نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه مهندسی تولید و ژنتیک گیاهی، دانشکده کشاورزی، دانشگاه شهید چمران اهواز، اهواز، ایران
2 بخش تحقیقات اصلاح و تهیه نهال و بذر، مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان خوزستان، سازمان تحقیقات، آموزش و ترویج کشاورزی،
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Introduction: Drought stress is one of the most important factors limiting rice production in dry-seeded cultivation systems, and the application of effective nutritional compounds can play a significant role in enhancing plant tolerance to water deficit. Foliar application of silicon–potassium aminochelate may alleviate drought damage by improving physiological performance and plant water status. Therefore, this study evaluated its effects on physiological traits, and grain yield of rice genotypes under water deficit stress.
Materials and Methods: The experiment was conducted using a split-factorial arrangement based on a randomized complete block design with three replications at the research field of Shavoor Station,, Khuzestan Province, Iran, during the 2025 growing season. The treatments included three irrigation regimes (2, 4, and 6 days) as the main factor, and a factorial combination of three levels of silicon–potassium aminochelate foliar application (0, 2, and 4 L ha⁻¹) and three rice genotypes, namely short-statured Anbarboo, tall -statured Anbarboo, and a promising aerobic rice line, as subplot factors. The measured traits included relative water content, photosynthetic properties such as chlorophyll index, photosynthetic rate, stomatal conductance, transpiration rate, and intracellular CO₂ concent,ration as well as morphological characteristics (plant height and the percentage of unfilled grains), grain yield and yield components (number of grains per panicle and 1000-grain weight), biological yield, and harvest index, which were evaluated at full maturity. To group the studied genotypes and traits, cluster analysis method was used and the respective dendrogram was drawn as a heat map using R-studio ver. 2023 software. Data analysis of variance was conducted using SAS ver. 9.1 software and mean comparisons was performed using Duncan’s multiple range test at 5% probability level.
Results and Discussion: Increasing the irrigation interval from 2 to 6 days reduced stomatal conductance by approximately 50–55%, relative leaf water content by 11%, grain number per panicle by 12%, 1000-grain weight by 15%, grain yield by 12%, and total biological yield by 21%. In contrast, foliar application of silicon–potassium aminochelate, particularly at 4 L ha⁻¹, increased stomatal conductance by 10–35% (depending on genotype and drought severity) and relative leaf water content by 6%. It also increased grain number per panicle by 17%, 1000-grain weight by 8%, grain yield by 13%, and total biological yield by 10% compared with the control. This treatment mitigated the adverse effects of drought by maintaining stomatal conductance, enhancing photosynthetic and transpiration rates, preserving chlorophyll content, and improving plant water status, ultimately leading to improved grain yield across all genotypes. Among the genotypes, the promising aerobic rice line exhibited significantly superior physiological and agronomic performance compared with both other cultivars. Even under severe drought stress, this genotype maintained higher stomatal conductance, photosynthetic rate, transpiration rate, and chlorophyll index, resulting in better preservation of grain yield. Its superior performance is likely attributable to a greater capacity to maintain plant water status, preserve photosynthetic activity, and utilize silicon and potassium more efficiently under drought stress.
Conclusion: Overall, the results of this study demonstrated that foliar application of silicon–potassium aminochelate, particularly at the rate of 4 L ha⁻¹, is an effective approach for mitigating the adverse effects of drought stress, improving physiological traits, maintaining yield components, and increasing rice grain yield under dry-seeded rice cultivation systems. Furthermore, the promising aerobic rice line, due to its greater tolerance to water deficit and more favorable response to foliar application, can be considered a suitable genotype for cultivation under water-limited conditions and for breeding programs aimed at developing drought tolerant rice genotypes.
کلیدواژه‌ها [English]
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