Plant Extracts Are a Promising Solution to Alleviate Salinity Stress at the Chili Pepper Germination Stage

Salinity is one of the most pervasive abiotic stressors limiting global agricultural productivity, particularly by impairing seed germination in sensitive species, such as chili peppers (Capsicum spp.). This study rigorously evaluated the potential of nature-derived biostimulants to alleviate salinityinduced germination inhibition in three agronomically important Yemeni chili pepper genotypes: Haimi (H), Hajjah (J), and Jawfi3 (V3). Aqueous extracts from red beetroot, prickly pear fruit, carrot roots, and moringa leaves and flowers were subjected to an optimized 18-hour seed priming protocol. The seeds were germinated at three salinity levels (0, 150, and 250 mM NaCl) in a randomized complete block design. The results revealed a striking mitigation of salinity stress at 150 mM NaCl by all plant extracts, with substantial protective effects observed at the extreme 250 mM NaCl concentration. Notably, beetroot extract emerged as the most potent biostimulant, consistently delivering the highest Extract Stimulation Index (ESI%) across all germination parameters including germination percentage (GrP%), mean germination time (MGT), germination speed (GSC), and radicle length. Its performance was robust across all genotypes and salinity levels, thereby highlighting its broad-spectrum efficacy.These findings provide the first empirical evidence that cost-effective natural extracts, particularly from red beetroot and prickly pear fruit, can match or surpass synthetic priming agents in enhancing seed germination under saline conditions.