Taoufik Hayek

Crop-livestock and feed systems have huge importance for Mediterranean regions to satisfy the increasing demand for animal products, increase the economic stabil ity of smallholders and produce typical animal products with high added-value, while contributing t o sustainable farming, environment protection and

Salinity is one of the important limiting factor for agriculture overall in the Mediterranean region. It affects about 7% of the world s total land area (Flowers et al., 1997). Approximately 930 million ha of cultivated land affected are currently threatened by salinity (Munns 2002; Kefu et al., 2002). Tunisia is concerned by the salinity problem. Based on FAO (2005), about 1.8 million hectares representing ISSN: 2319-7706 Volume 3 Number 2 (2014) pp. 647-661 http://www.ijcmas.com

In arid and semi-arid regions of the world, excess salts in agricultural land can limit crop production. Barley (Hordeum vulgare L.) is one of the most salt tolerant crop species. This study was conducted to determine the effects of salinity on seed germination, mineral content and yield production of 14 barley accessions from two regions in the Southern Tunisia. First experiment was conducted in laboratory to test the effect of nine levels of NaCl concentrations in different germination parameter. Second experiments were conducted in a greenhouse. The accessions were grown in soil and exposed to three salinity levels. Salinity decreased significantly the germination rate and the germination rate index for all accessions. Na+ content, total dry matter and grain yield vary significantly with increasing salinity levels. The degree of tolerance varies between accessions in the different growth stage. A significant correlation were observed between ranking using grain yield and multivar...

The decrease of rainfall amount due to climate change, and the reduction of irrigation water caused by growing water demand for non-agricultural uses, emphasize the importance of breeding novel alfalfa varieties that are more tolerant to drought under rain-fed cropping or modest supplemental irrigation, and more tolerant to salt to exploit lowquality, saline irrigation water. A sharp need for such improved germplasm is emerging in the Mediterranean basin, where alfalfa plays a key role for forage production. Drought-tolerant cultivars are needed also elsewhere, for example in Argentina, where they could allow to expand westward the alfalfa rain-fed cropping. Alfalfa typically features very low rates of genetic yield gain (Annicchiarico et al. 2015a), urging the development of cost-efficient marker-based selection.

Les effets d'un deficit hydrique sur le potentiel hydrique foliaire et les echanges gazeux ont ete etudies chez 9 varietes de cereales. Les plantes, cultivees dans des pots sous des conditions controlees, ont ete maintenues sous un regime hydrique optimal jusqu'au debut de l'epiaison (stade 49 selon l'echelle de Zadocks), puis elles ont ete exposees a un cycle de dessechement de 9 jours par arret d'irrigation. Les resultats ont montre des differences significatives entre les varietes aux niveaux du potentiel hydrique foliaire, de la photosynthese nette, de la conductance stomatique, de la concentration interne du CO 2 et de l'efficience de l'utilisation de l'eau. Pendant les premiers jours du traitement (du 1 er au 5 eme jour ), le deficit a ete modere, les echanges gazeux et le potentiel hydrique ont faiblement baisse et on a meme observe une amelioration chez certaines varietes. Au cours des derniers jours du cycle ( du 5 eme au 9 eme jour) et avec l'accentuation du stress, les differents parametres, a l'exception de la concentration interne de CO 2 , ont chute considerablement. Au 9 eme jour les plantes traitees ont ete re-irriguees, et la recuperation est observee chez toutes les varietes et pour les parametres etudies.

– This study aims to compare the growth and forage dry matter yield of 16 different Lucerne (Medicago sativa) genotypes, under the specific environmental conditions of south Tunisia. Plants were cultivated on the field and irrigated during the period (March 2005 to September 2007) and a water deficit treatment was applied, by interrupting irrigation, for 43, 56 and 65 days during the summer of 2005, 2006 and 2007, respectively. Results show significant differences between genotypes regarding forage dry matter yield, leaf-to-stem ratio and drought sensitivity index. Some genotypes show an interesting yield potential, mainly Ecotipo Siciliano, and to a lesser extent, ABT 805 and Ameristand 801S. Therefore, those varieties can provide local farmers in the region with a possibility for an alternative use. RESUME – "Développement de la croissance et rendement en matière sèche de 16 génotypes de luzerne cultivés dans le sud de la Tunisie". L'objectif de cette étude est de co...

Alfalfa (Medicago sativa L.) selection for stress‐prone regions has high priority for sustainable crop–livestock systems. This study assessed the genomic selection (GS) ability to predict alfalfa breeding values for drought‐prone agricultural sites of Algeria, Morocco, and Argentina; managed‐stress (MS) environments of Italy featuring moderate or intense drought; and one Tunisian site irrigated with moderately saline water. Additional aims were to investigate genotype × environment interaction (GEI) patterns and the effect on GS predictions of three single‐nucleotide polymorphism (SNP) calling procedures, 12 statistical models that exclude or incorporate GEI, and allele dosage information. Our study included 127 genotypes from a Mediterranean reference population originated from three geographically contrasting populations, genotyped via genotyping‐by‐sequencing and phenotyped based on multi‐year biomass dry matter yield of their dense‐planted half‐sib progenies. The GEI was very la...