between hunters and trained dogs in order to locate the shot wild boar in case the first shot was not fatal.
37
MELO, ORTIZ DORA INES. « STUDIO DI ADATTABILITA' COLTURALE DELLA QUINOA (CHENOPODIUM QUINOA WILD) IN ITALIA SETTENTRIONALE ». Doctoral thesis, Università Cattolica del Sacro Cuore, 2017. http://hdl.handle.net/10280/35878.
Texte intégralRésumé :
Nell’ambito della ricerca di colture alternative e di alimenti ad alto valore nutrizionale, presso il Dipartimento di Scienze delle Produzioni Vegetali Sostenibili, si è svolta un’attività di ricerca sull’adattabilità della quinoa in Italia Settentrionale. La sperimentazione è durata tre anni ed ha preso in considerazione areali pedo-climatici di pianura e di collina. Il primo obiettivo era quello d’identificare le varietà di quinoa più adatte alle condizioni ambientali del Nord Italia, e come secondo obiettivo individuare la tecnica di coltivazione appropriata per gli agrosistemi intensivi; come terzo obiettivo contribuire al miglioramento della tecnica di coltivazione della quinoa nei Paesi emergenti (Colombia).
In Italia settentrionale le attività di ricerca sono iniziate nel 2014 con un confronto varietale di 24 ecotipi di quinoa. Per il ciclo colturale 2015, sono state scelte le migliori 11 cultivar delle prove precedenti, insieme ad altre 5 nuove cultivar. Per quanto riguarda invece il 2016, le prove sono state divise in due:
1. Due prove riguardanti alla scelta varietale
2. Una prova con lo scopo di studiare la risposta produttiva della quinoa alla fertilizzazione azotata.
Per quanta riguarda la sperimentazione nei Paesi in Via di sviluppo sono state allestite due prove agronomiche nel dipartimento di Boyacà (Colombia).With the aim of finding alternative crops and foods high in nutrients, at the Department of Sustainable Crop Production (DI.PRO.VE.S.), a research on the adaptability of quinoa in Northern Italy was carried out. This activity has continued for three years both in the plain and in the hills. The first aim of this work was to identify quinoa varieties most suitable for Northern Italy environmental conditions and as a second purpose to identify the appropriate cultivation technique to adopt the quinoa crop in the sustainable intensive farming systems; the third aim was to contribute to the improvement of quinoa cultivation technique in emerging countries (Colombia). In Northern Italy the research activities began in 2014 with a varietal comparison of 24 quinoa ecotypes. During 2015 crop cycle, the best 11 varieties out of the previous trials were selected, together with 5 new cultivars. In the third year (2016), the trials were divided into: 1. Regarding the varietal screening, two different trials 2. In order to study the response of quinoa to nitrogen fertilization, a trial a split-plot trial was arranged. Furthermore, regarding the research in the developing countries, two agronomic trials were established in the Department of Boyacà (Colombia).
38
MELO, ORTIZ DORA INES. « STUDIO DI ADATTABILITA' COLTURALE DELLA QUINOA (CHENOPODIUM QUINOA WILD) IN ITALIA SETTENTRIONALE ». Doctoral thesis, Università Cattolica del Sacro Cuore, 2017. http://hdl.handle.net/10280/35878.
Texte intégralRésumé :
Nell’ambito della ricerca di colture alternative e di alimenti ad alto valore nutrizionale, presso il Dipartimento di Scienze delle Produzioni Vegetali Sostenibili, si è svolta un’attività di ricerca sull’adattabilità della quinoa in Italia Settentrionale. La sperimentazione è durata tre anni ed ha preso in considerazione areali pedo-climatici di pianura e di collina. Il primo obiettivo era quello d’identificare le varietà di quinoa più adatte alle condizioni ambientali del Nord Italia, e come secondo obiettivo individuare la tecnica di coltivazione appropriata per gli agrosistemi intensivi; come terzo obiettivo contribuire al miglioramento della tecnica di coltivazione della quinoa nei Paesi emergenti (Colombia).
In Italia settentrionale le attività di ricerca sono iniziate nel 2014 con un confronto varietale di 24 ecotipi di quinoa. Per il ciclo colturale 2015, sono state scelte le migliori 11 cultivar delle prove precedenti, insieme ad altre 5 nuove cultivar. Per quanto riguarda invece il 2016, le prove sono state divise in due:
1. Due prove riguardanti alla scelta varietale
2. Una prova con lo scopo di studiare la risposta produttiva della quinoa alla fertilizzazione azotata.
Per quanta riguarda la sperimentazione nei Paesi in Via di sviluppo sono state allestite due prove agronomiche nel dipartimento di Boyacà (Colombia).With the aim of finding alternative crops and foods high in nutrients, at the Department of Sustainable Crop Production (DI.PRO.VE.S.), a research on the adaptability of quinoa in Northern Italy was carried out. This activity has continued for three years both in the plain and in the hills. The first aim of this work was to identify quinoa varieties most suitable for Northern Italy environmental conditions and as a second purpose to identify the appropriate cultivation technique to adopt the quinoa crop in the sustainable intensive farming systems; the third aim was to contribute to the improvement of quinoa cultivation technique in emerging countries (Colombia). In Northern Italy the research activities began in 2014 with a varietal comparison of 24 quinoa ecotypes. During 2015 crop cycle, the best 11 varieties out of the previous trials were selected, together with 5 new cultivars. In the third year (2016), the trials were divided into: 1. Regarding the varietal screening, two different trials 2. In order to study the response of quinoa to nitrogen fertilization, a trial a split-plot trial was arranged. Furthermore, regarding the research in the developing countries, two agronomic trials were established in the Department of Boyacà (Colombia).
39
Arlinghaus, Kel R. « GENE FLOW IN NATURAL POPULATIONS OF CARICA PAPAYA IN THE FRAGMENTED LANDSCAPES OF COSTA RICA AND NICARAGUA ». Miami University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=miami1470400678.
Texte intégral
40
Kassa, Mulualem Tamiru. « Molecular analysis of genetic diversity in dometicated pigeonpea (Cajanus cajan (L.) Millsp.) and wild relatives ». Thesis, Rhodes University, 2011. http://hdl.handle.net/10962/d1003773.
Texte intégralRésumé :
Cajanus cajan (L.) Millsp. (Pigeonpea) belongs to the Leguminosae genus Cajanus which is composed of 34 species. Pigeonpea is the only cultivated member of the genus, while the remaining species are wild relatives belonging mainly to the secondary gene pool. DNA sequence data from the nuclear ITS region and the chloroplast trnL-F spacer were utilized to investigate the phylogenetic relationships between Cajanus and five other allied genera in the subtribe Cajaninae. This study revealed the non-monophyly of Cajanus and Rhynchosia and supported the monophyly of Eriosema and Flemingia, but more sampling ,especially from the large genera of Rhynchosia and Eriosema, is recommend to adequately test the hypothesis of generic monophyly. The phylogenetic relationships within the genus Cajanus resolved Cajanus scarabaeoides (L.) Thouars as the most basal species in the Cajanus clade. The study also utilized Single Nucleotide Polymorphism (SNP) markers derived from low copy orthologous genes and genotyped using the high throughput SNP-OPA Illumina golden gate assay. The aim was to understand phylogenetic and domestication history, genetic structure, patterns of genetic diversity, gene flow and historical hybridization between Cajanus cajan (pigeonpea) and wild relatives. The neighbor-joining tree resolved well-supported clusters, which reflect the distinctiveness of species and congruence with their geographical origin. It supported the ITS based phylogeny and resolved C. scarabaeoides as basal to the Cajanus clade. The phylogenetic signal and genetic signatures revealed insights into the domestication history of pigeonpea. Our results supported Cajanus cajanifolius as the presumed progenitor of pigeonpea and we speculate that for pigeonpea there was a single major domestication event in India. Genetic admixture and historical hybridization were evident between pigeonpea and wild relatives. Abundant allelic variation and genetic diversity was found in the wild relatives, with the exception of wild species from Australia, as compared to the domesticated pigeonpea. There was a reduction of about 75% in genetic polymorphism in domesticated pigeonpea as compared to the wild relatives, indicating a severe “domestication bottleneck” during pigeonpea domestication. We discovered SNP markers associated with disease resistance (NBS-LRR) loci. The SNPs were mined in a comparison of BAC-end sequences (BES) of C. cajan and amplicons of the wild species, C. scarabaeoides. A total of ~3000 SNPs were identified from 304 BES. These SNPs could potentially be used in constructing a genetic map and for marker assisted breeding.
41
Jenkins, Toni E. « Introgression of genes from rape to wild turnip ». Lincoln University, 2005. http://hdl.handle.net/10182/1844.
Texte intégralRésumé :
Introgression of genes from crops into ruderal populations is a multi-step process requiring sympatry, synchronous flowering, chromosomal compatibility, successful pollination and development of the zygote, germination, establishment and reproduction of hybrid progeny. The goal of this thesis was to generate data on as many steps in this process as possible and integrate them into a predictive statistical model to estimate the likelihood of successful introgression under a range of scenarios. Rape (Brassica napus) and wild turnip (B. rapa var. oleifera) were used as a model system. A homozygous dominant mutation in the rape genome conferring herbicide resistance provided a convenient marker for the study of introgression. Potential differences between wild turnip populations from a wide range of geographic locations in New Zealand were examined. Hand pollination established the genetic compatibility of rape and wild turnip and a high potential for gene introgression from rape to wild turnip. Interspecific hybrids were easily generated using wild turnip as the maternal plant, with some minor differences between wild turnip populations. The frequency of successful hybridisation between the two species was higher on the lower raceme. However, the upper raceme produced more dormant interspecific hybrid seed. Field trials, designed to imitate rare rape crop escapes into the ruderal environment, examined the ability of rare rape plants to pollinate wild turnip plants over four summers. At a ratio of 1 rape plant for every 400 wild turnip plants, the incidence of interspecific hybridisation was consistently low (<0.1 to 2.1 % of total seed on wild turnip plants). There was a significant year effect with the first season producing significantly more seed and a greater frequency of interspecific hybrid progeny than the other years. The frequency of interspecific hybrid progeny increases when the ratio of rape: wild turnip plant numbers increases. The relative importance of anemophily and entomophily in the production of interspecific hybrids was examined. Wild turnip plants produced twice as many seeds with bee pollination relative to wind pollination. However, the frequency of interspecific hybrids under wind pollination was nearly twice that for bee pollination. Light reflectance patterns under UV light revealed a marked difference between wild turnip and rape flowers compared to near identical appearance under visible light. The data indicates that bees are able to distinguish between rape and wild turnip flowers and exhibit floral constancy when foraging among populations with these two species. Hybrid survival in the seed bank, germination and seedling establishment in the field are important components of fitness. Seed banks established in the soil after the field trials described above germinated in subsequent spring seasons. The predominantly brassica weed populations were screened for herbicide resistance and the numbers of interspecific hybrids germinating compared to the original frequency in the field trial results. Frequency of interspecific hybrids was reduced in the populations compared to the original seed deposit. Seed with a known frequency of interspecific hybrid seed was sown in a separate trial, and the frequency of interspecific hybrids compared at 0, 4, 6, and 8 weeks after sowing. Poor germination resulted limited competition between seedlings, however the frequency of interspecific hybrids declined over time indicating low plant fitness. There were no significant population effects on any parameters tested. Interspecific hybrids grown in a glasshouse were backcrossed to the parental species and selfed within the plant and within populations. Pollen from the interspecific hybrids was found to have markedly reduced fertility. Interspecific hybrid plants had low female fertility, with the majority (88%) of the pollinated flowers aborting the siliques. Of the remaining siliques, most (98%) had only one to three seeds per silique. Inheritance of the herbicide resistance gene was regular in backcrosses but highly skewed following self pollination with an excess of herbicide-sensitive progeny. Production of a stochastic predictive model integrated the information acquired over the practical work phase of this thesis and utilised the capabilities of @risk, a new application of a risk analysis tool. The three outputs examined were the number of flowering plants resulting from backcrosses to rape and wild turnip and self pollination of the interspecific hybrid progeny. Five scenarios were modelled and all demonstrated the high likelihood of introgression failure in this system. In all scenarios, >75% of simulations resulted in no interspecific hybrid progeny surviving to flowering in the third generation. In all scenarios, and for all three outputs, the seed set on the interspecific hybrids of the second generation was the major factor that limited the number interspecific hybrid progeny surviving to flowering in the third generation.
42
CAPPA, FABRIZIO. « Wild boar impacts on crops and nemoral flora in lowland areas of northern Italy ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2021. http://hdl.handle.net/10281/305594.
Texte intégralRésumé :
La selezione degli habitat del cinghiale è stata studiata nel Parco Regionale della Valle del Ticino, raccogliendo dati sulla distribuzione e abbondanza dei segni di presenza lungo 30 itinerari (lunghezza media 8,02 km, SD = 2,97) rilevati in autunno-inverno e primavera. Abbiamo confrontato l'uso dei diversi tipi di habitat con la loro disponibilità dall'indice α di Manly-Chesson. Per stimare l'effetto della composizione dell'habitat sulla presenza di cinghiali, abbiamo formulato una funzione di probabilità di selezione delle risorse (RSPF) mediante analisi di regressione logistica binaria (BLRA). Per analizzare la presenza nei diversi tipi di habitat, abbiamo effettuato analisi di correlazione e regressione tra l'Indice di Abbondanza Chilometrica (IKA) e la percentuale di tipi di habitat sugli itinerari. Il cinghiale principalmente seleziona i boschi decidui durante tutto l'anno, le foreste di conifere sono utilizzate secondo la loro disponibilità mentre le risaie e le aree urbanizzate vengono evitate. I prati sono prevalentemente utilizzati durante l'autunno e l'inverno mentre in primavera la presenza del cinghiale è più alta nelle zone dove la lunghezza dei margini del bosco è maggiore. Il modello logistico formulato mostra che le foreste decidue ad alta densità hanno influenzato positivamente la probabilità di presenza di cinghiali. Prati e campi hanno invece mostrato un'influenza negativa. La Zona di Protezione Speciale “Risaie della Lomellina” è stata oggetto di uno studio per determinare l'impatto del cinghiale sui terreni coltivati e formulare un modello di previsione del rischio attraverso un'analisi di regressione logistica binaria. I danni hanno riguardato quasi esclusivamente il mais e si sono concentrati in primavera ed estate. Casi sporadici di danni hanno riguardato campi di riso, soia e sorgo. Il rischio di danni è risultato maggiore nei campi vicini alle foreste, lontano dalle strade principali, dalle aree urbane e dalle siepi continue, e nelle aree a bassa densità di popolazione umana. Nel Parco Naturale della Valle del Ticino, dal 2010 al 2017, il 49% delle denunce riporta un evento di danno al mais e il 43% ai prati. La spesa complessiva per rimborsi del mais è stata pari a 439.341,52 euro, con danni concentrati a maggio e tra agosto e settembre. Per i prati i rimborsi sono stati pari a 324.768,66 euro, con eventi di danno concentrati nei mesi di febbraio e marzo. Per ridurre i danni alle colture, l'amministrazione del Parco ha effettuato un controllo letale della popolazione di cinghiali. Dal 2006 al 2017, il metodo di controllo più utilizzato è stato l'abbattimento da altana. Non abbiamo trovato relazioni significative tra il numero di cinghiali abbattuti e l'entità del danno. I fattori che determinano la diminuzione della probabilità di danni alle colture sono principalmente legati al disturbo antropico e alle caratteristiche dei campi e il modello predittivo del rischio di danno ha mostrato una buona capacità predittiva. Le analisi della vitalità della popolazione hanno mostrato che non è possibile ottenere una riduzione drastica con l'attuale tasso di prelievo. Triplicandolo e concentrandolo sulle femmine e sui subadulti si otterrebbe una riduzione numerica del 50% della popolazione in 7 anni e la probabilità di sopravvivenza della popolazione sarebbe dimezzata in 3 anni. Tra marzo e agosto 2019 abbiamo studiato i fattori che influenzano la selezione dell'habitat alimentare del cinghiale e l'impatto del grufolamento sulla flora nemorale. L'alimentazione durante la primavera e l'estate sembra concentrata nelle zone boschive caratterizzate da suoli freschi, dove lo spessore della lettiera è maggiore e il contenuto di frutti, soprattutto ghiande, è maggiore. Nonostante la correlazione significativa tra rooting e presenza delle nemorali non sembra esserci un effetto significativo e negativo sul numero e l'abbondanza di specie presenti.The habitat selection by the wild boar was studied in the Ticino Valley Regional Park. The study was carried out collecting data on distribution and abundance of presence signs along 30 itineraries (average length 8.02 km, SD = 2.97) surveyed in autumn-winter and spring. We firstly compared the use of the different habitat types with their availability by the Manly-Chesson α index. To estimate the effect of habitat composition on wild boar presence we formulated a Resource Selection Probability Function (RSPF) by Binary Logistic Regression Analysis (BLRA). To analyse the attendance of the different type of habitats by the species we carried out correlation and regression analyses between the Index of Kilometric Abundance (IKA) and the percentage of habitat types on the itineraries. Wild boar mainly selected woodland during the whole year, coniferous forests are used as availability while rice fields and urbanized areas avoided. The meadows are mainly used during autumn and winter while in spring the presence of wild boar was higher in areas where the length of the forest edges is greater. The logistic model formulated show that high-density deciduous forests positively affected the probability of wild boar presence. Meadows and fields instead showed a negative influence. The Special Protection Area “Risaie della Lomellina” was the subject of a study that aimed to determine the impact of wild boar on croplands and to formulate a risk prediction model through a binary logistic regression analysis. Damage events almost exclusively involved maize, and were concentrated in spring and summer. Sporadic cases of damage concerned rice, soybean and sorghum fields. The risk of damage was higher in fields close to forests, far from main roads, urban areas and continuous hedgerows, and in areas with low human population densities. In the Ticino Valley Natural Park, from 2010 to 2017, 49% of the complaints report an event of damage to maize and 43% to meadows. The total expense for reimbursements of the maize amounted to € 439,341.52, with damages concentrated in May, after sowing period and between August and September, during the milky stage of maize. For meadows, reimbursements amounted to € 324,768.66, with damage events concentrated in February and March. To reduce damage to crops, the Park administration carried out lethal control of the wild boar population. From 2006 to 2017, the most used control method was culling from hides. In our analysis, we did not find significant relationships between the number of shot boars and the amount of damage. The factors that determine the decrease in the probability of damage to crops are mainly related to human disturbance and the characteristics of the fields. The predictive model of damage risk showed a good predictive ability. The Population Viability Analyses showed that it is not possible to obtain a drastic reduction with the current harvest rate. By tripling it and focusing on the females and sub-adult a numerical reduction of 50% of the population would be achievable in 7 years and the probability of population survival would be halved in 3 years. Between March and August 2019 we investigated the factors influencing feeding habitat selection of the wild boar, and the impact of rooting on nemoral flora. Feeding during spring and summer seems concentrated in wooded areas characterized by fresh soils, where the thickness of the litter is greater and the mast content, especially acorns, is greater. We found a significant correlation between the intensity of rooting and the presence of nemoral species, it does not seem to have a significant and negative effect on the number of species present or their abundance in the sampled areas. The floristic diversity and the dominance ratios are not influenced by the rooting intensity.
43
Bergman, Trygg Elias. « An investigation of human-wildboar conflict : - the perceived need for economical compensation among farmers due to crop damage caused by wild boars -a case study in Arboga, Sweden ». Thesis, Uppsala universitet, Kulturgeografiska institutionen, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-226839.
Texte intégral
44
Berlingeri, Chiara A. « Estudio sistemático de parientes silvestres de cultivos prioritarios en Venezuela : caso géneros Phaseolus y Macroptilium ». Doctoral thesis, Universidad de Alicante, 2017. http://hdl.handle.net/10045/82490.
Texte intégralRésumé :
Un requisito previo en cualquier programa de conservación de Recursos Fitogenéticos es la la estimación de la diversidad existente. El inventario de las especies parientes de cultivos prioritarios en Venezuela (PSC) se basó en los principales Catálogos de Flora del país, seleccionando los taxones próximamente relacionados con los cultivos. Se incluyeron 47 géneros, 217 especies y 228 taxones, correspondientes a 28 familias botánicas. De éstas, las que tienen mayor riqueza son: Fabaceae, Solanaceae, Araceae, Lauraceae, Dioscoreaceae, Poaceae, Rosaceae y Myrtaceae. Existen 26 especies endémicas, pertenecientes a los géneros Xanthosoma, Persea, Dioscorea, Prunus y Manihot. Los géneros nativos con especies del pool genético primario del cultivo son Manihot, Solanum (Sección Petota), Lycopersicon, Ananas, Capsicum, Dioscorea, Xanthosoma, Phaseolus, Theobroma, Ipomoea, Gossypium, Arracacia y Psidium. El número de taxones evaluados según los criterios de la IUCN es prácticamente nulo y la representación de accesiones venezolanas de PSC en los bancos de germoplasma nacionales e internacionales es muy baja. En relación con el estudio taxonómico del género Phaseolus, se reconocen tres especies en Venezuela: P. lunatus L., P. vulgaris L. y P. dumosus Macfad., que se diferencian fácilmente por la morfología de las flores, brácteas, bractéolas y legumbres. Phaseolus lunatus y P. vulgaris crecen en estado silvestre y cultivado y Phaseolus dumosus corresponde a la forma cultivada que se ha naturalizado. En relación al género Macroptilium, los resultados del análisis morfológico, molecular y biogeográfico de las especies del complejo Macroptilium gracile indican que los taxones pertenecen a una sola especie con tres taxones infraespecíficos, de los cuales dos son nuevas combinaciones: una subespecie no típica (Macroptilium gracile subsp. scolecocarpus (Piper) Berlingeri & M.B. Crespo, comb. nov.) y dos variedades en la subespecie tipo (M. gracile subsp. gracile var. gracile y M. gracile subsp. gracile var. subcoriaceum (Benth.) Berlingeri & M.B. Crespo, comb. nov.). Phaseolus diversifolius Pittier y P. unilobatus Pittier corresponden a sinonimias de Macroptilium gracile var. subcoriaceum y M. gracile var. gracile, respectivamente. En el género Macroptilium se reconocen seis especies en Venezuela: M. atropurpureum (DC.) Urb., M. lathyroides (L.) Urb., M. gracile (Poepp. ex Benth.) Urb., M. bracteatum (Nees & Mart.) Maréchal & Baudet, M. erythroloma (Mart. ex Benth.) Urb. y M. monophyllum (Benth.) Maréchal & Baudet. Macroptilium longepedunculatum (Mart. ex Benth.) Urb. y M. gracile (Poepp. ex Benth.) Urb., que algunos autores separan en el rango específico, corresponden a variedades extremas de una misma especie. Al tener prioridad el nombre M. gracile, M. longepedunculatum queda relegado a la sinonimia del primero.
45
Hamilton, Kim Nicole. « Ex Situ Conservation of Australian Citrus Species : Investigations on Seed Biology, Cryopreservation and in Vitro Culture ». Thesis, Griffith University, 2007. http://hdl.handle.net/10072/365585.
Texte intégralRésumé :
Many potentially economically important taxa of Australia are threatened in situ and are vulnerable to erosion of genetic diversity and extinction. In this study, over one hundred rare and threatened Queensland edible plants and/or crop wild relatives were identified. Many of these species have subtropical to tropical distribution and may have non-orthodox seed storage behaviour, thus excluding standard seed banking approaches for long-term ex situ conservation. There is an urgent need to develop alternative ex situ conservation strategies to conserve this diversity. Establishment of ex-situ collections of this valuable germplasm in field collections would be prohibitive in cost and would be susceptible to environmental damage, including disease and pest attack. In vitro and cryopreservation techniques offer alternative strategies for medium and long-term storage of germplasm. However, there have been very few attempts to apply in vitro storage and cryopreservation techniques to any wild Australian tropical or subtropical species. Moreover, limitations exist for the development of alternative ex situ storage techniques due to a lack of basic research on plant ecology or biology, including seed physiology and morphology. Further restrictions to the development of ex situ conservation of these species occurs because of a lack of supporting techniques needed for cryostorage, such as in vitro culture, germination protocols, propagation and acclimation. The Australian wild species of the Citrus genus are a priority for investigation of ex situ conservation strategies because of their conservation priority, potential socioeconomic importance (e.g. novel genes and fruits), probable non-orthodox seed storage behaviour and lack of corresponding techniques for their long term ex situ conservation. This study reports on seed biology, cryopreservation and in vitro culture of three Australian wild Citrus species, C. australasica (finger lime), C. inodora (Russell River lime) and C. garrawayi (Mount White lime), to facilitate germplasm storage and as a regeneration system. Descriptors of mature seed morphology and anatomy are reported in C. australasica, C. inodora and C. garrawayi - vital to the development and application of effective seed storage protocols (i.e. seed lot quality). C. garrawayi seed shape and seed coat morphology was found to be different to C. australasica and C. inodora. In addition, seed topography, as viewed by scanning electron microscopy, was found to be a useful tool for taxa identification. In terms of both germination and seedling growth, temperatures of _20ºC were found to be sub-optimal for germination. Germination from seeds of all the three species was optimal at 30ºC and above 80%. Both C. australasica and C. inodora displayed ‘essentially’ orthodox seed storage behaviour, i.e. desiccation and cryopreservation tolerance, whilst C. garrawayi displayed more complex seed storage behaviour. Overall, it appears that seed banking of germplasm of these species could be by standard orthodox protocols (i.e. 5%MC at -20ºC). However, because of variation in seed responses and other storage constraints in these species, cryopreservation is recommended as the safest storage option to prevent seed deterioration (loss of viability). Cryobiology studies have allowed the determination of the unfrozen water content (WCu) of C .australasica (11%), C. inodora (est. 8%MC) and C. garrawayi (14%). Desiccation of seeds to well below the WCu resulted in high levels of germination (radicle emergence <1mm) after liquid nitrogen exposure, but negligible levels of germination were observed from seeds above the WCu. This data both supports other studies undertaken on cultivated citrus and provides evidence that seed of these species will tolerate cryostorage when below the WCu. In addition, this study demonstrated in vitro culture systems for the micropropagation and medium term storage of C. australasica, C. inodora and C. garrawayi, as well as shoot-tip cryopreservation in C. australasica using a vitrification- based method. In vitro embryogenic potential, using a range of culture media, was low to moderate in C inodora and low in C. australasica, whilst C. garrawayi was recalcitrant to in vitro embryogenesis. The addition of citric acid to the embryo induction medium resulted in the best quality and highest number of somatic embryos from callus proliferated through liquid culture in C. inodora. This is the first report of the promotive affect of citric acid on embryo formation in the Citrus genus. Cryopreservation of encapsulated C. inodora embryogenic callus gave high levels of recovery (69%). However, further optimisation of embryo formation and plantlet recovery is needed to improve efficiency to be suitable conservation purposes. Micropropagation provides a useful tool, for medium-term storage of rare and threatened germplasm and offers a valuable step in the implementation of horticultural and restoration programs. Establishment of an in vitro culture system for shoot-tips also provides a technique for producing virus free material for germplasm exchange or maintenance. The findings of this study facilitate the development of ex situ conservation of Australian wild Citrus, which is of significant interest to complement in situ conservation and secure sustainable access to this rich biodiversity.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Biomolecular and Biomedical Sciences
Full Text
46
BARONE, Giulio. « Pianificazione per la conservazione della diversità dei progenitori selvatici delle piante coltivate e delle piante selvatiche raccolte in natura ». Doctoral thesis, Università degli Studi di Palermo, 2022. http://hdl.handle.net/10447/533631.
Texte intégralRésumé :
Le piante selvatiche raccolte in natura (Wild Harvested Plants - WHP) e i progenitori selvatici delle colture (Crop Wild Relatives - CWR), note collettivamente come “Risorse fitogenetiche” (PGR), rivestono molteplici ruoli di rilevanza ecologica, ambientale e socioeconomica perché ad essi si correlano numerosi usi diretti e indiretti, ma anche perché costituiscono un serbatoio di caratteri genetici potenzialmente utili per il miglioramento genetico delle piante coltivate. Ciò rende prioritaria la messa a punto di appropriate strategie di conservazione e valorizzazione. Nella presente tesi vengono presentate le attività che hanno portato alla elaborazione di due inventari delle CWR e delle WHP per l’Italia, suddivisa in Penisola italiana, Sardegna e Sicilia e per la Tunisia. Nel caso dell’Italia, si è reso opportuno un aggiornamento degli elenchi prioritari per tenere conto dei recenti lavori e revisioni della flora nativa ed esotica presente sul territorio nazionale nonché nuove valutazioni degli stati di minaccia che hanno reso obsoleto l’inventario esistente. Il nuovo inventario ottenuto comprende le informazioni circa la distribuzione, lo stato endemico, l’origine, le sinonimie, l’importanza economica delle specie coltivate connesse, le informazioni sugli usi noti, lo stato di minaccia etc. Sono stati dunque individuati 8.766 taxa (7.344 specie) CWR/WHP per la flora d’Italia (88% del totale), in particolare 6.839 (5.516) sono solo CWR, 108 (108) solo WHP e 1.821 (1.710) sia CWR che WHP (ovvero sono parenti di una specie coltivata e caratterizzati da un uso come piante spontanee). I taxa e le specie sono così distribuiti: 7.916 (6.641) per la Penisola Italiana, 2.745 (2.600) per la Sardegna e 2.952 (2.738) per la Sicilia. Ai taxa inclusi nell'elenco, sulla base di procedure in uso a livello internazionale è stata quindi assegnata una priorità per la conservazione utilizzando un approccio basato sul valore, lo stato nativo e la necessità di protezione o monitoraggio di ogni singolo taxon. Il processo aggiornato di prioritizzazione ha portato complessivamente per l’Italia all'identificazione di 102 taxa ad alta priorità (di cui 49 per la penisola, 17 per la Sardegna e 46 per la Sicilia), 57 a media priorità (di cui 23 per la penisola, 7 per la Sardegna e 12 per la Sicilia) e 735 a bassa priorità (di cui 547 per la penisola, 287 per la Sardegna e 322 per la Sicilia).
Nel caso della Tunisia, si tratta del primo inventario realizzato a livello nazionale per il Nord Africa. Per il continente africano, infatti, anche se ci sono diversi paesi dell’area meridionale con liste di controllo e inventari CWR, queste informazioni e quelle riguardanti le WHP mancano per i paesi nordafricani. Nell’inventario delle CWR e WHP della Tunisia i taxa sono stati classificati in base al valore economico della relativa coltura, al potenziale per il miglioramento delle colture, lo stato di minaccia, l’endemicità, l’inclusione nell'ITPGRFA (allegato I) e i contributi medi annui al fabbisogno energetico alimentare (kilocalorie pro capite al giorno) applicando un sistema di punteggio basato su 4 livelli di priorità. Su un totale di 2.912 taxa appartenenti alla Flora tunisina, sono stati identificati 2.504 CWR e/o WHP (86% del totale), appartenenti a 143 famiglie e 686 generi. L'elenco di priorità finale per la conservazione attiva comprende 1.036 CWR (43% del totale dei taxa CWR), con 139 taxa classificati come priorità alta, 660 priorità media e 237 priorità bassa. L'elenco di priorità finale per le WHP è composto da 346 taxa e comprende 8 taxa ad alta priorità, 256 a media priorità e 82 a bassa priorità. I nostri risultati confermano la Tunisia come un hotspot di diversità per CWR e WHP nell'area mediterranea e forniscono la base per lo sviluppo e l'attuazione di una strategia nazionale di conservazione delle CWR e WHP più mirata.
Nel complesso, i dati ottenuti forniscono un utile punto di riferimento per lo sviluppo di strategie a livello nazionale di conservazione, ex situ e in situ, di quelle risorse fitogenetiche importanti da un punto di vista ecologico, socioeconomico ed etnobotanico il cui stato di minaccia richiede più impellenti azioni coordinate di salvaguardia. A questo scopo, in ultimo, si delineano una serie di possibili interventi che consolidate esperienze condotte a livello internazionale suggeriscono di adottare.Wild Harvested Plants (WHP) and Crop Wild Relatives (CWR), collectively known as " Plant Genetic Resources" (PGR), play multiple roles of ecological, environmental, and socio-economic importance because they are related to numerous direct and indirect uses, but also because they constitute a reservoir of traits potentially useful for the genetic improvement of cultivated plants. This makes the development of appropriate conservation and enhancement strategies a priority. In this thesis the activities that led to the elaboration of two CWR and WHP inventories for Italy, divided into the Italian Peninsula, Sardinia, and Sicily, and for Tunisia are presented. In the case of Italy, an update of the priority lists was made to take into account the recent work and reviews carried out for the native and exotic flora present on the national territory as well as new threat assessments that made the existing inventory obsolete. The new inventory generated includes information about distribution, endemic state, origin, synonyms, economic importance of the related cultivated species, information on known uses, state of threat, etc. Therefore, 8,766 taxa (7,344 species) CWR/WHP were identified for the flora of Italy (88% of the total), in particular 6,839 (5,516) are only CWR, 108 (108) only WHP and 1,821 (1,710) are both CWR and WHP (i.e., relatives of a crop and characterized by a use as wild plants). The taxa and species are distributed as follow: 7,916 taxa (6,641 species) for the Italian peninsula, 2,745 (2,600) for Sardinia and 2,952 (2,738) for Sicily. The taxa included in the list, built upon internationally acknowledged procedures, were then assigned a priority for conservation using an approach based on the value, native status and need for protection or monitoring of each taxon. The updated prioritization process led to the identification of 102 high priority taxa (49 for the peninsula, 17 for Sardinia and 46 for Sicily), 57 medium priority taxa (23 for the peninsula, 7 for Sardinia and 12 for Sicily) and 735 low priority taxa (547 for the peninsula, 287 for Sardinia and 322 for Sicily). In the case of Tunisia, this is the first national inventory for a North African country. In fact, even if several countries in the southern part of the African continent have already developed CWR checklists and inventories, this information and that concerning WHP are missing for the North African countries. In the CWR and WHP inventory of Tunisia, taxa have been classified according to the economic value of the related crop, the potential for crop improvement, threat status, endemicity, inclusion in the ITPGRFA (Annex I) and the average annual contributions to human food energy needs (kilocalories per capita per day) by applying a scoring system based on 4 priority levels. Out of a total of 2,912 taxa belonging to the Tunisian Flora, 2,504 CWR and/or WHP (86% of the total) were identified, belonging to 143 families and 686 genera. The final priority list for active conservation includes 1,036 CWR (43% of the total CWR taxa), with 139 taxa classified as high priority, 660 medium priority and 237 low priority. The final priority list for WHP is composed of 346 taxa and includes 8 high priority, 256 medium priority and 82 low priority taxa. Our findings confirm Tunisia as a diversity hotspot for CWR and WHP in the Mediterranean area and provide the basis for the development and implementation of a more targeted national conservation strategy. Overall, the data obtained provide a valuable starting point for the development of ex situ and in situ conservation strategies at national level of those plant genetic resources that are important from an ecological, socioeconomic, and ethnobotanical point of view and it is especially urgent considering their state of threat. Finally, for this purpose, a series of possible actions are outlined based on consolidated experiences conducted at international level.
47
Dawit, Abigail Ngugi. « Improvement of Helicoverpa armigera resistance in pigeonpea (Cajanus cajan) through 'omics and breeding ». Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/226045/1/Abigail_Dawit_Thesis.pdf.
Texte intégralRésumé :
Pigeonpea (Cajanus cajan) is a sub-tropical and tropical pulse rich in plant-based protein, carbohydrates, minerals, and vitamins. Helicoverpa armigera is the most devastating insect pest in pigeonpea. This study focussed on deciphering the molecular host plant resistance (HPR) mechanisms applied by Cajanus scarabaeoides a wild pigeonpea against insect using transcriptomic and proteomic studies. These HPR mechanisms were transferred to the cultivated pigeonpea via interspecific hybridisation, and they are stable at F2 generation. The study outcome provides a unique insight into the insect resistance mechanisms employed by C. scarabaeoides and lays the foundation for further studies and applications.
48
Fagandini, ruiz Francesca. « Distribution des parents sauvages du quinoa cultivé en lien avec les pratiques et usages des communautés andines dans la région de Puno au Pérou ». Thesis, Paris, Institut agronomique, vétérinaire et forestier de France, 2019. http://www.theses.fr/2019IAVF0001/document.
Texte intégralRésumé :
Dans les hauts plateaux des Andes entre le Pérou et la Bolivie, à 3 800 mètres d’altitude s’étend le lac Titicaca, berceau des civilisations précolombiennes et l’un des principaux centres mondiaux de domestication des espèces végétales cultivées pour l’agriculture. Cette région est reconnue comme le centre d’origine du quinoa, C. quinoa Willd. Elle concentre la plus grande diversité génétique du quinoa, tant pour les variétés paysannes cultivées que pour les espèces sauvages apparentées. Notre recherche a été conduite dans la région de Puno, Pérou, qui reste l’une des principales régions productrices de quinoa au monde. Le quinoa y présente une distribution spatiale selon un gradient climatique nord-sud et une différenciation en zones agroécologiques liée à l’altitude. Actuellement, sept principales espèces de parents sauvages du quinoa y sont présentes : C.ambrosioides L., C.incisum Poiret, C.pallidicaule Aellen, C.petiolare Kunth, C.hircinum Schrad., C.quinoa ssp. melanospermum Hunz. et C.carnosolum Moq. Cette diversité de ressources génétiques a une grande valeur pour l’évolution adaptative du quinoa notamment face aux effets du changement climatique. Notre thèse s’inscrit dans l’importance économique et culturelle du quinoa, étant à la fois une ressource alimentaire des régions andines et l’objet des marchés internationaux du fait de ses qualités nutritives. Cette opportunité économique peut avoir des impacts en termes de sécurité alimentaire, d’agrobiodiversité, et de gestion de l’agroécosystème. Cette thèse a analysé comment les communautés agricoles andines intègrent la présence des espèces de parents sauvages dans leurs pratiques de gestion et leurs pratiques agricoles autour du quinoa. Des cartographies participatives et des enquêtes ethnobotaniques ont été réalisées avec les membres de six villages choisis selon des critères biogéographiques. La modélisation chorématique a été appliquée à deux périodes, avant et après 1970, année charnière au Pérou pour l’agriculture, dans le but de montrer comment les dynamiques socio-spatiales du milieu andin se modifient, notamment en lien avec l’évolution de la culture du quinoa. La distribution des espèces de parents sauvages du quinoa apparaît fortement liée à l’organisation socio-spatiale de l’agroécosystème. Ces espèces sont maintenues par les villageois pour leurs multiples usages alimentaires, médicinaux et culturels, dans des espaces naturels, des zones pâturées, aux abords et également à l’intérieur des champs cultivés. Ceci est à la fois le résultat de la gestion dynamique organisée par les communautés rurales et des savoirs liés à ces espèces qui se transmettent de génération en génération. Cependant cette gestion est en train de changer sous la pression d’enjeux globaux liés au marché international du quinoa, dont les exigences impliquent de réduire la présence de parents sauvages dans les champs cultivés. En conclusion, la thèse aborde la durabilité des pratiques de gestion et des pratiques agricoles dans un objectif de conservation dynamique in situ de la biodiversité sauvage et cultivée. Une mise en perspective historique des résultats nous a permis de questionner l’évolution des pratiques de gestion de ces différentes espèces par les communautés locales. En termes d’implication, deux types de projets pourraient être réfléchis. Le développement de projets prenant en compte le maintien de la présence des parents sauvages du quinoa dans le champ cultivé est favorable à l’introduction de gènes d’intérêt pour aider le quinoa à s’adapter à des conditions écologiques changeantes sous les effets du changement climatique. Egalement, des projets spécifiques de conservation in situ de l’agrobiodiversité, qui considèrent l’espace naturel et l’espace cultivé comme un ensemble cohérent, représentent une voie de gestion de pools de gènes importante pour l’agriculture et l’alimentation mondialeLake Titicaca, the cradle of pre-Columbian civilizations and one of the world’s main centres of domestication for farmed plant species, lies 3,800 m above sea level in the central Andean Highlands between Peru and Bolivia. The region is acknowledged as the centre of origin of quinoa, Chenopodium quinoa Willd. The greatest genetic diversity of quinoa and its wild relatives is concentrated there. Our research was conducted in the Puno region (Peru), which remains one of the main quinoa producing regions in the world. Quinoa displays spatial distribution along a North-South climate gradient in the region, with differentiation into mostly elevation-related, agro-ecological zones that explain its genetic diversity. Seven main quinoa crop wild relatives currently exist there: C. ambrosioides L., C. incisum Poiret, C. pallidicaule Aellen, C. petiolare Kunth, C. hircinum Schrad., C. quinoa ssp. melanospermum Hunz. and C. carnosolum Moq. This diversity of plant genetic resources is of great value for the adaptive evolution of quinoa, especially under the effect of climate change. This PhD thesis deals with the economic and cultural importance of quinoa, which is both a food resource in the Andean regions and an international commodity due to its exceptional nutritional qualities (protein-rich). This economic opportunity may have impacts on local food security, agrobiodiversity and agro-ecosystem management. One way of investigating this issue is to examine how the distribution of crop wild relatives is linked to the way quinoa cultivation is spatially organized. The thesis analysed how Andean farming communities incorporate the presence of wild relatives in their quinoa-related management and farming practices. Participatory mapping and ethnobotanical surveys were carried out with members of six villages chosen according to biogeographical criteria along a North South gradient, combined with data related to elevation and the proximity to Lake Titicaca. In order to show how the socio-spatial dynamics of the Andean environment are changing, notably linked to changes in quinoa growing, chorematic modelling was applied to two periods, before and after 1970, which was a pivotal year for Peruvian farming (agrarian reform, territorial rights of indigenous communities). The distribution of quinoa crop wild relatives seems to be closely linked to how the agro-ecosystem is spatially organized. Local communities keep these species for their multiple food, medicinal and cultural uses in natural areas, grazing areas, around and in farmed fields. This results from the dynamic management organized by rural communities, and from knowledge of those species passed down through the generations, by both women and men. However, management is changing under the pressure of global challenges arising from the international quinoa market, which calls for fewer wild parents in farmed fields. To conclude, the thesis looks at the sustainability of management and farming practices with a view to dynamic in situ conservation of wild and cultivated biodiversity. Choremes are used to place the results in historical perspective, to see how the management of these different species by local communities is evolving. In terms of implications, two types of project could be considered. Developing projects that keep quinoa crop wild relatives in farmed fields promotes the introduction of genes of interest, helping quinoa to adapt to ecological conditions being modified by climate change. Likewise, specific projects for in situ conservation of agrobiodiversity, which consider natural and cultivated areas as a coherent whole, are a way of managing gene pools that is important for agriculture and for feeding the world
49
Ragué, Maxime. « Dynamiques spatiale et temporelle des paysages agricoles : conséquences sur les interactions plantes-pollinisateurs et la pollinisation ». Thesis, La Rochelle, 2021. http://www.theses.fr/2021LAROS033.
Texte intégralRésumé :
Le maintien des insectes pollinisateurs en milieu agricole est essentiel car ils pollinisent les plantes sauvages et cultivées, il peut reposer sur l’augmentation de la disponibilité des ressources florales. Les cultures à floraison massive (CFM) fournissent des ressources abondantes et de façon discontinue dans le temps, au contraire des prairies et des plantes adventices présentes dans les cultures. Cet aspect temporel a été peu étudié alors que les paysages agricoles sont caractérisés par une dynamique temporelle importante du fait des successions culturales. L’objectif de la thèse est de comprendre l’effet de la distribution spatiale et temporelle des ressources florales dans les paysages agricoles sur les interactions plantes-pollinisateurs et la pollinisation. Nous montrons que les CFM au pic de floraison attirent les pollinisateurs sauvages des prairies et l’abeille domestique et supportent ainsi la fonction de pollinisation à cette période. Au sein des CFM, l’abeille domestique consomme les ressources fournies par les cultures préférentiellement en bordure de parcelle, et semble exclure les pollinisateurs sauvages des fleurs cultivées ceux-ci sont alors maintenus par les plantes adventices. A la fin de la floraison des CFM, les pollinisateurs dispersent vers les prairies et les céréales qui supportent ainsi la pollinisation. A cette période, les plantes adventices à travers leur abondance dans les céréales, et leur diversité dans les prairies supportent les pollinisateurs sauvages. La persistance des pollinisateurs et de la pollinisation dans les paysages agricoles, repose sur (i) le maintien des prairies et des plantes adventices qui assurent la continuité spatio-temporelle de la disponibilité en ressources florales, (ii) les CFM qui supplémentent les paysages en ressources florales, et (iii) la réduction de la taille des parcelles qui facilite l’accès aux ressources florales. Ces mesures sont compatibles avec la production agricoleMaintaining insect pollinators in farmland is essential for ensuring the pollination of crops and wild plants. This partly relies on the increase of floral resource availability. Mass flowering crops (MFC) provide a high amount of resources, but on a short period of time contrary to grasslands or weeds sheltered in fields. This temporal aspect is rarely studied, although it might be crucial in the maintenance of pollinators and insect pollination over the season. The aim of the thesis is to understand how the spatial and temporal distribution of the floral resources in farmland influence plant-pollinator interactions and pollination. Our results indicate that MFC at their peak flowering period, attract wild pollinators from grasslands and the honeybee; thus, supporting the pollination function. Within MFC, the honeybee preferentially consumes floral resources provided by crops, and may exclude wild pollinators from crop flowers which therefore foraged on weeds. After MFC flowering, pollinator insects spillover to grasslands and cereals which support pollination. Weeds, through their diversity in grasslands, and through their abundance in cereals support wild pollinators at this time period. The persistence of pollinators and pollination in farmland landscapes is based on (i) the maintenance of grasslands and weeds that ensure the spatio-temporal continuity of floral resources, (ii) MFC that supplement the landscapes in floral resources, and (iii) the reduction of field size that facilitates the access to the floral resources. Such measures appear to be compatible with crop production
50
LABRIOLA, MARIACELESTE. « BIODIVERSITY MANAGEMENT AND CONSERVATION : A COMPROMISE BETWEEN NATURE AND CULTIVATION ». Doctoral thesis, 2014. http://hdl.handle.net/2158/992630.
Texte intégralRésumé :
Le strategie di conservazione necessitano di una maggiore e approfondita conoscenza delle ripercussioni derivanti dalle introduzioni di specie aliene, essendo queste ultime, una delle minacce più importanti per la diversità biologica. Tra le specie aliene, possono essere considerati anche gli organismi geneticamente modificati (OGM); essi sono modificati e introdotti dall’uomo e, al contrario delle specie autoctone, non hanno subito un’evoluzione naturale nell'ambiente ricevente. Partendo dall’ipotesi che le attuali specie coltivate potranno presto essere sostituite da coltivazioni GM, lo scopo di questo lavoro è stato quello di indagare le possibili interazioni tra piante coltivate e l'ambiente circostante dal punto di vista della conservazione della diversità genetica. In particolare, è stata esaminata la potenziale ibridazione delle specie coltivate Populus spp. e Brassica spp. con le relative specie selvatiche affini.