Showing 2 results for Jafari Haghighi
Hasan Keshavarz, Barmak Jafari Haghighi, Abdolreza Jafari, Hamidreza Miri, Hamidreza Ebrahimi,
Volume 12, Issue 1 (4-2025)
Abstract
Objective: This study was conducted to investigate the effect of seed priming, sulfur application, and a biofertilizer containing Thiobacillus on seed yield and the fatty acid composition of sesame. Due to the importance of sesame as a valuable oilseed crop, evaluating the combined role of nutritional and biological management in improving both quantitative and qualitative traits of the crop holds significant importance.
Method: A field experiment was conducted during the 2023–2024 growing season in Fasa County, Fars Province, Iran, as a factorial arrangement in a randomized complete block design with three replications. Treatments included four seed priming methods (no prime, hydropriming, calcium chloride at 2.5% and 5%), four levels of sulfur application (0, 100, 200, and 300 kg ha-1), and three levels of Thiobacillus inoculation (0, 2, and 4 kg ha-1). Sesame cultivar ‘Darab 2’ was sown at a density of 40 plants m-2. Thousand-seed weight, dry matter and seed yield were measured. Oil quality was evaluated through fatty acid methyl ester analysis using gas chromatography according to ISIRI and AOAC standards.
Results: Seed priming, sulfur application, and Thiobacillus biofertilization significantly affected all the studied traits. Both two-way and three-way interactions were significant at 1% and 5% levels. The highest plant dry weight (23,580 kg ha-1) was observed in the treatment of hydro-priming combined with 300 kg ha-1 sulfur. Additionally, the highest thousand seed weight (5.33 g) and seed yield (2610 kg ha-1) were recorded in the treatment of hydro-priming combined with 300 kg ha-1 sulfur and 4 kg ha-1 Thiobacillus. The highest oil percentage (52.2%) and protein content (25.10%) were obtained in the treatment of 5% calcium chloride priming combined with 300 kg ha-1 sulfur and 4 kg ha-1 Thiobacillus. The fatty acid analysis revealed that integrated treatments increased the content of unsaturated fatty acids (linoleic, oleic, alpha-linolenic) while decreasing saturated fatty acids (palmitic and stearic).
Conclusions: The integrated use of seed priming (especially 5% calcium chloride or hydropriming), high-dose sulfur, and Thiobacillus inoculation significantly improved sesame seed yield, and oil quality. These practices enhanced nutrient uptake, stimulated microbial activity, and promoted biosynthesis of health-beneficial fatty acids.
Highlights
- Seed priming, sulfur application, and Thiobacillus inoculation significantly increased sesame seed yield.
- Combined treatments improved seed oil quality by increasing unsaturated fatty acids and reducing saturated ones.
Shahrzad Ghabeli, Hamidreza Ebrahimi, Hamidreza Miri, Barmak Jafari Haghighi, Abdolreza Jafari,
Volume 12, Issue 2 (10-2025)
Abstract
Objective: The objective of this research was to evaluate the effect of temperature, salinity, and seed priming on germination and to determine cardinal germination temperatures (i.e., base, optimum, and maximum) of Camelina seeds.
Method: Experimental treatments included different levels of seed priming (control, hydropriming, priming with gibberellic acid, and brassinosteroid at 50 ppm), salinity (0, 100, and 200 mM), and different temperatures (5, 10, 15, 20, 25, 30, 35, and 40°C). To estimate cardinal temperatures, three nonlinear regression models (dent-like, segmented, and beta) were fitted, and their accuracy was evaluated using RMSE, CV, R², and SE criteria.
Results: The results showed that Camelina seed germination was significantly affected by the interaction of temperature, salinity, and priming treatments, and none of these factors could be interpreted independently. The highest germination percentage and rate were obtained at 20°C under non-saline conditions, particularly with the application of gibberellic acid and brassinosteroid at 50 ppm; whereas the combination of high temperatures (especially 35°C) and 200 mM salinity caused a severe reduction or complete inhibition of germination. Hormonal priming, in addition to increasing germination percentage, reduced the time to 50% germination, thereby increasing germination rate, decreasing base temperature, and improving the thermal tolerance range. Among the three models evaluated, based on RMSE, CV, R², and SE criteria, the segmented and dent-like models were the most suitable for estimating the cardinal temperatures of Camelina. The results also showed that the most effective priming treatment was priming with brassinosteroid.
Conclusion: The use of priming, especially with brassinosteroid and gibberellic acid, can be recommended as an effective strategy to improve Camelina seed establishment under salinity stress and temperature fluctuations. The use of nonlinear regression models, including dent-like, segmented, and beta models, can be effectively used to quantify the response of Camelina seed germination to temperature, salinity, and seed priming. Therefore, by utilizing the output of these models across different temperatures, it is possible to predict the germination rate under various priming treatments and salinity levels.
Highlights:
- Assessing the combined effects of temperature, salinity, and priming on Camelina seed germination.
- Quantifying the impact of seed priming on cardinal temperatures of Camelina under salinity stress.
- Comparing and selecting the superior nonlinear model (dent-like and segmented) for estimating Camelina cardinal temperatures under salinity stress and priming.
