Document Type : Research Paper
Authors
1
Cotton Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Gorgan, Iran
2
موسسه تحقیقات پنبه کشور، سازمان تحقیقات، آموزش و ترویج کشاورزی، گرگان، ایران.
3
Cotton Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Gorgan, Iran,
4
Cotton Research institute, Agricultural research education and extention organization (Areeo)
10.22092/ijcr.2025.369104.1236
Abstract
Abstract
Background and Objectives
Understanding the water requirements and physiological responses of cotton genotypes under varying irrigation regimes is critical for improving water use efficiency and enhancing drought tolerance in cotton production systems. As climate change intensifies and water resources become increasingly limited, optimizing irrigation strategies and selecting drought-resilient cultivars have become essential for sustainable agriculture. This study aimed to evaluate the physiological and biochemical responses of different cotton genotypes under varying levels of irrigation and to determine the impact of these responses on yield and yield components. By identifying traits associated with drought resilience, including carbohydrate retention, biomass stability, and efficient water utilization, the research supports the development of cultivars suited for arid and semi-arid regions facing increasing water scarcity.
Materials and Methods
A field experiment was conducted over two consecutive cropping seasons in Golestan Province, using a strip-split plot arrangement within a randomized complete block design with three replications. The main plots were assigned to three irrigation regimes (100%, 75%, and 50% of crop water requirement), while sub-plots contained seven cotton genotypes: SkSH249, N2G80, GkTb113, SKT133, Bc244, NSK847, and the commercial cultivar Golestan, which served as the control. Physiological traits assessed included leaf area, leaf dry weight, biomass accumulation, and biochemical parameters such as carbohydrate and starch content. Yield components, including first-pick yield and total yield, were also recorded.
Results
The results showed that irrigation levels had a significant effect on all measured traits. Full irrigation (100%) resulted in the highest values for physiological traits and yield parameters across both seasons. In contrast, water deficit conditions (75% and 50% irrigation) led to substantial reductions in leaf area, dry weight, carbohydrate and starch content, and overall yield. The average carbohydrate content under drought stress dropped to 23.38 mg/g fresh weight, with starch content also declining significantly. Among the genotypes, the Golestan cultivar exhibited the lowest starch content (10.35 mg/g fresh weight) under water-limited conditions but still achieved the highest first-pick yield (1,104.8 kg/ha), demonstrating strong adaptation and yield stability across environments.
Conclusion
The study concludes that water availability strongly influences physiological and biochemical traits in cotton, with notable impacts on yield performance. While full irrigation optimized both plant growth and productivity, certain genotypes, particularly Golestan, maintained relatively high yield under reduced irrigation, indicating inherent drought tolerance mechanisms. These findings highlight the potential of the Golestan cultivar as a resilient option for cotton farming in regions with limited water resources and underline the importance of integrating physiological trait assessment into breeding programs for drought-prone environments.
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