Influence de la salinité sur le comportement agro-physiologique de quelques variétés de Sulla (Hedysarum coronarium et Hedysarum carnosum)

G. TIBAOUI ^1*

S. GUESMI ²

H. SELMI ²

O. HANNACH ³

¹Ecole Supérieure d’Agriculture de Mateur

²Institut Sylvopastoral de Tabarka

³Institut National Agronomique de Tunisie

Abstract – This study aimed to analyze the influence of salinity on ago-physiological behavior of sulla. Five varieties of the Hedysarum coronarium species and one of the Hedysarum carnosum species are tested. Changes in leaf area, transpiration, relative leaf moisture content, proline content and dry matter yield as a function of increasing control salt regimes (tap water), 2, 4, 6.8 and 10 g / l of NaCl were studied in pots of vegetation. The obtained results showed that salinity affects significantly (P <0.05) the majority of agronomic and physiological studied parameters. Relative water content and transpiration decrease under the effect of salt stress in all varieties. However, up to 8 g / l of NaCl, all the varieties keep a leaf area comparable to that of the control and consequently, they maintain an important dry matter yield especially in the variety Mateur.

Keywords : sulla, salinity, tolerance

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M. BEN LARBI ^1*

N. M’HAMDI ²

B. REKIK ¹

¹ Unité de Recherche : biodiversité et et valorisation des ressources dans les zones montagneuses (UR17AGR14). Ecole Supérieure d’Agriculture de Mateur, route de Tabarka 7030 Mateur

² Institut National Agronomique de Tunisie, 43 Avenue Charles Nicolle, Tunis 1082

Abstract – Genetic diversity refers to the total number of genetic characteristics in the genetic make-up of a species. It shows variation that exists between breeds of the same species. Genetic diversity serves as a way for populations to adapt to changing environment. An increasing loss of genetic diversity has been observed for all agriculturally used species and poultry genetic resources are considered to be the most endangered. Selective breeding by humans has led to the creation of many breeds characterized by high productivity, leading to the displacement of local breeds and posing a threat to the survival of many native breeds. Genetic resources are the building blocks for poultry development. The relevance of genetic diversity conservation in poultry production cannot be overemphasized because genes play a major role in formation of breeds and species. With recent advances in molecular technology, a number of techniques for in-depth genome analysis and evaluation of genetic variation in different breeds of poultry have been developed.

Keywords: Genetic diversity, conservation, poultry, genetic resources.

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L'amélioration génétique des bovins laitiers en Tunisie : état des lieux et perspectives d’introduction de l’information moléculaire dans les schémas de sélection bovine

S. BEN JEMAA^1*

¹ Laboratoire des productions animales et fourragères, Institut National de la Recherche Agronomique de Tunisie

Abstract – Dairy products are among the strategic products of the Tunisian agricultural economy, both in terms of their role in human nutrition and of their financial contribution. Breeding schemes make an important contribution to the improvement of animal productivity. Here, we summarize and develop a critical analysis of the current organization of the dairy cattle breeding scheme in Tunisia. Then, we propose new approaches of dairy cattle breeding schemes based on marker assisted selection (MAS). We noticed the absence of actual breeding schemes and emphasize the fact that the use of imported semen does not guarantee the improvement of the genetic level of the national herd because of gene/ environment interactions. We propose a short-term strategy that involves the use of gene mutations with major / moderate effects in gene-assisted breeding programs. In the medium term, we propose to start a first genome-wide marker-assisted selection experiment that will allow a better genetic gain of Tunisian animals.

Keywords: dairy cattle - breeding programs- Marker assisted Selection- Quantitative trait loci.

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omportement adaptatif de certaines espèces pastorales vis-à-vis de stress salin et osmotique en Tunisie (Cas d’Acacia salicina et de Leucaena leucocephala)

R. MECHERGUI¹*

H. NAJJAR¹

K. BOUAJILA²

M. KHOUJA¹

H. CHAAR²

S. SLM³

M. L. KHOUJA¹

¹ Institut National de Recherches en Génie Rural, Eaux et Forêts, Tunisie

² Institut National Agronomique de Tunisie

³ Ecole Supérieure d'Agriculture de Mateur, Tunisie

Abstract – Adaptative behavior of some pastoral species to salt and osmotic stress (Case of Acacia salicina and Leucaena leucocephala). During this work, we have characterized the seeds germinative performances Acacia salicina (exotic species native to Australia) and Leucaena leucocephala (exotic species native to South America). These plants are Fabaceae and constituted a capital element to maintain many arid ecosystems. The germination of these two species was followed to the darkness, under 25°C, and in the presence of increasingly high osmotic stress imposed by increasing concentration polyethylene glycol (PEG₆₀₀₀), (5,31 ; 15,3 ; 63,9 ; 80,36 et 107,47 g/l) , and salt stress caused by increasing concentrations of NaCl (3, 5, 7, 9 and 12 g/l). The increase of NaCl concentration gradually inhibit germination of seeds. The analysis of variance proves that there is a significant effect of NaCl on the germination rate. Acacia salicina presents generative capacity of 18.66% at 12g/l NaCl concentration and Leucaena leucocephala presents a lower rate of 9,5%. The hydrous deficit caused by PEG influences significantly the germination rate of two species. The obtained results encourage to widen the fields of investigation to other species of Acacia and Leucaena by imposing same abiotic stresses in order to determinate the thresholds limitation to select the most tolerant.

Keywords : Acacia salicina ; Leucaena leucocephala ; germination ; PEG ; NaCl

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Etude des variations des caractéristiques pomologiques des fruits d'olive suite à l'irrigation par les eaux usées traitées (EUT)

M. GHARSALLAOUI^1*

N. ZAANOUNI²

S. GABSI²

¹ Institut de l’olivier

² Ecole Nationale d’ingénieur à Sfax

Abstract – Olive growing is the most important crop in the Mediterranean area which has the central part of world oil production. In arid and semi-arid regions for yield maximization they use irrigation with treated wastewater, which is a very important alternative for these remarkable roles. Our study focused on changes in pomological characteristics following irrigation by treated wastewater in the South Sfax region, irrigation by these waters has been found to have no detrimental effect on these characteristics of the beneficial effects increase average fruit weight by 20 to 25%, so the results showed that the interruption of irrigation causes a depressive effect with reduced weight, moisture and even fat content. So, it is advisable not to interrupt.

Keywords: wastewater reuse, irrigation, olives, pomological characteristics.

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