Mohamed Neji

Traditional Mediterranean grapevine landraces represent irreplaceable reservoirs of adaptive diversity, yet many regional germplasm pools remain poorly characterized, limiting conservation strategies and climate-resilient breeding. This study presents the first comparative genetic assessment of 154 local Vitis accessions from three historically interconnected but genomically underrepresented Mediterranean regions: Greece, Morocco, and Slovenia. Using 12 highly polymorphic nuclear SSR markers, we detected substantial genetic diversity (168 alleles; mean heterozygosity He = 0.881) with distinct regional signatures. Moroccan accessions exhibited the highest allelic richness and 11 private alleles, reflecting diverse agroecological adaptation. Slovenian germplasm formed a cohesive, genetically stable cluster with high effective allele numbers. Greek accessions exhibited the highest observed heterozygosity and 14 private alleles, consistent with the Aegean’s role as a major diversification hotspot. Despite >90% of variance occurring within individuals, AMOVA and pairwise FST (0.050–0.061) revealed low to moderate but significant geographic differentiation. Multivariate analyses (PCA, UPGMA) and Bayesian clustering (sNMF, K = 3) consistently resolved three regional genetic groups with varying admixture levels, consistent with a mosaic domestication model, as previously proposed for the Mediterranean basin, shaped by recurrent introductions, wild introgression, and region-specific selection. Our results show that peripheral Mediterranean germplasm harbors meaningful, regionally distinctive, substantial, non-redundant diversity not fully represented in surveys focused on climate adaptation, disease resistance breeding, and long-term genetic resource conservation. These findings challenge simplistic diffusion models and emphasize the strategic importance of geographically comprehensive sampling in grapevine conservation programs.

Understanding interactions among genotype, environment, and management is crucial for optimizing crop performance under climate variability. Sweetpotato ( Ipomoea batatas (L.) Lam.), a nutrient‐rich root crop increasingly cultivated in temperate regions, exhibits complex source‐sink dynamics that remain insufficiently characterized in organic and mulch‐based systems. This study evaluated vegetative growth and storage root yield of four varieties (Martina, Janja, Lučka, and Purple Speclet) grown under conventional and organic production, with and without polyethylene mulch, across two contrasting seasons (2021–2022) in Slovenia. A randomized complete block design with four replications was used to assess 15 agro‐morphological traits, and linear mixed‐effects models and multivariate analyses quantified factor effects and interactions. Variety and cultivation method predominantly influenced vegetative traits ( η ² = 30.26% and 24.85%), while variety and growing season contributed most to yield variance (35.56% and 20.88%). Polyethylene mulch significantly increased above‐ground biomass (677–1329 g plant ^{− 1} ) and total storage root yield (922–1548 g plant ^{− 1} ), confirming its role in improving the soil‐plant microenvironment. Martina showed the highest and most stable yield across systems. Pearson correlations indicated strong positive relationship among yield components ( r = 0.77–0.93) and moderate positive correlations between vegetative biomass and yield ( r = 0.49–0.60), reflecting coordinated yet distinct source‐sink patterns. Principal component analysis separated treatment combinations and revealed significant genotype × management × season interactions, particularly under mulch in 2022. Overall, combining suitable varieties with polyethylene mulch substantially enhanced productivity, reducing the organic‐conventional yield gap to ∼11%. These results support climate‐adapted strategies based on efficient resource use and optimized biomass partitioning in temperate agroecosystems.

Arid rangelands face increasing threats from grazing pressure and climate variability, yet the combined effects of grazing intensity and environmental gradients on plant community structure remain poorly understood. This study investigates grazing impacts on plant communities in southern Tunisia using floristic composition, ecological indicators, and indicator species across 500 plots representing low, moderate, and high grazing intensities. Vegetation surveys during peak growth recorded 386 vascular plant species. Species diversity peaked under moderate grazing (H’ = 5.46), consistent with the Intermediate Disturbance Hypothesis, but was strongly influenced by soil nitrogen (r² = 0.692). Heavy grazing reduced diversity (H’ = 4.82), especially in nitrogen-poor sites, indicating that environmental stress amplifies grazing effects. Indicator species analysis identified 113 significant taxa, including 42 associated with moderate grazing, reflecting compositional rather than functional responses. Redundancy analysis showed that environmental variables explained 67% of community variance, with soil nitrogen as the dominant gradient, followed by sand content, minimum temperature, and longitude. Ordination analyses revealed distinct assemblages under high grazing intensity associated with sandy, nutrient-poor soils. These findings demonstrate that grazing impacts are highly context-dependent and support the need for site-specific, soil-informed grazing management under increasing climate stress.

The sunflower (Helianthus annuus L.) is one of the most essential oil crops in the world. Several component traits, including flowering time, plant height, stem diameter, seed weight, and kernel weight, determine sunflower seed and oil yield. Although the genetic mechanisms governing the variation of these yield-related traits have been studied using various approaches, genome-wide association studies (GWAS) have not been widely applied to sunflowers. In this study, a set of 342 sunflower accessions was evaluated in 2019 and 2020 using an incomplete randomized block design, and GWAS was conducted utilizing two complementary approaches: the mixed linear model (MLM) and the fixed and random model circulating probability unification (farmCPU) model by fitting 226,779 high-quality SNPs. As a result, GWAS identified a number of trait-associated SNPs. Those SNPs were located close to several genes that may serve as a basis for further molecular characterization and provide promising targets for sunflower yield improvement.

Increased soil salinity significantly inhibits crop production around the world. Over the last decade, biochar has been used in agriculture to improve plant productivity, soil quality, and as an alternative to plant amendment. This study was aimed to study the effect of biochar, NPK, and their combination on the growth, physio-biochemical traits, mineral contents, and grain yield of barley (Hordeum vulgare L.). Thus, a pot factorial experiment based on a completely randomized design with three replications was performed. Experimental treatments included four levels of biochar (0, 2, 5 and 10% of total pot mass), four different NaCl levels (0, 75, 125, and 200 mmol L⁻¹), and with or without NPK fertilizer. The results showed that a negative effect on gas exchange parameters, photosynthetic pigments, SPAD value, minerals contents, and grain yield of barley under salinity treatments. In addition, our funding showed the negative effect on biochemical traits such as proline, soluble sugars, individual sugar, and phenolic compounds. The use of biochar, combined with NPK fertilizers, considerably increases these parameters and especially improves barley grains yield under severe salinity conditions (200 mM) with a dose of 2% and 5% (394.1 and 280.61 g m⁻², respectively) of total pot mass. It is concluded that biochar amendment could be a promising practice to enhance barley growth under severe saline irrigation and NPK fertilization regimes.

Characterisation of genetic diversity is critical to adequately exploit the potential of germplasm collections and identify important traits for breeding programs and sustainable crop improvement. Here, we characterised the phenotypic and genetic diversity of a global collection of the two cultivated buckwheat species Fagopyrum esculentum and Fagopyrum tataricum (190 and 51 accessions, respectively) using 37 agro-morphological traits and 24 SSR markers. A wide range of variation was observed in both species for most of the traits analysed. The two species differed significantly in most traits, with traits related to seeds and flowering contributing most to differentiation. The accessions of each species were divided into three major phenoclusters with no clear geographic clustering. At the molecular level, the polymorphic SSR markers were highly informative, with an average polymorphic information content (PIC) of over 0.65 in both species. Genetic diversity, as determined by Nei’s expected heterozygosity (He), was high (He = 0.77 and He = 0.66, respectively) and differed significantly between species (p = 0.03) but was homogeneously distributed between regions, confirming the lack of genetic structure as determined by clustering approaches. The weak genetic structure revealed by the phenotypic and SSR data and the low fixation indices in both species suggested frequent seed exchange and extensive cultivation and selection. In addition, 93 and 140 significant (p < 0.05) marker-trait associations (MTAs) were identified in both species using a general linear model and a mixed linear model, most of which explained >20% of the phenotypic variation in associated traits. Core collections of 23 and 13 phenotypically and genetically diverse accessions, respectively, were developed for F. esculentum and F. tataricum. Overall, the data analysed provided deep insights into the agro-morphological and genetic diversity and genetic relationships among F. esculentum and F. tataricum accessions and pointed to future directions for genomics-based breeding programs and germplasm management.