Modified Drum-Priming and Biochemical Agents for Enhancing Germination and Seedling Growth of Hot Pepper Under Salinity Stress

Salinity is a critical environmental stressor that inhibits seed germination and seedling growth globally. This study aimed to determine the optimal priming conditions for hot pepper (Capsicum annuum L.) seeds to alleviate salt stress-induced germination and growth reductions. Priming treatments included hydro-priming, chemical-priming (24-epibrassinolide (EBL), sodium nitroprusside (SNP), and polyamines), halo-priming (KNO3), and modified drum-priming. Following treatment, germination characteristics, total polyphenol content (TPC), ABTS+ radical scavenging activity, and seedling growth traits were evaluated under 100 mM NaCl stress. Optimal conditions were identified as hydro-priming (50 h), chemical-priming (10−6 M EBL, 10−4 M SNP, 50 mM putrescine), halo-priming (300 mM KNO3), and drum-priming (20 h hydration and 60 h incubation). Although NaCl treatment significantly reduced all germination traits, priming effectively mitigated these declines. A modified drum-priming method resulted in the shortest mean germination time (MGT) of 4.0 days, the highest germination rate (GR) of 25.2%·day−1, and a 94% healthy seedling percentage (HSP), whereas the results for the untreated control were recorded as 6.6 days, 15.2%·day−1, and 66%, respectively, under stress conditions. EBL and drum-priming showed the highest TPC and ABTS+ radical scavenging activity. Furthermore, priming prevented salt-induced reductions in seedling growth. EBL and drum-priming treatments resulted in the highest vitality index (VI). These results indicate that drum-priming and EBL priming are highly effective strategies for enhancing salt tolerance and ensuring uniform stand establishment in pepper seeds.