نشریه پژوهشهای زراعی ایران
سال بیست و سوم شماره 1 (پیاپی 77، بهار 1404)

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.

Henna (Lawsonia inermis L.) is a perennial, dicotyledonous plant native to North Africa and Southeast Asia. This plant is cultivated in tropical regions as an ornamental species and for its dye production (Singh, Luqman, & Mathur, 2015). Drought stress directly affects a range of physiobiochemical and phytochemical processes, as well as molecular responses (Farooq, Wahid, Kobayashi, Fujita, & Basra, 2009; Rady, Belal, Gadallah, & Semida, 2020). Salicylic acid is a phenol-based phytohormone that regulates vital physiological activities within the plant, including water uptake, ion transport, transpiration, and photosynthesis (Klessig, Choi, & Dempsey, 2018). Sodium nitroprusside is a nitric oxide-releasing compound (Farouk & Al-Huqail, 2020). Nitric oxide inhibits free radicals by inducing gene expression and enhancing the activity of antioxidant enzymes, thereby protecting cells from damage caused by abiotic stresses (Ahmad et al., 2016).

This experiment was conducted in 2021 on a farm located in Qaleganj City, Kerman Province. The climate of Qaleganj is classified as semi-desert according to the dry amber method. The characteristics of the soil at the test site are detailed in Table 1. The experiment was carried out in the form of split plots based on a randomized complete block design with four replications. The main factor included three levels of irrigation (50%, 75%, and 95% of crop capacity), while the secondary factor involved foliar spraying with growth regulators (control, salicylic acid, sodium nitroprusside, and a combination of salicylic acid and sodium nitroprusside). The seeds of the henna plant (Lawsonia inermis L.) were obtained from the Faculty of Agriculture at Bahonar University, Kerman, Iran. The planting date for the henna plant was April 1, and the harvesting date was November 5.

The results showed that drought stress caused a decrease in traits such as plant height, leaf area index, and yield. Additionally, drought stress increased traits such as malondialdehyde concentration, ascorbate peroxidase enzyme activity, catalase enzyme activity, and phenylalanine ammonialyase enzyme activity. The application of the combination of salicylic acid and sodium nitroprusside enhanced the leaf surface index, ascorbate peroxidase enzyme activity, catalase enzyme activity, and phenylalanine ammonialyase enzyme activity. The highest seed yield from the treatment with the combination of salicylic acid and sodium nitroprusside was 3546.66 kg.ha-1 under irrigation conditions of 95% of crop capacity, while the lowest seed yield, from the treatment without growth regulator application, was 2243.33 kg ha-1 under 50% crop capacity conditions.

When faced with drought stress, the henna plant employs osmotic regulation mechanisms by increasing the accumulation of proline, thereby tolerating water deficit conditions to some extent. Spraying the combination of salicylic acid and sodium nitroprusside resulted in an increase in antioxidant enzymes, leaf surface index, and leaf density per hectare, helping to mitigate the destructive effects of stress. Based on the results of this research, it is recommended to use a salicylic acid and sodium nitroprusside solution under drought stress conditions to maintain performance in henna plants.

Thyme (Thymus vulgaris L.) is a perennial plant that belongs to Lamiaceae family, and native to the Mediterranean regions. Thyme is used in the medical, cosmetic and food industries due to its unique aroma and taste. The yield of thyme can be affected by environmental factors and agricultural management. Harvest cutting is one of the important factors determining the quantitative and qualitative characteristics of the thyme. It has also been reported that exogenous application of plant growth regulators at low concentrations has led to yield improvement. Cytokinins (CKs) are one of the five main types of plant growth regulators (PGRs) that affect plant growth and development. In addition to enhancing cell division and growth, CKs also prevent plant aging by inhibiting the breakdown of chlorophyll, nucleic acids, proteins, and other substances. CKs play a role in the transport and accumulation of photosynthesis products and affect the activity of enzymes. CKs also stimulate the growth of lateral branches, too. This study was conducted to investigate the effect of foliar spraying of cytokinin (benzylaminopurine) during harvest cuttings on the essential oil production and growth of thyme plant.

This experiment was carried out at the research farm of Razi University, Kermanshah, Iran (Longitude 47°, 9' east and latitude 34°, 21' north, 1319 m above sea level) during three consecutive years of 2017, 2018 and 2019. The research was conducted as a factorial experiment based on a randomized complete blocks design with three replications. The first factor was the harvest cutting (late June and late September) and the second factor was the concentrations of cytokinin (0, 100, 200 and 400 μM BAP). The measured traits included plant height, stem diameter, number of branches, leaf, stem and total dry weight, percentage and yield of essential oil. The analysis of variances (ANOVA) of data was performed using SAS ver.9 software and the means comparison was done using LSD test at 5% probability level.

The results of analysis of variance showed that the effect of harvest cutting on the traits of plant height, stem diameter, number of branches, leaf, stem and total dry weights and essential oil yield was significant, but its effect on the essential oil percentage was not significant. Also, the effect of foliar spraying of BAP was significant on all the mentioned traits. The interaction effect of harvest cutting × BAP spraying was significant on the number of branches, dry weight of leaves and stems, total dry weight and essential oil yield. A comparison of means showed that the highest plant height, number of sub-branches, leaf dry weight, stem dry weight and total dry weight (4355 kg ha-1) were obtained by foliar spraying of 400 µM BAP. The percentage of essential oil increased with the increase of BAP concentration. The highest essential oil (2.35%) was obtained by foliar spraying of 200 μM BAP. The highest and lowest essential oil percentage were obtained in 2020 and 2018 experiments, respectively. Also, the yields of essential oil were different in different cuttings under the influence of BAP foliar application. The increasing of the essential oil yield in the first harvest was higher compared to the second harvest. Foliar spraying of 400 μM BAP in the first harvest produced the highest essential oil yield (59.95 kg ha-1).

In general, the results of this study indicated that cytokinin spraying during the first harvest significantly influenced on the enhancement of traits such as plant height (16%), number of lateral branches (59%), leaf dry weight (200%), total dry weight (194%), and essential oil production (108-217%) in thyme. Additionally, as the plant aged (in the third year of the experiment), this enhancement in essential oil production was more. To enhance essential oil yield and vegetative growth of thyme, it is recommended to apply 400 µM cytokinin spraying during the first harvest.

The food security of any country is directly dependent on the production of its agricultural sector, and any disruption in the production process of this sector can directly threaten the food, social, economic and even political security of the country. In other words, the agricultural sector, as a productive sector, is responsible for eliminating and reducing poverty and ensuring food security. In the current situation, due to the ever-increasing demand and the significant growth of the population, the indiscriminate and incorrect exploitation of limited and non-renewable resources and reserves, as well as the occurrence of challenges such as climate change, ensuring food security and maintaining it, are of great importance. The purpose of this study was to investigate the availability of crop products in Razavi Khorasan province in two horizons of 5 and 10 years under two scenarios of full irrigation and deficit irrigation in accordance with the water capacity of the province and to provide appropriate solutions.

This study was carried out in Razavi Khorasan province for the time period of 2017-2020 as the baseline and 2024-2028 and 2024-2033 as 5- and 10-year horizons, respectively. The information needed for this study was obtained through documentary and library studies, generally by referring to the official centers that publish the country's information and published documents (especially the Ministry of Agriculture and the Agricultural Jihad Organization of Razavi Khorasan province), field information and also by completing the questionnaire from national experts and holding meetings with stakeholders and experts. Finally, the changes in the harvested area, yield, production, volume of water consumption and water productivity of important irrigated (under two scenarios of full irrigation and deficit irrigation) and rainfed crops, as well as indicators of per-capita consumption, production, demand, trade, and the percentage of self-reliance of these crops were estimated and evaluated in 5- and 10-year horizons compared to the baseline (2017-2020).

According to the results, if the objectives of this study are achieved, the crop water requirement and total water consumption will decrease across both scenarios and time horizons, while water productivity will improve compared to the baseline. In the projected horizon periods, the yield of both irrigated and rainfed crops will increase compared to the baseline. The harvested area of irrigated crops will decrease, while the harvested area of rainfed crops will expand. However, under deficit irrigation conditions, the production of both rainfed and irrigated crops will rise, whereas irrigated crop production under full irrigation conditions will decline, aligning with water balance objectives. These changes will occur mainly due to the increase in the harvested area and production of fodder sorghum, silage, fodder beet, and autumn beet and the decrease in the harvest area and production of alfalfa, irrigated vegetable crops, and spring beet. Despite the increase in the demand of important crop products of the province in 5- and 10-year horizons by 10 and 17% (considering population growth and improvement in per-capita consumption), respectively, the amount of production of these products will decrease by 2% in 5-year horizon and increase by only 1% in 10-year horizon. Therefore, it is predicted that the self-reliance of the province's total production will decrease from 74% in the baseline to 68% and 67% in the 5- and 10-year horizons, respectively. In order to achieve the results of this study, solutions such as paying attention to aquifers and watersheds, cultivation of fallow lands, increasing soil organic matter, real development of conservation agriculture, development of autumn and waiting planting, development of alternative crops (especially fodder crops), and provision, production, distribution, and consumption of inputs in a timely and appropriate manner are suggested.

In total, the results of this research showed that the proposed production pattern for crops in Razavi Khorasan province and 5 and 10-year horizons will be consistent with the water capacity of the province, especially in the deficit irrigation scenario. However, the realization of the results of this study requires the categories of "research", "technology", "education and empowerment", and "promotion of achievements".

In recent years, population growth on the one hand and climate change on the other, have increased the need for higher agricultural production. With the expansion of cultivated areas and increasing use of chemical fertilizers, the health of the environment and humans has been jeopardized. Consequently, recent studies have begun on the type of fertilizers used, the best fertilizer composition, and how to use them. Various studies have shown that organic fertilizer can ensure the sustainability of agricultural systems’ production, sometimes as a replacement and most often as a supplement to chemical fertilizers. In conditions where climate change and the salinization of agricultural lands have had noticeable effects on the production of various crops, the need for resilient plants becomes more apparent. Quinoa (Chenopodium quinoa Willd.) is a crop that is resistant to environmental stresses and is nutritionally very rich, to the extent that its amino acid composition is compared to that of mother’s milk. The current research aims to investigate the effects of foliar application with seaweed extract on the growth and performance of different quinoa genotypes.

This research was conducted in the summer and autumn of 2020 at the educational and research farm of the Faculty of Agriculture and Natural Resources of the Islamic Azad University, Karaj unit. The study was carried out as a split-plot experiment (5×3), based on a randomized complete block design with three replications. The main factor in this research was the fertilizer factor, which included 3 treatments: control: (without foliar application with seaweed extract), foliar application with seaweed extract at a concentration of 10 percent, and foliar application with seaweed extract at a concentration of 20 percent, placed in the main plot. The other factor was the genotype of the quinoa plant, which included 5 genotypes: Giza1, Titicaca, Rosada, Kancolla, and Q12, placed in the subplot. At different stages of plant growth, traits such as seed saponin content, thousand seed weight, seed yield, days to physiological maturity, days to flowering, dry plant weight, fresh plant weight, stem diameter, inflorescence length, and plant height were measured.

The foliar application of seaweed extract had a significant effect on various traits, with a **1% significance level** for days to flowering, days to physiological maturity, inflorescence length, thousand seed weight, and seed saponin content, and a **5% significance level** for plant height. The simple effect of genotype was significant at the 1% level for all traits except for thousand seed weight. The interaction effect of foliar application × genotype was significant at the 5% level for days to flowering. The application of seaweed extract reduced the number of days to flowering by **3.8 days**, days to maturity by **4.8 days**, plant height by **5%**, and inflorescence length by **10%**. However, it had no significant effect on seed yield, as well as the fresh and dry weight of aerial parts. The highest seed yield was related to genotype Q12 (2477 kg.ha-1) and the highest thousand seed weight was related to the Giza 1 variety (2.47 g). Plant height showed a significant negative correlation with seed yield and thousand seed weight.

The use of seaweed fertilizer in the nutrition of different quinoa genotypes showed varying effects. However, the impact of this fertilizer in reducing the growth period of quinoa, which is one of the most important issues facing quinoa cultivation in our country, is very significant. The differences between the genotypes studied in this research were quite evident, but it seems that special attention should be paid to the purpose of quinoa cultivation when selecting the superior genotype. If the goal of quinoa cultivation is forage production, the Rosada genotype is recommended, otherwise, the Q12 genotype is advised.

Wheat (Triticum aestivum L.) is important in the food regime of three-quarters of the world's population because it is nutritious and cheap compared to other similar foods. The competition between wheat and weeds is considered as one of the most important limitations of global wheat production. In Iran, weeds are of particular importance in reducing wheat yield, and according to the surveys, the average damage caused by weeds in the country's wheat fields is 23%. The most common way to manage wheat weeds is herbicide application. Every crop resists herbicides at a given growth stage, otherwise, herbicide application will damage the main crop. In recent years, the most frequent broadleaf herbicides used for weed chemical control in wheat are 2-4-D + MCPA (U46 combi fluid). To apply the 2,4-D herbicide, wheat should be at the tillering to the appearance of the first visible node stage. Application of 2,4-D after the first node will cause spike deformation and yield reduction due to the adverse effect of herbicide on sporogenesis. This study investigated different application times effects of 2-4-D + MCPA (U46combifluid) and Bromoxynil + MCPA (Bromicide MA) on winter wheat yield and weed control. The study aimed to determine the application time of the best herbicide with minimal damage on dryland wheat.

To investigate the effect of hormone herbicides on weeds and the yield of dryland bread wheat in different vegetative growth stages in cold dryland areas, a field experiment was conducted as a randomized complete block design arrangement with four replications during 2021-23 cropping seasons at the Dryland Agriculture Research Institute, Maragheh, East Azerbaijan. Treatments included the application of 2-4-D + MCPA (U46combifluid) and Bromoxynil + MCPA (Bromicide MA) (1.5 L ha-1) at the tillering (Z29), the 2nd   node (Z32), and the booting stages (Z45) with two control treatments of weeding (weed infested) and no weeding (weed free). The Varan wheat cultivar was sown at a depth of 4–6 cm with a seeding density of 380 seeds per square meter. To evaluate weed type and density (plant m-2), sampling was done 30 days after herbicide application. The crop was harvested at full maturity to collect data for grain yield and a thousand grain weight and grain/spike. After checking the normality of the data, they were analyzed with GenStat (V.12) software and the mean comparison was performed by the Least Significant Difference (LSD) test at the 5% probability level.

The results indicated that the weed growth time is affected by the rainfall in dryland conditions so that in the 2021-2 year, the main spring precipitations occurred in May while in the 2022-23 year, it happened in April. Therefore, for the first cropping season, the highest weed density was recorded in the second   node stage whereas at the tillering stage in the second cropping season. In the first year, due to lower rainfall, and drought stress, a further decrease in wheat yield was observed in response to the delayed herbicide application so that it was higher in the 2-4-D + MCPA herbicide treatment. In the 2021-22 year, the lowest yields were recorded for 2-4-D + MCPA and Bromoxynil + MCPA herbicides in the booting stage with 1568 and 1710 kg ha-1, respectively. In the 2022-23 year, the lowest grain yield was observed for 2-4-D + MCPA in the second node, and booting stages, respectively, 1701 and 1747 kg ha-1.

Based on the results, wheat is more sensitive to delayed application of 2-4-D + MCPA and reduces wheat yield more, in contrast, it is more tolerant to bromoxynil + MCPA herbicide (Bromicide MA), and it can be applied up to the 2nd node stage (Z32).

Chickpea (Cicer arietinum L.) is an important pulse crop that also serves as a soil enhancer. Among the abiotic stresses, water deficit under rain-fed conditions limits crop production. In this regard, stress modifiers application (such as humic acid, nano iron oxide, and vermicompost) can decrease the effects of water deficit under rain-fed conditions and increase grain filling components, relative water content and quantum yield of plants. Iron (Fe) is an essential element in crop plants. Application of iron and humic acid alleviates drought effects due to enhancement in chlorophyll content, relative water content and nodulation in chickpea plants under stress. The aim of this study was to evaluate the effects of supplementary irrigation and stress modifiers (such as humic acid, nano iron oxide and vermicompost) on nodulation and yield of chickpeas under rain fed conditions.

A factorial experiment was performed at a farm near Ardabil city in 2023 using a RCBD with three replications. Experimental treatments were vermicompost (without application as control, application of 4 and 8 ton.ha-1), irrigation at two levels (rainfed as control and supplementary irrigation at the flowering stage) and application of humic acid and nano iron oxide (no application as control, application of humic acid, nano iron oxide, humic acid and nano iron oxide foliar application). The chickpea cultivar ‘Adel’ was planted with the optimal density of 35 seeds.m-2. Vermicompost was prepared by Gilda Corporation and nano iron oxide from Pishgaman Nanomaterials Company. Application of nano iron oxide and humic acid was in two growth stages (vegetative growth and before flowering). In order to study the nodulation, three pots (with a diameter of 45 and depth of 60 cm) were sown in each plot before planting. The pots were removed at flowering and after washing, some traits like the number of inactive and active nodules were recorded. To investigate grain filling components, the first sampling was taken 14 days after podding and other samplings were taken in 5-days intervals to determine the accumulation of grain weight. The protein amount was calculated by multiplying the nitrogen content by 6.25. For the determination of grain yield, 0.5 m2 were harvested in each plot.

The results showed that chlorophyll index, relative water content, quantum yield and number of pod per plant were significantly affected by the main effects of irrigation levels, vermicompost and humic acid. Also, irrigation levels×vermicompost×humic acid interactions had a significant effect on grain filling components (grain filling period; grain filling rate; effective grain filling period; maximum of grain weight) and grain yield. The results indicated that water deficit under rainfed conditions compared to supplementary irrigation at flowering stage led to a significant decrease in chickpea yield and yield components. However application of stress modulators (vermicompost, nano iron oxide and humic acid) and supplementary irrigation at flowering stage moderated the adverse effects of stress. Modulating effects of studied vermicompost, nano iron oxide and humic acid were emerged by physiological traits improvement‎ (SPAD, quantum yield, grain filling components, number of active nodules  and  nodule dry weigh, and improvement of the water status (relative water content). The use of supplementary irrigation and stress modifiers (vermicompost, nano iron oxide and humic acid) increased grain filling rate (51.96%), grain filling period (62.5%) and effective grain filling period (44.61%) in compared to the no application of stress modifiers under rainfed condition. Application of vermicompost with nano iron oxide and humic acid increased number of active nodules (2.8 fold), nodule dry weigh (45%) and percentage of active nodules (2.3 fold) in compared to control (no application of stress modulators). Also, the application of stress modulators and supplementary irrigation at flowering stage had the highest efficiency in improving grain yield and led to 57% increase in grain yield compared to the no application of theirs under rain fed conditions.

Based on the results of this study, applying supplementary irrigation at flowering along with stress modifiers can enhance nodulation, grain filling components, and grain yield of chickpea under rainfed conditions.