Document Type : Research Paper

Authors

• Sulmaz Samfar ¹
• Hojatollah Latifmanesh ²
• ali Moradi ³
• Hamid Alahdadi ⁴
• Amin Mirshekari ⁵

¹ M.Sc. Student of Agrotechnology-Crop Physiology, Department of Agronomy and Plant Breeding, Faculty of Agriculture, Yasouj University

² Assistant Professor/Yasouj University

³ Agromomy Dep. Agriculture Faculty, Yasouj university

⁴ M.Sc. Graduate of Agrotechnology-Crop Physiology, Department of Agronomy and Plant Breeding, Faculty of Agriculture, Yasouj University

⁵ Assistant Professor, Department of Agronomy and Plant Breeding, Faculty of Agriculture, Yasouj University

Abstract

Introduction: Beans (Phaseolus vulgaris L.) are among the most valuable and strategic legumes, both in Iran and globally, primarily due to their high protein content and nutritional benefits. In recent years, the growing global demand for protein-rich foods has further underscored the importance of bean cultivation. However, the economic consequences of the water shortage crisis present significant challenges to food production and security worldwide. This issue is particularly critical in Iran, where the geographical landscape is situated along the global desert belt, resulting in limited rainfall—less than one-third of the worldwide average. As water scarcity intensifies, it becomes essential to explore sustainable agricultural practices that can enhance crop resilience and yield. Brassinosteroids, a group of plant growth regulators, have emerged as a promising solution. These compounds positively influence the physiological activities of crops, improving their growth characteristics and enabling better responses to environmental stresses, such as drought. Moreover, research has shown that brassinosteroids can directly correlate with increased plant yield, making them a valuable tool for farmers. This study aims to evaluate the effects of foliar application of brassinolide hormone under low irrigation conditions on various physiological characteristics and grain yield of pinto beans. By examining these relationships, we hope to provide insights that could lead to more sustainable bean production practices in arid regions.

Materials and methods: This study aimed to examine certain physiological parameters and the potential for increasing seed yield in common beans through the application of 24-epibrassinolide under low irrigation stress conditions. The experiment was conducted using a split-plot design within a randomized complete block design with three replications, in a farm located in eastern Shiraz during the 2022 growing season. The irrigation regime was applied at three levels: full irrigation (100% of the moisture requirement) and low irrigation stress at 80% and 60% of the moisture requirement, as the main factor. Four concentrations of 24-epibrassinolide, including control (distilled water), 0.05, 0.1, and 0.2 mg per liter, were applied as the subplot factor.

Results and Discussion: The results revealed that both low irrigation stress and the application of 24-epibrassinolide had significant effects on all traits examined. Applying 24-epibrassinolide at a concentration of 0.2 mg per liter led to increases in the chlorophyll index and relative water content of the leaves by 7.42% and 11.77%, respectively, compared to the control treatment (without the hormone). Significant interactions between the irrigation regime and hormone application were observed, where at the 60% and 80% moisture requirement levels, the application of 0.2 mg per liter of 24-epibrassinolide increased the activity of antioxidant enzymes, such as catalase, peroxidase, and superoxide dismutase by 172%, 105%, and 0.35% and by 131%, 115%, and 0.45%, respectively, compared to the control. Similarly, the highest concentration of the hormone at 100%, 80%, and 60% of the water requirement resulted in increases in seed yield by 72.38%, 56.02%, and 44.35%, respectively, compared to the control.

Conclusion: Based on the findings of this study, the application of 24-epibrassinolide at a concentration of 0.2 mg per liter is recommended as an effective strategy to reduce reactive oxygen species, prevent cell wall damage, and minimize macromolecule degradation. This approach ultimately leads to improved seed yield in beans, even under varying irrigation conditions, including both full and low irrigation scenarios (60% and 80% of the plants' water requirements). By mitigating the adverse effects of water stress, this treatment offers a promising solution for enhancing bean production in water-scarce environment

Keywords

• 24-epibrassinolide
• Antioxidant enzymes
• Beans
• Grain Yield

Main Subjects

• A: Crops Physiology