To cope with the rising food demand, modern agriculture practices are based on the indiscriminate use of agrochemicals. Although this strategy leads to a temporary solution, it also severely damages the environment, representing a risk to human health. A sustainable alternative to agrochemicals is the use of plant metabolites and plant-based pesticides, known to have minimal environmental impact compared to synthetic pesticides. Retama raetam is a shrub growing in Algeria’s desert areas, where it is commonly used in traditional medicine because of its antiseptic and antipyretic properties. Furthermore, its allelopathic features can be exploited to effectively control phytopathogens in the agricultural field. In this study, six compounds belonging to isoflavones and flavones subgroups have been isolated from the R. raetam dichloromethane extract and identified using spectroscopic and optical methods as alpinumisoflavone, hydroxyalpinumisoflavone, laburnetin, licoflavone C, retamasin B, and ephedroidin. Their antifungal activity was evaluated against the fungal phytopathogen Stemphylium vesicarium using a growth inhibition bioassay on PDA plates. Interestingly, the flavonoid laburnetin, the most active metabolite, displayed an inhibitory activity comparable to that exerted by the synthetic fungicide pentachloronitrobenzene, in a ten-fold lower concentration. The allelopathic activity of R. raetam metabolites against parasitic weeds was also investigated using two independent parasitic weed bioassays to discover potential activities on either suicidal stimulation or radicle growth inhibition of broomrapes. In this latter bioassay, ephedroidin strongly inhibited the growth of Orobanche cumana radicles and, therefore, can be proposed as a natural herbicide.

Cereal production in arid land can contribute to ensuring food security. However, arid climates pose significant challenges for agriculture. This study presents a novel contribution by specifically evaluating the salinity tolerance of three durum wheat (Triticum durum L.: Vitron, Boussellam, Cirta) and a triticale genotype (x Triticosecale Wittmack.: Elkouahi) from Algeria’s Souf region. Salt stress bioassays during germination tested four NaCl concentrations (0,100, 200 and 400 mmol/L), measuring germination indices, root/shoot length, and seedling weight. Salt tolerance was evaluated and categorized based on the Membership Function Value (MFV), which was calculated using Salt Tolerance Indices (STI). Results classified Vitron as salt-tolerant (MFV = 0.94), triticale and Boussellam as moderately tolerant (MFV = 0.13–0.94), and Cirta as salt-sensitive (MFV = 0.06). Under 200 mmol/L NaCl, germination percentage (R²=0.89) and seedling length (R²=0.96) showed the strongest correlations with MFV, identifying them as key indicators for salt tolerance. This method offers a rapid, practical tool to screen salt-resistant genotypes, crucial for improving cereal yields in saline Saharan soils. The findings highlight the potential of selecting resilient varieties like Vitron and triticale to enhance agricultural productivity in arid climates, addressing food security challenges amid increasing soil salinity. This approach can be expanded to other crops, optimizing their adaptation to harsh environments and supporting sustainable agriculture in Saharan regions.