EFFECT OF SALINITY STRESS ON GERMINATION OF FIVE TUNISIAN LENTIL (LENS CULINARIS L.) GENOTYPES

Salinity is one of the major stresses especially in arid and semi-arid regions, which severely limites crop production. It is a significant problem affecting agriculture worldwide and is predicted to become a larger problem in the coming decades. This study was conducted to assess the effect of different salinity level (0, 50, 150, 250 mMol of NaCl) on lentil seed germination efficiency (germination, seedling shoot length, seedling root length, seedling fresh shoot weight and seedling fresh root weight). Five Tunisian genotypes of lentil (Lens culinaris M) namely: Kef, Siliana, Nefza, Ncir, and Local oueslatia were investigated. Results showed that there were significant differences among the different NaCl solution for all evaluated traits. Indeed, the experiment showed that the concentrations of salt have a negative impact on the germination and growth of lentil. As a result when the concentration of salt increases, the germination, length of root and shoot and fresh weight of root and shoot decreases. At 250 mM salt stress level, seed germination percentage of all genotypes was notably reduced compared with non-stress condition (0.0 mMol). Moreover, the seeds were not germinated by the 250 mM salinity level for kef genotype. From the results of this present investigation, it can be concluded that seeds of Kef and Ncir genotypes were susceptible to higher concentrations of salt solutions in germination stage. However, Siliana, Local oueslatia and Nefza genotypes can be considered as tolerant to salt stress compared to the other ones. These genotypes could be used for further analysis and for hybridization in the breeding program for enhancing lentil cultivation in newly reclaimed soils

EFFECT OF SALINITY STRESS ON GERMINATION OF FIVE TUNISIAN LENTIL (LENS CULINARIS L.) GENOTYPES

Salinity is one of the major stresses especially in arid and semi-arid regions, which severely limites crop production. It is a significant problem affecting agriculture worldwide and is predicted to become a larger problem in the coming decades. This study was conducted to assess the effect of different salinity level (0, 50, 150, 250 mMol of NaCl) on lentil seed germination efficiency (germination, seedling shoot length, seedling root length, seedling fresh shoot weight and seedling fresh root weight). Five Tunisian genotypes of lentil (Lens culinaris M) namely: Kef, Siliana, Nefza, Ncir, and Local oueslatia were investigated. Results showed that there were significant differences among the different NaCl solution for all evaluated traits. Indeed, the experiment showed that the concentrations of salt have a negative impact on the germination and growth of lentil. As a result when the concentration of salt increases, the germination, length of root and shoot and fresh weight of root and shoot decreases. At 250 mM salt stress level, seed germination percentage of all genotypes was notably reduced compared with non-stress condition (0.0 mMol). Moreover, the seeds were not germinated by the 250 mM salinity level for kef genotype. From the results of this present investigation, it can be concluded that seeds of Kef and Ncir genotypes were susceptible to higher concentrations of salt solutions in germination stage. However, Siliana, Local oueslatia and Nefza genotypes can be considered as tolerant to salt stress compared to the other ones. These genotypes could be used for further analysis and for hybridization in the breeding program for enhancing lentil cultivation in newly reclaimed soils

GENETIC DIVERSITY OF FABA BEAN (VICIA FABA L.) POPULATIONS ESTIMATED BY ISOZYMIC AND MOLECULAR MARKERS: RELATIONSHIP BETWEEN THE TWO METHODS

In our previous studies, the genetic diversity among nine Tunisian faba bean (Vicia faba) populations was analysed using isozymes and sequence-specific amplification polymorphism (SSAP) markers. The objectives of this study were to compare the application and utility of isozymes and sequence-specific amplification polymorphism (SSAP) techniques for analysis of genetic diversity among nine Tunisian faba bean (Vicia faba) populations. A high genetic diversity within populations was detected by both isozymes (SOD, 6-PGD, ME, EST, SKDH, FDH and GDH) and (SSAP) markers (PDR1, Tps19 and Tvf4). For all populations, the genetic diversity revealed by SSAP was more pronounced than that detected with isozyme, based on polymorphic profiles. The analyses of correspondance between the tow methodes based in Mantel test revealed a low correlation ( r=0.177). The low correspondance indicated the absence of correlation and therfore the complimentarit

Characterization of Pisum sativum Mediterranean accessions by qualitative traits.

Nowadays, pea field is getting more attention because of its nutritional values.  The objective of this paper is to characterize and identify relationships among 21 Mediterranean pea accessions.  Fifteen accessions of Pisum sativum subsp. elatius and six accessions of Pisum sativum subsp. arvense were provided by ICARDA (International Centre for Agricultural Research in Dry Areas). Twenty qualitative traits were selected according to the guidelines of the International Union for the Protection of New Varieties of Plants (UPOV). We measured eight vegetative qualitative traits such as presence or absence of leaflets, type of plant axis development and presence or absence of anthocyanin coloration. We measured twelve floral qualitative traits such as standard color, pod color and curvature of the pod. In order to study the clustering of our accessions, we used Past4.03 with the test UPGMA (unweighted pair group method with arithmetic mean). The biometric and descriptive analysis we carried out reveals the presence of traits that discriminate accessions. Among these traits, we can cite C15 (vegetative qualitative trait), C23, C31 and C35 (floral qualitative traits). C15 discriminates the accessions TUR10, TUR8, SYR1 and SYR2. C23 distinguishes TUR6, TUR11 and AL2 accessions from other accessions. C31 is a discriminating trait for TUR13 accession. The type of starch grain (C35) discriminates the TUR14 accession. Cluster analysis led to establishing dendrogram allowing a grouping of accessions according to their geographical affiliation. In fact, it is possible to discriminate significantly the accessions TUR10, SYR1 and SYR2 from the accessions TUR12, TUR13, GR1 and TUN which could be an incentive for further improvement and better exploitation

Genetic variability, chemotype distribution, and aggressiveness of Fusarium culmorum on durum wheat in Tunisia

Fusarium culmorum is the most commonly reported root rot pathogen in Tunisian durum wheat. Isolates of the pathogen from four durum wheat growing areas in the north of Tunisia were analyzed for their chemotypes. Two chemotypes were detected at unequal abundance (96% of 3-ADON and 4% of NIV). Distribution of a SNP mutation located at the position 34 bp after the first exon of the EF-1α partial sequence was analysed, to verify whether the haplotype was specifically associated to Fusarium root rot. A and T haplotypes were homogeneously distributed in three different Tunisian regions (Mateur, Beja and Bousalem) but not for the region of Bizerte, from which greatest number of A haplotype strains were detected. The isolates were tested for their virulence under glasshouse conditions, and a mean of 91% of crown and root infection was observed. Chemotype influenced virulence, but there was no significant influence of the geographical origin or haplotype on virulence. The distribution of three inter simple sequence repeats (ISSR) was examined, to better understand the structure of F. culmorum populations in Tunisia. A total of 27 fragments were obtained with eight polymorphic bands. Cluster analysis showed a high level of similarity between isolates. Analysis of molecular variance confirmed that there was little genetic differentiation among F. culmorum strains from different locations

Pod, seed traits and cytotaxonomic studies of some Vicia narbonensis L. accessions (Fabaceae)

This study aimed to characterize eight accessions of Vicia narbonensis L. originated from different Mediterranean countries. The cytology of these species is rarely known despite the fact of its great socio-economical and ecological interest in these arid and semi-arid zones. This work aimed mainly to characterize the karyotype, morphological pod and seed traits of the species. Karyotypes of all accessions were similar to a diploid number of 2n = 2x = 14. All the accessions have submetacentric chromosomes with a secondary constriction attached to the long arm of pair VII close to the centromere. Variation in chromosome size was observed; it ranged from 5.86 μm to 7.62 μm. Indices of karyotype asymmetry were calculated as the total form percentage (TF%) and symmetric indices (Syi) which ranged from 33.75% to 35.42% and from 51.01% to 54.85%, respectively. The predominance of submetacentric chromosomes indicated that the karyotype is symmetrical and can be considered as primitive. However, the analysis of quantitative parameters measured on pods and seeds showed a significant variation between accessions. A relationship between centromeric index and the pod beak length was found. Estimation of phenotypic diversity using the Shannon diversity index (H′) showed that the length, the seed color and the number of seeds per pod are the most polymorphic traits with respectively, H′ = 0.92, 0.80 and 0.83. Cluster analysis of karyological, pod and seed traits showed four groups of accessions. This clustering is partially due to the geographical origin of the studied accessions. The variation in chromosome size, pod and seed traits could offer potentially valuable genetic resources for the improvement of V. narbonensis which is considered as neglected and underutilized crop species (NUCS)

Agro-Morphological, Biochemical and Antioxidant Characterization of a Tunisian Chili Pepper Germplasm Collection

Pepper species have been described as being highly sensitive to climate change. Here, we discuss the variability of the agro-morphological and phytochemical responses of pepper cultivars in the context of ongoing climate changes during seven stages of maturity, including heat stress. The effects and interactions were calculated to determine the source of variation according to rising temperature. Capsaicin content (CAP), total phenolic (TPC) and flavonoid (TFC) levels and antioxidant activity (AA) were also determined at different harvest times (at 10, 25, 40, 55, 70, 85 and 100 days after anthesis, DAA). Agro-morphological data showed that the highest variation was recorded for fruit traits compared to flower and plant ones. In particular, calyx shape margin, calyx annular constriction, fruit shape at blossom end and fruit size had a significant impact on the morphologic diversity among accessions. Levels of bioactive compounds and antioxidant activity depended on the genotype and the harvest time. TPC and AA increased at 100 DAA, while TFC were highly detected at the early harvest. Principal component analysis (PCA) allowed us to separate three clusters with well-defined biochemical traits. In particular, regardless of harvest time, Baklouti Chébika, Baklouti Sbikha and Chaabani accessions presented higher levels of TPC, TFC and AA regardless of the considered harvest time. In conclusion, high genetic variability was noted within the analyzed pepper germplasm, thus suggesting the need for major consideration of both agro-morphological and biochemical traits for pepper breeding programs. The current research was conducted to facilitate better management under high-stress conditions due to global warmin

Volatile compounds and bioactivities properties of Opuntia microdasys (Lehm.) and Opuntia macrorhiza (Engelm.) seeds

The seeds of Opuntia sp. require additional investigations because they could contain several active molecules. Therefore, the present study analyzed the chemical composition and biological activities of Opuntia microdasys and that of Opuntia macrorhiza using in vitro and in vivo models.  The headspace of the powders of the seeds of Opuntia have been analyzed by gas chromatography–mass spectrometry (GC–MS). The analgesic activity was assessed using the acetic acid-induced abdominal constriction response on mouse. Chemical analyses showed that the powders of the seeds of O. microdasys and O. macrorhiza were rich in nonanal and camphor. Also, the O. macrorhiza seeds has a high antioxidant activity (EC50 =0.12 mg/ml). The results showed that the ethanolic extracts, at a dose of 200 mg/kg of body weight, caused a significant (P< 0.05) inhibition of the abdominal constriction response (75.17% and 56.22% for O. microdasys and O. microdasys). The microdilution assay revealed that ethanolic extract of O. macrorhiza seeds is more active and could inhibit the growth of almost all the evaluated bacterial and fungal strains, with the minimal bactericidal concentration values (MIC) ranging from 0.039 to 2.50 mg/mL. The overall results highlighted the potential of the tested Opuntia seeds that can be used as a source of bioactive compounds that confer various important biological activities to it, which could imply other pharmacological applications

Chemical Composition and Anti-Leishmania Major Activity of Essential Oils from Artemesia spp. Grown in Central Tunisia

peer reviewedNatural products are a very important source of bio-molecules for drug to treat infectious diseases. New antileishmanial agents are timely needed, due to leishmania toxicity, drug-resistant strains and high costs treatments. In this study, we report the chemical characterization and antileishmanial activity of oil extracts from three medicinal plants belonging to genus Artemisia (Asteracea), that grow in central Tunisia. The chemical composition of volatile compounds had been elucidated by gas chromatography-mass spectroscopy analysis. Chemical analysis revealed that essential oils were composed of 34 compounds: α-thujone (29.3%), chamazulene (39.2%) and β-pinene (32%), were the main constituents for the essential oils of Artemesia herba alba, Artemesia absinthium and Artemesia campestris, respectively. The hydrodistilled essential oils from these three species of Artemisia showed significant anti-leishmanial activities against Leishmania major. Oils from A. herba alba, A. absinthium and A. campestris exhibited IC50 values of 1.20 ± 0.043 μg/mL, 1.49 ± 0.05 μg/mL and 2.20 ± 0.11 μg/mL respectively against promastigotes of Leishmania major. Among three oils tested, A. campestris exerted a remarkable antileishmanial activity and it has the lowest cytotoxicity effect compared to amphotericin B. Overall, it was proved that our investigated essential oils possess potential antileishmanial properties and could be used as a promising alternative treatment for leishmaniasis disease in the future