نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه مهندسی تولید و ژنتیک گیاهی، دانشکده کشاورزی، دانشگاه شهید چمران اهواز، اهواز، ایران
2 دانشگاه شهید چمران اهواز
3 دانشکده کشاورزی، دانشگاه شهید باهنر کرمان، کرمان، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Introduction
In arid and semi-arid regions, drought stress particularly during the reproductive stages and late-season, often accompanied by high temperatures significantly reduces wheat yield. The adoption of early-maturing cultivars with shortened growth cycles, which complete their development prior to the onset of stress, represents an effective strategy to alleviate the detrimental impacts of drought. Assessing the response of these cultivars to irrigation cutt-off during the reproductive phase facilitates the identification and selection of drought-tolerant genotypes.
Materials and methods
To evaluate the response of morphological, phenological, and yield-related traits of bread wheat cultivars and Near-isogenic lines to drought stress induced by irrigation cut-off at different reproductive growth stages, a field experiment was carried out as a split-plot design based on a randomized complete block design with three replications during the 2024–2025 growing season at Shahid Chamran University of Ahvaz. The main plots consisted of three irrigation treatments; full irrigation (control), irrigation cut-off from the beginning of flowering to early dough stage (BBCH 61–83), and irrigation cut-off from early dough stage to full grain maturity (BBCH 83–92), and the sub-plots consisted of five bread wheat cultivars and Near-isogenic lines; Roshan, Mahdavi, Near-isogenic line of Roshan, Near-isogenic line of Mahdavi, and Mehrgan (as control). Phenological traits, including days to heading and days to maturity, and morphological traits, including plant height, peduncle length, and yield components (spike weight, grain number and weight per main spike, and 1000- grain weight), biological yield and harvest index were measured at full maturity.
Research findings
The results of this study indicated that there was a significant difference between cultivars and Near-isogenic lines in terms of most traits. Irrigation cut-off treatments imposed at different growth stages caused a significant reduction in the number and weight of grains per spike, 1000-grain weight, and days to maturity resulting in decreased grain yield for all cultivars and Near-isogenic lines. Higher reductions were obsberved in cultivars compared with their Near-isogenic lines. Under irrigation cut-off applied at the flowering stage, the grain yield of the cultivars and Near-isogenic lines; Roshan, Near-isogenic line of Roshan, Mahdavi, Near-isogenic line of Mahdavi and Mehrgan decreased by 33, 38, 29, 29, and 20%, compared with the full irrigation treatment. The reductions under irrigation cut-off treatment at the grain-filling stage were 12, 15, 15, 15, and 8%, respectively, compared with the full irrigation treatment. Grain yield in Mahdavi cultivar and Near-isogenic line of Mahdavi, as well as in Mehregan, were considerably higher than those of the Roshan and Near-isogenic line of Roshan under all irrigation cut-off treatments. In all irrigation cut-off treatments, the number of days from planting to maturity in Near-isogenic lines of Roshan and Mahdavi was 10 to 15 days fewer than cultivars. The earliness was considered one of the reasons for minimizing the effects of drought stress during the flowering and grain-filling stages, contributing to their higher yield stability. Irrigation cut-off treatments during reproductive growth stages further truncated the reproductive cycle of cultivars and Near-isogenic lines by 3 to 5 days compared with the full irrigation treatment.
Conclusion
Overall, the findings of this study showed that the the near-isogenic lines outperformed their parent cultivars in terms of yield and other agronomic traits. The near-isogenic line of Mahdavi, by employing an earliness strategy and shortening the time for flowering and maturity, achieved the highest grain yield under both full irrigation and cut-off irrigation treatments. Therefore, similar to the Mehregan cultivar, it is recommended for cultivation under mild water stress conditions in the Khuzestan region.
کلیدواژهها [English]
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