https://ijfcs.ut.ac.ir/ Iranian Journal of Field Crop Science en daily 1 Sat, 21 Mar 2026 00:00:00 +0330 Sat, 21 Mar 2026 00:00:00 +0330 https://ijfcs.ut.ac.ir/article_105733.html Introduction. Climate change and its impact on agriculture has become a very important issue worldwide. Climate change is generally associated with global warming, which is caused by the obvious increase in greenhouse gas emissions. The effects of climate change can be harmful or beneficial for agriculture, depending mainly on the region and the type of crop. The impact of climate change on crop production has been studied using global circulation models (GCM) along with crop growth simulation models under different scenarios in different parts of the world. The studies of crop yields in recent years show an increasing trend due to advances in technology (such as new varieties and agricultural management methods, etc.). An analysis of the 50-year trend of wheat production in Iran also shows that the increase in wheat production in the country, especially in recent years, was not due to an increase in the cultivated area, but mainly due to an increase in yield per unit area, which is due to technological development in production. Therefore, to accurately estimate future yield changes, it is necessary to consider technological development as an influential factor in addition to changes in climate variables and CO2 effects. Materials and Methods. In the study, the Coupled Model Intercomparison Project Phase 6 (CMIP6) was used to investigate the future climate situation using two scenarios (SSP585 and SSP245). To simulate wheat growth, the DSSAT-Nwheat model in DSSAT software, which effectively simulates crop growth, development, and yield, was utilized. In order to parameterize and validate the model, data from field experiments conducted for the compatibility of promising wheat genotypes and lines at the country's grain research stations in the main wheat production regions of the country were used. In each region, data from two years 2019 and 2020 were used to parameterize the model, and data from two years 2021 and 2023 were used to evaluate the model. To evaluate the model, the normalized root mean square error (NRMSE) and the model efficiency (EF) criterion were used. Comparison of the fitted linear regression between the simulated (y) and observed (x) data with the 1:1 line was also used to evaluate the model. To quantify the impact of technological advancements on future wheat yields, the method developed by Ewert et al. (2005) was utilized. To calculate the impact of CO2 on wheat yield, the future CO2 concentration was first estimated, and then the increase in yield per unit increase in CO2 was evaluated. Finally, the combined effects of influencing factors (climate change, CO2, and technological development) on wheat yield in future conditions were estimated. Results and Discussion. The results of the climate model evaluation showed that the climate data have acceptable accuracy for simulating climate variables, due to the low values of the NRMSE index. The crop growth model has an acceptable estimate for simulating traits in wheat plants based on the NRMSE and ME statistical indices. Simulation of the effect of technological development on wheat yield in future conditions in different scenarios showed that in all different regions of the country, the effect of technology was positive compared to the baseline years, and the extent of this effect varied from 1% to 27%, depending on the region, scenario, and time period. The results showed that an increase in carbon dioxide will lead to an increase in wheat production in the future, such that the increase in production due to an increase in CO2 varied from 2.6 to 27.8% compared to the baseline years, depending on the year and scenario. Simulation of the effect of climate change on wheat production in different regions of the country showed that climate change caused a decrease in wheat production compared to the baseline years in both scenarios and in all time periods, the extent of this decrease varies by scenario, region, and time, ranging from 3% to 86%. In general, the combined effects had the least impact in the first time period and the greatest impact in the third time period on wheat yield in different regions. During the second period (2051-2075), the overall impact of various factors resulted in a decrease in wheat yield across most regions compared to the base year. However, in some regions, such as Ardabil, Ilam, Tehran, Zanjan, Sari, Shahr-e-Kord, Karaj, and Hamedan did not experience a decline in yield under the SSP245 scenario. In the third period (2076-2100), the combined effects showed a negative and decreasing effect on wheat yield compared to the base year in all regions of the country. The highest negative effect was observed in the Ahvaz region in the SSP245 scenario with a 57% decrease in production compared to the baseline years and the lowest negative effect was observed in the Ardabil region in the SSP585 scenario with an 8% decrease in production compared to the baseline years. Conclusion. It seems that the development of technology and carbon dioxide in the first and second time periods has the potential to offset the negative effects of climate change, especially in cold regions of the country, and even in the first time period it has led to an increase in wheat production compared to the base year. However, with the passage of time and in the third time period, the negative effects of climate change have intensified and prevailed over the positive effects of technology and carbon dioxide, leading to a decrease in wheat production, especially in tropical and arid regions. https://ijfcs.ut.ac.ir/article_105734.html Introduction. The increasing salinity of soils and water resources in various regions of Iran, particularly in the central and southern parts of Khorasan Razavi Province, has restricted agricultural expansion and reduced the economic performance of crops. Quinoa (Chenopodium quinoa Willd.), a pseudo-cereal with remarkable salt tolerance, has recently attracted considerable attention in breeding and crop development programs due to its high protein content, essential amino acids, and exceptional nutritional value. Previous studies have demonstrated that salinity stress can significantly reduce water and nutrient uptake, photosynthetic efficiency, chlorophyll synthesis, and grain yield. Therefore, identifying physiological compounds that enhance stress resistance, such as melatonin and crucial micronutrients like zinc, can offer effective strategies for improving plant responses under salinity stress conditions. Melatonin, beyond its regulatory function in plant growth under normal conditions, plays a critical role in activating plant defense systems and scavenging reactive oxygen species (ROS). This compound mitigates oxidative damage and improves photosynthetic efficiency in plants exposed to salinity stress. On the other hand, zinc is one of the most important micronutrients involved in over 300 enzymatic processes, playing a vital role in stabilizing chlorophyll structure, promoting protein synthesis, and reducing the uptake of Na⁺ and Cl⁻ ions. Hence, the simultaneous use of melatonin and zinc sulfate could physiologically and biochemically alleviate the adverse effects of salinity stress and ultimately enhance crop performance.  Materials and Methods. Given the growing need to expand crop cultivation in saline lands, the present study was conducted to evaluate the effects of seed priming and foliar application of melatonin and zinc sulfate on agronomic, physiological, and yield traits of two quinoa (Chenopodium quinoa Willd.) cultivars under contrasting ecological conditions (saline and non-saline). The experiment was carried out during the 2023–2024 cropping season in two locations—Kashmar (non-saline) and Bardaskan (saline)—as a factorial arrangement based on a randomized complete block design (RCBD) with three replications. Experimental treatments consisted of two quinoa cultivars (Red Carina and Titicaca), three levels of seed priming (control, 100 µM melatonin, and 40 mM zinc sulfate), and three levels of foliar application (control, 0.2 mM melatonin, and 0.5% zinc sulfate). Seed priming was performed by soaking the seeds in the respective solutions for six hours, while foliar spraying was applied at the beginning of the flowering stage under favorable environmental conditions. Soil and water analyses revealed that Bardaskan had a considerably higher electrical conductivity (EC ≈ 16,880 µS cm⁻¹) compared with Kashmar (EC ≈ 538 µS cm⁻¹), confirming the saline nature of the former site. Following the application of treatments, various traits were measured, including final field emergence percentage, stem height, panicle length, collar diameter, shoot dry weight, forage index (percentage of digestible dry matter), concentrations of chlorophyll a and b, protein yield, and grain yield. Data were analyzed using SAS statistical software. Bartlett’s test was applied to examine error homogeneity, and based on its significance, either separate or combined analyses of variance were performed accordingly. Results and Discussion. The results revealed that in the Bardaskan region, salinity stress caused a significant reduction in seed protein yield in the Red Carina cultivar (by approximately 30.02%) and in the Titicaca cultivar (by about 35.39%) compared with the same cultivars grown in the Kashmar non-saline area. Furthermore, grain yield of the Titicaca cultivar was 23.25% higher in Bardaskan and 25.81% higher in Kashmar than that of Red Carina, indicating the relatively greater salt tolerance of Titicaca. In the non-saline condition (Kashmar), combined seed priming and foliar spraying with melatonin increased grain yield by 17.85%, and zinc sulfate by 18.04%. Under saline conditions (Bardaskan), simultaneous application of melatonin and zinc sulfate resulted in even greater yield improvements of 36.91% and 35.70%, respectively. These findings demonstrate that the regulatory role of melatonin and zinc is strengthened under salt stress conditions, and their synergistic effects are more pronounced compared with non-stress environments. Evaluation of physiological traits showed that salt resistance in melatonin and zinc treatments was associated with increased concentrations of chlorophyll a and b, higher stem height, and an improved forage index. Analysis of variance (ANOVA) indicated that all main factors (cultivar, seed priming, and foliar application), as well as their two-way and three-way interactions, had significant effects (p < 0.01) on most measured traits. In saline conditions, the greatest responses were observed for shoot dry weight and chlorophyll content, which were directly related to enhanced photosynthetic activity and accumulation of energetic compounds. Protein determination using the Kjeldahl method indicated that quinoa plants under saline stress could maintain acceptable seed protein levels when micronutrients were supplied, highlighting the nutritional and economic importance of these treatments. According to the results, combined seed priming and foliar application of melatonin and zinc sulfate were more effective in the Titicaca cultivar than in Red Carina. This superiority is likely attributed to the genetic characteristics of Titicaca, including a shorter growth cycle and better adaptation to ionic and osmotic stresses. The primary mechanism of action for these compounds involves activation of the antioxidative defense system, maintenance of ionic balance, enhancement of chlorophyll efficiency, and mitigation of oxidative cellular damage. Conclusion. From an agronomic perspective, this study confirmed that the simultaneous application of melatonin and zinc sulfate not only improves plant growth and yield attributes but also enhances physiological stability under saline conditions. Thus, this integrated approach can be regarded as a cost-effective biotechnological strategy for improving the productivity of saline and semi-saline lands in Iran. In conclusion, the combined use of two bio-regulatory compounds—melatonin and zinc—exhibited synergistic effects in improving salinity tolerance, resulting in significant increases in grain yield and protein yield. The Titicaca cultivar showed overall better responses compared with Red Carina across both experimental sites, with the highest mean yield obtained under concurrent seed priming and foliar application of these two compounds. Accordingly, within the scope of this study, cultivation of the Titicaca cultivar together with simultaneous melatonin and zinc sulfate application is recommended as an effective salinity management strategy to enhance grain yield and protein productivity in quinoa. https://ijfcs.ut.ac.ir/article_105731.html The use of bio-stimulants to create eco-friendly products in conjunction with contemporary agriculture, particularly the foliar application of seaweed extract, can be successful in raising crop yields both quantitatively and qualitatively under stressful environmental conditions. On the other hand, removing or reducing the application of chemical inputs and substituting them with bio-fertilizers and growth stimulants such as seaweed extract can be considered as an important step towards achieving sustainable agriculture goals. The present research was conducted to investigate the effects of foliar application of the seaweed extract on seed and oil yields and seed yield components of rapeseed genotypes in the marginal areas around Urmia Lake. The research was done in the Khosro Shah station of East Azerbaijan Agricultural and Natural Resources Research and Education Center (46º 2´E, 37º 56´N) during the 2023-2024 cropping season. The mentioned research station is located in marginal areas east of the Urmia lacke. The experiment was done as a split-plot based on a randomized complete block design with three replications. The experimental factors included the foliar application of seaweed extract (seaumic acid) at two levels (control and seaumic acid with 5 g L-1 concentration) as the main factor and 40 rapeseed genotypes as the sub-factor. The seaweed extract solution was made with distilled water and stirred until the extract was fully dissolved in the water in 25ºC. The Institute for Research on Breeding and Seed Preparation of the Ministry of Agricultural Jihad selected genotypes, were used in current study from preliminary tests of adaptation to the nation's cold climates. These genotypes have economically acceptable adaptation and seed and oil yields for cultivation in the marginal areas of cold climates. There were four rows in each subplot, separated by 30 centimeters (cm). It was determined that each row was five meters long. Seven cm was the set spacing between each plant on the row. The planting time was 11th Sept. 2023. Seaweed extract was applied topically to rapeseed plants during their shoot elongation (main inflorescence elongation in 20% of the plants) and flowering (when 20% of flowers appeared) stages. The results of the study showed that the foliar application of seaweed extract during stem elongation and flowering stages, increased the number of sub-branches (about 2%), chlorophyll index (about 36%), number of the pods per plant (about 12%), 1000-seeds weight (about 13%), harvest index (about 10%), and seed and oil yields (about 21% and 8% respectively). Genotype HL3721×Rohan had the highest amounts of pods per plant (131.4), seeds per pod (27.6), and seed and oil yields of 3657 and 1683 Kg ha-1, respectively. HL2012×GK Csenge (737 Kg ha-1) and ES Kamilo×SW102 (859 Kg ha-1) genotypes indicated lower seed yields compared to others. The results of principal components analysis among the studied traits showed significant correlation between seed and oil yields. In the study of parameters influencing seed and oil yields, the number of pods per plant, revealed positive and significant correlations with plant height, stem diameter, number of the branches per plant, plant biomass, harvest index and seed and oil yields. It seems that the effect of the number of pods per plant on seed and oil yields, was more than other yield components. Among the studied traits, chlorophyll index, 1000-seeds weight, and pod area showed positive correlations with seed yield. Therefore, the role of the mentioned traits in the formation of seed yield was more important. By cluster analysis with Ward's method, after HL3721×Rohan, eighteen genotypes with an average seed yield of 2311 Kg ha-1 were placed in same group. These genotypes can be cultivated as promising genotypes in the marginal areas around Urmia Lake. The use of plant growth promoters such as seaweed extract as bio-fertilizers has been increasingly proposed as a way to reduce the use of chemical fertilizers in agricultural systems. This can be considered in the production process of rapeseed plants under different conditions, based on different aspects of production. Seaweed organic fertilizer has had a positive effect on the growth and yield of rapeseed genotypes due to its growth stimulants and nutrient. It is concluded that the use of the above-mentioned organic fertilizer can play an acceptable role in achieving economic yields in rapeseed production, especially in difficult environmental conditions and marginal areas. https://ijfcs.ut.ac.ir/article_105737.html Introduction. Rice (Oryza sativa L.) is one of the world’s most important cereal crops, serving as a staple food for billions of people and providing a primary source of income for many agricultural communities. It is cultivated in over 100 countries, with Asia accounting for the majority of production and consumption. Rice contributes substantially to daily caloric and protein intake, supplying approximately 60% of daily caloric intake and nearly 50% of dietary protein in many regions (FAO, 2018). With the increasing global population, rising food demand, and climate variability, developing high-yielding, high-quality, and environmentally adaptable rice varieties has become essential for global food security and sustainable agriculture. Grain yield is a complex polygenic trait influenced by multiple morphological, physiological, and quality characteristics, which complicates direct selection in breeding programs (Debsharma et al., 2020; Nath, 2015). Understanding the relationships among yield and related traits is therefore critical for effective breeding. The exploration of genetic and phenotypic diversity within rice germplasm provides opportunities to identify superior genotypes and develop improved varieties, providing valuable resources for breeding programs (Thomson et al., 2007). Evaluating this variability using biometric parameters such as genetic and phenotypic variation, heritability, and expected genetic advance allows breeders to select traits with the greatest potential impact on yield and performance (Begna & Teressa, 2024). Multivariate statistical analyses, including principal component and cluster analyses, are effective tools for quantifying genetic diversity, revealing hidden patterns among traits, and guiding the selection of superior genotypes (Sharifi, 2018). These methods reduce data dimensionality, clarify complex trait interactions, and help prioritize traits for breeding programs, enabling more efficient improvement of rice varieties. In this context, the present study aimed to evaluate a population of rice genotypes in terms of agronomic and yield-related traits using multivariate statistical methods, with the goal of identifying genotypes possessing optimal combinations of traits for use in future breeding programs. Materials and Methods. A total of 144 backcross inbred lines (BILs, BC2F4) derived from a cross between Hashemi (recurrent parent, with superior cooking quality) and IR67418-110-32222 (donor parent, contributing desirable agronomic traits) were evaluated. The study aimed to combine the high-quality traits of Hashemi with improved morphological and yield-related characteristics from the donor parent. The experiment was conducted under field conditions in a randomized complete block design with three replications. Seedlings were transplanted at a spacing of 20 × 20 cm, and standard agronomic practices, including fertilization, irrigation, and pest and weed management, were applied. Ten quantitative traits were measured following the Standard Evaluation System (SES) for rice (IRRI, 2002): Grain yield, panicles per plant, spikelets per panicle, filled grains per panicle, 1,000-grain weight, plant height, panicle length, flag leaf area, days to 50% flowering, and days to maturity. Data were analyzed using SAS 9 (SAS Institute, 2002) for analysis of variance and mean comparisons, SPSS 24 (IBM SPSS Statistics, 2016) for correlation, factor, and cluster analyses, and Python 3.13 (Python Software Foundation, 2025) for heatmap visualization of trait associations. Superior and diverse genotypes were identified for potential use in future breeding programs. Results and Discussion. Descriptive statistics revealed wide variation among the BIL genotypes for all evaluated traits, including plant height, panicle length, panicles per plant, spikelets per panicle, flag leaf area, 1,000-grain weight, filled grains per panicle, and grain yield. The broad ranges observed for flowering and maturity times indicated the presence of early-, medium-, and late-duration genotypes within the population. Frequency distributions for most agronomic and yield-related traits were continuous and near-normal, suggesting polygenic inheritance and sufficient quantitative variation for effective selection. Analysis of variance showed significant differences among genotypes for all traits. Combined with the high heritability estimates, this indicated that much of the observed variation was genetically controlled. Correlation analysis revealed significant positive associations between grain yield and traits such as panicles per plant, flag leaf area, spikelets per panicle, filled grains per panicle, and panicle length, highlighting their value as indirect selection criteria. In contrast, the correlations between flowering traits and grain yield were small and non-significant, likely due to environmental conditions during the late growth stages and the stronger contribution of yield-component traits to final productivity. Factor analysis extracted four major components explaining 76.97% of the total variation, corresponding to growth and phenology, reproductive capacity, yield-defining traits, and grain physical characteristics. Cluster analysis grouped the genotypes into two groups: Group I contained high-yielding lines with superior values for major yield components, whereas Group II, which included the recurrent parent Hashemi, exhibited lower performance for yield-related traits. The cophenetic correlation coefficient of 0.88 confirmed the robustness of the clustering pattern. Overall, the results indicated that grain yield in the BIL population is governed by multiple interacting traits, and traits such as panicle length, filled grains per panicle, and flag leaf area are key indicators for identifying superior lines for breeding programs. Conclusion. The findings of this study demonstrated that the backcross-derived inbred population developed from Hashemi and IR67418-110-32222 provides a valuable genetic resource for improving both grain yield and quality in rice. Multivariate analyses confirmed that grain yield resulted from the combined influence of multiple morphological and reproductive traits rather than any single attribute, underscoring the need for multi-trait selection strategies. The clear genetic variation revealed through variance analysis, factor structure, and clustering further indicated the presence of distinct groups of superior genotypes that can serve as promising parents in future breeding programs. Overall, the study highlighted the importance of integrating morphological traits, yield components, and grain characteristics when selecting elite genotypes. These results provided practical guidance for breeders aiming to develop high-performing and high-quality rice cultivars adapted to diverse environments and support the continued use of multivariate approaches to accelerate breeding efficiency. https://ijfcs.ut.ac.ir/article_105736.html Introduction. Drought stress is a critical abiotic factor limiting crop productivity, particularly in arid and semi-arid regions. Gamma-aminobutyric acid (GABA), a non-proteinogenic amino acid, plays a pivotal role in modulating stress responses by enhancing osmoprotection, regulating stomatal conductance, and mitigating oxidative damage. Despite its known protective functions, the potential of exogenous GABA application in improving drought tolerance in camelina (Camelina sativa), an emerging oilseed crop with promising agronomic attributes, remains insufficiently explored. This study aimed to elucidate the physiological and biochemical responses of camelina to foliar-applied GABA under varying drought stress conditions, with a focus on its effects on growth, photosynthetic pigments, antioxidant enzyme activities, and yield components. Materials and Methods. A field experiment was conducted during the 2023–2024 growing season at the research farm of the Faculty of Agriculture, University of Maragheh, East Azerbaijan province, Iran. The study was employed a split-plot experimental design based on a randomized complete block design (RCBD) with three replications. The main factor comprised three irrigation regimes based on soil moisture depletion levels (25%, 50%, and 75% of maximum allowable depletion), while the sub-factor included five concentrations of foliar-applied GABA (0, 0.5, 1, 2, and 4 mM). Morphophysiological traits (plant height, biomass accumulation, chlorophyll content), biochemical responses (antioxidant enzyme activities, hydrogen peroxide accumulation), and agronomic characteristics (seed yield, oil content, and oil yield) were evaluated. Data were subjected to analysis of variance (ANOVA) using SAS software, and mean comparisons were performed using the LSD test at a significance level of p<0.01. Results and Discussion. The findings revealed that drought stress significantly reduced camelina growth, photosynthetic pigment content, and yield attributes. However, foliar application of GABA substantially alleviated the adverse effects of water deficit by enhancing physiological and biochemical responses. The highest plant height (62.2% greater than severe drought without GABA) was observed under optimal irrigation with 4 mM GABA. Similarly, seed and oil yield reached their maximum in the same treatment, exhibiting respective increases of 120.87% and 241.4% compared to the severe drought control. Drought stress markedly reduced chlorophyll a, chlorophyll b, and carotenoid contents, but exogenous GABA application significantly improved amount of these pigments. Under non-stressed conditions, foliar-applied GABA at 4 mM enhanced chlorophyll a, chlorophyll b, and carotenoid contents by 137.1%, 131.6%, and 76.4%, respectively, compared to severe drought without GABA. Additionally, GABA application activated key antioxidant enzymes, including ascorbate peroxidase (260.4% increase), peroxidase (190.8% increase), and superoxide dismutase (201.1% increase) under moderate drought stress at 4 mM GABA. Concomitantly, hydrogen peroxide accumulation was reduced by 76.4%, indicating lower oxidative stress levels. These results suggest that GABA-mediated drought tolerance is primarily associated with enhanced antioxidant defense mechanisms and improved photosynthetic efficiency, contributing to higher productivity under water-limited conditions. Conclusion. This study provides compelling evidence for the efficacy of foliar-applied GABA in mitigating drought-induced damage in camelina. The application of 4 mM GABA proved the most effective in enhancing physiological and biochemical responses, leading to substantial improvements in seed yield and oil productivity under drought stress. Given its role in modulating stress tolerance, GABA can be integrated into sustainable agronomic practices to enhance crop resilience in water-limited environments. Future research should explore the molecular mechanisms underlying GABA-mediated drought tolerance and assess its practical applicability across diverse agroecological conditions.  https://ijfcs.ut.ac.ir/article_105728.html This experiment aimed to forecast the yield of various rain fed wheat cultivars under climate change in Khorramabad Province using the APSIM-Wheat sub model.To identify the genetic coefficients of cultivars and parameterize the model, management, soil, plant and climate data from field experiments were utilized. An experiment was conducted experiment was conducted under optimal management conditions and using a randomized complete block design with three treatments and three replications at the research farm of the General Directorate of Meteorology of Lorestan Province located in Khorramabad City during the 2021-2022 growing season. Data from ten selected farms were used to evaluate the model under. The normalized root mean square error was less than 10 percent for seed yield, biological yield, and flowering and maturity stage of the cultivars. Thus, the APSIM model demonstrated excellent quality and acceptable accuracy. In all studied climate periods and scenarios, the grain and biological yield of wheat decrease by 7.3 to 57.0 percent and 2.6 to 27.9 percent, respectively, compared to the base period. In the2061-2080 and the pessimistic scenario (RCP8.5), despite an increase in rainfall, the yield of the increase plants significantly decreased due to rising minimum and maximum temperatures compared to the base period and a reduction in the length of the plant growth period. Therefore, under climate change conditions, farmers and agricultural planners can mitigate the negative effects of climate change the regional production and food supply by making appropriate management decisions, including selecting suitable cultivars. https://ijfcs.ut.ac.ir/article_105730.html One of the key stages in producing synthetic varieties in alfalfa (Medicago sativa L.) is estimating the combining ability of parents by evaluating the forage yield of polycross progenies. In this regard, this experiment was conducted with 20 genotypes, including 10 polycross progenies and 10 parent alfalfa ecotypes/varieties, including two varieties, Ahang and Mandegar, two ecotypes from Bami and Yazdi alfalfa, and six cold and temperate region alfalfa ecotypes with codes KFA16, KFA4, KFA3, KFA13, KFA11, KFA15. The experiment was carried out in a randomized complete block design with three replications in the 400-hectare farm of the Seed and Plant Improvement Institute in Karaj during the years 2020-2022. The traits studied included plant height, stem number per square meter, regrowth rate, fall dormancy score, and dry and fresh forage yield. Statistical analysis results showed a significant difference between the means of polycross progenies (half-sib families) and their parents for all traits except fresh forage yield. The half-sib family Poly-KFA3 had the highest dry forage yield with 22.91 tons per hectare, and Poly-KFA15 had the lowest with 19.48 tons per hectare. The highest percentage of heterosis in plant height, stem number per square meter, regrowth rate, fall dormancy score, fresh and dry forage yield were 13.25%, 7.94%, 57.03%, 150.49%, 10.92%, and 14.25%, respectively. Based on the general combining ability estimates for the traits studied, five parents (Bami, Yazdi, KFA3, KFA13, and KFA16) were selected for crossing and creating a new synthetic population. https://ijfcs.ut.ac.ir/article_105732.html Drought stress is a major limiting factor for crop production in arid and semi-arid regions. Given the importance of lentil (Lens culinaris) and its rainfed cultivation in Iran, this study aimed to investigate the response of two sensitive and tolerant lentil genotypes to drought stress at different levels (control, moderate stress, and severe stress corresponding to 90%, 60%, and 30% of field capacity). Morphological, physiological, and biochemical traits, as well as the relative expression of key genes involved in drought tolerance pathways, including Beta Amylase, DREB1C, ABAWDS, HCF136, and MIMP, were evaluated using qRT-PCR. Results showed that increasing drought stress intensity led to significant reductions in traits such as plant height, shoot and root fresh and dry weight, relative leaf water content, leaf area index, chlorophyll, and total leaf protein. Conversely, traits like leaf hair density, electrolyte leakage, accumulation of proline and carbohydrates, and the concentrations of malondialdehyde and hydrogen peroxide increased. Gene expression analysis in the tolerant genotype revealed a significant increase in the expression of ABAWDS and HCF136 genes and a decrease in the expression of Beta Amylase, DREB1C, and MIMP genes under increasing stress. These findings highlight the role of these traits and genes in the mechanism of drought tolerance in lentil and can be utilized in breeding programs to develop drought-tolerant varieties. https://ijfcs.ut.ac.ir/article_105735.html Drought stress is one of the most important abiotic stresses that threatens the production of crops. The objective of the present study was to evaluate certain physiological and biochemical traits in common bean under drought stress conditions. For this purpose, a field experiment was conducted at the Research Farm of the Department of Agronomy, College of Agriculture and Natural Resources, University of Tehran, Karaj, during the 2022 growing season. The experiment was carried out as a split-factorial arrangement in a randomized complete block design with three replications. Treatments included three irrigation levels (normal irrigation and irrigation at 30% and 60% of field capacity), two levels of salicylic acid (0 and 0.5 mM), two bacterial treatments (without and with inoculation of nitrogen-fixing Rhizobium leguminosarum biovar phaseoli strain R160), and two bean genotypes (Sadri and Yas). The results showed that increasing drought stress intensity led to a reduction in protein content and an increase in proline, malondialdehyde (MDA), electrolyte leakage, catalase, peroxidase, ascorbate peroxidase, and glutathione peroxidase activities. Moreover, the application of salicylic acid and Rhizobium inoculation, compared with the control (no hormone or bacteria), enhanced protein content and enzymatic activities while decreasing MDA levels and electrolyte leakage. Significant differences were also observed between the sensitive and tolerant genotypes in terms of electrolyte leakage, protein content, and MDA. These findings support the idea that the combined application of salicylic acid and Rhizobium inoculation can serve as an effective strategy to improve drought tolerance in both sensitive and tolerant common bean genotypes.