Document Type : Research Paper - Crops Physiology
Authors
1 Former Msc. Student, Department of Plant Production and Genetics, Shahid Chamran University of Ahvaz, Ahvaz, Iran
2 Associate professor. Department of Plant Production and Genetics, Shahid Chamran University of Ahvaz, Ahvaz, Iran
3 Associate Professor, Department of Agronomy and Plant Breeding, College of Agriculture, Shahid Chamran University of Ahvaz, Iran
Abstract
Introduction
Oilseed plants hold a significant position among crops by providing the energy and calories required by humans and animals. Sesame (Sesamum indicum L.), a member of the Pedaliaceae family, stands as one of the oldest cultivated oil plants globally, particularly thriving in tropical and semi-tropical regions. Sesame seeds boast the highest oil content among oil plants, holding special significance due to their diverse applications in food, medicine, and industry. Effective irrigation management is indispensable for summer crops in most regions of Iran, especially during summer. The susceptibility of crops to water scarcity varies across different phenological stages.
Materials and Methods
This research aimed to investigate the impact of irrigation cut-off at various phenological stages on some growth and yield traits of indehiscent sesame cultivars. The study was conducted using a split-plot arrangement based on a randomized complete block design with four replications during the 2021-2022 cropping season in the southern regions of Khuzestan province. The primary factor consisted of three levels of irrigation limitations: irrigation cut-off from the middle to the end of the flowering stage, irrigation cut-off from the end of the flowering stage to physiological maturity, irrigation cut-off from physiological maturity to full maturity, and a control without any irrigation cut-off. The secondary factor involved three new commercial cultivars of indehiscent sesame: Mohajer, Barekat, and Chamran.
Results and Discussion
In the treatment where irrigation was cut off from physiological maturity until full maturity, the Barekat cultivar exhibited the tallest plant height at 87 cm and the highest number of capsules per plant at 58. Conversely, the Chamran cultivar showed the lowest number of capsules per plant at 27 when irrigation was cut off from the end of the flowering stage until physiological maturity. The average seed weight per capsule ranged from 0.12g in the treatment with irrigation cut-off from the middle to the end of the flowering stage to 0.30g in the control treatment. Remarkably, the maximum grain yield of 1362 Kg.ha-1 was achieved in the Chamran cultivar with irrigation cut-off from physiological maturity until full maturity, while the Barekat cultivar yielded the lowest at 510 Kg.ha-1 with irrigation cut-off from the end of the flowering stage until physiological maturity. Furthermore, the highest harvest index (HI) of 28% was recorded in the Chamran cultivar with irrigation cut-off from the end of flowering to physiological maturity, while the lowest HI of 10% was observed in the Barekat cultivar with irrigation cut-off from the end of flowering to physiological maturity. The highest percentage of sesame seed oil was also obtained in the Chamran cultivar of the control treatment (53%).
Conclusion
The findings suggest that under water-limited conditions, irrigation management through cut-off at specific phenological stages of sesame may not lead to a significant reduction in seed yield. This implies that strategic irrigation practices can be implemented to optimize water usage without compromising yield potential. Given the climatic conditions of the southern regions of Khuzestan province, it is recommended to consider cultivating the indehiscent Chamran cultivar. This cultivar has shown promising results in terms of growth, yield traits, and oil content under the specified irrigation conditions, making it a suitable choice for cultivation in this region.
Keywords: Number of capsules, Number of seeds, Oil percent, Resistance to seed shuttering
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