فهرست مطالب a. bakhshandeh

In the pursuit of a resilient and progressive agricultural system, the incorporation of diverse fertilizers is deemed essential. This practice not only enhances product quality but also aids in cost reduction. However, over-reliance on a specific type of input can inadvertently lead to unintended repercussions. The unrestricted utilization of chemical fertilizers, for instance, can precipitate adverse outcomes such as imbalanced pH levels, the accumulation of heavy elements, soil structure deterioration, and environmental contamination. Conversely, organic fertilizers, while environmentally friendly, often release nutrients at a slower rate, potentially disrupting optimal plant growth. To attain a balanced and sustainable agricultural approach, the combined application of organic and chemical fertilizers is advocated. Moreover, harnessing the biological potential inherent in soil ecosystems, including beneficial microbial communities encompassing bacteria and fungi, emerges as a promising avenue in cultivating sustainable agriculture. Acknowledging the adverse impact of late-season heat stress on wheat production in Khuzestan and recognizing the significance of reducing chemical fertilizer usage while augmenting organic and biological fertilizers to foster ecological health, this experiment undertakes the exploration of the effects of a synergistic approach. Specifically, it delves into the combined utilization of nitrogen and compost fertilizers, complemented by the incorporation of plant growth-promoting rhizobacteria. This endeavor aims to shed light on how this combined strategy operates within the context of terminal heat stress, assessing its influence on the physiological attributes and yield of the wheat cultivar Chamran 2.

This experiment was carried out as split-split plots based on a randomized complete block design with three replications in the crop year of 2021-2022 in the research farm of Agricultural Sciences and Natural Resources University of Khuzestan. The experimental factors include three planting dates: December 1st, December 20th, and December 10th in the main plots; Six levels of combined use of nitrogen fertilizer with compost fertilizer include control (without nitrogen and organic), 100% nitrogen, 75% nitrogen+ 25% compost, 50% nitrogen+ 50% compost, 25% nitrogen+ 75% compost and 100% compost in sub-plots and two levels of application and non-application of plant growth promoting rhizobacteria in sub-plots. Each sub-plot was 3 meters long and 2 meters wide (with an area of 6 square meters) and included 10 crop lines at a distance of 20 cm from each other. The distance between the main and secondary plots was considered to be half a meter and the distance between the blocks was two meters. After physiological maturity, the plants were harvested and the physiological traits and grain yield were measured.

Variance analysis showed that the interaction effect of planting date, combined use of nitrogen with compost, and plant growth promoting rhizobacteria, on the traits of relative leaf water content, planting to flowering, and grain yield were significant at the 1% probability level. Also, the interaction effect of planting date and the combined use of nitrogen with compost on all traits except the length of the grain filling period and the length of sowing to physiological maturity was significant at the probability level of 1%. The mean comparison showed that the highest relative leaf water content, cell membrane thermostability, and canopy temperature depression were obtained from the treatment of 100% compost, and the highest traits of the length of sowing to flowering and length of sowing to physiological maturity were obtained in the use of 100% nitrogen. Also, the longest grain filling period, grain filling rate, and grain yield were obtained in the combined use of 50% nitrogen+ 50% compost and plant growth-promoting rhizobacteria, and the lowest value was obtained in the control of not using nitrogen and compost. In general, the delay in planting and the occurrence of terminal heat stress caused a decrease in grain yield, but on different planting dates, the combined use of 50% nitrogen+ 50% compost compared to the treatment of 100% nitrogen increased wheat grain yield.

According to the obtained results, in areas with terminal heat stress, the combined use of 50% nitrogen+ 50% compost and plant growth-promoting rhizobacteria can be considered to increase the growth and yield of wheat.

Water is now the main limiting factor for crop production in arid and semi-arid regions. Water-cut or irrigation interruption has been suggested as one of the main strategies agro-technique to get the most benefit from limited water resource available. In this regard, plant growth stage, time of stress induction and the genotype are the main key factors to determine the degree of success. Canola is one of the most important oil crop. It can survive some degree of water stress while there is a need for research to find the most appropriate genotypes for plantations in water-limited areas.

In order to determine the effect of water stress at the various growing stages of canola genotypes a split-plot experiment was conducted based on the randomized complete block design with three replications at the research farm of the department of plant production and genetics, Agricultural Sciences and Natural Resources University of Khuzestan, Iran during 2020-2021. Main plots included three irrigation treatments: control (without interruption of irrigation), interruption of irrigation in the beginning of the flowering stage (phenology code 60) to the formation of 50% pods (phenology code 75), and interruption of irrigation in the stage of formation of pods until harvest (Phenology code 99) in the main plots and the cultivars (Long pod, Aram, RGS 003, Jankom, Solar, Hayola 4815, Mahtab, Julius, Agamax and Sala) were arranged in sub-plots with respect to irrigation treatments. At the end of the growing season, plant height, number of branches, silique length, number of pods per plant, number of seeds per pod, 1000 grain weight, and grain oil percentage were measured. Also, after removing the marginal effect, economic performance, biological performance and harvest index were measured.

Our results revealed there was a significant interaction effect between irrigation interruption stress and genotype on all studied traits. The number of sub-branch among cultivars varies as a result of Irrigation interruption stress. The genotypes of the long pod and Hayola 4815 had the highest number of branches compared to other genotypes when irrigation was interrupted at the flowering stage up to 50%, while when applied stress at the stage of flowering up to harvest, genotype, solar exhibited the highest number of sub-branch. The lowest number of sub-branches in all interruption of irrigation and control treatments was obtained by Jankom genotype. The mean comparisons in the conditions without irrigation interruption (control) the highest percentage of seed oil was obtained from Solar (48.3%), Hayola 4815 and 4815 (46.3%), stress application in flowering stage up to 50% sowing of a long pod (45%) and Hayola 4815 (43%) genotypes in the sowing stress to harvest the highest percentage of seed oil from Sala and Long pod genotypes with average (44.3%) the lowest percentage of seed oil in all present treatments belonged to Jankom genotype. In the present study, the highest (2093.8 kg.ha-1) and the lowest (540 kg.ha-1) grain yield and the highest (986.51 kg.ha-1) and the lowest (191.21 kg.ha-1) grain oil yield in both conditions without irrigation interruption (control) and terminal drought stress were obtained from Hayola 4815 and Jankom genotypes, respectively.

The highest and the lowest grain yield, seed oil and biological yield were obtained from Hayola 4815 and Jankom, respectively. According to the results, Hayola 4815, long pod and Solar are highly recommended to cultivate in the regions where there is terminal water stress at the end of the growing season.

Iran is located in the dry belt of the earth and is predicted to face water stress in the next half-century. Currently, the area of sugarcane cultivation in Khuzestan is over 85,000 hectares and due to the high water needs of sugarcane and drought conditions, optimization of water consumption and irrigation management is necessary to continue production. Therefore, in this study, the values of soil moisture, canopy cover, biomass yield in five treatments and irrigation levels (start of irrigation at 40%, 50%, 60%, 70%, and 80% soil moisture discharge) during 2 planting dates in the crop year 2015-2016 on sugarcane cultivar CP69-1062 in Amirkabir sugarcane cultivation and industry located in the south of Khuzestan was simulated by AquaCrop model. The measured data on the first culture date (D1) and the second culture date (D2) were used to calibrate and validate the model.  The results of NRMSE statistics in canopy cover simulation in calibration and validation sets with values of 2.1 to 15.6% and 3.8 to 18.3%, respectively, and in biomass simulation with values of 6.2 to 15.2%, and 9.5 to 12.6%, respectively and coefficient of determination (R2), range 0.98 to 0.99 indicated that the high ability of the AquaCrop model in simulation canopy cover and biomass yield. whereas, the values of NRMSE of soil depth moisture in the calibration and validation sets ranged from 11.6 to 23.8, and 12.2 to 22.7, respectively, with a coefficient of determination (R2), 0.73 to 0.96 (calibration) 0.8 to 0.93 (validation) showed less accuracy of the model in the simulation. The best scenario is related to the third proposal that water consumption, water use efficiency, and yield are 1710 mm, 1.53, and 42.27 tons per hectare, respectively, which shows a reduction in water consumption of 360 mm.

In order to study the effect of mycorrhiza inoculation and zeolite-enriched manure compost on photosynthetic pigments content and qualitative properties of triticale grain, a factorial experiment in a completely randomized complete block design with four replications were conducted at Research Field of Agricultural Sciences and Natural Resources University of Khouzestan during 2016-2017 growing season. The experimental factors included mycorrhiza application at two levels (application and non-application of mycorrhiza), and mixing of zeolite to manure in six levels (0, 5, 10, 15, 20 and 25% w/w of zeolite/manure). According to the results, under conditions of mycorrhiza application with increasing zeolite up to 15% leaf greenness index (SPAD) increased but decreased afterwards. The highest chlorophyll a (2.68 mg g-1) was obtained from 15% zeolite treatment and the lowest (1.82 mg g-1) was detected in control. Mycorrhiza inoculation caused a 14% increase in carotenoid content compared to non-inoculation. Grain phosphorus content (0.43 mg kg-1) was increased in mycorrhiza inoculation condition compared to non-inoculation (0.37 mg kg-1). Under inoculation conditions, the highest grain yield (3510.7 kg ha-1) belonged to application of 10% zeolite. Under non-inoculation condition more zeolite was needed (in compare to inoculation treatment) to obtain the highest grain yield. The highest protein yield (329.97 kg ha-1) was obtained from mycorrhiza inoculation treatment with 15% zeolite and the lowest protein yield (1152 kg ha-1) was obtained from mycorrhiza inoculation treatment with 25% zeolite. Finally, the results of this study showed that the application of zeolite in manure and inoculation of mycorrhiza fungi can increase the concentration of photosynthetic pigments and grain quality of triticale.

One of the basic principles of sustainable agriculture is application of biologic and organic fertilizers in order to reduce chemical inputs consumption and increase soil fertility. Application of manure improves biological activity, physicochemical properties and water holding capacity in soil. Despite these positive effects, increased weed seed bank, outbreak of pests and diseases and accumulation of ammonia in the root of plants are the disadvantages of manure application. Due to the unique attributes of zeolites if they were added at the beginning of composting process can provide ventilatory condition for the activity of aerobic microorganisms and absorbs nutrients, especially nitrogen. Another important solution of improving efficiency of sustainable agriculture ecosystems is use of biofertilizers as the most natural solution to increase biological activity of soil. Symbiosis of plant with mycorrhiza fungi improves nutritional status of plant by increasing water and nutrients absorption. Triticale is a commercial cereal with a vast potential to feed human and animal. This plant can be cultivated in poor soils that are not suitable for wheat production. Finally the aim of this study was to achieve maximum yield of triticale by increasing efficiency of manure compost and simultaneous use of this fertilizer and mycorrhiza.

The experiment was conducted at Research field of Agricultural sciences and Natural Resources University of Khuzestan during 2017-2018. Experimental design was a factorial based on randomized complete block design with four replications. The experimental factors included mycorrhizal application at two levels (application and non-application of mycorrhiza), and mixing of zeolite to manure in six levels (0, 5, 10, 15, 20 and 25% by weight of zeolite manure). The size of each experimental unit was 2×2 m2 and planting density was 400 plants per m2. Before the sowing, biofertilizer were shaken completely to cover the whole seeds surface after which the seeds were shadow-dried and planted, irrigation was done immediately after seed sowing. Traits included plant height, peduncle length, spike length, spikes per square meter, number of grains per spike, 1000 grain weight, grain yield, biological yield and harvest index were assessed in this experiment.

Based on the results, the interaction between mycorrhizal inoculation and mixing of zeolite with cattle manure were significant on plant height, peduncle length, number of grains per spike, 1000 grain weight and grain yield. The main effect of zeolite and mycorrhiza were significant on spike length, number of grains per spike and biological yield. In inoculation condition the most plant height (124.32 cm) was obtained at the level of 10% zeolite, while in non-inoculation condition the highest plant height (106.62) was obtained at the level of 20% zeolite. The number of spikes per square meter at the level of 20% zeolite (456) was 36% higher than the non-use of zeolite treatment (303). Under inoculation conditions, the highest grain yield (3510.7 kg.ha-1) was belonged to application of 10% zeolite and the lowest grain yield (1579.69 kg.ha-1) was gained from non-application of zeolite treatment. In non-inoculation condition compared to the inoculation treatment, more zeolite was needed to obtain high grain yield and by application of zeolite up to 20 percent gain yield increased.

According to results of the present experiment, application of 10% zeolite in manure compost along with mycorrhiza is recommended to increase the yield of triticale. It can be stated that the addition of zeolite to manure and the use of mycorrhiza fungi is a suitable method for achieving high yield in triticale cultivation.

Grain yield of bread wheat (Triticum aestivum L.) is reduced by heat stress، particularly when occurs in reproductive phase، in many countries worldwide، including Iran. In order to study the effects of different levels of nitrogen and cytokinin on wheat yield and yield components at normal and heat stress conditions in Khuzestan، Iran، this research was conducted at Ramin Agriculture and Natural Resources University in 2010-2011. This study was carried out in two separate factorial experiments in randomized complete block design with four replications. The first experiment was planted in a normal date and the second experiment was planted late (Terminal heat stress). In both experiments، nitrogen (N) was applied in four levels (0، 75، 150، and 225 kgha-1) and Cytokinin (Ck) sprayed in three levels (0، 50 and 100 µM). The results of both experiments (normal and stress conditions) showed that by increasing the N rate، the grain yield (5652. 1 and 3874. 7 Kg/ha respectively)، biological yield، number of spikes per m2، spikelet’s per spike، grains per spike were significantly (p<0. 01) increased. Application of Ck at normal sowing date increased the grain yield (4856. 7 kg/ha) and 1000 grain weight (41 gr) significantly (p<0. 01) and at late sowing date only increased 1000 grain weight (30. 2 gr) significantly (p<0. 01). Application of N and Ck in both experiments significantly increased grain yield (p<0. 05) and only at late sowing date increased 1000 grain weight significantly (p<0. 01). Based on our findings، application of N and Ck may lead to the amelioration of terminal heat stress effects on bread wheat in hot regions such as Ahwaz.

In order to study the effects of different waterlogging duration in growth stages ZGS11, ZGS13 and ZGS31 on root and shoot growth of three wheat genotypes Chamran, Vee/Nac and Yavaros, a pot experiment was carried out in the Ramin Agricultural and Natural Resources University in 2004. The experiment was a factorial according to a Randomized Complete Block Design with three replications. Study of root dry weight and root elongation trend showed different responses among genotypes, start of waterlogging periods and different waterlogging levels, as short period of waterlogging (10 days), had unrecoverable effects on the growth. Analysis of variance of root dry weight and root length at the anthesis and physiological maturity stages indicated significant different among all of treatments levels. Vee/Nac genotype was found superior with respect of root dry weight and root length to other genotypes. ZGS11 and ZGS31, had the highest and the lowest responses to waterlogging, respectively. Duration of 10, 20 and 30 days waterlogging at anthesis stage decreased 37.75, 44.31 and 54.01% of root dry weight, and 25.85, 47.02 and 58.88% of root length compared to control, respectively. Investigation of the root anatomy of wheat genotypes under waterlogging stress showed formation of cortical root aerenchyma as a waterlogging-resistantce mechanism.