تنش خشکی

Durum wheat is considered one of the most important crop plants globally and in Iran, and it’s growth and yield is consistently affected by drought stress in Mediterranean regions, especially with global climate changes. However, local varieties or landraces of this crop can serve as valuable genetic resources for identifying and introducing drought-tolerant genotypes. The objective of the present study was to evaluate the drought tolerance of Iranian and foreign durum wheat landraces (primarily from the Fertile Crescent) in order to identify and introduce superior genotypes.

In this study, 150 durum wheat landraces from the Fertile Crescent were assessed for drought tolerance using stress tolerance indices. The experiment was conducted in an augmented randomized complete block design with four check varieties under supplementary irrigation and rainfed conditions in the research field of Razi University, Kermanshah, Iran, during two consecutive years (2019-2020 and 2020-2021). Stress tolerance indices were calculated after measuring grain yield under both supplementary irrigation and rainfed conditions. Cluster analysis, principal component analysis, and biplot analysis were used to screen the studied landraces for drought tolerance. R software version 4.3.1 was used to calculate stress tolerance indices and homogeneity test of variance of experimental errors. R software was used to perform principal component analysis and determine the optimal number of groups based on Silhouette method in Factoextra package.

The results of combined analysis of variance of the two years data revealed a significant difference among the studied durum wheat landraces for grain yield under both supplementary irrigation and rainfed conditions. The interaction of genotype × year was also significant, indicating different responses of the genotypes during two experimental years. Biplot analysis of genotype × index for the first year data showed that all the studied stress tolerance indices appeared in the first, third, and fourth zones of the coordinate axes, but more important stress indices including MP, TOL, GMP, HM and STI were located in the fourth zone, which were used to identify superior with high yielding drought-tolerant genotypes. A similar trend with minor differences was observed in the second year. In total, the studied durum wheat landraces were categorized into four distinct groups from drought-sensitive to drought-tolerant based on the genotype × index biplot.

Based on the results of this study, TOL, GMP, HM, STI and MP indices were selected as suitable and useful indices for distinguishing and identifying high-yielding drought-tolerant durum wheat landraces. Accordingly, the studied durum wheat landraces in terms of drought tolerance or sensitivity were grouped into four distinct groups from sensitive to tolerant. Among the studied landraces, two landraces, 44SAU and 9IRQ from Sudan and Iraq, respectively, were identified as superior landraces.

Roselle (Hibiscus sabdariffa L.) is a medicinal plant belonging to the Malvaceae family that has been used as medicine since ancient times. Sepals of roselle are a source of anthocyanin, vitamin C and other antioxidants, such as flavonoids (hibiscetine, gossypetine, and sadderetine). Due to the fact that drought is one of the prominent geographical features of Iran, saving water by cultivating drought-resistant crops can be considered as a solution to deal with drought. However, it should be noted that applying deficit irrigation without careful planning can lead to a reduction in quantitative or even qualitative yield. Therefore, due to the medicinal importance of roselle and its resistance to drought, the aim of this study was to investigate the effect of different irrigation regimes and planting method on some quantitative and qualitative traits of roselle plant.

The experiment was carried out as split plot based on randomized complete blocks design with three replications at the Research Farm of Kashmar Agricultural and Natural Resources Research Station, during two growth seasons 2016 and 2017. Treatments included seven levels of Irrigation (I1: 100% crop water requirement (CWR), I2: 80% CWR from 8-leaf stage to end of flowering, I3: 80% CWR from 8-leaf stage to beginning of flowering, I4: 80% CWR from beginning to end of flowering, I5: 60% CWR from 8-leaf stage to end of flowering, I6: 60% CWR from 8-leaf stage to beginning of flowering, I7: 60% CWR from beginning to end of flowering) and two level of planting method (direct and indirect) as main plots and sub plots, respectively. In the transplanting method, the seeds were sown in the transplant tray on March 10, 2016 and 2017 and transplanted to the farm in four-leaf stage. Direct cultivation was also carried out in April, in 2.5 × 7 meter plots at a depth of 1.5 cm. At the harvest time, two square meters of each plot were harvested to measure number seed and sepal yield, biological yield, and harvest index. In addition, qualitative traits including vitamin C, anthocyanin, total phenol, seed protein and oil were measured. Data from the two field experiments were analyzed with SAS software; obtained averages compared with using Tukey's Studentized Range (HSD) Test at the 5% probability level.

The results showed that the interaction effect between irrigation and planting method was significant on biological yield, vitamin C, total phenol, seed protein and oil. The highest seed oil (21.25%) was obtained in I1 and transplanting treatment. I7 and direct planting method treatment had the highest total phenol (41.96 mg g dry weight-1) and seed protein (31.32%). The maximum biological yield (9064.33 kg ha-1) and vitamin C (32.35 mg 100 ml-1) were observed in I1 and direct planting method and I4 and direct planting method, respectively. There was no significant difference in any of the irrigation levels between the two planting methods except for the total phenol at two levels of I5 and I6, which its amount was higher in the direct planting method than transplanting. Seed yield, sepal yield, seed harvest index, sepal harvest index, and anthocyanin were only affected by the main effect of irrigation. As the intensity of stress increased, the yield and harvest index decreased and the amount of anthocyanin increased. The highest seed (667.54 kg ha-1) and sepal yield (392.73 kg ha-1) were obtained in I1 treatment, which had no significant difference with I2 treatment. The lowest seed and sepal yield were also obtained in I7 treatment. According to the harvest index, the only I7 treatment showed a significant difference with other treatments. So that the lowest of seed (7.85%) and sepal harvest index (4.5%) were obtained in this treatment.

The results of this study revealed that water stress had the negative effect on the sepal, seed, and biological yield and number of fruit per roselle plant in both transplanting and direct sowing methods. However, with increasing drought stress, the plant's quality traits, including vitamin C, anthocyanin, total phenol, and seed protein improved. The extent of drought effect varied depending on the growth stage of the plant; however, there was no significant difference in seed and sepal yield obtained in stress-free and irrigation at 80% water requirement from 8-leaf stage to end of flowering treatments. The most significant impact was observed during the sensitive growth stage of the plant, particularly from early to late flowering, under drought conditions. Additionally, the results indicated that the transplanting method did not significantly enhance the studied traits at various irrigation levels compared to direct cultivation. Based on the climatic conditions of the study area, irrigating at 80% of the water requirement from the eighth leaf stage to late flowering of the roselle plant appears to be a viable strategy for achieving satisfactory quantitative and qualitative performance while conserving water resources.

Lack of fodder for feeding livestock is one of the main problems of dry areas, especially in the southern regions of Iran. In this situation, the climate changes and the decrease of rainfall in the southeast of the country in recent years, have doubled the important of compatible plants with the potential to produce fodder in water shortage conditions. Fodder cactus is a drought-resistant plant that adapts to dry and low-water conditions as a source for fodder production in dry areas. This research was conducted to explore the effect of drought stress on yield, water productivity, and some agronomic characteristics of cactus as a new crop in the climatic conditions of Shahmaran region of Kerman, Iran.

The experiment was carried out in the form of randomized complete block design with four replications. Three treatments of normal irrigation, moderate and severe drought stress were considered based on 160, 210 and 260 mm cumulative pan evaporation. The cladodes (Opuntia ficus-indica) used for planting, originating from Tunisia. In each plot, 32 cladodes were planted at a distance of 2 meters between rows and 1.5 meter between cladodes on a row. At the time of irrigation of each treatment, volumetric soil moisture was measured at the active depth of root development using a calibrated Time-Domain Reflectometry device (Trime-FM, IMKO, Ettlingen, Germany). To calculate the fodder yield of cactus, the cladodes produced on plants in each plot were harvested and weighed. For measuring the length, width, and thickness of the cladode in each plot, 10 cladodes were randomly selected, and the average of each trait was finally determined.

The number of pads produced under the influence of drought stress was significant. The highest number of pads per plant was observed in the normal irrigation treatment (27.7 pads per plant) and the lowest in the severe drought stress treatment (15 pads per plant). The maximum thickness of the pad under normal irrigation condition was 2.4 cm and the minimum thickness was observed under severe drought stress condition. The main reason in reducing the thickness of the pad in water stress condition was the decreasing of the pad moisture content.The effect of drought stress on the length and width of the pad, was significant. Minimum length and width of the pad was observed with 29.5 and 18 cm in severe drought stress treatment and the maximum with 37.7 and 24.7 cm in normal irrigation treatment.The percentage of pad dry matter at the time of sampling was significantly affected by water stress treatments. The dry matter percentage was the lowest in the normal irrigation treatment with 8% and the highest in the severe water stress treatment with 12.7%.The weight of the each pad and the yield of wet and dry fodder per hectare were significant under the influence of different water stress treatments. The wet weight of the pad per plant was the highest in the normal irrigation treatment with 1245 g and the lowest in the severe water stress treatment with 870 g. Normal irrigation treatment produced the highest yield by producing 112 and 8.97 t.ha-1 of fresh and dry fodder, respectively. The lowest wet and dry yield belonged to severe water stress treatment with production of 46.77 and 6.05 t.ha-1.The highest water productivity for wet and dry cactus fodder was 41.02 and 3.29 kg m-3 respectively, which belonged to the normal irrigation regime. There was no significant difference between moderate and severe water stress treatments for dry fodder in terms of water productivity.

Overall, the research results showed that drought stress has a significant effect on fodder yield, water productivity, cladode thickness, cladode length and width, cladode weight, and crude protein of cactus fodder. Despite the physiology of the cactus and its resistance to water stress, with the increase of drought stress, the wet and dry yield, water productivity, and fodder protein content showed a significant decline. According to the results, reduction of 58.2% in wet fodder yield and of 32.5% in dry fodder yield were seen in severe drought stress treatment compared to normal irrigation. The average water consumption was 2507.6 m3.ha-1. According to the results, in order to benefit from the potential of the cactus to produce fodder, it is necessary to avoid long-term and severe drought stress. The vegetative growth period of cactus was mainly found in spring and early summer. With the cooling of the air from late fall to early March, the plant is going to be entered the stage of growth stagnation. Due to the evergreen nature of the plant, the fodder of this plant can be used for feeding livestock in the fall and winter seasons, when there is a lack of fresh fodder. This research determined that there is a possibility of growing and developing cactus plant as a new plant in Shahmaran region with a subtropical climate. Also, through cultivation of this plant with low water consumption, part of the fodder shortage for livestock in Kerman province can be resolved.

  Wheat is the most important crop that occupies the most area under rainfed cultivation. Drought stress is the most important factor in wheat yield reduction. The scope of this stress is expanding day by day in the world. Drought resistance is a quantitative trait with a complex phenotype that is affected by plant growth stages. Breeding requirements for resistance to drought stress in wheat are two factors: high genetic diversity among cultivated and wild genotypes of wheat and selection based on traits related to this resistance. One of the important strategies to deal with moisture stress is using wild relatives of wheat, especially the genus Aegilops, as one of the important gene sources containing genes for resistance to environmental stresses. Based on this limitation, the use of wild wheat relatives is one of the important goals of wheat breeding programs. This research aimed to evaluate the relationship between grain yield and 32 different phenological and agro-physiological traits in ten ecotypes of Aegilops tauschii which was carried out under moisture-stress conditions and for two period. 

 This study was conducted for two consecutive periods in the research greenhouse of the Faculty of Agriculture of Bu-Ali Sina University in Hamedan. In this study, 33 phenological, morphophysiological, and root traits were evaluated in ten ecotypes of diploid wheat Aegilops tauschii (2n=2x=14, DD) under drought stress conditions. These ten different ecotypes of Aegilops tauschii were collected from different geographical regions of Iran.The mentioned ecotypes were evaluated in a randomized complete block design with three replications. At first, the seeds of the plant samples were grown in seedling trays containing equal proportions of perlite and cocopeat. Then, for the vernalization of the plants, after the initial germination of the seeds, in the two-leaf stage of the seedlings, the culture trays were moved to a cold room with a temperature of 4 degrees Celsius for about 35 days. After this stage, the vernalized seedlings were transferred to 10 kg pots, containing a combination of agricultural soil, sand, and rotted animal manure at a ratio of 50, 25, and 25%. After transplanting, the pots were irrigated at 100 percent of the soil's field or pot capacity for about two weeks. Then, in order to apply drought stress treatment, the humidity of the pots was kept at 45% of the field or pot capacity until the plants were harvested, by weighted moisture method. 

 Economic yield has a positive and significant correlation (p≤0.01) with the traits of grain water use efficiency, peduncle length, plant harvest index, main spike weight, grain weight in main spike, number of fertile spikes per plant, thousand-grain weight, plant height, excited leaf water retention, number of grains per plant, peduncle weight and leaf surface index. This was despite the fact that most of the phenological and root traits had a significant negative correlation with grain yield. According to the stepwise regression results, the traits of grain water use efficiency and the number of fertile spikes per plant with a positive coefficient and the traits of root diameter and days to heading, with a negative coefficient, as the most important traits affecting grain yield, were entered into the regression model respectively. The results of the path analysis indicated that the trait of grain water use efficiency had the most direct and positive effect on increasing grain yield. Also, the trait of water use efficiency, through the trait of day to heading, had the most negative indirect effect on grain yield. 

 According to our findings, the selection based on higher values of grain water use efficiency and the number of fertile spikes per plant and lower values of phenological and root traits may lead to improvement of wheat grain yield under drought stress conditions.

Periwinkle herb, with the scientific name (Catharanthus roseus (L.) G.DON), is one of the most important medicinal plants globally. Besides having aesthetic features and ornamental applications, the plants’ leaves and root are rich in very important alkaloids. It is used in the chemotherapy of various cancers and the treatment of hypotension.

In order to investigate the effect of growth regulator and spraying by zinc and magnesium nanoparticles under the conditions of drought stresses on total alkaloids, anthocyanin, total chlorophyll, the weight of wet and dry branches contain alkaloids, and the number of lateral branches of the periwinkle herb, an experiment was arranged with a factorial layout based on a completely randomized design under greenhouse conditions during years 2020 and 2021 in Tehran, Iran. The first factor was the dryness factor using evaporation pans (at three levels of 40, 60 and 80 mm), the second factor comprised the growth regulators (Shahid, auxin, gibberellin, cytokinin each at a concentration of 50 ppm) and the third factor included the nanoparticles (control, Zn, and Magnesium, each at a concentration of 1 mg, and the combination of zinc and magnesium, each at a concentration of 0.5 mg) were applied.

The results showed that in study of the effects of drought stress and spraying of zinc and magnesium nanoparticles on all investigated traits (total alkaloid, anthocyanin, total chlorophyll, fresh and dry weight of alkaloid-containing branches, and the number of lateral branches), there was a statistically significant difference at the level of 1% (P≤0.01). Also, in the investigation of the effects of growth regulators on investigated traits other than total alkaloid, a statistically significant difference was established at the level of 1% (P≤0.01). In the investigation of the mutual effects of drought stress and growth regulators on the fresh weight of alkaloids-containing branches, a statistically significant difference was established at the level of 1% (P≤0.01). The highest dry weight of aerial parts was observed under optimal irrigation conditions and under the influence of the gibberellin hormone (34.96 gr). However, in other cases, no statistically significant effect was observed on the target traits.

Drought stress revealed defense mechanisms such as anthocyanin pigments and secondary compounds, and total alkaloids also increased with increasing drought stress. The highest percentage of total alkaloids was obtained under severe drought stress (1.57%). The use of micronutrient fertilizers in nano form increased the accumulation of dry matter and secondary compounds, and the effect of magnesium was greater than the effect of zinc. In the application of hormones, the use of gibberellin hormone had a greater effect on the fresh and dry weight of shoots under optimal irrigation conditions and drought stress.

Basil (Ocimum basilicum L.) is one of the plants of the mint family, it has many uses as fresh food and medicinal uses. Water is one of the most important factors in the production of plants, and its limitation in Iran, especially in recent years, is the main factor that reduces the yield of plants. In order to investigate the evaluation of antioxidant enzymes activity, proline content and Basil (Ocimum basilicum L.) essential oil yield under leaf foliar application of salicylic acid in drought stress conditions, an experiment was conducted in the form of split plots based on randomized complete block design in 3 replications in a private farm located in Mahdasht area of Karaj city in 2015-2016 and 2016-2017 crop years. Irrigation regimes in 4 levels: I1: 100%, I2: 80%, I3: 60% and: I4: 40%. The volume of water required in the main plots and salicylic acid in 5 levels: SA1: No application (spraying solution with water net as control), SA2: foliar spraying with a concentration of 50 μM, SA3: 100 μM, SA4: μM and SA5: 200 μM were placed in the subplots. The results showed that the amount of amino acid proline and the activity of antioxidant enzymes catalase, superoxide dismutar and ascorbate peroxidase increased with increasing drought stress. Also, salicylic acid foliar application, by increasing proline as an osmolyte and increasing the activity of antioxidant enzymes, moderated the drought stress and maintained yield to a large extent. The highest yield of essential oil from the treatment of 100% water requirement with the use of 200 µM salicylic acid is 11.982 kg/ha) and in humidity conditions of 40%, 60% and 80% of the water requirement of the plant with the use of 200 µM salicylic acid, respectively, at the rate of 11.730, 11.287 and 10.329 kg/ha were obtained. A significant increase in the performance of essential oil was observed in this study by increasing the consumption of salicylic acid from zero to 200 μM. Finally, due to the adverse effect of drought stress on the growth and production of basil plant, it is recommended to use a concentration of 200 μM salicylic acid to moderate drought stress and improve yield.

Drought stress is one of the most important abiotic factors that can limit plant growth and yield. The response of plants to water limitation has been evaluated based on genetic, biochemical, and morpho-physiological traits. Plants are constantly affected by drought stress and re-irrigation. Therefore, rapid and efficient recovery from water deficit stress may be one of the key determinants of drought adaptation in plants. The aim of this research was the evaluation of drought stress tolerance and recovery in lentil cultivars after stress conditions.

In order to evaluate the response of lentil cultivars to drought stress and re-irrigation, a factorial split-plot experiment based on a randomized complete block design with three replications was conducted in the greenhouse. Drought stress was applied at the flowering stage. The factors include 4 lentil cultivars (Namin landrace and Sepehr, Gachsaran, and Kimiya cultivars), drought stress (control (irrigation at 80% FC), medium stress (irrigation at 55% FC) and severe stress (irrigation at 30% FC)) and 3 sampling times (three and six days after drought and recovery (two days after re-irrigation)). All the plants were allowed to grow until the flowering stage (50 days after sowing) under well-watered conditions (80% FC (field capacity) of soil). Afterward, the plants were randomly assigned to three different groups and were exposed to different irrigation regimes including the control (well-watered and maintained at 80% FC), medium stress (watered and maintained at 55% FC), and severe drought stress (watered and maintained at 30% FC). The moisture content of the soil was controlled and maintained within a defined range using the weight method. Stress conditions were kept until the crop maturity and harvesting stage. The leaf samples from 5 seedlings of each pod were collected at 3 and 6 days after drought stress exposure, and two days after re-irrigation and used for physiological and biochemical analysis. The samples immediately were frozen in liquid nitrogen and stored at −80°C until analysis.

The results showed that adaptation to drought stress was closely related to the recovery ability of plants. Drought stress caused a decrease in chlorophyll a, chlorophyll b, total chlorophyll, carotenoid, protein and proline, yield, and yield components. The reduction of these traits was more remarkable at six days after stress. However, during the recovery time remarkable increase was observed in these traits. The results showed that the correlation between H2O2 and MDA was significant and positive. Furthermore, drought stress increased the amount of H2O2 and MDA, which increased the activity of antioxidant enzymes (catalase, polyphenol oxidase, and peroxidase). An increase in the intensity and duration of the drought stress also caused an increase in proline (63%), H2O2, (19%), and MDA (110%) content, and the activity of CAT (33%), PP0 (56%), and POX (24%) compared to the control treatment. An increase in the intensity and duration of the drought stress also caused an increase in H2O2 and MDA content and the activity of antioxidant enzymes. In addition, in the recovery conditions, a significant reduction in the destructive effects of stress (H2O2, MDA content) and the activity of antioxidant enzymes was visible. The results of the present study indicated that the effects of drought stress on lentil cultivars' yield and yield components (seed numbers, number of pods, 100-seed weight, and seed yield) were varied. Drought stress at the flowering stage decreased the number of seeds (20%) and pods per plant (37%), and 100-seed weight (16%), which led to 29% yield losses. Although the Gachsaran cultivar had the highest yield under normal conditions. However, under drought stress conditions Gachsaran and Sepehr cultivars showed the highest plant yield. On the other hand, the Namin landrace exhibited the lowest yield (40%) under stress conditions.

The water stresses markedly increased the reactive oxygen species (ROS) level and impaired the biosynthesis of the photosynthetic pigment, resulting in the reduction of plant growth and yield with fewer seeds and pods number per plant. However, re-irrigation (recovery) remarkably improved plant growth and reduced the negative effects of drought stress, such as reducing the amount of MDA and H2O2 and improving the activity of antioxidant enzymes and proline content. In conclusion, based on physiological traits Gachsaran, and Sepehr cultivars seem to be suitable cultivars for culture in the regions challenged with water deficit stress.

Drought stress, as the most important abiotic stress, plays an important role in reducing crop production. Wheat is the most important crop in Iran. In arid and semi-arid regions, it is very important to obtain cultivars that have more tolerance to water limitation and water deficit irrigation. By achieving such cultivars and determining their tolerance to low irrigation, it is possible to prevent the loss of water resources to a large extent and at the same time obtain a suitable yield in the conditions of water limitation. Although genetic improvements in grain yield under favorable and stress conditions have been clearly seen over the past few decades, the search for genetic differences and more effective selection criteria, especially under stress conditions, should be continued. Investigating the effects of different irrigation regimes in different phonological stages on wheat grain yield and introducing the best irrigation regime for this crop in the dry weather conditions of Aran Va Bidgol region are the main aims of this research.

In order to evaluate the effect of drought stress on yield, yield components and some physiological traits of three bread wheat cultivars, the experiment was conducted during 2013-2014, in Aran va Bidgol province. A split factorial experiment based on randomized complete block design with three replications was used. The main plots considered irrigation regimes (irrigation after 60, 95 and 130 mm cumulative evaporation from class A evaporation pan), and sub-plots considered two growth stage (from elongation to heading and from heading to ripening) and three wheat cultivars (Sepahan, Roshan Back-Cross and Kavir) as factorial. Sowing was done by hand with a density of 400 seeds per square meter. Weeds were controlled by mechanical method. In the stages of elongation, heading, pollination and grain filling, the amount of water consumed in each irrigation was estimated for the main plots and was introduced to the plots during irrigation. The SPSS software was used to analyze the data. If the effect of the experimental factor was significant, the LSD test was used at the 5% probability level to compare the means.

Results showed that delay in irrigation from 60 to 130 mm cumulative pan evaporation significantly reduced plant height, number tiller, yield and yield components, harvest index, relative water content, leaf chlorophyll content and increased the wax of coticule and water use efficiency. Irrigation after 90 and 130 mm cumulative evaporation from class A evaporation pan decreased grain yield 12 and 41.8 percent compared controlled, respectively. The reduction of water consumption in mild and severe stress treatments compared to the control treatment was 20 and 43%, respectively. Applying drought stress from the heading to ripening, led to a greater decrease in grain yield and harvest index compared to applying stress from the elongation stage to heading. The Kavir, Sepahan and Back-cross Roshan cultivars had the highest to the lowest grain yield, with 3941, 3868 and 3757 kg. ha-1, respectively. The Kavir cultivar had low plant height, high the wax of coticule (both control and stress conditions), resume high relative water content (both control and stress conditions), high leaf chlorophyll content, harvest index and water use efficiency, caused to higher grain yield.

It was concluded that by irrigation the Kavir wheat cultivar after 95 mm cumulative pan evaporation from elongation to heading, water could be saved by 20% with 12% loss in grain yield under these conditions.

Durum wheat (Triticum turgidum L. var. durum) is the second most important species of wheat and the tenth most important agricultural crop in the world. Pasta made from this type of wheat is utilized as a staple food in many countries worldwide. Additionally, durum wheat is more compatible with dry conditions in Mediterranean regions than bread wheat. On the other hand, performance alone is not a suitable indicator for adaptability and drought tolerance due to its low heritability. Therefore, attention to other aspects of drought tolerance, such as physiological characteristics, is important due to their cost-effectiveness and ability to select genetic materials in the early stages of plant growth.

In this study, the grain yield and some physiological traits in 154 recombinant inbred lines (RILs) obtained from the cross between the local cultivar of Zardak with Kermanshah origin and the G1252 variety with Turkish origin along with their parents were evaluated using alpha lattice design in two replications under rainfed conditions during 2020-2021. Also, Genetic parameters were calculated for the studied traits.

The results of this study showed a significant difference among the RILs for all studied traits, except for water saturation deficit. Lines ZG-110, ZG-090 and ZG-060, exhibited the highest flag leaf width, flag leaf length and flag leaf area, respectively. Overall, ZG-150 and ZG-126 lines were the superior lines in terms of leaf relative water content among the studied RILs. The highest grain yield belonged to ZG-118 and ZG-102 lines. The highest broad-sense heritability values were observed for flag leaf width and relative water loss (85%), grain yield (63%) and excised leaf water retention (41%), respectively. The grain yield exhibited a positive and significant correlation with excised leaf water retention and a negative and significant correlation with excised leaf water loss. Cluster analysis grouped the RILs into three different groups, and the third group included the RILs with the highest desirable traits in terms of leaf water content. The analysis of the principal components showed that the first two components explained 59.96% of the total variance. Also, the RILs with low first component and high second component values had more water retention power in the leaf.

The results of this study demonstrated genetic differences among the RILs for traits related to flag leaf, physiological traits related to leaf water content and grain yield under rainfed conditions. The existing differences indicate the presence of genetic diversity and also provide the opportunity to select superior RILs. On the other hand, high heritability and genetic advance were observed for traits such as flag leaf width, flag leaf area, the percentage of lost water in the leaf and grain yield, indicating the potential impact of additive genes.

Drought stress is one of the most critical challenges in agriculture, particularly in arid and semi-arid regions, significantly affecting crop growth and yield. Due to the direct impact of drought stress on food security, the importance of identifying and improving drought-tolerant genotypes has increased. Maize (Zea mays L.), as one of the world’s most important crops, plays a crucial role in food and industrial supply chains. Ensuring its sustainable production under water-limited conditions is vital with increasing demand for maize. This study aimed to evaluate the drought tolerance of 40 maize advanced inbred lines (8 generations of selfing) and identify tolerant genotypes for use in breeding programs. The experiment was conducted in a randomized complete block design with three replications under two conditions: normal moisture (5-day irrigation interval at 80% field capacity) and drought stress (10-day irrigation interval at 50% field capacity) at the Research Farm of the Graduate University of Advanced Technology, Kerman, Iran. Forty maize lines were evaluated for agronomic and morphological traits, including days to maturity, plant height, first ear height, leaf dimensions, number of ears per plant, number of grains per ear, grain rows per ear, grain length and width, 100-grain weight, and grain yield per plant. Data analysis involved combined ANOVA, Tukey’s mean comparison, and multivariate methods such as cluster. Results revealed significant environment × line interactions for most traits, highlighting variations in the response of lines to different irrigation regimes. The mean trait results indicated that drought stress reduced the traits of yield/plant, number of grains/ear, grain width and number of ears/plant by 50.8, 32.8, 28.2, and 27.1, respectively, while the lowest changes were shown by the traits of days to maturity (6.6) and plant height (13.3). Lines 1, 6, and 35 had higher yields under both conditions and were identified as tolerant genotypes based on the stress tolerance index. Therefore, these lines can be used as suitable genetic bases for creating new and more tolerant cultivars. Cluster analysis classified the lines into different groups and revealed high genetic diversity, indicating high potential for selecting suitable genotypes in breeding programs. The cluster analysis results of traits also showed that the number of grains/ear trait and yield/plant are in the same group, and this trait is a key criterion in identifying high-yielding tolerant lines. This study demonstrated that drought stress significantly affects maize agronomic and morphological traits, with yield-related traits showing the highest sensitivity. Lines 6, 1, and 35 were identified as the most drought-tolerant and are recommended for inclusion in breeding programs to improve drought resistance. Cluster analysis highlighted substantial genetic diversity among the lines, providing a robust foundation for selecting optimal genotypes for breeding. Utilizing the number of grains/ear traits as a selection criterion in breeding programs is recommended to ensure stable and improved maize yield under drought-stress conditions.

Given the expected population growth in the coming years and the necessity to provide food for people, legumes, especially chickpeas (Cicer arietinum. L), hold significant importance in terms of economics, nutrition, soil improvement, and crop rotation. Legumes are considered one of the most important sources of protein in most developing countries. Researchers believe that early cultivation of chickpeas leads to better performance due to the longer vegetative growth period and concurrent reproductive phase with appropriate rainfall and desirable moisture. On the other hand, studies show that spring planting of chickpeas leads to a reduction in all growth factors due to the simultaneous sensitive growth stages with water deficit and drought stress. This study was conducted to grouping of candidate chickpea genotypes in response to water deficit based on their yield performance and components at different planting dates.

This study was conducted at the research farm station of the Faculty of Agriculture, Ferdowsi University of Mashhad, in the year 2018-19. In this research, six genotypes and two cultivars were evaluated in a randomized complete block design with four replications as a split-plot design. Seeds were obtained from the seed bank collection of Research Center for Plant Sciences, Ferdowsi University of Mashhad. Planting was done in two dates in 5 March and 13 April with a density of 40 plants per square meter. Also, irrigations were done only at two stages; the first stage was irrigated with the purpose of achieving the emergence and the second irrigation at the time of 50% flowering with 20 mm in both stages. To measure traits such as emergence time, flowering time (50% of plants in flowering stage) and biomass, plant height, number of pods per plant, percentage of fertile pods, and 100-seed weight at the end of the growth stage and harvest time, five plants were randomly selected from each plot, and the desired traits were examined and recorded. At the time of full maturity and drying of the plants, after removing half a square meter margin from each plot, biological and seed yield were measured, and for calculating biological yield, the dry weight of seeds was added to the dry weight of plant residues.

The results indicated a significant superiority in all traits for the first planting date (5 March) compared to the second planting date (13 April). Significant differences were observed among the different genotypes in terms of emergence percentage, days to maturity, plant height, days to flowering, biological yield, podding, and seed yield. Genotype MCC352 had the highest number of pods per plant (34 pods), and genotype MCC427 had the highest number of days to flowering. Genotype MCC537 was superior in plant height and biological yield, but genotype MCC696 was superior in days to maturity and seed yield, indicating that these two genotypes had better responses to environmental conditions. Based on cluster analysis of chickpea genotypes in the first planting date, eight genotypes were classified into four clusters. Cluster 1 included genotypes MCC352, MCC537, MCC552, MCC80, and Jam cultivar. Cluster 2 included Samin cultivar. Cluster 3 included genotype MCC427, and cluster 4 included genotype 696MCC. Cluster 1 had the highest coefficients in terms of emergence percentage and days to maturity, and cluster 2 had the highest coefficients of days to maturity and days to flowering. Similarly, in the second planting date, eight chickpea genotypes were classified into three clusters. Cluster 1 included genotypes MCC696, MCC537, MCC552, MCC80, and Jam cultivar. Cluster 2 included genotypes MCC352 and MCC427. Cluster 3 included Samin cultivar. Cluster 1 had the highest coefficients in terms of emergence percentage and days to maturity, and cluster 2 had the highest coefficients of days to maturity and emergence percentage. Furthermore, the Principal Component Analysis of the studied genotype traits showed that in the first planting date (5 March), PC1 (43.4%) and PC2 (25.7%) accounted for a total of 69.1% of the variance, while in the second planting date, PC1 (36.8%) and PC2 (27%) accounted for a total of 63.3% of the variance. Overall, the studied genotypes had better performance and yield components in the first planting date.

In general, it can be concluded that delayed planting and exposure to drought stress during the critical growth stages of the plant at the end of the season resulted in a decrease in chickpea yield and its components. It was observed that planting chickpea on time to avoid late drought stress at flowering and podding stages would lead to a better yield and its components.

The production of oil, especially organic oil, from oilseed plants is important, so that oilseed plants occupy the second food reserves in the world after cereals. Sesame is an industrial plant that can be cultivated in arid and semi-arid regions, however, its growth and yield are limited by drought stress. Drought stress is considered as one of the most important factors limiting the performance of plants. Therefore, proper and principled management of agricultural inputs, including fertilizers, can partially reduce the negative effect of drought stress. This study aimed to examine the effects of chemical fertilizers, biofertilizers, and humic acid—applied individually and in combination—on the yield, yield components, and protein content of sesame grain under different irrigation regimes.

This research was carried out in the form of a split plot experiment based on the complete blocks design with three replications during the 2022 and 2023 at a research farm in Hormozgan province. The experimental treatments included irrigation regimes at three levels (irrigation after 40, 60 and 80% moisture discharge as main plots and fertilizer treatments at seven levels (control (F1), 100% need plant to phosphorus chemical fertilizer (F2), plant inoculation with arbuscular mycorrhizal fungus (F3), humic acid (F4), 50% chemical fertilizer+mycorrhiza (F5), 50% chemical fertilizer+humic acid (F6) and 50% chemical fertilizer+Mycorrhiza+humic acid (F7) was in sub-plots. In this experiment, agronomic characteristics, yield, yield components and grain protein of sesame were investigated.

The results showed that irrigation regimes and fertilizer treatments showed a significant effect on the studied characteristics of sesame. Irrigation at 80% moisture reduced the plant height, the number of sub-branches, the number of leaves, the number of capsules, the weight of 1000 grain, the biological yield, the grain yield and the harvest index by nearly 35, 50, 37, 48, 42, 52, 61 and 13% respectively compared to irrigation at 40%. Therefore, increasing the plant's access to water improved cell growth and division by increasing cell mass. It has been reported that there is a direct relationship between the increase of drought stress and the decrease of each of the growth characteristics of the plant, so that drought stress can cause damage to the growth characteristics and plant yield components, depending on the growth stage, which will reduce economic yield. On the contrary, irrigation after 80% treatment led to an increase in nitrogen and grain protein concentration compared to irrigation after 40%. In addition, among the fertilizer treatments, the F7 treatment resulted in an increase in growth characteristics, yield components, yield and nitrogen content of sesame grain. In this research, the individual application of mycorrhiza and humic acid could have more favorable growth characteristics than the application of 100% phosphorus chemical fertilizer or its non-application. Different mechanisms have been described for the effect of mycorrhizae on the growth characteristics of plants, such as increasing the absorption of nutrients, nitrogen, phosphorus, and low-use elements. Because in a mycorrhizal plant compared to a non-mycorrhizal plant, the creation of a wide hyphal network of fungi between the soil and the root provides a large surface for the absorption of nutrients. Humic acid is also able to improve the vegetative characteristics of plants by increasing the photosynthetic capacity, leaf water content and the metabolism of antioxidant compounds.

Increasing water availability, along with the combined application of reduced amounts of chemical fertilizers, mycorrhiza, and humic acid, resulted in improved quantitative and qualitative yield of sesame. The enhanced performance of the combined treatments compared to other fertilizer treatments can be attributed to the lack of organic matter in the region's soil. The best results were observed with the integrated treatment of mycorrhiza, humic acid, and chemical fertilizers, as it provided the plant with the most access to essential nutrients.

In recent years, silicon (Si) fertilizer has attracted attention of farmers and researchers as a potential mitigator for adverse effect of drought stress, offering means to enhance the resilience and functional traits of agricultural crops. Numerous studies have demonstrated the positive effects of Si application in alleviating water deficiency, though most have utilized foliar spraying methods. Soil application (fertilization) may serve as a suitable alternative for utilizing this beneficial element (Mostofa et al., 2021). This study aimed to determine the beneficial role of silicon as a plant biostimulant through fertilization, reducing water stress effect and improving the biochemical and physiological characteristicsas well as yield of quinoa.

To investigate the physiological, biochemical, and yield responses of quinoa to silicon fertilization under drought stress conditions, a field experiment was conducted during the 2023–2024 growing season at the Gandoman research farm of Payame Noor University, Chaharmahal and Bakhtiari province, Iran. The experiment was carried out as split-plot arrangements in randomized complete block design with three replications. The experimental treatments included irrigation at four levels in the main plots (40%, 60%, 80%, and 100% field capacity; defined as severe, moderate, mild and full irrigation, respectively) and silicon fertilizer at four levels (0, 1, 2, and 3 l.ha-1) in the sub-plots. Analysis of variance was performed using SAS software and the means were compared using LSD test at the 5% probability level. Graphs were made using Excel software.

The results indicated that reducing irrigation levels led to a decrease in photosynthetic pigments, antioxidant enzyme activities, and seed yield, while the application of silicon fertilizer mitigated the negative effects of the drought stress. Under the 40% field capacity irrigation level, the chla, chlb, carotenoids and total chlorophyll content in the treatment with 3 l.ha-1 of silicon were higher by 103%, 52%, 117%, and 99%, respectively, compared to the control (without silicon). Additionally, the activity levels of catalase, superoxide dismutase, and peroxidase enzymes in the 3 l.ha-1 of silicon level were higher by 264%, 65%, and 176%, respectively, than in the control under the 40% field capacity irrigation condition. Moreover, in the 40% field capacity irrigation level, compared to the 100% field capacity level, the increase in relative water content of leaves, seed yield, and biomass in the treatment with 3 l.ha-1 of silicon was higher by 51%, 40%, and 9%, respectively, than the control without silicon application. Based on the results, the treatment with 40% field capacity and 3 l.ha-1 of silicon (equivalent to 1250 kg.ha-1) prevented more effectively the reduction in seed yield. Under the 40% field capacity treatment (severe drought stress), the highest proline content (1.56 µmol.g-1 FW) and soluble carbohydrate content (20.7 mg.g-1 FW) were observed with the application of 3 l.ha-1 of silicon.

Overall, the results of this experiment demonstrated that drought stress led to reductions in photosynthetic pigments (chla, chlb, and carotenoids by 29%, 79%, and 38%, respectively, compared to the control), relative leaf water content (by 11% compared to the control), seed yield (by 49% compared to the control), and biomass (by 68% compared to the control). Under drought conditions, antioxidant enzyme activity, proline, and soluble carbohydrate content increased. Moreover, silicon fertilization mitigated the negative effects of drought stress. In conclusion, the results of this experiment showed that although drought stress led to reduction in physiological traits and seed yield, however, the application of silicon fertilizer significantly lessened the negative effects of drought stress.

In order to investigate the effect of foliar spraying of salicylic acid on some traits and dry matter performance of basil plants under the influence of water limitation, an experiment was conducted in the form of split plots based on randomized complete block design in 3 replications in a private farm located in Mahdasht area of Karaj city in 2015-2016 and 2016-2017 crop years. Irrigation in 4 levels: I1: 100%, I2: 80%, I3: 60% and: I4: 40%. The volume of water required in the main plots and salicylic acid in 5 levels: S1: No application (spraying solution with water net as control), S2: foliar spraying with a concentration of 50 μM, S3: 100 μM, S4: μM and S5: 200 μM were placed in the subplots. The results showed that the simple effects of drought stress and salicylic acid on the traits of stem diameter, inflorescence length, total chlorophyll, carotenoid and plant dry weight at 50% of flowering are significant at 1% level and the interaction effect of these two factors is also significant except for stem diameter. It was significant at 1% level on all studied traits. In general, salicylic acid increased stem diameter, inflorescence length, total chlorophyll and carotenoid, and with more water limitation, salicylic acid showed more positive effects in increasing the mentioned traits. With the increase in concentration of salicylic acid in all drought stress treatments, the dry weight of the bush showed a significant increase. The maximum dry weight of the bush was 3144.88, 3105.45 and 3045.67 kg per hectare related to the concentration of 200, 150 and 100 μM salicylic acid under the conditions of 100% water requirement. The highest dry weight of the bush in severe drought stress (40% water requirement), severe stress (60% water requirement) and mild drought stress (80% water requirement) belongs to the dose of 200 µmol/l salicylic acid, respectively, at the rate of 1596.45, 2033/2033 and 2327/36 kg per hectare. Our study showed that foliar spraying with salicylic acid is more effective in increasing the dry weight of the plant under water-limited conditions. According to the obtained results, it is recommended to use salicylic acid for the production of basil plants in order to adjust the drought stress in climatically semi-arid areas such as Karaj.

Safflower is an oily plant native to Iran, and at the same time, it has good resistance to drought and salt stress, which is a suitable plant for self-sufficiency in this field due to the lack of oil and the large volume of its import to the country. This research was conducted in order to evaluate three varieties of winter safflower under drought stress conditions in different stages of growth in terms of seed and oil yield and other traits. This experiment was carried out in the form of split plots in the form of a basic design of randomized complete blocks in three replications, the main plots containing five levels of drought stress, respectively: Drought stress at budding stage, Drought stress at the beginning of flowering stage, drought stress in the mid-flowering stage, drought stress in the seeding stage and no drought stress and the sub-plots included three cultivars I.L.111, L.R.V.51.51, and K.W.2. Seed yield, oil yield, oil percentage are important traits measured. The obtained results show that among the different levels of drought stress, the stress in the stages of budding and the beginning of flowering caused a significant decrease in terms of seed and oil yield. Also, among the studied cultivars, L.R.V.51.51 had the best seed and oil yield. and the lowest sensitivity of safflower to drought stress is in the seed setting stage, because the yield of seeds and oil in this stage of stress did not have any significant difference compared to non-stressed conditions.

Water shortage has become a global problem and has caused many problems in agriculture and food supply for the growing world. Barley (Hordeum vulgare L.) as the fourth mostly-cultivated cereal, is one of the most strategic crop plants which is produced almost all over the world as a source of and important staple food and animal feed (Thabet et al., 2020). Food uncertainty is a comprehensive obstacle becomes more serious hazard all over the world in particular in developing countries for the sake of overpopulation and dwindling accessibility of croplands, water and other resources related to agricultural scopes. Water scarcity, results in plenty of disturbances in plant functions like cell division and elongation, water and nutrients relations, photosynthesis, enzymes activity, stomata movement, assimilate partitioning, respiration, oxidative damage, growth, and productivity, as several types of researches show that water shortage in the soil cause many disorders in plant tissues, which in turn leads to a punctual diminish in the photosynthesis rate (Todorova et al., 2022). In such a trouble circumstances, most of the plants are not capable to absorb abundant water, which is required for optimized growth (Danish et al., 2020).

To investigate the impact of different irrigation regimes as well as foliar application of methyl jasmonate on growh, physiological and biochemical characteristics of barley varieties, an experimental research using factorial split plot design in 3 replications was carried out in experimental farm of the faculty of agriculture at the University of Zanjan in 2021-2022 cultivation season. In this experiment, irrigation regimes as the main factor, including complete irrigation as the control, withholding water in flowering stage, withholding water in grain filling period and complete dry farming, varieties as the secondary factor including Bahman, Sahand, Jolgeh, Abidar as well as Ansar, and foliar application of methyl jasmonate including without spraying (control) and spraying 50 μmol of methyl jasmonate were investigated. Results showed that the effect of irrigation regime had significant impact on almost all of the characteristics except chlorophyll a/b.

Varieties showed considerable difference from the aspect of height, concentration of soluble sugar and grain yield. Effect of Methyl jasmonate on the relative water content (RWC), photosynthetic pigments, soluble sugar content, proline content, Malondialdehyde (MDA) and grain yield was significant. The highest grain yield (4762 kg ha-1) was detected when variety of Jolgeh was irrigated normally and was sprayed by 50 μmol of Methyl jasmonate and the lowest grain yield (432 kg ha-1) was seen when variety of Bahman was dry-farmed without foliar application of methyl jasmonate.

The current study illustrated that barley can be grown in drought stress conditions if the right management is set on its cultivation. Methyl jasmonate showed a significant impact on the growth characteristics, biochemical and physiological attributes of the barley, despite the fact that drought had substantial adverse effects on the studied parameters of barley. However, drought resulted in different properties in barley varieties.

Indigo (Indigofera tinctoria L.) is a flowering plant belonging to the Fabaceae family. This plant has a high ability to grow again after harvesting, and the low sensitivity of this plant to the attack of pests and diseases in hot weather conditions is one of the reasons for increasing the yield of this plant. Global climate changes have led to changes in rainfall patterns and it is predicted that periods of insufficient rainfall will lead to drought with a gradual decrease in water available to the soil of plants, causing an impact on the growth and development or early death of the plant. The unreasonable long-term use of chemical inputs, including fertilizers and pesticides, has increased environmental pollution and in some cases has had a negative impact on the yield and quality of agricultural products. One solution is to use the principles of sustainable agriculture, especially the use of organic inputs in agricultural ecosystems. Humic acid (HA) is an organic biostimulant that significantly affects plant growth and increases crop yield. The purpose of the experiment is to investigate the effect of irrigation intervals and foliar spraying of humic acid on the physiological characteristics and indigo content of Indigofera tinctoria.

This research was carried out as split plot layout based on randomized complete block design with three replications during 2019 in the agricultural research institute of Zabol Research Institute in Zahak city of Sistan and Baluchistan province in Iran. The experimental treatments were irrigation intervals of 7, 9 and 11 days as the main factor and five levels of humic acid foliar application as the sub-plot (no foliar application, foliar application with a concentration of 20, 30, 40 and 50 liters per hectare). Irrigation treatments were carried out two months after the planting date. Humic acid foliar application was started after three months from the date of planting in the flowering stage, every 15 days. The foliar spraying was done at the end of the day and at sunset with a back pump sprayer and with the same pressure on the bushes. In order to calculate the leaf yield by removing the marginal effect, the crop was harvested in the last week of November 2019 and kept in the warehouse at room temperature for 23 days. Then the dry leaves were separated and the weight of the leaves was obtained in each plot and its yield was calculated in terms of tons per hectare. Wilson's method was used to prepare ash and extract to measure the concentration of iron, zinc, phosphorus and potassium elements. The amount of photosynthetic pigments was calculated by Arnon's method. To measure guaiacol peroxidase enzyme by Fielding and Hall method, calculate ascorbate peroxidase by Yoshimura method, catalase enzyme by Beers and Caesar method, proline amount in leaves was measured by Bates method. Also, the indigo content was measured based on the method provided by Stoker et al. (1998) and Sales et al. (2006).

The results of analysis of variance showed that the effect of different levels of irrigation on chlorophyll a, catalase, iron and zinc was significant. The effect of different levels of humic acid foliar application on chlorophyll a and b, carotenoid, ascorbate peroxidase, catalase, guaiacol peroxidase, iron, zinc, potassium, phosphorus and indigo content was significant. Also, the results of the analysis of variance showed that the interaction effect of irrigation in foliar application of carotenoid humic acid, ascorbate peroxidase, catalase, guaiacol peroxidase, iron, phosphorus and indigo content was significant. The highest (39.32 mg.g-1 fresh weight) and the lowest (24.49 mg.g-1 fresh weight) content of indigo were obtained at the 7-day irrigation interval under the conditions of foliar spraying of 50 liters per hectare and the 11-day irrigation interval under the conditions of no humic acid application

The results of investigating the effect of reducing different levels of irrigation and increasing humic acid foliar spraying on indigo showed that the amount of chlorophyll a and b and zinc increased. Also, the increase in humic acid caused an increase in potassium and blood. At each level of irrigation, it was found that the amount of carotenoid and indigo content increased with the increase of humic acid foliar application. Some other physiological characteristics of indigo such as proline, ascorbate peroxidase, catalase and guaiacol peroxidase showed a decrease in each irrigation level with increasing humic acid foliar application. In future researches, it is possible to consider the comparison of soil application and foliar application of humic acid. In general, for the production of vesme leaves, 9-day irrigation interval in foliar application of 40 L ha-1 of humic acid is suitable; and In order to obtain more indigo content, an 11-day irrigation interval in foliar application of 40 L ha-1 of humic acid seems appropriate.

Modern intensive agriculture has boosted crop yields through chemical inputs. However, this approach has caused decreased biodiversity, harm to human health, and environmental degradation. Developing sustainable agricultural practices that increase productivity while minimizing negative effects, especially in arid and semi-arid regions, requires strategies like deficit irrigation and environmentally compatible weed control methods such as intercropping. This study aims to assess the performance of an intercropping system comprising buckwheat and cowpea under deficit irrigation and minimal weeding. The research seeks to provide insights into the viability of this approach for sustainable agriculture in water-limited environments.

A field experiment was conducted in 2022 at the Agriculture and Natural Resources campus of the University of Tehran research farm in a randomized complete block design with split-split plot arrangements. The main plot factor included three levels of irrigation: 100% of the plant's water requirement (control), 85% of the water requirement and 70% of the water requirement compared to the control. The subplot factor consisted of five planting patterns: sole cultivation of buckwheat, sole cultivation of cowpea, and three intercropping patterns of buckwheat and cowpea with different row ratios (1:1, 3:1, and 1:3). Timing of weed removal, as the sub-subplot factor, was implemented at five levels: no weeding (control), weeding until the second, fourth, sixth, and eighth weeks after cultivation.

The highest grain yield of buckwheat (2436.9 kg ha-1) and cowpea (2495.5 kg ha-1) was observed in the sole cultivation plot with eight weeks of post-planting weeding under full irrigation. These results are attributed to higher planting densities in sole cultivation compared to intercropping. The 1:1 intercropping pattern with eight weeks of post-planting, exhibited the best cowpea leaf area index (3.36), and buckwheat (4.1) and similarly, this intercropping pattern with six weeks of post-planting resulted in the highest number of branches per plant (16). Sole cowpea plot under 85% deficit irrigation exhibited the highest weed dry weight (145.7 g m-2). The highest Land Equivalent Ratio (1.08), was observed in the 1:1 intercropping pattern with two weeks of post-planting weeding under full irrigation. Interestingly, the 1:1 intercropping pattern also showed the lowest weed biomass (12.1 g m-2) without specific weed management under 70% irrigation.

Most intercropping treatments achieved a land equivalent ratio greater than one, highlighting the superior efficiency of this planting method compared to sole cultivation. Specifically, the 1:1 intercropping pattern successfully controlled weed biomass, increased grain yields under deficit irrigation, and some for both crops. Therefore, intercropping offers a promising strategy to reduce reliance on herbicides and improve overall land use efficiency.

As one of the most important plants of the cereal family, wheat plays a very important role in world food security. The problem of food security in the world is facing a serious challenge due to severe climate changes and a lack of supplementary irrigation resources. Understanding the responses of plants to drought is the main part of the development of stress-resistant cultivars. The relative performance of genotypes under drought stress conditions and optimal conditions is one of the necessary and preliminary points in choosing the optimal genotypes for dry conditions. This study was conducted with the aim of identifying the relationships between indicators and determining the best indicators of drought tolerance, as well as selecting the best wheat lines suitable for cold and rainy regions for future breeding programs.

In order to identify the relationships between drought tolerance indices and determine the best index as well as select the best lines for future breeding programs, 144 wheat lines in the form of Alpha Lattice design in two replications and in two conditions of rain and supplementary irrigation in The rain research station of Zanjan Agricultural Research Center were investigated. Different tolerance and sensitivity indices including relative stress index (RSI), stress sensitivity index (SSI), stress resistance index (SRI), performance index (YI), performance stability index (YSI), relative reduction index (RR), Abiotic Stress Index (ATI), Tolerance Index (TOL), Mean Production Index (MP), Stress Tolerance Index (STI), Geometric Mean Productivity (GMP), Stress Sensitivity Percentage Index (SSPI), Harmonic Mean (HM) ), the index of product of stress and non-stress environment (SNPI) and yield loss ratio (PRR) were calculated.

The results of combined variance analysis showed that the effect of wet and rainy environment on the performance of lines was significant at the level of 1%. Also, the lines showed a significant difference in grain yield at the level of 1%. Drought stress decreased the grain yield of most lines in dry conditions. Line 82 had the highest yield in potential (2876 kg/ha) and rainfed (2000 kg/ha) conditions. Line 21 also had the lowest performance in two conditions (rainfed 825 and supplementary irrigation 1113 kg/ha respectively). Correlation results showed that grain yield in supplementary irrigation conditions had a positive and significant correlation with MP (0.56), GMP (0.56), HM (0.56), YI (0.55) and TOL (0.56) indicators. had 0.53). In the conditions of stress, MP (0.54), GMP (0.54), HM (0.54), and YI (0.53) indicators had the highest correlation with performance. Based on the first two selected components resulting from the decomposition into main components, which justified 91.35% of the changes, lines 90 and 102 were selected, which were also confirmed based on the three-dimensional diagram. The results of the cluster analysis of the lines also placed them in four groups, and lines such as 90, 131, 102 and 132 were also included in the group with high performance in both conditions. According to the results of this study, it is suggested to use the indicators of stress resistance, harmonic mean, geometric mean, and performance stability, which have the most significant positive correlation with performance in wet and dry conditions, in the selection of lines; Also, screening should be done based on the results of analysis into principal components and biplot and clustering using several indicators.

This experiment was conducted in order to investigation the effects of using different quantities of mineral biochar and spraying of methyl Jasmonate on some of the physiological and biochemical characteristics of spring barley under moderate and severe levels of drought stress at the experimental greenhouse of the university of Zanjan as a factorial experiment in randomized complete block design in pots in five replications in 2019-2020. In this experiment levels of stress included in three levels of drought stress (100% FC as the none stressed, 60% FC as the mild stress and 30% FC as the severe stress), biochar application before cultivation in three levels (without biochar, 1.5 % and 3% of the soil weight) and foliar spraying of methyl Jasmonate in three levels (0, 75 and 150 μmol per liter). Results showed that drought both in moderate and in severe levels caused significant difference in studied factors. Drought led to reduction in photosynthesis, stomatal conductance, photosynthetic water use efficiency, SPAD index as well as increasing in concentration of MDA, proline and soluble carbohydrate but using different levels of biochar in soil and spraying Methyl Jasmonate caused enhancement in these characteristics. Although using higher levels of these materials didn’t have considerable positive effects on studied factors. Moreover, application of higher levels of these materials, did not make considerable positive effects in some attributes and indexes. It seems that using these anti-stress substances, can be a stimulating approach against lack of water, however, utilization of higher levels can be more disastrous for crop plants.