Differences in Seed Germination, Plant Growth, and Proline Content of Some Pepper (Capsicum annuum L.) Genotypes Under Salinity Stress

Salinity is a major abiotic stress that can affect plant growth and development adversely. However, there is bare knowledge about its role in the quality of the seeds obtained from the plants that are grown under salinity. The present study aimed to explore the effect of salinity stress (control (0.7), 3.5, and 7 dS m⁻¹) on the seed germination parameters, 1000-seed weight, plant growth, and proline content of pepper (Capsicum annuum L.) genotypes (Maras, Carliston, and Dolmalik) in the greenhouse in 2018. The results showed that salinity stress significantly affected pepper genotypes, but their response to salinity stress was different. In this respect, the Maras genotype showed the highest proline content, leaf area, and plant biomass and showed tolerance to salinity stress relative to the other genotypes. Concerning seed germination rates, Carliston and Dolmalik experienced severe reductions of 60 and 68%, respectively, under 7 dS m⁻¹ salinity level compared to the control, while the Maras genotype showed a mild drop of 27%. At a higher salinity level of 7 dS m⁻¹, there was a negative impact on 1000-seed weight, resulting in reductions of 20.73%, 36.12%, and 34.39% in Maras, Carliston, and Dolmalik, respectively. Importantly, the study findings underscored that salinity stress had a less severe adverse effect on the seed germination parameters and 1000-seed weight of the Maras genotype compared to the other genotypes, signifying its heightened tolerance to salinity. Furthermore, the present findings revealed that a reduction in both plant growth and biomass during the vegetative growth phase exerts adverse effects on seed weight and seed germination parameters. Moreover, the research identified the Maras as a salinity-tolerant genotype, which makes it a potential candidate for breeding programs.