Durum wheat is the most widely grown cereal in Tunisia, but its production is threatened by drought, which is exacerbated by climate change. This study aimed to identify drought-tolerant durum wheat genotypes from five modern varieties and six landraces in a multi-environment trial at two sites (Kef and Siliana, Tunisia) during three growing seasons under rainfed and irrigated conditions. Six drought tolerance indices (mean productivity (MP), geometric mean productivity (GMP), stress susceptibility index (SSI), tolerance index (TOL), stress tolerance index (STI), and yield stability index (YSI)) were used to evaluate the 11 genotypes. The environment was the dominant source of variation for grain yield (GY; 94.27%), followed by the environment × genotype interaction (4.06%) and genotype (1.65%). Cluster analysis based on GY identified four environment-based groups with distinct water treatments, extreme minimum/maximum temperatures, and rainfall. Principal component analysis and a correlation matrix revealed that drought tolerance indices significantly correlated with GY in non-stressed and stressed conditions and could be separated into four groups. Based on STI, MP, and GMP, G6 and G8 (landraces) were the most drought-tolerant genotypes attaining high GY in both conditions. TOL was able to discriminate G1, G3, and G5 (modern varieties) as well as drought-susceptible genotypes, all of which were suitable for irrigation. Genotypes G7, G9, G10, and G11 (landraces), which had high SSI and lowest STI, MP, GMP, and YSI values, were susceptible to drought and were thus not suitable for cultivation in both conditions. Finally, G2 and G4 (modern varieties), which had an intermediate rank for different indices, were classified as semi-tolerant or sensitive genotypes. Drought tolerance indices and genotype ranks were helpful tools to screen drought-tolerant genotypes with a large adaptation to a range of environments, namely irrigated and rainfed conditions (landraces G6 and G8), or genotypes with the ability to adapt (modern varieties G1, G3, and G5) to irrigated conditions.

In Mediterranean regions, the performance of durum wheat (Triticum turgidum L. var. durum Desf.) yield often varies due to significant genotype × environment interaction (GEI); therefore, yield stability is an important consideration in breeding programs. The aim of this research was to explore the GEI pattern and yield stability of 24 promising durum wheat lines, selected by ICARDA in several African countries (seven elites, four commercial varieties, and 13 durum wheat wide crosses, generated by hybridization of elites and Triticum dicoccoides Koern. ex Schweinf., Triticum araraticum Jakubz, and Aegilops speltoides Tausch) against a Tunisian local check variety ‘Salim’. Yield assessment was conducted across six environments under rainfed conditions, at the field station of Kef in a semi-arid region during four cropping seasons (2014–2015, 2015–2016, 2016–2017, and 2017–2018) and in a sub-humid region at the station of Beja during two cropping seasons (2015–2016 and 2018–2019). The analysis of variance showed that the environment is the main source of variation of grain yield (72.05%), followed by the interaction environments × genotypes (25.33%) and genotypes (2.62%). The genotype × genotype by environment model (PC) based on grain yield identified a mega-environment including Kef (2016–2017 and 2017–2018) and Beja (2015–2016 and 2018–2019) and elite line 22 as a widely adapted genotype. Combined analysis, computed using the average grain yield of lines and the yield stability wide adaptation index (AWAI), showed that elite lines 9 and 23 (2.41 and 2.34 t·ha⁻¹, respectively), and wild relative-derived lines, 5, 1, and 10 (2.37, 2.31, and 2.28 t·ha⁻¹, respectively) were more stable and better yielding than the national reference (2.21 t·ha⁻¹). This finding supports the good yield potential of wild relative-derived lines. The five selections are recommended to be developed in multi-environments in several regions of Tunisia, especially in semi-arid area.

In the literature, little information is available on the effect of Selenium (Se) on durum wheat yield and grain quality performances. A field investigation was conducted to explore the effect of exogenous Se foliar supply on two types of durum wheat germplasm; i.e., 16 advanced lines and nine modern varieties. The Se effect was assessed on grain yield as well as on technological quality traits (moisture, protein and gluten contents, Zeleny sedimentation index, and deformation energy) in two contrasting environments in Tunisia, namely Kef–Boulifa (semi-arid region) and Beja (sub-humid region). The results displayed significant effects of environments, Se foliar application, and cultivars on grain yield and quality attributes. For grain yield performance, the beneficial effect of Se was more pronounced under the Kef–Boulifa environment, and conversely for the grain quality. A genetic variation was observed within and among the two environments under both Se treatments (with and without Se). Notably, the Se-treated advanced lines displayed the highest grain yield under Kef–Boulifa and Beja conditions. Although these cultivars showed better grain quality in both sites, the modern varieties valorized the Se foliar application better. Cultivars that recorded the highest values for the studies attributes were not necessarily those that valorized the Se supply better. Interestingly, some advanced lines have noted superiority compared to the modern varieties. In this study, cultivars that combine both good yield and good grain quality were determined for semi-arid (L11, L1, Dhahbi, and Maali) and sub-humid (L2, L14, L6, L3, Salim, and INRAT 100) zones. The screening results provide genetic material that could be exploited in breeding programs to improve Se use efficiency.

The overuse of chemical pesticides and fertilizers in crop farming has led to a decrease in crop quality and negative impacts on soil and the environment. It is crucial to adopt alternative strategies to maintain soil and environmental quality while enhancing crop growth and yield. To explore this, a study was conducted under greenhouse conditions to investigate the effect of Rhizobium tropici CIAT 899 alone, as well as in association with mycorrhizae (Rhizophagus irregularis) and endophytic fungus (Serendipita indica), on the growth, yield, and nutrient status of snap bean plants. At harvest, the rhizobial strain CIAT 899 demonstrated the highest effectiveness. It significantly increased the number of nodules in both Contender and Garrafal Enana varieties by 6.97% and 14.81%, respectively, compared with the control without inoculation. Furthermore, the results indicated that co-inoculation of Rhizobium and symbiotic fungi had positive effects on nitrogen content, phosphorus availability, and overall plant growth. Regardless of the variety, plants inoculated with R. tropici CIAT 899 and Serendipita indica exhibited the highest values for plant growth parameters. This combination resulted in 168% and 135% increases in root dry biomass, as well as 140% and 225% increases in the number of pods for Contender and Garrafal Enana, respectively, compared with the control at harvest. Additionally, this study highlights the potential benefits of combining R. tropici with either Serendipita indica or Rhizophagus irregularis in terms of nitrogen and phosphorus uptake. These symbiotic microorganisms demonstrated synergistic interactions with snap bean plants, leading to improved mineral nutrition and enhanced growth. Overall, these findings suggest that utilizing these symbiotic microorganisms can effectively enhance the mineral nutrition and growth of snap bean plants.