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Browsing by Author "Aranda, Ismael"

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  • Évaluation préliminaire des essais de provenances de chêne-liège et perspectives de recherche
    Publication . Varela, Maria Carolina; Almeida, Maria Helena; Sampaio, Teresa; Patrício, Maria Sameiro; Dettori, Sandro; Filigheddu, Maria Rosaria; Sirca, C.; Belarosa, R.; Vessella, Federico; Simeone, M.; Iglesias, S.; Aranda, Ismael; Khouja, M.; Khaldi, A.
    Le réseau international des essais de provenance et de descendance de chêne-liège (établie dans le cadre du projet Action Concertée FAIR CT 95-202 “European network for the evaluation of genetic resources of cork oak for appropriate use in breeding and gene conservation strategies” financé par l’Union Européenne) constitue un matériel vivant unique pour la recherche, qu’elle soit appliquée, ou fondamental, sur l’espèce. Les essais génétiques ont été réalisés sur une base méthodologique harmonisée au niveau des plants utilisés (tous les plants ont été élevées dans une même pépinière au Portugal) et sur terrain un même dispositif expérimental a été suivi. En 1997/98, 13 essais de provenances ont été établis. Ceux ayant réussi sont situés en Espagne (2), France (1), Italie (3), Portugal (3) et Tunisie (1). Concernent les essais de descendances il existe 4 des 5 initiales - Espagne (1), Portugal (2) et Tunisie (1). Dans ce travail nous présentons quelques résultats du comportement des provenances à travers des caractéristiques adaptatifs tels que la survie, l’efficacité d’utilisation de l’eau et des études de génomique. Nous avons procédé à la comparaison de chaque provenance dans les essais - niveau horizontal- et à la comparaison de chaque provenance entre les essais - niveau vertical afin de discuter la plasticité phénotypique et l’interaction génotype X environnement. Les données disponibles pour hauteur en 2006 montre des différences de comportement entre provenances et entre les essais. Par exemple, les provenances du Maroc montre une croissance supérieure dans l’essai plus au Sud au Portugal et aussi dans un essai en Espagne. Pour l’essai de Sardaigne les meilleures provenances sont de Tunisie et d’Espagne. A la fin on discute sur les avantages des essais comme matériel vivant dénominateur commun pour une recherche avancée, multidisciplinaire, synergétique, transnational et concertée. Les perspectives pour la recherche sur les grands thèmes tels que la gestion durable du chêne-liège, notamment la sélection, amélioration génétique, adaptation aux changements globaux, fluxes génétiques, problèmes phytosanitaires, qualité du liège en liaison avec la respective génomique sont adressées.
    2011Conference object Open access Show more
  • Genetic variation of cork oak a tool for improving regeneration of cork oak woodlands
    Publication . Almeida, Maria Helena; Aranda, Ismael; Chambel, Maria Regina; Silva, F. Costa e; Dettori, Sandro; Faria, Carla Maria Gomes Marques; Filigheddu, Maria Rosaria; Fernández, Elena; Khaldi, Abedelhamid; Patrício, Maria Sameiro; Perez, Felipe; Ramirez-Valiente, José Alberto; Rodrigues, Ana; Sampaio, Teresa; Varela, Carolina
    The European Academies' Science Advisory Council (2017) reports that the Mediterranean forest is already being affected by climate change (IPCC, 2014) and cork oak woodlands are particularly vulnerable to high-end climate scenarios that go above the Paris Agreement 2° C increase in temperature. Since longer, more frequent, and more intense drought periods are expected, stress caused by the expansion of arid and semi-arid climate will affect the species distribution. Consequently, not only established stands may be prone to tree mortality, but also the current reforestation effort may be jeopardized by low survival rates attributed to the use of unsuitable genetic material. It is expected that, through genetic adaptation and/or phenotypic plasticity, cork oak populations may have developed significant differences in fitness and the traits related to it. In this context, provenance and progeny trials are the best resource of material to assess the variability between and within populations from seed sources sampled in a wide range of locations (stands) covering the geographical distribution of the species. Profiting from the multi-locality provenance and progeny trials belonging to a Network, established in 1998, in the initiative frame of FAIR I CT 0202 for the evaluation of genetic resources of cork oak for appropriate use in breeding and gene conservation strategies”, where 35 cork oak populations covering all the natural distribution area are represented. The provenance trials that where set up in different countries are entering now the age of first debarking and this should allow to have first data about the influence of genetics on production by different site qualities. INCREDIBLE project should document this knowledge
    2019Conference object Open access Show more
  • Provenance behavior in the cork-oak International network trials fair 202
    Publication . Varela, Maria Carolina; Sampaio, Teresa; Filigheddu, Maria Rosaria; Zucca, G.M.; Patrício, Maria Sameiro; Almeida, Maria Helena; Ramirez-Valiente, José Alberto; Aranda, Ismael; Tessier, C.; Ladier, Jean; Dettori, Sandro
    The international network of provenance trials in cork-oak was established as a result of the EU Concerted Action FAIR 202, 1995-2000. 34 provenances were selected in the natural range of cork oak and trials were established in 1996/97 in France, Italy, Portugal, Tunisia and Spain. This study compares the behavior of provenances in the trials of Grighini (Sardinia), Monte Fava and Quinta da Nogueira (Portugal), Monfrague (Spain), Les Maures (France) and Tebabe (Tunisia). Observations on total height (Ht) and diameter at beast height (DBH) are used to compare and assess adaptation within sites and among sites. Climate at the provenance site seed collection and at trials sites is used to characterize the behavior of provenances. The results reveal that the provenances, ES 5 (1063 mm), IT16 (910 mm), IT12 (937 mm), 937, TU32 (948 mm), FR2 (958 mm, FR1 (963 mm, MA31 (970 mm), ES8 (993 mm) are able to adapt and show good growth under conditions of decrease of total annual rainfall and strong decrease in case of TU33 (1610mm), MA27 (1280 mm). On the other hand provenances coming from sites of low precipitation not always show relevant performance in sites of higher precipitation as IT14 (448 mm), ES10 (455 mm), MA29 (479 mm). These results are discussed in the impact climate change (CC) may have in adaptation and evolution of cork oak. Our results show that cork oak will not face serious threats if drought increases in the Mediterranean region, since some populations are showing capable to cope successfully with decrease of total precipitation. The ongoing results from the cork-oak international network trials FAIR 202 show the importance of this line of research and the need to establish harmonized criteria on data collection to enhance the comparability. As cork quality is a key issue on cork-oak economic sustainability it is critical to establish harmonized criteria in cork harvesting for further studies to compare cork quality with special reference for the assessment of the genetic control of cork production and heritability.
    2017Conference object Open access Show more
  • Quercus suber geographic variation: preliminary results of the Iberian Península provenance trials
    Publication . Almeida, Maria Helena; Aranda, Ismael; Chambel, Maria Regina; Fachada, Ivone; Gil, Luís; Lourenço, Maria João; Monteiro, Maria do Loreto; Nunes, Ana Margarida; Patrício, Maria Sameiro; Pereira, João Santos; Ramirez-Valiente, José Alberto; Rocha, Sara; Sampaio, Teresa; Varela, Maria Carolina
    Cork oak (Quercus suber L.) has a great social and ecological importance in the Iberian Peninsula. Yet, a large proportion of cork oak stands is old and natural regeneration is often problematic. During the last decade large areas were reforested with this species in the context of the Common Agriculture Policy (CAP) both in Portugal and Spain. Survival rates were often low due to inappropriate nursery and installation techniques, as well as to the use of unsuitable genetic material. In fact, the cork oak adaptability to environmental conditions is poorly understood; moreover climate change scenarios foreseen enhanced water deficits in the Mediterranean region. In order to allocate the most adequate seed sources to each set of climatic conditions in future afforestation activities and considering that an important source of variation in the characteristics related with adaptability may be at the provenance level, we evaluated inter-provenance variability and phenotypic plasticity for growth, survival, morphological structure and drought tolerance five years after plantation, in four test sites located across the Iberian Peninsula and covering a wide range of ecological conditions. Such trials are part of a multi-locality provenance test belonging to a Network that was bring up by Concerted action. European network for the evaluation of genetic resources of cork oak for appropriate use in breeding and gene conservation strategies. where 35 cork oak populations covering all the natural distribution area are represented.
    2006Conference object Open access Show more