Iranian Journal of Seed Research

Salinity is one of the most important factors limiting agricultural production. Cotton, as an oil-fiber plant, is one of the most important industrial plants and is sensitive to salinity, especially at germination and seedling stages. Therefore, in this study, 14 allotetraploid varieties of commercial and local cotton were selected. The study was carried out as factorial with a completely randomized design and three three replications, using the sandwich method. Germination tests were performed at three salinity levels of 0, 8 and 16 ds.m^-1. Afterwards, root and shoot length, fresh and dry weight of root and shoot, germination percentage, allometric coefficient, seedling water percentage and seed vigor index were measured and stress tolerance indices were calculated based on yield (seedling dry weight) in stress and non-stress conditions. Given these indices, all cultivars were aalyzed at two levels of 8 and 16ds.m^-1, using principal component analysis and biplot diagrams were drawn. Finally, the dendrogram classification of genotypes was plotted based on STI indices (stress tolerance index), SSI (stress susceptibility index), and the performance (dry weight plantlet) in stress and non-stress conditions. The result of variance analysis for genotype, salinity and salinity×genotype demonstrated that dry weight root, dry weight shoot, fresh weight root, stem length, vigor index seedling, allometric coefficient, dry weight seedling, and length seedling were significant in p-value 0.01, and fresh weight shoot, length root were significant in p-value 0.05. Clustering and the biplot of the genotypes based on STI and SSI indices at salinity levels of 8 and 16 ds.m^-1 indicated that the Sepid and Giza genotypes were tolerant and that the Kashmar genotype was sensitive to salt levels at germination stage.

Extended abstract
Introduction: Rice (Oryza sativa L.), as one of the world's most important cereals, serves as a staple food for more than one-third of the global population. This strategic crop plays a key role in the economies of many countries. Seed priming is a biotechnological tool and a simple, practical, effective, eco-friendly, and cost-efficient approach to enhancing a plant's tolerance to various environmental stresses and improving seed germination. This study was designed and conducted to investigate the germination and physiological responses of two rice cultivars under varying intensities and durations of electromagnetic field exposures.
Materials and Methods: A factorial experiment in a completely randomized design with the factors of electromagnetic field intensity at 4 levels, time at 3 levels, and two cultivars (Tarom and Hashemi) in three replications was conducted at the Islamic Azad University, Astara Branch in 2023. Rice seeds were treated in a plastic bag under magnetic fields with intensities (0, 50, 100, and 150 mT) and times (10, 50, and 100 minutes). A plastic tray was used for the second experiment and seedling establishment. Healthy seedlings were transferred to plastic pots containing sand. After 25 days, the desired traits were measured.
Results: The analysis of variance results indicated that the effects of the magnetic field, time, cultivar, and their interactions were significant for most traits. The electromagnetic field at 100 mT for 50 minutes led to an increase in germination percentage compared with the control. In contrast, the treatment of 150 mT for 100 minutes caused a significant reduction in all germination-related traits. The highest values were observed under the 100 mT for 50-minute treatment, including germination percentage (98.8%), germination rate (12.5 seeds per day), radicle length (68.1 mm), plumule length (47.5 mm), seedling length (116 mm), radicle dry weight (0.715 mg), plumule dry weight (2.02 mg), seedling dry weight (2.74 mg), seedling length vigor index (11422), seedling weight vigor index (271), chlorophyll-a (0.846 mg g^-1 FW), chlorophyll-b (0.96 mg g^-1 FW), and carotenoids (0.44 mg g^-1 FW).
Conclusion: The electromagnetic field had a significant effect on germination-related traits and physiological characteristics, including germination percentage, germination rate, and chlorophyll content, leading to an increase in these indices. In the present study, the 100 mT treatment for 50 minutes improved seedling vigor in terms of both length and weight. Based on these findings, magnetopriming within the studied treatment range enhances germination and improves rice plant establishment by increasing chlorophyll levels.

Highlights:

1. The effect of the magnetic field on the germination and physiological characteristics of rice seeds was investigated.
2. Seed priming at 100 mT for 50 minutes increased chlorophyll and carotenoid content.