مجله به زراعی کشاورزی
سال بیست و سوم شماره 4 (زمستان 1400)

In order to investigate the possibility of reducing the negative effects of late-season heat stress using phosphate-solubilizing bacteria, this experiment is carried out as split factorial based on a complete randomized block design with three replications in a farm located in Haftkol city under the supervision of Ramhormoz Islamic Azad University, during the growing season 2016-2017. The main factor consists of planting date in two levels (22 November and 2 January) and the sub factors as a factorial consisted of five bread wheat cultivars (Chamran2, Mehregan, Sirvan, Shush and Barat) and of two levels application of phosphate solubilizing bacteria (inoculation and without inoculation). The results show that with a delay in planting and occurrence of heat stress in grain filling period, grain yield, biological yield, harvest index, and effective grain filling period are decreased and grain filling rate is increased. Also, the reaction intensity has varied depending on the cultivar. Mehregan cultivar has high yield in both planting dates and in the delayed planting date with the highest increase in grain filling rate and the lowest decrease in number of seeds per spike, had the highest grain yield and harvest index. By inoculating the seeds with bacteria, on both planting dates, on average, the number of seeds per spike is increased by 4.6%, grain yield by 7.6%, and biological yield by 7%, but the interaction effect between planting date, cultivar and bacteria on yield and its related traits is not significant. Therefore, the effect of phosphate solubilizing bacteria on mitigating the effect of heat stress is not proven and the positive effect of bacteria is the same on both planting dates. Overall, in this study, higher ability to increase grain filling speed and maintain more grain number per spike are identified as two important traits for achieving higher grain yield under late-season heat stress conditions.

In order to investigate the effect(s) of biologic and organic fertilizers on light consumption efficiency in growing maize-bean mixture, an experiment has been conducted in the form of split plots in a randomized complete block design with 12 treatments. Main plots, containing different fertilizer systems in four levels, include 30 kg/ha urea, Azotobacter, vermicompost, and Azotobacter + vermicompost, and the subplots contain cultivation compound of pure maize and pure bean being 50% maize + 50% bean, 60% maize + 60% pinto bean, and 80% maize + 80% pinto bean. Results show that leaf area index, dry matter accumulation, and light consumption efficiency of maize have been significantly higher than pure culture. The highest light use efficiency is related to the combined use of Azotobacter and vermicompost in mixed culture of 80% maize + 80% pinto beans with an average of 2.29 g / MJ, which increase light use efficiency by 63%, compared to 30 kg/ha of pure culture. Also, the highest dry matter, related to the mixed culture of 60% maize + 60% pinto beans, belongs to the amount of 1728 g/m2, which increase the dry matter accumulation by 16%, compared to pure culture. In general, the combined composition of organic and biologic fertilizers in intercropping has the ability to compete with urea chemical fertilizer in terms of mechanistic indicators of plant growth analysis.

The Potential Climatic Water Productivity (PCWP) is an important indicator to quantify the effect of intrinsic factors on physical water productivity. The crop calendar is one of the important factors affecting this index. Considering the importance of maize farming and the necessity of improving water productivity, PCWP index has been investigated for eight agronomic calendars and five maize farms between 2015 and 2016. Crop calendars were extracted from available official sources and expert meetings. The PCWP components are determined from the FAO Growth Model (yield) and the standard FAO Penman-Monteith method (evapotranspiration). The mean PCWP for maize forage in the second crop cultivation has increased by 23%, compared to the first cultivation; therefore, the use of second cultivation calendars is recommended in regard to the promoting water productivity. In spite of a 13.7% increase in PCWP in the second maize-grain cultivation, the use of the first cultivation calendars is recommended. Due to changes in water productivity (WP) and its components, water allocation and irrigation scheduling based on ETc appropriate to the crop calendar is essential. However, WP based ETc and actual yield are not appropriate for correct comparison, analysis, and crop calendar selection, so it is necessary to use PCWP values based on climatic potential production (CPP) under water conditions (IPP) and ETc.

In order to evaluate grain yield of wheat cultivars in two planting dates and determination of proper cultivars for autumn and entezari culture, a study is carried out during two years, between 2015 and 2017 in Torogh research station in Mashhad. Two planting dates of autumn and entezari culture are the main plot and 16 genotypes of wheat (14 cultivars and 2 promising lines), including Baran, Rasad, Sardari, Sabalan, Crosssabalan, Rijav, Karim, Koohdasht, Dehdasht, Azar2, Homa, Ohadi, Ghaboos, and Aftab cultivars are the subplot. Results show that significant difference exist between cultivars in terms of agronomic characteristics and grain yield. Flowering date of cultivars differ and no cultivar start flowering in the optimum temperature range for flowering. Cultivars of Karim and Rijav with mean yield of 1430 and 1326 kg/ha, respectively, have had the maximum yield and cultivars of Ohadi and Rasad with mean yield of 893 and 925 kg/ha, respectively, the minimum. The difference between maximum and minimum grain yield is about 60%. Delay in planting leads to delay in pollination in all cultivars; therefore, autumn planting date could be recommended. Also for autumn planting, cultivars of Karim and Rijav can be advised and for entezari planting date only spring cultivars such as Karim and Aftab are recommended.

The present study investigates the effect of combined application of biochar, Azospirillium lipofrom bacteria and nitrogen in two flooding and intermittent irrigation methods on yield and yield components of rice (Oryza sativa L. cv. ‘Tarom Hashemi’). The experiment is done in split-split plot arrangement based on a complete randomized block design with three replications at the research farm of Sari Agricultural Sciences and Natural Resources University between two consecutive years of 2017 and 2018. The treatments are two irrigation methods (flooding and alternation irrigation regimes) as main plot and nine fertilizers levels (100%, 75%, and 50% nitrogen in combination with control (without biochar), 20 and 10 tons of biochar per hectare) and seedling inoculation with Azospirillum lipoferum (inoculation and non-inoculated control) as sub and sub-sub plots, respectively. According to the significance of the studied factors’ effects on the measured traits, application of 20 tons of biochar along with 75% to 100% of the recommended nitrogen show the greatest impact on rice yield and yield components in both intermittent and flooding irrigation methods. Since, the effectiveness of biochar in imtermittent irrigation is more significant, it can be concluded that the application of 20 tons of biochar per hectare plus 75% to 100% of the recommended nitrogen could greatly compensate the yield reduction due to reduced water consumption in intermittent irrigation, compared to the flooding irrigation.

In order to study the effects of late-season drought stress and foliar application of potassium silicate on yield and yield components of spring genotypes of canola, a factorial split-plot experiment is conducted in Karaj, Iran in a randomized complete block configuration with three replications for two years of cultivation (2016-2018). The irrigation is performed at two levels in this study, including routine irrigation (control) and interruption of irrigation from the pod formation stage. Potassium silicate foliar application at two levels is comprised of 0 and 4 g liter-1 in factorial status in main plots and five Brassica napus L. genotypes including OG×AL, RGS×SLM, DALGAN, RGS003 and RGS×Okapi in subplots.  The results show that the measured properties are affected by the applied treatments. Full irrigation with foliar application in OG×AL genotype results in highest seed yield (5620 Kg/ha) and total chlorophyll content (1.71 mg/g.FW) increase stomatal resistance, leaf proline, leaf soluble and carbohydrates, decreasing total chlorophyll content and relative leaf water content. Under drought stress conditions, DALGAN and RGS× SLM genotypes have higher yield, which indicates its better performance under stress conditions. Finally, our research demonstrates Potassium Silicate's beneficial effects in improving the drought tolerance of canola plants, particularly at the end of the season. Our study will act as a foundation for any attempt in new approaches to mitigate drought damage, establishing a functional connection between the position of potassium silicate, physiological response, and drought stress tolerance in canola plants.

In order to investigate the effect of mycorrhizl fungi on dry matter remobilization of barley in dryland conditions, a field experiment has been carried out in factorial analysis based on randomized complete block design with three replications at the farm station of Sarablah Agricultural Research Cente, Ilam during 2019-2020 cropping season. Experimental factors include different barley cultivars (Mahali, Mahoor, Khoram, and Fardan) and fertilizer application is the control (without fertilizer application), 50% P chemical fertilizer, mycorrhizal fungi (Glomus mosseae, Glomus etunicatum and Rhizophagus irregularis), mycorrhizal fungi along with 50% P chemical fertilizer and 100% P chemical fertilizer. The results of this study indicate that the interaction of cultivar along with fertilizer application have had significant influence on dry matter remobilization efficiency from spike, contribution of spike reserves to grain yield, dry matter remobilization efficiency from stem, contribution of stem reserves to grain yield, current photosynthesis rate, contribution of current photosynthesis, and grain filling rate. Thus, the interaction of Fardan cultivar and mycorrhizal fungi along with 50% P chemical fertilizer has had the highest dry matter remobilization effeciency from spike, contribution of spike reserves to grain yield, current photosynthesis rate, contribution of current photosynthesis, and grain filling rate. In return, in this study the highest stem dry matter remobilization effeciency, contribution of stem reserves to grain yield, have been obtained from the interaction of Mahali cultivar along with control treatment. According to the results, in dryland conditions of the region, new cultivar of Fardan as well as mycorrhizal fungi along with 50% P chemical fertilizer can be recommended.

One of the important activities to achieve drought tolerant cultivars is screening and selection of cultivars, based on yield and biochemical characteristics. A split-plot experiment arranged in a randomized complete blocks design with three replications has been carried out in Safiabad Agricultural Research Center during two growing seasons (2017-19). The main plots are consisted of different irrigation regimes based on crop’s water requirement (25%, 50%, 75%, and 100%) and sub plots include five levels of alfalfa cultivars (Baghdadi, Nikshahri, Yazdi, Omid, and american Mesa-Sirsa). Results show that drought stress due to irrigation regimes have resulted in a significant reduction of forage dry matter yield and considerable changes of soluble sugar, glutation peroxidase, and catalase in alfalfa leaves. However, it has not greatly affected total protein. For forage dry matter yield, the highest statistical class belongs to Baghdadi cultivar under 100% water requirement supply treatment (2.824 t.ha-1). The lowest statistical class for forage dry matter yield has been observed in Yazdi and Mesa-Sirsa cultivars under 25% water requirement supply treatment (0.598 and 0.546 t.ha-1), respectively. Among the cultivars, examined in this experiment, Yazdi has been identified as a drought tolerant cultivar due to the stability of dry forage yield as well as high leaf antioxidants content.

This study attempts to evaluate the effects of planting date and spraying CCC on some biochemical characteristics and qualitative and quantitative yield of sugar beet. It has conducted an experiment, using a Split factorial based on randomized complete block design with three replications in 2015-2016 growth season in field experiment of university of Abourayhan, Tehran University. The treatments include planting date (2nd of October and 22nd of October) as the main factor and cultivars (Suprima and 9597) and foliar spraying (1000 ppm) / non-application of CCC as sub plots. The results show that the highest percentage of bolting (54.58%) and sodium content (equivalent to 9.16 mEq / 100 g of sugar beet pulp) take place on October 2, while the highest root yield (26.15 ton per hectare) and white sugar yield (equal to 1.44 tons per hectare) happen on October 22. Also, it has been observed that most values of the studied traits (except bolting percentage and sodium content of sugar beet pulp) have occurred through the cultivation of Suprema with CCC spraying. Overall, it can be concluded that the best conditions to determine the best root and sugar yield in the area of ​​research, on 22nd of October, the Suprima and application of 1000 ppm are recommended in order to cultivate sugar beet in the Pakdasht area.

To study the effect of vermicompost and plant growth promoting rhizobacteria (PGPR) on yield indices, oil and protein percent and element concentration of seed in sesame (Sesamum indicum L.), a greenhouse experiment has been conducted in factorial based on completely randomized design with four replications at Vali-e-Asr university of Rafsanjan in 2014. Experiment factors include four levels of vermicompost (zero (V0), 1 (V1), 2 (V2), and 4 (V3) percent) and five bacterial levels (without bacteria (B0), inoculation with an isolate from fluorescent pseudomonads group, having ability to dissolve inorganic phosphate (B1), Azospirillum sp. (B2), Azotobacter sp. (B3), and with the ability to fix nitrogen and a mixture of three bacteria (B4)). The results show that the application of vermicompost and PGPR alone significantly increase oil percentage (up to 80.7% and 15.4%, respectively), potassium, iron, and manganese concentration in seed sesame. Also, simultaneous application of vermicompost and PGPR are significantly enhanced along with weight of seeds, number and weight of capsule, protein of seed and concentration of nitrogen, phosphorous and copper in seed sesame. In general, the combined application of vermicompost and growth-promoting bacteria, through a synergistic relationship, have increased the yield and the content of mineral elements of sesame seeds.

In order to investigate the effect of Piriformospora indica and different levels of salicylic acid on morphological characteristics and activity of antioxidant enzymes of thyme (Thymus vulgaris L.) irrigation cut-off stress, an experiment has been conducted in the water year 2016. It has employed a split factorial experiment based on randomized complete block design with four replications in the research farm of Dehloran Agricultural Research Center. The treatments are consisted of four levels of salicylic acid (0, 150, 300, and 600 μm) as foliar application and a mycorrhiza fungus agent at two levels of inoculation and non-inoculation and irrigation cut-off stress at three levels (irrigation at 90%, 50%, and 30% filed capacity). The results of this study show that with increasing irrigation cut-off stress up to 30% filed capacity plant height, total weight of shoot, number of leaves, colonization percentage, and the enzymes Catalase and Peroxidase have decreased. Inoculation and treatment with salicylic acid up to a concentration of 300 μM could significantly reduce the destructive effects of irrigation cut-off stress on these traits. However, increasing the concentration of salicylic acid to the level of 600 μM intensifies the effects of irrigation cut-off stress, preventing the positive effects of the fungus.

In order to investigate the physiological responses of black cumin seed (Nigella sativa L.) under different concentrations of silver nanoparticles (0, 2.5, 5, 10, 20, 40, and 80 mg/L AgNPs), a completely randomized design experiment is conducted with 5 replications in the greenhouse of Shahed University in 2018. In the present study, growth traits, photosynthetic pigments, anthocyanins, proline content, glycine betaine, soluble and insoluble sugars, phenolic compounds and gas exchange, and fluorescence parameters of the photosynthetic apparatus are investigated. The results show that the AgNPs treatments significantly inhibit biomass production and the growth of root and shoot, decreasing the contents of chlorophyll a and b at high concentrations (20, 40 and 80 mg/L), while the AgNPs treatments increase the content of carotenoids, proline, glycine betaine, soluble sugars, anthocyanins, and phenolic compounds, compared to the control. By increasing the concentration of AgNPs, photosynthetic rate, transpiration rate, stomatal conductance, the maximal quantum yield of PSII photochemistry, photochemical quenching coefficient, and effective quantum yield of PSII photochemistry decline. Measurement of fluorescence show strong evidence of inhibitory effects on energy transfer from light harvesting complexes to reaction centers, the deterioration of the PSII water splitting system and the inactivation of PSII reaction centers at high concentrations of AgNPs. In conclusion, the results demonstrate that AgNPs induce an inhibitory mechanism on photosynthetic processes and biomass of black seed plants.

Food security reduction due to climate change is one of the most important challenges in the 21st century. This study was carried out to predict the potential yield and production of the country’s strategic crops examining various climate change scenarios. In this study, the potential yield & production of 17 crops (Wheat, barley, rice, common bean, rapeseed, chickpea, grain maize, cotton, lentil, potato, sesame, soybean, sugar beet, sugarcane, sunflower, alfalfa and Silage maize) were estimated under current conditions (period 2005-2014) & two climatic scenarios (optimistic:1.5 ° C increase in temperature with 14% increase in precipitation period 2005-2014; pessimistic: 1.5 ° C increase in temperature & 14% decrease in precipitation period 2005-2014) applying SSM-iCrop2 model. The results showed that the pessimistic scenario reduced the potential production of wheat & legumes (about 1%) & the optimistic scenario increased the potential production of these crops (4 & 2%, respectively). Both climate change scenarios reduced the potential production of rice, potato, oilseeds & sugar crops (4, 10, 5 & 7%, respectively). Furthermore, the potential production of Silage maize increased in both climate change scenarios (2% & 3%, respectively). The results showed that the major factors which alter crop yield could be the growing season duration, radiation use efficiency and transpiration efficiency. In general, wheat, barley, potato, and sugarcane were more affected by climate change than other crops.

In order to study the foliar application of melatonin on plants grown from safflower in different seed qualities under drought condition, two field experiments have been carried out at research farm of Aburaihan Campus, University of Tehran, between 2017 and 2018 growing seasons. The experimental design is split-factorial in a randomized complete block design with four replicates, with the treatments being consisted of two levels of drought stress (1- normal irrigation (no-stress) and 2- irrigation after reaching 85% of soil moisture depletion of field capacity at flowering stage (drought stress)), in the main plots. The subplots include 4 treatments, including a factorial combination of seed quality (stored seed and recently harvested seeds) and foliar application (the control and melatonin foliar application). Results from these experiments illustrate that melatonin foliar application has significantly increased the seed yield of stored seed by 589Kg.ha-1, compared to the control. It is also shown that SOD and CAT activities have been increased in response to melatonin in plants grown from recently-harvested seeds under drought condition. Furthermore, it is indicated that foliar application of melatonin decrease the amount of leaf soluble proteins by 28% in plants grown from recently-harvested seeds under drought conditions. According to the results, the amount of malondialdehyde is decreased by 37% in plants grown from recently-harvested seeds by foliar application of melatonin under drought conditions. It seems that seed quality has an enormous influence on grown plants and that using melatonin may play a substantial role in ameliorating the injuries derived from stress on safflower plant.

In order to study the effect of methanol and seed inoculation with plant growth promoting  rhizobacteria on grain filling components, chlorophyll content and grain yield of safflower (Carthamus tinctorius L.) under various irrigation levels, a factorial experiment has been conducted based on randomized complete block design with three replications at the research farm of University of Mohaghegh Ardabili in 2020. The experimental factors include irrigation (full irrigation as control, irrigation withholding at 50% heading-bud, and flowering stages), biofertilizers application (no application as control, seed inoculation with Flavobacterium, Pseudomonas and both application of Flavobacterium and Pseudomonas), and methanol foliar application: (foliar application with water as control and foliar application with 10% and 20% volume of methanol). The results show that the content chlorophyll a (41.57%), b (74.59%) and total chlorophyll (49.33%), grain filling period, and effective grain filling period (27.32% and 72.89% respectively) and grain yield (69.2%) have increased under full irrigation condition, foliar application 20% volume of methanol, and both application of Flavobacterium with Pseudomonas in comparison with irrigation withholding at 50% heading-bud and no application of biofertilizers and methanol. Generally, the results show that application of plant growth-promoting bacteria and methanol can increase grain yield of safflower by improving chlorophyll content and grain filling components under water limitation condition.

This study aims at investigating the morpho-physiological responses of potato superelite mini-tubers to different coating treatments factorial experiment, based on randomized complete block design with three replications in Research Farm of Mohaghegh Ardabili University between 2018 and 2019. Experimental factors at four levels include mini-tubers filler (zeolite and cocopeat), superphosphate (soil and pellet application), chitosan, and superabsorbent with control treatment (without pelleting). Application of cocopeat with superphosphate leads to the highest average number of tubers per plant (8.36), fresh and dry tuber yield (18.23 and 3.88 tons per hectare), and biological yield (21.69 tons per hectare). The use of chitosan in mini-tuber pelleting decrease the activity of catalase and peroxidase enzymes (19.67% and 16.37%, respectively), increasing the activity of polyphenol oxidase (37.80%). Zeolite increase and cocopeat decrease the tuber protein percentage, compared to the control. This increase in protein percentage with increasing tuber yield leads to a 32.23% increase in tuber protein yield in zeolite application, compared to control treatment. The use of superphosphate in mini-tuber pelleting also increase the protein percentage, thus leading to a 30.30% increase in protein yield, compared to control mini-tuber. In principal component analysis (PCA), the first component, with which 35% of the changes could be explained, include the yield of protein, lysine, and methionine, and the second component, with which 25% of the changes could be explained, include the protein, methionine, lysine, and total nitrogen. Finally, the results show that the mini-tuber pelleting by superphosphate, zeolite, and superabsorbent have had significant additive effects on yield and quality traits.

In order to investigate the effect of pea (Pisum sativum L.) cultivar as well as replacement and additive intercropping ratios of pea and spinach (Spinacia oleracea L.) on yield and competition indices, a factorial experiment has been conducted based on randomized complete block design with three replications at Gonbad Kavous University research field during 2016-2017. Intercropping ratios at nine levels consisted of pure pea, pure spinach, 33%, 50%, and 67% spinach instead of pea, addition series of 33%, 50%, 67%, and 100% spinach to pea. Also, pea cultivars have been Shamshiri and Pofaki. Land equivalent ratio and relative crowding coefficient in additive treatments have been more than replacement treatments, above one in all treatments. The highest land equivalent ratio with 1.333 has been observed in 100% pea + 100% spinach. In replacement series, pea has been the dominant plant, while in additive series spinach has dominated. No actual yield loss is observed in all treatments. The highest system productivity index has been related to 100% pea + 100% spinach with 3045. Overall, the land equivalent ratio of more than one and positive system productivity index of especial treatment, equal to 100% pea + 100% spinach indicate the benefit of pea and spinach intercropping.

In this study, the drought tolerance threshold and relationships between some biochemical and physiological responses of two stone fruit rootstocks, Cadaman and GF677, have been investigated. For this purpose, a pot experiment has been carried out in a greenhouse using factorial trial based on a completely randomized design with three replications. One-year-old rooted cuttings of two rootstocks are exposed to drought stress (-0.1 (control), -0.6, -1.1, -1.6 MPa) by adding different amounts of polyethylene glycol-6000 to Hoagland nutrient solution. Significant increase in electrolyte leakage and decrease in leaf relative water content of Cadaman and GF677 rootstocks has occurred at -0.6 and -1.1 MPa, respectively. Concentration of photosynthetic pigments and quantum yield of photosystem II (FV/FM) are less affected by drought stress, decreasing significantly in Cadaman and GF677 rootstocks at -1.1 and -1.6 MPa, respectively. Under severe drought stress, photosynthesis, transpiration, intercellular CO2 concentration, and stomatal conductance in Cadaman rootstock decline more considerably, compared to GF677. Moreover, at drought stress of -1.6 MPa, GF677 does not significantly reduce its photosynthesis, despite a substantial decrease in transpiration; however, the relative decrease in photosynthesis of Cadaman at -1.6 MPa has been much greater than the relative decrease in its transpiration and intercellular CO2 concentration, which, in turn, results in a drop in water use efficiency and mesophilic conductance of Cadaman leaves, compared to GF677. It seems that considerable reduction in photosynthesis in Cadaman rootstock, along with stomatal limitations, is largely due to non-stomatal constraints such as loss of cell membrane intact and reduction of chlorophyll, carotenoids and chlorophyll fluorescence. Results show that GF677 rootstock has higher tolerance to severe drought stress, compared to cadaman.

One of the problems faced by Phoenix dactylifera L growers in different parts of the country is the lack of a favorable fruit set for tissue culture seedlings of some cultivars recently. This study is conducted to investigate the effects of pollen of different cultivars on the fruit set of Phoenix dactylifera L tissue culture and offshoot palms of Barhi, Piaroom, and Mazafati cultivars in the garden of Jahrom Agricultural Research Station. During the years 2018 - 2019, in a factorial experiment, three factors have been performed in three replications with a randomized complete block design. The first factor involves different pollen with five levels (i.e., codes 7001 (control), 7005, 7013, 7030, and Boyer 11 obtained from tissue culture (B11)) with the second factor being the cultivar type in three levels (Barhi, Pyaram, and Mazafati), and  the third one, the type of seedlings, all applied on 90 ten-year-old trees in two levels (tissue culture and offshoot). Results show that the highest percentage of natural fruit set has been observed in Mazafati cultivar with 7013 and 7030 pollens and 7013 pollen in Barhi cultivar. The lowest percentage of natural fruit set belongs to tissue culture method in Barhi cultivar with pollen 7001 (control). In general, 7013 and 7030 pollens have been identified as the most suitable pollinator base to increase the percentage of normal fruit set and reduce parthenocarpic and fallen fruits of Barhi, Piaroom, and Mazafati cultivars obtained from tissue culture and offshoot.