نشریه تولیدات گیاهی
سال چهل و چهارم شماره 2 (تابستان 1400)

Delay in sowing date results in yield production change in wheat. Belated sowing time of wheat cultivars always encounters terminal heat stress, particularly after flowering, in south of Iran. Heat stress is one of the main obstacles influencing crop production worldwide. Currently, producing heat tolerant genotypes is so essential in plant breeding programs. In spite of previous research on physiological aspects of heat stress tolerance, a consensus among scientists on the most important traits controling heat stress tolerance in plants is not available. Phenological traits of wheat genotypes are the major traits influencing heat tolerance and very important in breeding programs.

In order to investigate the effects of sowing date and terminal heat stress on phenological traits, yield and yield components of bread wheat, a field experiment was conducted in a randomized complete block design with three replications on 30 genotypes including: Pars, Bahar, Sistan, Dez, Shiraz, Bam, Arvand, Chamran 2, Kavir, Neyshabour, Roshan, Pishtaz, Hamoon, Kaz, Arta, Sepahan, Mehregan, Shuosh, Verinak, Arg, Ghods, Hirmand, Chamran, Alvand, Falat, Aflack, Marvdasht, Mantana, Babax and Weebile with different length of phonological stages in experimental fields of Shahid Chamran University of Ahvaz during 2014-2015. The cultivars were planted in normal and late sowing dates (terminal heat stress) and the data were combined and run in a combined analysis of variance.

In this research, sowing date and consequent heat stress significantly reduced (P≤0.01) the phenological traits. The average of the number of days from sowing to tillage was reduced by 23% under terminal heat stress in comparison with the normal condition. The yield and yield components were also strongly affected by seasonal heat stress and the number of spikelets per spike (16%), number of kernels per spike (18%), thousands kernel weight (11%), biological yield (40%), harvest index (14%) and grain yield (46%) reduced under heat stress. Based on the results, the correlation between phenological traits and yield components was positive in normal conditions and in most cases it was negative under heat stress conditions. The reults of canonical correlation showed that phenological traits in the first canonical correlation could interprete 38% of the variance of yield components in the normal and 47% in the heat stress conditions, which shows the more effective role of phenological traits on yield components under heat stress than normal conditions. Cluster analysis also displayed the important role of phonological features in comparison with other traits in the classification of commercial wheat cultivars of Iran. Generally, under hot climatical conditions such as Khuzestan the length of different phonological stages over the course of plant life significantly influence the grain performance. If the phenology of genotypes is locally engineered based on the optimum length, the promising heat tolerant cultivars will be achieved with ability to produce and maintaine the yield production.

Generally, under hot climatical conditions such as Khuzestan the length of different phonological stages over the course of plant life significantly influence the grain performance. If the phenology of genotypes is locally engineered based on the optimum length, the promising heat tolerant cultivars will be achieved with the potential to produce and maintaine the yield production.

Weeds are among the most important factors reducing sugarcane yield in Khuzestan province. Sugarcane has a vegetative stage susceptible to weed competition, which is about 3 to 6 weeks from the time of planting in a warm and humid season. Therefore, the control of weeds in the early part of the growing season before the canopy closure of sugarcane and covering more than half the rows of planting is very critical. In order to investigate the effect of combination of mechanized weeding and application of three herbicides including indaziflam, 2,4-D + MCPA + metribuzin, on weed control and sugarcane yield, a field experiment was conducted in Ratoon2 field in 2017-2018 growing season in Dehkhoda Sugarcane Plantation and Industry Company, Khuzestan, Iran.

The experimental design was split plot based on randomized complete block design with three replications. Mechanical weeding at three levels (sweep cultivator, rotavator, and no cultivation) was considered as the main plots. Herbicide application was considered as sub plot at three levels [indaziflam (50 ml ai ha-1), 2,4-D + MCPA + metribuzin (675 ml ai ha-1 + 1050 g ai ha-1) and no herbicide application (as weedy control)]. A weed- free check was included for comparison. Herbicide applications were made using backpack sprayer with TeeJet 11004 flat fan nozzle calibrated to deliver 250 L ha-1 at pressure of 2.5 atm. Sugarcane cultivar was CP-614. Weed sampling was carried out 60 days after treatment. Single stem weight, cane yield, final sugar yield, brix, pol, sugar purity and recoverable sugar were measured at the end of growing season and after sugarcane harvest.

The results showed that mechanical weeding treatments lead into reduced weed dry weight. As a result, weed control was more effective in rotavator treatment than cultivator. Maximum reduction weed dry weight (52.47%) was observed in integrated rotavator and indaziflam treatment. The results of the quantitative traits of sugarcane showed that using mechanized weeding and herbicide application, caused an increase in weight of single stem and yield of cane compared to the control. The greatest single stem weight was observed in cultivator treatment plus 2,4-D + MCPA + metribuzin (1.65 Kg m-2), rotavator + 2,4-D + MCPA + metribuzin (1.63 Kg m-2) and indaziflam (1.61 Kg m-2). The final sugar yield (9.79 t ha-1) in indaziflam treatment was greater than other treatments (except weed -free treatment). However, the measured values of Brix, pol, sugar purity and recoverable sugar did not differ significantly among treatments. Results showed that the use of mechanized weeding combined with herbicide applications would have an effective role in improving sugarcane yield and inhibition of sugarcane weeds.

The use of herbicides at the beginning of the sugarcane growing season led to more effective weed control; As a result, competition between sugarcane and weeds in access to food resources decreased, which led to the growth and development of sugarcane. However, the indaziflam did better than 2,4-D + MCPA + metribuzin due to its slight superiority in single-stem weight and cane yield. In general, it can be said that the use of mechanical weeding has an important role in controlling sugarcane weeds and the use of rotivator had a significant advantage over cultivator. According to the results of single stem weight, the use of combination weeding with herbicides will play an effective role in improving the weight of sugarcane.

In recent years, in order to increase public awareness about maintaining a healthy body, a lot of research has been done on the use of sweeteners to find ingrained types of them. Accordingly, new sources have been proposed for the preparation of these food additives one of the most appropriate plant of which is Stevia. In the leaves of Stevia, different varieties of steviol glicosides are produced which are much sweeter than normal sugar. The success percentage of the uptake of food elements through leaf feeding is about 95%, and in the way of attraction through the root is about 10%. In fact, foliar spraying is a shortcut for plant nutrition. Although potassium is one of the essential macro elements in the enzymatic activities of the plant, there is little recognition about its impact on the plant. Also, boron is an essential micro element for vascular plants and is involved in the transport of carbohydrate, cellular differentiation, cell wall synthesis and membrane health. The aim of this study was to consider the effect of potassium and boron foliar spraying on qualitative and quantitative yield of Stevia.

This research was conducted as a factorial experiment based on a randomized complete block design with four replications in experimental field of Khoozestan Agricultural and Natural Resources Sciences University, during 2016-2017 cropping season. Experimental factors were included: boron foliar spraying from boric acid source at four levels (0, 25, 50 & 75 ppm) and potassium foliar spraying from potassium sulfate source at three levels (0, 10000, 15000 ppm). 

The results revealed that the interaction of potassium and boron foliar spraying resulted in significant difference dry matter yield, leaf yield, plant height, leaf area index, percent of leaf stevioside, percent of leaf nitrogen, leaf potassium contentnt and leaf boron content. The treatments combination of 15000 ppm potassium and 50 ppm boron produced the highest dry matter yield (1495/8 kg/h), but created no significant difference with treatments combination of 15000 ppm potassium and 75 ppm boron (1490/2 kg/h). Also, treatments combination of 15000 ppm potassium and 75 ppm boron had the highest leaf yield (1134/68 kg/h) and percent of leaf stevioside (10/34 %). The treatments combination of no potassium foliar spraying and 25 ppm boron had the lowest dry matter yield (1407/73 kg/h) and leaf yield (725/6 kg/h). The results of this study indicate that potassium and boron foliar spraying had positive effects on dry matter yield, leaf yield and percent of stevioside. Potassi increased enzyme activity through its role in photosynthesis improving synthesis of protein and carbohydrates, translocation of photosynthetic and boron through its role in improving root deployment, carbohydrates translocation. In addition, cell wall synthesis and structure, had significant effect on dry matter yield and leaf yield of stevia.

Due to its more effective and faster effect of foliar sprying than nutrition (through the root, Salim et al., 2009), the compilation of macro element (potassium) and micro element (boron) foliar sprying did better to achieve the high qualitative and quantitative yield of stevia.

Drought is one of the major environmental constraints that limits plant growth and productivity more than any other environmental factors. Recent Mycorrhizal arbescular application to affeviate drought stress in many plants has been reported. Vermiwash can be used in two forms of foliar application or drench. It contains several enzymes, plant growth hormones, vitamins and macro and micro nutrients which can enhance plants tolerance to biotic and abiotic stress, as well as crop yield efficiency.

In order to investigate Mycorrhizal arbuscular fungi and Vermiwash foliar application on Gazania (Gazania rigens L.) growth and flowering characteristics under drought stress a greenhouse experiment with factorial design was conducted based on complete randomized blocks by considering three factors including MA fungi in two levels (incubation with MA and non- incubated plants), Vermiwash foliar application in four levels (0, 50, 100 and 200 ppm) and imposing drought stress in three levels (irrigation based on 40, 70 and 100% field capacity) with three replications in the greenhouse and laboratory of the Campus of Agriculture and Natural Resources of Tehran University in 2018. Studied traits involved plant height, number and leaf area, flower diameter and number, aerial fresh and dry weight, chlorophyll and carotenoid amount, N, P and K quantity of leaves. Analysis of variance’s results indicated that the influence of main effect of droughtt stress, MA and Vermiwash on the measured traits were considerably functional.

The maximum value of leaf’s carbohydrate was achieved in drought stress with the high severity in 40% of FC witch was 32.46 mg/gr. MA caused elevation in macro elements amount of the leaves. Foliar application of Vermiwash increased flower number and dimention and macro elements amounts as well. Among the Vermiwash treatments, foliat application of 200 ppm treatment reduced the negative effects of drought stress on plants. Comparison of the mean of dual effect of vermicompost in drought stress showed that the highest plant height in 200 ppm Vermiwash was 100% irrigation and the lowest value was in 50 ppm Vermiwash in irrigation 40% of field capacity. The lowest amount of chlorophyll a was observed in 40% water capacity and no Mycorrhizal fungi application. The highest leaf carbohydrate content was observed in irrigation treatments with 40% and 200 ppm Vermiwash.

vegetative growth decreased with increasig drought stress intensity from optimal irrigation level to severe stress. The use of Mycorrhiza and Vermiwash was positive compared to the control (Non-use), consumption of 100 and 200 ppm Vermiwash has better performance than other levels. Gazania responds to intense stress with more intensity than mild stress. It is recommended to prevent severe stress during the plant growth period. In this regard, the use of symbiotic fungi as well as Vermiwash foliar application (100 and 200 ppm) can help maintain plant growth by increasing plant tolerance to increasing stress intensity.

Drought stress is one of the most important environmental factors, which limit the growth of plants. By the end of the 21st century, the incidence of drought stress is expected to increase because of the global warming phenomenon. As a consequence, trees growth and viability in the forests and urban greenspace will reduce. Thus, selection of plants that are more tolerant to severe drought stress and are able to cope with such environmental conditions needs to be considered in future silvicultural strategies. This study was carried out to identify candidate drought-tolerance proteins in Maclura pomifera. Therefore, we aimed to explore the performance of Maclura pomifera under a severe drought stress and analyse the proteome changes of Maclura pomifera leaf in response to drought.

The experiment was carried out on 4-year-old Maclura pomifera saplings genotypes cultivated on a flat field in the Botanical Garden of University of Tehran. Saplings were exposed to irrigation regimes of 100% and 25% field capacity in a completely randomized design. Leaf samples were collected and were frozen immediately in liquid nitrogen and then stored at −80◦C to be used for further analyses. Experiments were performed using the gradient pH 3-10 NL IPG strips for the isoelectric focusing. IEF was carried out using the PROTEAN IEF. Strips were then equilibrated first for 15 min in reducing solution and then 15 min in alkylating solution. Equilibrated IPG strips were then placed and fixed using hot agarose on the top of home-made 12 % SDS- polyacrylamide gels. Separation of proteins in the second dimension was carried out in Protean XL cell. The protein spots were visualized by staining with BioSafe Coomassie gel stains following manufacturer’s instructions.

After doing two-dimensional gel electrophoresis, 25 protein spots that had displayed significant protein level changes were identified. Differentially expressed, proteins were divided in three groups. The first group included stress and defense proteins such as lipoxygenase, two types of heat shock protein, Allergen, Convicilin and legumin A2 precursorm; the second group included oxidative stress proteins such as Catalase, Chloroplast stromal ascorbate Peroxidase, Cytosolic ascorbate peroxidase, Iron superoxide dismutase and Manganese superoxide dismutase. Thethird group included energy and metabolism proteins such as Ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit, Ribulose -1,5- bisphosphate carboxylase /oxygenase small subuni, Translation elongation factor, Aldolase, Hydroxy-acid oxidase, Isopentenyl diphosphate isomerase, Dihydrolipoamide dehydrogenase and glyoxalase. The present results indicate that most proteins have been identified and their changes caused an increase in tolerance and adaptation of Maclura pomifera to drought stress. Also, our data suggest that drought tolerance of M. pomifera might be correlated with diminishing oxidative damage by activation of the antioxidant systems.

The present results indicate that most proteins have been identified and their changes caused an increase in tolerance and adaptation of Maclura pomifera to drought stress. Also, our data suggest that drought tolerance of M. pomifera might be correlated with diminishing oxidative damage by activation of the antioxidant systems.

Soil salinity and alkalinity seriously affect about 932 million hectares of land globally, reducing productivity in about 100 million hectares in Asia. Plants in alkaline soil must cope with physiological drought and ion toxicity, and also maintain intracellular ion balance and regulate pH outside the roots. Alkaline stress result into decrease in chlorophyll concentration, stomatal conductance and transpiration rate and inhibite the growth of plant. Nitrogen sources affect the pH of nutrition solution, which can affect plant growth, so nitrate increases the pH of nutrient solution while ammonium decreases pH of nutrition solution.

In order to evaluate the effect of nitrogen sources on vegetative growth, physiological and chlorophyll fluorescence of white and purple garlic genotypes under sodium bicarbonate stress, an experiment was carried out as factorial base on completely randomize desigen with three factors; sodium bicarbonate at three levels (0, 10 and 20 mM), nitrogen sources (5 mM ammonium sulfate, ammonium nitrate and calcium nitrate in nutrient soulotion) and genotypes (white and purple) with three replications in 2017 in Greenhouse of Faculty of a Agriculture, University of  Vali-e-asr Rafsanjan.

The results showed that shoot and root fresh and dry weight decreased by increasing sodium bicarbonate from 10 mM to 20 mM in nutrient solution and application of ammonium nitrate and ammonium sulfate sources decreased the negative effect of sodium bicarbonate on shoot and root fresh and dry weights. Among nitrogen sources, ammonium sulfate produced the highest soluble sugar content in both garlic genotypes. Proline content was enhanced by increasing sodium bicarbonate concentration in nutrient solution. The highest photosynthetic pigments were absorbed in plant that nourished by ammonium nitrate and ammonium sulfate, respectively. The sources of nitrogen, sodium bicarbonate and their interaction had no significant effect on chlorophyll fluorescence parameters, but genotype had significant effect on these traits.

According to the results of this experiment, the use of ammonium sulfate and ammonium nitrate sources has a better performance on growth and yield of garlic under bicarbonate stress conditions.

Ocimum basilicum L. (O. basilicum) or sweet basil belongs to the family Lamiaceae which has been used as a medicinal plant and its essential oils are used to flavor foods, in dental and oral products and in fragrances. One of the methods to increase yield and availability of minerals in the soil, with the decreased use of inorganic fertilizers, is to apply biological fertilization, which also affects the essential oil of aromatic plants. Hence, this study was carried out to describe detailed growth and chemical investigation of basil essential oil affected by chemical and biological fertilization.

This study was carried out as factorial based on completely randomized design with three replications. The first factor involved plant (O. basilicum var. Thyrsiflora and O. sanctum.L ) and the second factor was fertilizer types (0%, 50% and 100% of the plant phosphorus requirement, only bacteria, bacteria with 50% of plant phosphorus requirement, bacteria with 100% of plant phosphorus requirement). The pots filled with five kilograms of soil. Phosphorus fertilizer was added to the pots from the triple super phosphate source based on the experimental treatments. Overnight culture of Pseudomonas putida in nutrient broth was prepared and applied under each seed. At full bloom stage, the leaves and inflorescences of each plant were completely separated and their number counted. Extraction of leaf samples was performed using 70% methanol solvent to measure phenolic compounds and the flavon and flavonol content of the extract was read by measuring the absorbance at 425 nm. The amount of phosphorus content of plant leave was also determined.

Shoot dry weight, number and length of inflorescence were significantly (p<0.01) affected by the interaction effect of fertilizers and plant species. The highest shoot dry weight, number and length of inflorescence were recoded with only bacteria without the use of phosphate fertilizer treatment and followed with samples treated with bacterial + 50% chemical fertilizer. The maximum phosphorus concentration in both basilicum and sanctum leaves (4.92 and 4.82 mg g-1 dry weight, respectively) and phenols, flavonoids and flavonoid compounds were obtained in treatments containing only bacteria without using phosphate fertilizer and followed with samples treated with bacterial + 50% chemical fertilizer, as well. The highest percentage inhibition of free radicals was recorded in basilicum and sanctum (67 and 75 percent respectively), in the presence of the bacteria without using phosphorus fertilizer. Applied bacterium in this research improved the quantity and quality of basil, thus to recommend it as a biological fertilizer considering its potential needs to be examined at farm conditions.

According to the results, using biofertilizer in this research reduced the demand for phosphorous fertilizer and improved the quantity and quality of basil; so as a result to recommend it as a biological fertilizer considering its potential needs to be examined at farm conditions.

Salinity stress is one of the main factors that limited crop production. Salt stress causes physiological effects by decreasing soil water potential. Azomite is an inorganic mineral that contains more than 60 forms of nutrients (macro and microelements). This material modifies and improves the soil, and the high ionic exchange capacity of this substance has resulted in some of it being used to reduce the effects of salinity stress. Mexican Parsley (Tagetes minuta) is a medicinal plant from Asteraceae family that used in the food and cosmetic industries. The purpose of this experiment was to investigate biochemical response and dry aerial biomass of Tagetes minuta under salinity stress and Azomite application.

A pot experiment was conducted at the research greenhouse of Ferdowsi University of Mashhad as factorial based on completely randomized design with three levels of salinity (0, 30 and 60 mM NaCl in irrigation water) and four levels of Azomite (0, 4, 8 and 12 g/kg soil) in three replications in 2018. The studied traits were included biochemical characteristics (RWC, Electrolyte leakage, chlorophyll a, chlorophyll b, carotenoid, total chlorophyll, antioxidant activity, total phenol, soluble carbohydrates, and proline) and dry biomass. Statistical analysis was performed using Minitab 17 software. The mean comparison was done by Bonferroni test at the 5% probability level. The figure drew by Microsoft Excel software.

The results of this experiment showed that the interaction effects of salinity and Azomite had a significant effect at a probability level of 1% on all of the studied traits. The highest amount of dry biomass (30.25 g.plant), RWC (74.2 %), chlorophyll a (7.5 mg.g-1FW), chlorophyll b (9.26 mg.g-1 FW), carotenoid (16.73 mg.g-1FW), total chlorophyll (33.39 mg.g-1FW) and essential oil content (0.46 %) were observed in treatment without salinity and 12 g/kg soil of Azomite. The highest amount of Electrolyte leakage (83.55 %), antioxidant activity (9727 %), Total phenol (95.10 mg.g-1FW), soluble carbohydrates (114.4 mg.g-1FW) and proline (0.12 µM/gDW) was observed on 60mM salinity and without the use of Azomite. NaCl stress can reduce nutrient uptake by the root of the plant and cause to decrease the growth of plants (Dry aerial biomass), RWC, Chlorophyll a, b, carotenoid and total chlorophyll and increase antioxidant activity, total phenol, soluble carbohydrates, and proline. Azomite in salinity stress increase water holding and inhibited the plants from Na uptake. Therefore it prevents plants from Na toxicity. The result of this study showed that the highest salinity level (60 mM NaCl) and application of Azomite especially at 12 g/kg soil level had the highest effect on ameliorating biomass and biochemical characteristics of the plant.

Micrografting is a relatively new technique for propagation of plants. This technique has been used on woody species to produce viruses-free plants, rejuvenation, and reinvigoration, analysis of grafting compatibility and incompatibility and clone's propagation. Pistachio (Pistacia vera L.) is one of the most important commercial trees grown in arid and semi-arid regions of Iran where it is of vital importance to the permanent farming. Increase of pistachio cultivation areas during last three decades caused a continuous growing demand for pistachio planting materials in Iran. The benefits of applying in vivo and in vitro micrografting to the pistachio are obvious, especially when considering the need to improve the genetic quality of the planting stock of this slow-growing species while increasing crop potential. The objectives of this study were to determine the influence of scion storage and grafting time on clonal propagation of pistachio from elite-mature trees.

In order to evaluate the effect of scion storage and grafting time on grafting success of in-vivo micrografting of Pistachio, an experiment was achieved an factorial based on compeletly randomized design (CRD) during 2017-2018 under greenhouse condition. In the experiment, the success of micrografting in "Ahmad aghaiee " Pistachio on 14-days "Badami-Riz-Zaran" rootstocks were examined. The scion of "Ahmad aghaiee" were prepared from shoot tips of mature trees at three different times (February, march and may) and grafted immediately or after one month storage at 4 °C using inverted cleft grafting method. 21 days after grafting, some traits such as graft union percentage, scion growth, time to graft union, scion leaf number and total soluble sugar were recorded.

The results showed that the highest graft union percentage (100%) was observed on the grafted plants of February, immediately after grafting. Based on the results, soluble sugars were significantly increased in freshly harvested scions in February and March. The results also showed that the maximum time (18 days) for time graft union was obtained in April with the stored scion whereas the lowest time graft union (11 days) was observed in February with scion taken at the same time. In addition, we found that the highest scion growth rate was due to freshly harvested scions and grafts in February.

It was found that February was the best time of micrografting with scion taken at the same time because in this period carbohydrate content of the scions was higher than other months. Also, pistachio contain high amount of phenolic compounds. Exudation of phenolic compounds from the cut surfaces and their oxidation by polyphenoloxidase and peroxidase enzymes cause discoloration of the tissues which results in poor micrografting.

Water is the first and the most important limitation in increasing agricultural production. Topical root dryness is a new method of low irrigation, which improves the water utilization efficiency, without significantly reducing the yield of the plant. Maize is a plant that is very sensitive to plant densities, and if the density is low, then the factors of exploitation are not optimized. On the other hand, excessive plant density causes flower sterility and reduced grain yield. Therefore, this experiment aims to investigate the role of low irrigation and plant density changes on the water use efficiency and grain yield components of corn.

The experiment design was implemented as a split plot design in a randomized complete block design with three replications. The main plots Include: 1- full furrow irrigation (control), 2- furrow irrigation in the form of a fixed and 3-variable furrow irrigation. Sub plots include different planting densities: 65,000, 75,000, and 85,000 plants per hectare.

The results showed that different low irrigation methods had significant effects on ear tick length, number of seeds per ear, 1000 grain weight, grain yield, biological yield, harvest index and water use efficiency. Differences among plant densities in terms of ear tick length, number of seeds per ear, 1000 grain weight, grain yield, biological yield and water use efficiency were significant. The highest grain yield was observed in full irrigation (6858 kg ha-1) and at a density of 85,000 plants per hectare (6159 kg ha-1). The highest water consumption efficiency was obtained in irrigation as variables (17.33%) and at 85,000 plants per hectare (15.52%). Single plant yield decreased at 85 thousand plants, but this deficit was compensated by increasing plant number per unit area and grain yield increased. Single plant yield increased by 65 thousand plants. But because of the less plant per unit area, its yield decreased. Grain yield increased by about 14% in irrigation of one side of the variable compared with one in the constant. Changes in performance components are expected to trigger these changes. With increasing plant density per unit area, water use efficiency also increased, which is due to more cover and less shade and evaporation from the ground. Plant density per unit area also affects water use efficiency by reducing evaporation and increasing the share of transpiration that results in high yield. Water use efficiency in treatments with intermittent furrow irrigation was higher than constant furrow irrigation.

The full furrow irrigation (control) method was able to obtain the highest yield and grain yield components. As a result, in one irrigation in between fixed and variable, 25 and 12% reduction in yield was observed compared to full irrigation, respectively.

Anethum graveolens L is used to treat colds, coughs, urinary problems, bloating, and spasms. Water deficit may cause significant changes in the yield and composition of essential oils of medicinal plants. In order to improve water stress tolerance of plants, various mechanisms have been proposed. The use of materials such as vermicompost, zeolite, superabsorbent and methanol can partially compensate for the lowering of yield from drought stress. Therefore, it is important to use methods that can tolerate plants under drought stress conditions.

To evaluate the effect of organic and chemical growth improvers application on yield and essential oil percentage of dill (Anethum graveolens L.) under water deficit stress conditions, a field experiment was conducted as split plot in randomized complete block design with three replications in Birjand, Iran, during 2017 growing season. The main factor included three levels of water stress (60, 120, 180 mm evaporation form class A pan) and the sub-factor included five levels of organic and chemical growth improvers; control (no application), zeolite (5 t.ha-1), vermi compost (6.5 t.ha-1), super absorbent polymer (100 kg.ha-1) and methanol (20 v/v).

The results showed that water deficit significantly reduced all studied traits except harvest index and essential oil percentage. Also, organic and chemical improvement agents had a positive and significant effect on plant height, number of umbrellas per plant, grain yield, biological yield and essential oil yield. Interaction of water deficit stress and organic and chemical improvement agents was significant on number of umbrellas per plant, number of seeds per umbrella, grain yield, biological yield and essential oil yield. By increasing the intensity of water deficit stress, the use of organic and chemical improvers increased the yield of seeds and essential oils. Under severe stress conditions and in comparison, with control treatment, super absorbent application increased the yield of seeds and essential oil to 34.43 and 37.27%, respectively, and methanol spraying increased the yield of seeds and essential oils by 34.17% and 42.85. The results of this experiment showed that the use of organic and chemical improvers reduced the damage to seed yield and essential oil yield under water deficit stress conditions. Also, the results revealed that when the plant is exposed to intensive stress, substances such as superabsorbent and methanol can be used to modify the stress. Using these materials under severe stress conditions increased the grain yield by 34% compared to the control. In order to achieve maximum yield of essential oil, use of organic and chemical improvers has been beneficial. Under severe stress conditions, methanol spraying and super absorbent application increased the essential oil yield of dill (Anethum graveolens L.) in Birjand region.

In order to achieve the maximum yield of essential oil, use of organic and chemical improvers has been beneficial. Under severe stress conditions, methanol spraying and super absorbent application increased the essential oil yield of dill (Anethum graveolens L.) in Birjand region.

Concurrency of cereals late-season irrigation with early irrigation of sugar beet season and lack of water resources at this time, has made some farmers to delay sugar beet cultivation. The planting date plays a key role in growth, quality and yield of sugar beet. Delayed cultivation leads to reduced sugar beet yield. In late cultivation of sugar beet (Beta vulgaris L.), the use of nitrogen fertilizer and growth promoting bacteria can be of great importance in accelerating growth and compensating for lost time. The aim of this study was to find a sustainable way to increase the growth rate of sugar beet in delayed cultivation, so as to compensate for the delayed growth season as possible.

This experiment was conducted as a split split plot in a randomized complete block design with 6 replications on Arta sugar beet cultivar at the Research Farm of Ferdowsi University of Mashhad in 2018. The factors included planting date (regular and delayed sowing) as main factor, nitrogen fertilizer (based on recommendation and 25% less than recommended) as sub-factor and Nitrobacter application and non-Nitrobacter were considered as sub-factors.

The results showed that the inoculation effect of Nitrobacter on leaf area, total dry matter, root yield and sugar content increased by 13, 20, 9 and 8 percent, respectively. Also, Nitrobacter treatment had the least effect on the amount of sodium, potassium and nitrogen of root in both sowing dates. For delayed planting date, using nitrogen fertilizer plus growth promoting bacteria can offset the delay in planting date. Therefore, this recommendation can reduce water consumption by reducing sugar beet growing season and reduce fertilizer use. It seems that the combination of chemical and biological fertilizers is effective on sugar beet delayed cultivation in order to compensate for lost time.

The combination of chemical and biological fertilizers is effective on sugar beet delayed cultivation in order to compensate for lost time.