grain yield

Drought stress and the amount of nitrogen are considered as two factors limiting the yield of corn grain. To investigate the effect of the time of occurrence of drought stress and different amounts of nitrogen on the yield and yield components of corn variety 770 SC, this research was carried out factorial in the form of a randomized complete block design in Three repetitions were carried out in the summer of 2013 in the research farm of the Faculty of Agriculture of the Islamic Azad University, Shushtar branch. The investigated treatments include the time of stopping irrigation in different stages of growth (at the stage of 10 leaves to tassels, stopping irrigation at the stage of emergence of 50% of tassels until the silks turn brown and control without stress) and amounts of nitrogen fertilizer (100, 150 and 200 kg of pure nitrogen per hectare). The results showed that in the treatment of no irrigation in the flowering stage, the grain yield decreased due to the number of seeds in the cob despite the increase in the weight of 1000 seeds. In the full irrigation treatment (control), despite the weight of 1000 seeds being less, but due to the significant increase in the number of seeds in the cob, a higher seed yield was obtained. Increasing the amount of nitrogen under stress conditions caused an increase in the number of seeds, but due to the sensitivity of the reproductive stage to drought stress, the yield of seeds was less than the optimal conditions. Irrigation at the 50% stage until the silks turned brown, the harvest index decreased significantly. The stress in the 10-leaf stage caused a decrease in plant height due to the decrease in cell growth and development. The results of this study showed that in conditions where the plant faces drought stress during the flowering period, nitrogen consumption increases during the vegetative growth stage in order to reduce the effects of stress. Dryness seems beneficial.

This research was performed as a factorial in a completely randomized design in a pot with four replications. The studied treatments include salinity of irrigation water as irrigation with ordinary water (0.4) (control) and with salinity of 4 and 8 dS/m and seed priming including no priming and seed priming in 25 and 50 mM of hydrogen peroxide solutions. In this experiment, the number of spikes per pot, number of spikelets per spike, number of seeds per spikelet, 1000-grain weight, root dry weight, grain yield and grain protein were investigated. In this study, the effect of salinity of irrigation and hydrogen peroxide on all studied traits were significant. The interaction effect of salinity of irrigation and hydrogen peroxide on the studied traits except grain number per spikelet and grain protein were significant. The maximum root dry matter (0.95 g/pot) and grain yield (7.49 g/pot) were observed under irrigation with normal water and application of 50 mM hydrogen peroxide and the minimum root dry matter (0.82 g/pot) and grain yield (3.17 g/pot) was obtained at salinity of 8 dS/m and non-application of hydrogen peroxide. The maximum grain protein (14.25%) was obtained in the application of 50 mM hydrogen peroxide and the minimum protein percentage (11.05%) was obtained under irrigation with normal water. In general, the application of hydrogen peroxide can be effective in increasing the quantitative and qualitative yield of wheat and reducing the effect of salinity of irrigation water and it can be considered and recommended by researchers and farmers.

n order to study the effect of application of different biochar species and phosphate solubilizing microorganisms on soil enzymatic activity and agronomic traits of safflower during two cropping seasons of 2018 and 2019 in a part of cultivated lands of Sardorood district of Razan, Hamedan province, an experiment as split plots on the basis of randomized complete block design with three replications was implemented. The main factor at 4 levels of biochar including: cow manure, wheat straw, wood biochar and control. The sub factors were phosphate solubilizing microorganisms included the mycorrhizal fungi (Glomus etunicatum and G. mosseae), Bacillus lentus, Pseudomonas fluorescence and control. The results of mean comparison showed that highest number of heads per plant (8.12, 8.14) and the maximum seed weight (24.60 g) were observed in mycorrhizal inoculation treatments and the lowest were in control treatment, also the highest number of heads per plant (8.26) and seed weight (24.18 g) was observed in cow manure biochar treatment. The results of mean comparison showed that the highest biological yield (5454 kg/ha) was obtained in mycorrhizal inoculation treatments. Also, application of other phosphate solubilizing bacteria increased the biological yield of safflower compared to the control treatment.

One of the most important and valuable plants in the pharmaceutical industry is the hull-less pumpkin (Cucurbita pepo L. var. Hamedani) plant, which belongs to the cucurbitaceous family. The aim of this research was to evaluate the effect of deficit irrigation and kaolin clay on yield and yield components of (Cucurbita pepo L.). Experiment was laid out as a split plot design with randomized complete block design with three replications at the field located in Siahbaz village, Khoy district, Iran. The main factors included irrigation at four levels (complete irrigation, deficit irrigation from the shoot stage, deficit irrigation from flowering stage, Deficit irrigation from seed filling stage) and sub-factor including three levels of kaolin (control, 3% kaolin, 6% kaolin) was considered. Analysis of variance showed that the effect of deficit irrigation and kaolin on number of seeds per fruit, fruit yield, 1000 grain weight, grain and biological yield, harvest index, oil and protein percentage, oil yield and protein yield were significant. Analysis of variance showed that irrigation treatment at different growth stages had significant effect on leaf number at 1% probability level, but application of kaolin and interaction of irrigation and kaolin on number of leaves per plant was not significant. The results showed that the highest grain weight (294.55 gr), grain yield (807.2 kg/ha), oil percentage (46.2) and oil yield (373.3 kg/ha) were related to complete irrigation treatment. Irrigation at grain filling stage had no significant effect. Deficit irrigation treatment at the stem stage showed the lowest of studied traits. The highest grain weight (257.07 gr), grain yield (733.7 kg/ha) and fruit yield (23.84 kg/ha) were observed in the 3% kaolin spraying treatment. Kaolin 3% increased oil yield, oil percentage, protein percentage and protein yield compared to control treatment. Interaction between deficit irrigation and kaolin consumption was not significant on any of the traits of pumpkin. According to the results of means of oil and protein yield, complete irrigation and cessation of irrigation at filling of grain, were in a statistical group and there was no significant difference with kaolin 3% and cessation of irrigation in filling of grain, the desired quantitative and qualitative yield can be achieved in Pumpkin.

In order to evaluate the physiological and biochemical characteristics of rapeseed (Brassica napus L) cultivars in terms of irrigation interruption and delay planting date، an experiment was implemented in two crop years as a factorial split-plot in the form of a randomized complete block design with three replications in Karaj region. In the present study، irrigation in two levels including normal irrigation (80 mm evaporation from Class A evaporation pan) and irrigation cut-off from the stage of sowing and pod formation stages in two levels including Sep، 26 and Oct، 26 was placed in main plot and four winter rapeseed cultivars including Tassilo، Elvise، Neptune and Okapi were placed in subplots. According to the results، the highest content of chlorophyll in both planting dates (Sep. 26 and Oct. 26، respectively، with values of 1.59 and 1.88 mg. g-1 FW) and under normal irrigation conditions belonged to Elvise cultivar. The results showed that irrigation cut-off reduced the relative water content of leaves and increased leaf proline، soluble protein content and soluble carbohydrate content. Elvise and Neptune cultivars had the highest grain yield under normal irrigation conditions with 3346 and 3220 kg / ha، respectively، and under irrigation cut-off conditions، with a mean of 3211 and 3081 kg / ha، respectively. According to the Stress Tolerance Index (STI)، Elvise cultivar was identified as the most tolerant cultivar under dehydration stress in the pod formation stage onwards.

Fungal symbiosis can be beneficial for plant growth and nutrition by increasing the absorption of nutrients and using biochar as a soil conditioner that improves the physical, chemical and biological conditions of the soil. Different amounts of biochar and mycorrhiza on yield and some morphophysiological traits in wheat were performed during the cropping years of 2016-2017 and 2017-17 in Zohreh city located in southwestern Iran. The experiment was performed as a factorial experiment in a randomized complete block design (CRBD) with four replications. mycorrhizal fungus at two levels including non-use (control) and use of Glomus intradiaces and biochar values from plant biomass and agricultural wastes as soil modifiers at three levels of non-use (control) and application 4 and 8 Tons per hectare. The results of analysis of variance showed that mycorrhiza and biochar at 1% level had no significant effect on biological yield, grain yield, harvest index and some components of grain yield such as number of spikes per square meter and grain per square meter. The interaction of different amounts of biochar and mycorrhiza on 1000-seed weight, number of spikelets per spike, numbers of seeds per spikelet and grain protein percentage were significant at the level of 1% probability. The results showed that the amount of grain protein (8%), number of spikelets per spike (11%) and 1000-seed weight (16%) showed a significant increase compared to control plants. the application of four tons per hectare of biochar in plants inoculated with mycorrhizal fungi had the best conditions and yield (23%).

In order to determine the best sowing date in two soybean cultivars, an experiment was done in Ramhormoz Agricultural Research Farm in split plots on the basis of randomized complete blocks design with three repetitions in 2017. Treatments includes three planting dates 1 August, 16 August, 1 September were placed in the main plots and two soybean varieties including 504 and Saland in subplots.Results showed that planting date had significant effect on plant height, number of pod per plant, number of seed per pod, number of seed per plant, number of plant per square meter, harvest index and seed protein percent. The effect of cultivar was significant on plant height, number of seed per pod, number of plant per square meter, total dry weight, biological yield and grain yield. Saland cultivar in the second planting date produced the highest 1000-grain weight with an average of 148.2 g and on the third planting date, the smallest one was obtained with an average of 103.8 g. Saland cultivar in the second sowing date had the highest grain yield (2059 kg. ha-1) and the highest biological yield (3305 kg. ha-1). In the third planting date, Saland cultivar yielded the lowest grain yield (506 kg. ha-1) and the lowest biological yield (954.3 kg. ha-1).Seed oil percentage was not significant in any of treatments, but in the third planting date it was less than two other planting dates. Seed protein percentage was affected by planting date and in the third planting date its reduction was significant.Thousand-grain weight had significant positive correlation with grain protein percentage at 1% probability level, which indicates that with increasing grain weight, more protein is stored in the grain.In general, it is possible to recommend Saland cultivar for sowing date in 16 August and 504 for sowing date in 1 August and 1September.

This study was done to investigate the response of vegetative traits of sunflower cultivars in the presence of fenugreek as living mulch at Razi University in 2017. The experiment was conducted as split-plot based on randomized complete block. First factor was the sowing fenugreek at four levels (control (without living mulch), 15 days before sowing of sunflower, simultaneous sowing with sunflower, 15 days after sowing of sunflower) and the second factor was three sunflower cultivars (Progress, Farrokh, Lakomka). Results showed that with planting of fenugreek before sunflower, height, stem weight, number of leaves, leaf weight, leaf area index, content of chlorophyll a, b and total of chlorophylls were decreased by 26.4%, 62.1%, 24.8%, 68.5%, 63%, 7.4%, 3.7% and 6.8% compared to control, respectively. The lowest relative water content was also obtained by planting fenugreek before sunflower (65.2% and 52.7% at the 1/3 of primary growth season and flowering stages). The effect of presence mulch under the simultaneous and 15 days after sunflower conditions had no significant effect on growth characteristics of sunflower compared to control condition. Among thecultivars, the highest of grain yield was assigned to Lacomka (3426 kg/ha). However, Progress had the highest height (212 cm), stem weight (523 g/plant), leaf number (25.5 per plant), leaf weight (157.4 g/plant), leaf area index (6.2) and relative water content (77.8% and 70.5% at the 1/3 of of primary growth season and flowering stages). The highest of leaf area ratio (0.013 m2/g) and carotenoid content (2.5 mg) belonged to Farrokh.

To evaluate of the role of remobilization in yield of corn (S.C. 704)in conditions of change of density and nitrogen, this experiment was conducted as a factorial based on randomized complete block design with three replications in Ramhormoz city, southwest of Iran, during 2015-2016 cropping season. a factor consisted of plant density per square meter (8, 10 and 12) and another factor of pure nitrogen consumption (from 46% urea source) included 50, 100, 150 kg. ha-1.The results showed that the plant density and nitrogen fertilizer significant effect on grain yield, biological, remobilization, remobilization and contribution of current photosynthesis is. The highest grain yield (8090.4 kg. ha-1) of 8 plants per square meter and the lowest (6480.1 kg. ha-1) were obtained from 12 plant per square meter. The highest grain yield (8650.7 kg. ha-1) was obtained from 150 kg. ha-1 nitrogen fertilizer treatment and the lowest (6160.7 kg. ha-1) was obtained from 50 kg. ha-1nitrogen fertilizer treatment. Most current photosynthesis and remobilization and current photosynthesis contribution of 8 plants per square meter and 150 kg of nitrogen per hectare, respectively. Most remobilization of 8 plants per square meter (143.1 g.m-2), respectively. Overall, the experimental results showed that consumption of 150 kg / ha of pure nitrogen at a density of eight plants per square meter could increase grain yield by 46% compared to consumption of 50 kg / ha nitrogen and a density of 12 plants per square meter and improve corn production.

In order to study effect of seedling age and plant density on yield and yield components of rice (Sadri cultivar), a field experiment was conducted at the Ordukhan Agricultural Research Center, Heart Province - Afghanistan (Geographical longitude: 62°11'29" east and geographical latitude: 34°20'35" north) during the cropping season 2017-2018. The experiment was laid out in complete block design with three replications. Seeding ages with three levels (20, 30 and 40 days) were considered as main plots and plant densities with four levels (13, 17, 22 and 33 plants/m2) were allocated as sub plots. Analysis of variance showed that the effect of seedling age on number of tillers per plant, numbers of grains per panicle and grain yield was significant. The plant density had significant effect on all traits (expect, 1000grains weight). Interaction of two factors had no significant effect on any of the traits. The means comparison showed that the highest of number grains per panicle and grain yield were obtained for 30 days seedling age. Also, the highest of number of tiller per plant, number of fertile tiller per plant, number of grains per panicle and percent of unfilled grain were obtained by 13 plants per m2. But the highest biological yield, harvest index (HI) and grain yield obtained by 33 plants per m2. Based on simple correlation coefficient of traits, grain yield had significant positive correlation with biological yield, number fertile tiller per plant and number grains per panicle.

In order to investigate the comparison of urea and sulfur cotaed urea fertlizer on quantitative and qualitative yield of rice, Anbar Najafi cultivar under different silica, this research was conducted in Shadegan in 2017 carried out as split-plot based on randomized complete blocks design with three replications. Treatments consisted of urea fertilizer sources in two levels: simple urea fertilizer (250 kg net nitrogen) and sulfur coated urea fertilizer in main plots and silica at four levels: one in a thousand, two in thousand, three in thousand and four in thousand were in sub plots. The results showed that urea fertilizer and silica fertilizer significantly affected on grain yield, number of spikes per square meter, 1000 grain weight and protein content. Sulfur coated urea effectively yield compared to conventional urea fertilizer at a rate of 23.22 percent. Also, the interaction of urea and silica fertilizers on all measured traits was significant. The highest grain yield (290.41 g/m2) was obtained from urea fertilizer treatment with sulfur coating and spraying two in 1000 of silica. The highest protein content (10.04%) obtained in  sulfur coted urea fertilizer with two per thousand spray of silicon , respectively. Therefore, according to the results, values of two per thousand silica and urea fertilizer with sulfur coating due to increased protein and grain yield as a suitable treatment in the study area are introduced.