نشریه پژوهشهای زراعی ایران
سال بیست و دوم شماره 1 (پیاپی 73، بهار 1403)

Nowadays, the cultivation of plants adapted to adverse conditions, such as drought and salinity, in the country has been considered. Meanwhile, Kochia scoparia, one of the forgotten plants, due to its classification in the group of halophytes, has specific characteristics suitable for cultivation in low-water and saline areas (Salehi, Kafi, & Kiani, 2012). This plant is known as an important annual forage crop, and its grains also have high nutritional value and oil, which can be considered for future industrial applications (Salehi et al., 2012). Studies on the salinity tolerance of the Kochia plant have shown that it is suitable for cultivation in saline areas, and in terms of quantity and quality, can compete with conventional forage plants. The use of natural organic materials, such as humic acid, has received more attention. These materials, as part of soil organic matter, are influenced by physical, chemical, and microbiological changes in biological molecules (Sabzevari & Khazaei, 2009; Dong, Córdova-Kreylos, Yang, Yuan, & Scow, 2009). Additionally, nitrogen is the most important element needed for plant growth and development. It is also a key component in many biological compounds, including proteins, nucleic acids, some hormones, and chlorophyll. Nitrogen plays an essential role in photosynthetic processes and the final function of plants (Kaur, Gupta, & Kaur, 2002; Taiz, Zeiger, Møller, & Murphy, 2015). As a result of this research, a combination of nitrogen and humic acid can be used as nutritional resources in salt stress conditions.

This experiment was conducted in the form of split plots based on the randomized complete block design with three replications in the Saline Research Farm of Ferdowsi University of Mashhad in the 2015 growth season. The main plot included drought stress with a four-week interruption of irrigation at three levels of control (irrigation until the end of the growing season), after establishment (50 days after planting), the beginning of flowering (71 days after planting) and late flowering (82 days after planting) The subplot was included nitrogen application at three levels of zero, 100 and 200 kg.ha-1 from urea fertilizer source. The optimum level of humic acid (2 per thousand) was done as seed at the time of planting for all treatments.

The results showed that the drought stress during vegetative and reproductive growth stages had a negative effect on the Kochia plant. However, its effect in the early stages of vegetative growth (after establishment) was greater than the stress at the end of the season (late flowering). Drought stress has a negative effect on Kochia grain yield by reducing the concentration of chlorophyll a, altering the chlorophyll a to b ratio, decreasing carotenoid concentration, and affecting relative leaf water content. However, seed treatments of humic acid and its combination with 100 kg.ha-1 nitrogen level by increasing the concentration of total phenol, soluble carbohydrate concentration, and DPPH free radical scavenging capacity improved photosynthetic pigments and finally kochia grain yield. In general, the most suitable treatment for use in drought stress and saline water source conditions was the combined method of sowing humic acid seeds with 100 kg.ha-1 nitrogen fertilizer.

In general, the occurrence of drought stress in vegetative and reproductive growth stages had a negative effect on the kochia plant. However, its effect in the early stages of vegetative growth (after establishment) was greater than the stress at the end of the season (late flowering). The most suitable treatment was using the combined method of seed of humic acid with 100 kg.ha-1 nitrogen fertilizer.

Chickpea (Cicer arietinum L.) is one of the most important crops in the human food basket worldwide. It is a highly nutritious pulse crop with low digestible carbohydrates, protein, essential fats, fiber, and a range of minerals and vitamins. As the human population grows, the demand for this protein source increases and various approaches to its sustainable products are being developed. Autumn cultivation of chickpea in cold regions requires the introduction of cultivars tolerant to freezing stress. The ability of plants to overwinter depends on the biochemical and physiological responses induced by their cold acclimation duration. Cold acclimation mechanisms in the plant are a fundamental reason for plant tolerance increase in autumn cultivation. Hence, investigating the mentioned traits can help identify cold-tolerant genotypes. Identifying attributes that provide a suitable description of the diversity between genotypes is critical through canonical correlation analysis, cluster analysis, and determining the genetic distance.

This experiment was conducted during the 2017-18 growing season in the research field of Ferdowsi University of Mashhad, Iran (Lat 36° 15′ N, Long 59° 28 E; 985 m Altitude). Chickpea germplasm, including 29 Desi-type chickpea genotypes and one cold tolerant cultivar (cv. Saral), was studied in terms of morpho-physiological and biochemical attributes and their relationship with yield and yield components. Chickpea seeds were provided from the Mashhad chickpea collection at the Research Center for Plant Science. Following seedbed preparation by ridge tillage in October 2017, chickpea seeds were sown with a density of 40 plant m-2. Irrigation was conducted three times during the growth period: immediately after sowing, two weeks after the first irrigation and flowering stage. Hand-weeding was done three times during the growth stage in early March, early April, and early May. Data were analyzed using the SAS 9.4 software, and the mean comparison was performed by the Duncan Multiple Range Test (DMRT) at a 5% probability level. Statistica software also performed a cluster analysis (based on Euclidean distance) and principal component analysis (PCA).

Evaluating the morpho-physiological performance of chickpea genotypes is valuable for breeding programs that integrate chickpea cold tolerance. Based on Pearson's correlation coefficient results, a significant positive correlation was observed between the survival of chickpea germplasm with seed yield and biological yield. Also, a significant negative correlation between survival with photosynthesis pigment content and Fv'/Fm' revealed a high relationship between these parameters. Traits with the highest canonical discriminate coefficients had the best effect on the diversity across the studied genotypes. Based on the factor analysis results, the first factor with 22.8%, and the second with 12.1% explained the most differences. In the first factor, the most critical traits with a positive charge are Fv'/Fm', the total content of photosynthetic pigments, starch, the number of fertile pods, and the number of seeds, and the critical trait with a negative charge was the survival. The genotypes of the five cluster analysis groups had a higher mean in 54% of the traits compared to the total mean. The crossing of genotypes of group one due to higher survival and seed yield and genotypes of group five due to plant height and first pod height (compared to the total mean), which also have a considerable genetic distance, can lead to the release of new varieties. Also, the genotypes of the three cluster analysis groups (MCC32, MCC34, MCC155, MCC194, MCC199, and MCC291) have high-priority traits for selection by breeders and can be used in breeding programs for autumn cultivation.

According to the results of the present study, selection for successful overwintering of desi-type chickpea genotypes in cold regions is recommended based on the mentioned characteristics in breeding programs. The group three chickpea genotypes of cluster analysis (MCC32, MCC34, MCC155, MCC194, MCC199, and MCC291) and morpho-physiological and biochemical attributes affecting the yield and yield components determined from this study may be helpful for genetic engineering and breeding programs that integrate chickpea cold tolerance.

Agriculture is a cornerstone of many developing economies, providing food, income, and employment for millions of people. It is also projected to play a vital role in feeding a global population of 9.1 billion people by 2050. However, there are growing concerns about the environmental impact of agriculture, particularly in arid and semi-arid regions like Iran. Managing water and fertilizer usage in agriculture is crucial to ensuring food security and sustainability. However, conducting field experiments to assess the interaction of all factors involved is expensive and time-consuming. This research focuses on optimizing maize production in Kerman province, a region where maize is a major crop. The research is motivated by the need to improve resource management in Iran, where water and fertilizer resources are limited. The APSIM model is used to determine the best management scenario for maize production in Kerman province. APSIM is a crop growth simulation model that can be used to predict the impact of different management practices on crop yield, water use efficiency, and nutrient use efficiency. The use of APSIM in this research provides a cost-effective and time-efficient alternative to conducting extensive field experiments. The results of this research will contribute to the development of sustainable and efficient agricultural practices in Kerman province and similar regions. These regions are characterized by resource constraints, such as limited water and fertilizer availability. The research aimed to simulate the effect of management parameters (planting date and irrigation) on Crop yield and subsequently achieve the optimal management scenario.

The APSIM model was used for simulation in three regions of Bardsir (temperate to cold climate), Jiroft (hot and humid climate), and Orzuye (hot and dry climate). The model requires four series of data: climate, soil, management, and crop data. The required climate data (from 1998 to 2018) including daily maximum and minimum temperatures, length of sunny hours, and daily precipitation were collected and prepared from the synoptic weather stations of the three mentioned regions.The management data set for each of the study regions was prepared in the form of questionnaires and field research from experts of the Agricultural Jihad Organization, the Agricultural Research Center Organization, and prominent farmers in those regions. The crop data includes the plant genetic coefficients of the maize single cross hybrid 704, which were obtained from the calibration of the APSIM model. To optimize planting date and irrigation management in the studied areas, different planting and irrigation date treatments were investigated. In this research, planting date treatments included the conventional planting date of the region, 20 days before the conventional planting date (as early planting date), and 20 days after the conventional planting date (as late planting date). Irrigation treatments included the usual number of irrigations in the region (13 irrigations), less irrigation (11 irrigations), and more irrigation (15 irrigations).

Our results showed that the model successfully simulated maize phenology, especially maturity date, with high accuracy for all fertilizer amounts tested. The model performance in predicting biomass under different nitrogen treatments was also satisfactory, with a minimal difference between observed data and model results. The nRMSE of grain yield in the calibration stage was 11.2% and in the validation stage was 9%. The nRMSE for calibration of the biological yield of SC 704 was 14.8% and for validation was 13.9%. Also, the model was able to simulate phenology with very high accuracy (especially the days to maturity). Overall, the nRMSE of days to flowering was less than 10% and for the days to maturity was less than 5%. Late planting dates consistently showed better performance across regions and irrigation treatments, resulting in significantly increased grain yield compared to conventional and early planting dates. The highest seed yield was obtained with 15 times of irrigation, among the various irrigation treatments. Late planting combined with 15 times of irrigation yielded the best results in Kerman province, particularly in Bardsir, with a yield of 9300 kg ha-1. Optimal moisture and air conditions, along with the cultivation of a late-maturing variety, contributed to the higher seed yield. These findings are consistent with previous research that has confirmed the positive impact of late planting and extended ripening periods on maize yield.

Our results showed that the model simulates the growth and yield of single cross 704 corn in Kerman province well, even after 20 days of late planting. Long-term simulation experiments showed that maize grain yield varied depending on the region, with the highest yield in Bardsir (8317 kg ha-1) and the lowest yield in Jiroft (4735 kg ha-1). The optimum maize grain yield (8872.8 kg ha-1) was obtained by the interaction effect of late planting date and 15 times of irrigation.

Deficit irrigation offers a solution for optimizing crop production under water stress conditions, albeit with an initial reduction in yield per unit area. Employing deficit irrigation aids in farm management in scenarios where land availability isn’t constrained, enabling the determination of optimal cultivation patterns while conserving water consumption. However, deficit irrigation may influence plant growth and development by inducing drought stress. Due to several capabilities, quinoa shows resistance to solar radiation, temperature, water availability, and atmospheric CO2 concentration, which makes it possible to cultivate it in different agricultural areas. Quinoa also has a great capacity for cultivation in dry and low-water soils. Although growth analysis sometimes provides valuable clues, it does not provide any physicochemical information related to the environmental reactions of plants; in other words, the main benefit of many quantities involved in growth analysis is to provide an accurate estimate of the ability and efficiency of the plant in the community at certain time intervals. In general, growth analysis evaluates the system based on the results of physiological manifestations. The purpose of this research was to evaluate the physiological growth analyses of three quinoa cultivars under different moisture levels in summer and spring planting dates in the South Khorasan region.

To evaluate the physiological traits of three quinoa cultivars under deficit irrigation conditions, four separate experiments were conducted using a factorial layout based on a randomized complete block design. These experiments included three replications and were carried out in two regions (Birjand and Sarbisheh) during two planting dates (March and July) in 2018-2019. The experimental factors consisted of five moisture levels (ranging from 25% to 125% of crop water requirement) and three quinoa cultivars (Titicaca, Giza1, and Redcarina). To compare the cultivars and assess the impact of humidity levels, several physiological indices—such as leaf area index (LAI), crop growth rate (CGR), relative growth rate (RGR), and net assimilation rate (NAR)—were studied. Regression curves were fitted to the data from all four experiments separately, and separate analyses of variance were also performed for each sampling time.

The trend of changes in the leaf area index (LAI) showed that the time needed to reach the maximum LAI was observed between 106 to 107 days after emergence in March and between 73 to 76 days after emergence in July in Birjand, respectively. In Sarbisheh, the maximum LAI was observed on day 104 after emergence in March and between 65 to 72 days after emergence in July. In March, in both studied areas, Redcarina had the highest LAI values (4.5 in Birjand and 6.7 in Sarbisheh), along with the maximum crop growth rate (CGR) of 17.93 g m-2 day-1 in Birjand and 20.63 g m-2 day-1 in Sarbisheh. Conversely, in July, Giza1 exhibited the highest LAI (6.4 in Birjand and 6 in Sarbisheh), along with the maximum CGR of 19.32 g m-2 day-1 in Birjand and 18.11 g m-2 day-1 in Sarbisheh. Additionally, the highest relative growth rate (RGR) and net assimilation rate (NAR) at the beginning of the growing season in March were observed for Redcarina, while in July, Giza1 demonstrated the highest RGR and NAR in both studied areas. Considering the effect of humidity levels, the highest levels of LAI, CGR, RGR, and NAR indices were observed at the 125% water requirement level. Specifically, the maximum LAI values in March (in Sarbisheh and Birjand) and August (in Sarbisheh and Birjand) were 8.2, 5.3, 6.5, and 7.2, respectively. The maximum CGR values were 28.78, 23.56, 22.96, and 26.18 g m-2 day-1, respectively. Furthermore, the highest RGR at the beginning of the growing season ranged from 0.189 to 0.214 g g-1 day-1, and the highest NAR at the beginning of the growing season ranged from 6.16 to 10.22 g m-2 day-1. Conversely, the lowest values of these indices were observed at the 25% water requirement level.

Overall, Redcarina, cultivated in March, and Giza1, cultivated in July, exhibited the most favorable growth analysis indices and grain yield compared to other cultivars. Additionally, deficit irrigation resulted in a decrease in all of these indices and grain yield.

Sunflower, one of the primary oilseed crops worldwide, is cultivated extensively due to its suitability for agricultural needs, high oil yield, and nutritional and medicinal value. However, drought remains the most critical limiting factor affecting sunflower productivity. In arid and semi-arid regions, the intensity of drought stress is predicted to increase in the future. Unfortunately, severe drought stress leads to significant reductions in both seed and oil production. While sunflower is moderately drought-tolerant, understanding the physiological and agronomic aspects of drought stress is crucial for sustainable management. Given that water, scarcity poses a significant threat to crop productivity and environmental resources are diminishing, effective irrigation management under water scarcity is becoming increasingly important.

In order to study the effects of deficit irrigation on grain yield and physiological traits of six sunflower cultivars, a field experiment was carried out in a split-plot arrangement based on randomized complete block design with three replications in 2019-2020 growing season. The experimental site was located in the research farm of the Safiabad Agricultural and Natural Resources Research and Education Center. Main plots consisted of three irrigation regimes including; control, moderate, and severe deficit irrigation (50, 70, and 90% of available moisture, respectively), and sub plots consisted of six sunflower cultivars including; Oscar, Felix, Shakira, Savana, Labad and Monaliza.

Different levels of deficit irrigation differently caused a significant reduction in stomatal conductance, photosynthetic rate, chlorophyll index, relative water content, grain yield, grain number per head, grain weight per head, and oil yield, when compared to control. Oscar cultivar with the highest stomatal conductance, photosynthetic rate, and chlorophyll index, produced the highest economic oil and grain yield while the Shakira cultivar showed the lowest grain yield values in different levels of deficit irrigation. Oscar in 50% of field capacity and Shakira in 90% of field capacity showed the highest and lowest grain yield values (5.34 and 2.67 ton ha-1, respectively). Labad maintained the highest grain yield in 70 and 90% of field capacity relative to the control (4.41 and 4.28 ton ha-1, respectively). It seems that deficit irrigation leads to a significant reduction in grain yield by reducing the reproductive stage, producing fewer seeds, and the impossibility of transferring assimilates to fill the grains. Moreover, the reduction of oil percentage is probably due to the acceleration of achene ripening, giving the plant a chance to escape from drought, because carbohydrates first accumulate in the achenes and then turn into oil or any other substance. Photosynthetic rate, stomatal conductance, light absorption, relative water content, leaf area index, chlorophyll index, and transpiration rate decreased by 49, 25, 28, 26, 48, 22 and 78%, respectively in severe deficit irrigation, while water use efficiency and canopy temperature increased by 58 and 16 % respectively. 

Various levels of deficit irrigation exerted an influence on the physiological characteristics and grain yield of sunflower cultivars. The extent of water scarcity emerged as a significant factor shaping the cultivar responses to deficit irrigation. Felix and Labad exhibited higher oil yield and are thus recommended for cultivation in Dezful and analogous regions, owing to their superior grain yield and ability to sustain grain yield under deficit irrigation conditions.

Prolonged droughts and lack of water resources, followed by the salinity of water and soil resources, have faced many limitations in the production of some conventional agricultural and garden plants, especially in arid and semi-arid regions of the country. Therefore, the introduction of new plants with high yield potential, which have suitable growth in saline soils, the threshold of their seed yield reduction is high, and the production product is of high quality has been considered in Iran. Quinoa with the scientific name Chenopodium quinoa Willd. It is an annual plant originating from Latin America, which, despite its high nutritional value, tolerates a wide range of abiotic stresses and can grow in marginal lands. For this reason, this experiment was conducted to investigate the performance of quinoa plant genotypes against different levels of salinity in the research field of the Gorgan Agricultural Meteorological Research Department.

Cultivation of seeds of nine genotypes Titicaca (control number), Giza1, RedCarina, Q18, Q21, Q22, Q26, Q29, and Q31 obtained from Karaj Seedling and Seed Breeding Research Institute in a factorial experiment based on a complete random block design. Plastic pots were made with a bed of sand and clay in a ratio of two to one on March 5, 2019. The application of NaCl salt solution treatments at the levels of zero, 10, 20, and 30 decisiemens/m started after the establishment of the plant and reached the six-leaf stage and lasted for 45 days. After salinity treatment, morphological traits including plant height, stem diameter, number of sub-branches, inflorescence length, inflorescence width, biomass, 1000 seed weight, and seed weight per plant were measured.

According to this study, with the increase in NaCl salinity level, there was a significant decrease in all traits. Different genotypes also had significant differences in most traits in each salinity treatment. The RedCarina and Q12 genotypes consistently exhibited poor performance across all salinity levels in the examined traits, whereas the Giza1 and Q21 genotypes demonstrated high performance in most traits, indicating sensitivity and tolerance, respectively. These two groups of genotypes consistently clustered together in both cluster analysis and biplot tests across different salinity levels. However, some genotypes displayed relative performance variations at different salinity levels. For instance, the Titicaca cultivar excelled at high salinity levels of 20 and 30 dS.m-1, while the Q29 and Q31 genotypes exhibited high performance and tolerance to salinity stress at low salinity levels of zero and 10 dS.m-1. Genotypes that had high yield potential at low salinity levels had the highest yield in vegetative traits at salinity levels of 20 and 30 decisiemens, but had the lowest values in reproductive traits, especially in seed weight. In Principal Component Analysis, reproductive traits explained the most changes in high salinity levels. Salinity stress caused a significant decrease in most of the traits of the quinoa plant. The response of genotypes to different salinity levels was different. In addition, the genotypes showed different performance even in different growth phases. The high performance in traits related to the vegetative phase and weak response in the reproductive phase show that the granulation stage in the quinoa plant can be introduced as a salinity-sensitive stage. These results also show the high diversity of quinoa plant genotypes in each of the different salinity levels.

Rapeseed is the second most important plant for oil production in the country due to having more than 40% of oil in the seed, resistance to some environmental stresses, and suitable combination of fatty acids. Water deficit in the stage of reproductive growth severely affects the rapeseed yield because the number of seeds and the weight of seeds decrease. Water shortage in the flowering stage also reduces the seed oil percentage and oil yield of rapeseed. In some areas of Khuzestan province, rapeseed is mainly cultivated as a beak crop. This issue causes the growth period of rapeseed to coincide with the growth of some other crops. In this situation, some irrigation turns are necessarily allocated to other plants (including wheat, which is in the pollination stage, and okra, which is in the germination stage), which causes rapeseed to face water shortage, even in the flowering stage. Therefore, it is necessary to apply appropriate management methods to reduce the effects of drought stress on rapeseed during the flowering stage. Among these methods is the use of vermicompost fertilizer and changing the planting date. The present study aimed to address the following inquiries: What impact does vermicompost fertilizer, planting date, and drought stress during the flowering stage have on rapeseed seed and oil production? Can the utilization of vermicompost fertilizer and adjustments to planting dates mitigate the adverse effects of water deficit stress on rapeseed yield?

A field experiment was conducted at the research farm of Shadegan Payam Noor University, Khuzestan, Iran in 2022-23 growing season. The experiment was carried out as a three-factor factorial 2x3x2 with three repetitions. The experimental factors included planting date (November 25 and December 25), vermicompost fertilizer (0.0, 10, and 20 ton ha-1), and irrigation (full irrigation and interruption of irrigation during the flowering stage). In each irrigation stage, the volume of irrigation water was measured and to calculate the efficiency of water consumption, the yield (seed and oil) was divided by the amount of evapotranspiration. At the maturity stage, the seed yield and its related traits included the number of pods per plant, the number of seeds per pod, the weight of 1000 seeds, biological yield, harvest index, oil and protein percentage of seed were calculated.

Rapeseed had the highest seed yield (2667 kg ha-1) on the planting date of November 25 with full irrigation, while delay in planting (planting date of November 25) and interruption of irrigation during the flowering stage resulted in the lowest seed yield (1247 kg ha-1) which means a decrease of more than 50% in seed yield. However, if rapeseed is planted on December 25 and fully irrigated, it has a higher seed yield (about 15%) than planting on November 25, along with stopping irrigation during the flowering stage. A similar trend was observed in seed oil percentage and oil yield, so the highest and lowest percentage and yield of rapeseed oil were obtained on the planting date of November 25 with full irrigation and the planting date of December 25 and stopping irrigation at the flowering stage, respectively. The delay in planting and drought stress in the flowering stage reduced the percentage of rapeseed oil by 6% and the yield of oil by about 60%. On the planting date of November 25, rapeseed was superior to the planting date of December 25 in terms of the number of seeds, 1000-seed weight, biological yield, and water efficiency by 35, 25, 23, 18, and 38%, respectively.

Vermicompost fertilizer helped to improve rapeseed seed yield by providing important nutrients. Stopping irrigation during the flowering stage and delaying planting caused a decrease in seed yield and rapeseed oil production. Therefore, to obtain the maximum yield of seed and oil, it is recommended to plant on the 25th of November and full irrigation. It is better to modify the planting pattern in the region to prevent the flowering stages of rapeseed from encountering water shortage.