مقالات رزومه دکتر هادی پیراسته انوشه

This research was conducted in order to compare conservation tillage methods compared to conventional tillage on the moisture retention, organic matter and bulk density of the soil. Experiments were conducted on permanent raised bed (PRB), no-till with SFOGGIA (NT) and Jab Planter (JP) equipments, in a wheat- rapeseed-corn cropping system, during 2018-2020, as a randomized complete block design with three replicates. Barzegar and Neptune cultivars and SC704 hybrid were used for wheat, rapeseed and corn, respectively. The examined characteristics included levels of soil moisture, bulk density and amount of soil organic matter. Average of organic matter in 0-30 cm soil depth was increased from 0.23% at the beginning of experiment to 0.53%, 0.67% and 0.48% at the end of experiment in PRB, NT and JP treatments, respectively. The amount of soil organic matter in CT treatment was about 0.49% at the end of the experiment. The highest amount of available water was observed in PRB (0.207 %), CT (0.193 %) and JP (0.163 %) treatments, respectively. The lowest value of this parameter was observed in NT treatment (0.143%). The lowest value of the average bulk density of soil was observed in the CT treatment (1.47 g/cm3) and the highest value was observed in the NT treatment (1.60 g/cm3). The use of conservation tillage methods and preservation of residues in the field can help to improve soil organic matter. Also, the average bulk density, water holding capacity of the soil are strongly affected by the application of different tillage methods.

In the present study, the effect of different levels of water and salinity stresses was investigated on dry matter production, biochemical attributes, and activity of antioxidant enzymes in sorghum [Sorghum bicolor (L.) Moench] in Marvdasht and Arsanjan regions in 2017. The treatments included four levels of water stress: 100%, 85%, 70%, and 55% of field capacity (FC) in the main plots and four levels of salinity stress: 1.5, 4.5, 7.5 and 10.5 dS m-1 in the sub plots, which were arranged in split plots based on randomized complete block design, with three replications. The results showed that water and salinity stresses in both regions were associated with decreased dry matter production and concentrations of chlorophylls a and b and carotenoids, while the concentration of free proline and the activity of antioxidant enzymes catalase, peroxidase and superoxide dismutase were increased depending on the stress level. Ascorbic peroxidase activity was increased only under water stress. The highest dry matter yields were obtained from 100% FC irrigation with 4.5 dS m-1 salinity and were 1.292 and 1.198 kg ha-1 in Marvdasht and Arsanjan, respectively. Non-significant effect in 85% FC irrigation regime showed that only 70% and 55% FC irrigation regimes led to water stress in sorghum. On the other hand, no significant difference was observed between non-saline conditions and 4.5 dS m-1, which indicates salinity tolerance of sorghum, at least up to this level. In both regions, the intensity of changes due to water and salinity stress was correlated with the intensity of that stress. The results of this research showed that due to antagonistic effects, drought and salinity stresses have a greater effect on reducing plant yield; therefore, water deficit irrigation strategies are not recommended in case of using water with salinities of 7.5 dS m-1 and more for sorghum irrigation.

In regions with severe limitation of fresh water, salinity poses a serious threat to agriculture production due to its toxicity to most plants. Salinity tolerant plants that can survive and grow in high-salinity conditions are called halophytes. Halophyte cultivation has the potential to restore saline environments, provide for global food demands, produce medicine and biofuels, and conserve fresh water. Two approaches are presented to developing tolerant plants of seawater salinity; the first is increasing tolerance of conventional plants, and the second is choice from the large pool of halophytes, which already have the requisite salt tolerance. The difference between the upper limit of salt tolerance of conventional plants and required tolerance level to seawater salinity is huge. It has been shown that Salicornia spp. has the potential to tolerate salinity of seawater. Salicornia is a genus of succulent, halophyte flowering plants in the family Amaranthaceae that grow in salt marshes, on beaches, and among mangroves. Pickleweed (Salicornia bigelovii Torr.) is an obligate halophyte that has been considered as a promising plant due to the tolerance to hypersaline water and economic values such as forage production, oilseed production and fresh consumption. This study evaluated the response of Salicornia bigelovii to different water salinity treatments, determines its salt tolerance threshold and shows trend of the accumulation of Ca2+, Cl-, Na+ and K+ ions in the plant shoots.

This experiment was conducted as a completely randomized design with 4 replicates in the greenhouse of the National Salinity Research Center, Yazd, Iran. Saline water treatments included 2, 5, 8, 11, 14 and 17 dS m-1, which were prepared using dilution of Persian Gulf water. Salinity treatments were applied as irrigation of pickleweed (Salicornia bigelovii) plants with related saline water treatments. The 10 uniform seeds were sown in pots and were kept in a controlled environment with 26/18 °C (±3) day/night temperature regimes. The 84 days plants were harvested and were immediately transferred to the laboratory. Fresh and dry weight, dry matter, ash content and concentration of calcium (Ca2+), chloride (Cl-), sodium (Na+) and potassium (K+) were measured in shoots. Data were subjected to analysis of variance, and the means were compared using LSD at 5% probability level. Response cure was used to determine the threshold level of reduction after reaching the peak.

The results showed that salinity treatment was significant on all traits, except dry matter percent and potassium concentration. The results showed that increasing salinity up to 8 dS m-1 increased fresh and dry weight, however higher salinity levels were associated with reduction. The threshold level of reduction after reaching to the peak were 8.65 and 7.01 dS m-1 for fresh and dry weight, respectively. The amounts of reduction in fresh weight in 2, 5, 11, 14 and 17 dS m-1 treatments compared to 8 dS m-1 treatment were 26.9%, 9.5%, 12.0%, 20.0% and 35.8%, respectively. These reductions were 23.4%, 20.7%, 27.4%, 38.9% and 41.7%, respectively in dry weight. With increasing salinity of water, the ash content of shoots had an ascending and significant trend. The lowest and the highest shoot ash were related to 2 and 17 dS m-1 water salinity, by 24.8% and 41.3%, respectively. As salinity was increased, the concentration of chlorine and sodium in shoots were enhanced, while the concentration of calcium and potassium were reduced. Correlation and stepwise regression analyses revealed that concentration of calcium and potassium were the most important traits in salinity tolerance of salicornia. It seems that salinity tolerance in salicornia occurs by osmotic regulation as the accumulation of salts in its tissue.

According to the results of this study, it can be concluded that the capability of ions accumulation strengthens the phytoremediation ability of salicornia, however increasing in ash content could have a negative effect on the forage value of the plant. Therefore, determining the nutritional value of salicornia and feed analyzing in the presence of livestock require further evaluation.

In current research, some soil properties and growth of camelthorn (Alhagi maurorum Medik.) were monitored in saline lands in Yazd Province during 2019-2020 and accordingly, the ability of this species was determined for growing in the saline lands. For this purpose, seven rangelands in Yazd consisted of Bafgh, Javadieh, Bahabad, Jolgeh, Ardakan, Aghda and Abarkooh were selected, in which Alhagi was dominant vegetation. Salinity of saturated extract (ECe) and pH of soil, salinity and pH of water, fresh and dry weight were measured by sampling and apparent soil salinity (ECa) was assessed by electromagnetic induction device (EM38). The results showed that regression coefficients (R2) of estimating soil salinity using EM38 device in different regions were accepted and varied between 0.52-0.86. Soil salinity levels varied over the surveyed lands from 2.17 g salt/kg soil in Aghda to 226.5 g salt/kg soil in Ardakan for 0-30 cm soil depth and from 0.4 g salt/kg soil in Bafgh to 118.3 g salt/kg soil in Ardakan for 30-60 cm soil depth. The maximum production of ryegrass, equal to 25 tons ha-1 of fresh weight and 7 tons ha-1 of dry weight, was observed in Bafgh with water salinity of 12 dS m-1 and soil salinity of 11 g kg-1. On average, the highest production was observed in Bafgh, Bahabad, Abarkooh, Aqda and Ardakan, respectively, which was almost consistent with changes in soil salinity and acidity. It seems that Alhagi has high tolerance to water and soil salinity, however, is sensitive to soil pH. The use of EM38 device to evaluate soil salinity in lands with camelthorn cover of Yazd province was reasonably accurate, and is recommended for monitoring soil salinity of other rangelands, but calibration in each area and for each soil depth separately is necessary.

Due to the scarcity of water resources, the use of saline water to cultivate forage halophytes is a practical solution. However, the main problem of forage of halophytes is their low energy content and high salt. In these conditions, mixed consumption and halophytes-crops intercropping can be useful. The current research was carried out in order to evaluate the effect of salinity of irrigation water on growth and some physiological characteristics in different ratios of sorghum-kochia intercropping in the National Salinity Research Center. The treatments included three levels of salt stress: 2, 7 and 14 dS m-1 in the main plots and five planting systems: sole sorghum, ⅔ sorghum (2 parts sorghum, 1 part kochia), ½ sorghum (1 part sorghum, 1 part kochia), ⅓ sorghum (1 part sorghum, 1 parts kochia) and sole kochia in the sub plots arranging in a split plot experiment based on randomized block design. Results showed that salinity, depended on the severity, significantly changed growth and physiological characteristics in both sorghum and kochia. Salinity at 14 dS m-1 was associated with reduction in dry weight (62%) and K+ concentration (22%) and increasing Na+ concentration (427%), Cl- concentration (175%) and activity of catalase (88%), peroxidase (77%), superoxide dismutase (86%) and ascorbic peroxidase (154%) in sorghum. These increasing and decreasing were less in kochia (23%, 22%, 37%, 105%, 237%, 77%, 406% and 294%, respectively); which indicated higher salinity tolerance of kochia. The optimum intercropping system for sorghum was ⅔ sorghum and were ½ and ⅓ sorghum for kochia; which reflected more sensitivity of sorghum to intra species completion in intercropping systems than kochia. According to the different reactions of two plants to salt stress, sorghum tolerated the salt stress probably via induced antioxidant system in order to ameliorate oxidative stress and kochia tolerated the salinity probably through ionic distributions in tissues via reduced transport to shoots and/or ions compartmentation in organelles. It seems that proper kochia density (⅓) enhanced salinity tolerance of sorghum, therefore, it is recommendable for saline conditions.

Camelthorn (Alhagi maurorum) has a high tolerance to salt and water stresses, and its forage quality is greater than cereal straw and is equal to alfalfa. Seeds of camelthorn do not germinate easily due to the hard seed coat. Therefore, camelthorn cultivation as an agricultural crop needs more research, especially on breaking seed dormancy and increasing germination. Despite numerous studies about camelthorn as a weed, there are few studies on evaluating agronomic factors of camelthorn as a field crop. Hence, in this study, some aspects of germination and salinity tolerance of camelthorn were examined.

In this research, different aspects of camelthorn germination were examined at the National Salinity Research Center in 2018. In the first experiment, different pretreatments including control, sandpaper, hydro-priming, hot water, and sulphuric acid were assessed. With the selection of sulphuric acid as the best treatment, varying durations (0, 5, 10, 15, 20, and 25 min) and concentrations (98% and 75%) of sulphuric acid priming were compared in the second and third experiments. In the fourth experiment, the seeds collected in 2018 were compared with the seeds collected in 2017 and 2016. The effect of different salt stress levels (0, 6, 12, 18, 24, 30, and 36 dS m-1) was evaluated on camelthorn germination and early growth in the fifth experiment. In the sixth experiment, lighting regimes including continuous dark, continuous light, and an alternative period of dark- light were examined and in the seventh experiment sibling factors (together and individual seeds) were evaluated. Seed germination and seedling length were calculated and salinity tolerance threshold levels and 50% reduction threshold were estimated.

The results of the first experiment showed that the highest germination percentage was obtained in sulphuric acid priming (56.6%), which was six folds greater than the control. In the second experiment, it was shown that the highest germination percentage (81.1%) and seedling growth (5.7 cm) was observed in sulphuric acid priming 98% for 25 min. Important note was that these results were related to domestically produced sulphuric acid, and the highest germination and seedling growth were observed in 75% concentration for the imported sulphuric acid. In the fourth experiment, it was found that at least 3 years of seed longevity had no significant effect on seed germination. Considerable losses in germination and growth were observed from 30 dS m-1 salinity level; however, germination did not completely stop even at 36 dS m-1 salinity. In the sixth and the seventh experiments, it was found that there were no significant differences between seeds germination in the continuous dark, continuous light, and an alternative period of dark- light as well as between individual and together seeds. So, camelthorn seed is not photoblastic and had no negative sibling factor.

Generally, it was concluded that the best method for improving germination is priming with sulphuric acid 98% (internal) or 75% (imported) for 25 min. According to achievement of high germination in sulphuric acid pre-treatments (chemical scarification), it seems that seed dormancy in camelthorn is presumably physical. Furthermore, although the salinity tolerance threshold of this plant is estimated 14.2 dS m-1, it can germinate minimally even in very higher salinity. Light salt stress not only decreases the germination of this plant but also is necessary for growth promoting. Based on the high salinity tolerance of camelthorn in the germination stage, its cultivation in haloculture systems is recommended for more investigation.

1- Sulphuric acid 98% priming for 25 min led to breaking seed dormancy and acceptable camelthorn germination. 2- In moderate salinity, germination was not significantly changed and seedling growth was promoted compared with the non-stress conditions. 3- Salinity tolerance threshold level of camelthorn was estimated 14.2 dS m-1.

To evaluate the effect of varied concentrations of chlormequat chloride (CCC) on yield, yield components and grain quality of rapeseed under different nitrogen (N) levels, a field study was conducted as factorial experiment based on randomized complete block design with three replications during 2014-2015 growing season in Marvdasht. The treatments were consisted of nitrogen fertilizer at four levels: 50, 100, 150 and 200 kg ha-1 and CCC spraying at three concentrations: 0, 1.5 and 3 g.L-1. IThe results of analysis of variance showed that the effect of N on all traits, the effect of CCC on all traits except hundred grain weight and the effect of N and CCC interaction on all traits except hundred grain weight and protein percentage were significant. Nitrogen and CCC had positive and significant effect on yield, yield components as well as protein and oil percentage of seed. In general, increasing N up to 150 kg ha-1 was associated with enhanced quantity and quality of rapeseed crop, whereas more amount of N had no significant effect on yield components but reduced oil percentage of seed. There is no significant difference between 1.5 and 3 g.L-1 CCC spraying. Under no CCC application, N up to 150 kg.ha-1 and under CCC foliar application N up to 200 kg.ha-1 increased grain yield. Exceeded amount of N stimulate tillering and increase infertile tillers and reduce N efficiency, while CCC as a growth retardant increased uniformity intra plants and increased fertile tillers via prolong of development during.

Salinity stress is known as a worldwide plant growth limiting factors (Alavimatin et al., 2015: Atlasipak 2018). In addition, it is estimated that around 50 percent of arable lands are affected by salinity stress by 2050 (Butcher et al., 2016: Qadir et al., 2014). The use of chemical fertilizers is a common practice in arid soils for improving plant performance grown under non-fertile soils. While there is little evidence of yield benefits due to application of fertilizers in salt affected soils at rates beyond optimal in non-saline conditions, there is enough evidence indicating that soil salinity does not affect or decrease plant fertilizer requirements (Hanson, 2006). Accordingly, the objectives of this field study were to (a) evaluate the interactions between phosphorous nutrition and the salinity of irrigation water and their effects on wheat growth and (b) test the possibility of wheat improvement at saline conditions by applying higher levels of phosphorous fertilizer.

A field experiment was conducted on wheat at Sadooq Salinity Research Station, Ashkezar, Yazd, Iran. The soil at the experimental site was calcareous with 30.92% total nutrient value, sandy loam texture, pH 8.06 and 0.22 % organic carbon. Mean annual temperatue is 18°C and precipitation is 70 mm. The treatments, four triple superphosphate application rates (0, 100, 200 and 300 kg ha-1) and three irrigation water qualities (1.88, 7.22 , 14.16 dS/m), arranged in a randomized block with three replications. Consisting 12 rows of wheat, each field plot was 3*5 m. All plots received common agricultural practices including tillage and fertilizer application. Rgarding typical recommendations and guidelines for this region and soil type (Balali et al., 2000: Moshiri et al., 2015), all fertilizers, except urea that applied in 4 splits, were soil-applied before planting and included 40 kg ha-1 ZnSO4, 40 kg ha-1 MnSO4 and 20 kg ha-1 CuSO4. To model the relationship between plant properties and irrigation water salinity, the data were subjected to different regression models at the probability level of 0.01 and 0.05 with the help of the Sigmaplot software. The analysis of variance for different parameters was done following ANOVA technique. When F was significant at p ≤ 0.05 level, treatment means were separated using LSD.

The results showed that increasing irrigation water salinity to 7.22 dS/m did not significantly affect wheat grain yield. This is due to the positive effect of salinity on 1000 seed weight and harvesting index. At the same time, the results showed 50% decrease in wheat grain and straw yield due to the increase in the salinity of irrigation water from 1.88 to 14.16 dS/m. The heighest graine yield for treatments irrigated with irrigation water salinity of 1.88, 7.22 and 14.16 dS/m was obtained from application of 40, 20 and 0 kgha-1 FeSO4, respectively.

Overall, it was concluded that application of triple superphosphate at a rate of 150 kgha-1 is recommended for wheat yield improvement at irrigation water salinity of 1.88 and 7.22 dS/m. As wheat performance irrigated with irrigation water salinity of 16.14 ds/m was not affected by different rates of phosphorous fertilizer, it can be concluded that wheat phosphorous requirement decreased at irrigation water salinity beyond salt tolerance.

To comparison biomass production, accumulation of some elements and ash content of shoots in five halophytes species including Salicornia bigelovii Torr., S. sinus persica, Atriplex lentiformis Torr., Halocnemum strobilaceum Bieb., and Halostachys caspica Botsch irrigated with seawater, a research was conducted at Salinity Research Station in Bushehr province. The results showed that there was a significant difference between the halophytes species in terms of concentration of Na+, K+, Cl-, Na+/K+ ratio, fresh weight, dry weight, shoot water content and ash. The highest and lowest Na+ concentrations were obtained in S. sinus persica and A. lentiformis species, respectively, whereas the rate of shoot Na+ in S. sinus persica was more than A. lentiformis by 101.3%. The highest concentration of K+, Cl- and Na+/K+ were obtained in leaves of A. lentiformis and shoots of two species of Salicornia and H. strobilaceum species, respectively. A. lentiformis with the production of 18.98 and 7.75 ton ha-1, had the highest fresh and dry biomass, respectively. The lowest fresh and dry biomass were also found in S. bigelovii by 10.13 and 2.49 ton ha-1, respectively. The highest and lowest ash content were related to shoots of S. sinus persica equal to 48.8% and leaves of Atriplex lentiformis equal to 37.5%, respectively. According to the results, Salicornia species has no mechanism of preventing salt entrance in the plant due to high concentration of Na+ and Cl- ions in their shoots. These species follow the mechanism of salt accumulation in plant tissues with the aim of osmotic regulation for survival in high saline conditions. Atriplex lentiformis also produced the highest amount of biomass, which could attributed to the low shoot water content of this species due to the presence of hard stems in the plant in comparison to the succulent stems and higher shoots water content in the other species. According to the production amount and ash content, it seems that A. lentiformis is a suitable species for forage producing in the regions with limited freshwater. Furthermore, Salicornia species could be also considered as part of a livestock diet in this regions.

Intensified salinization of water and soil resources has promoted interest for research and approaches of improving crop yield under saline conditions. Reviewing the literature showed that the records on understanding of different aspects of salt stress and enhanced salinity tolerance in the world goes back to more than a century. Different approaches have been suggested to increase crop yield under saline conditions, among which one is using plant growth regulators (PGRs). Application of PGRs has begun since 1930s and their global annual sales are about US$ 1.2 billion. Nearly 40 active ingredients og PGRs are now in use, applied either as a single or combined treatments, among which the most important are auxins, cytokinins, gibberellins, ethylene, abscisic acid, brassinosteroids, salicylic acid, chlormequat chloride, paclobutrazol, jasmonic acid, ascorbic acid, triacontanol, strigolactones, nitric oxide, polyamines and plant peptide hormones. There have been large body of reports showing quantitative and quality improvement of crops as well as salinity tolerance as the consequences of PGRs application.However, most of these studies were conducted under controlled conditions (i.e. out of field conditions), as one season experiments, and this makes the results unreliable. In this paper, with having in mind the applicability for the field conditions, crop yield improvement as the result of using PGRs has been reviewed.

This research was conducted to compare the salinity tolerance of wheat promising lines during 2015-2017. The greenhouse experiment was carried out at Seed and Plant Improvement Institute, Karaj, Iran, and the field experiment was conducted at National Salinity Research Center, Yazd, Iran. The treatments in greenhouse experiment were irrigation water salinity at two levels (2 and 14 dS.m-1) and five wheat genotypes (MS-89-13, MS-89-12, MS-90-13, MS-90-15 and Narin as check, and in the field experiment including salinity of irrigation water at five levels (2, 5, 8, 11 and 14 dS.m-1) and the same five wheat genotypes mentioned above. The results of greenhouse experiment showed that salinity stress of 14 dS.m-1 significantly decreased plant height, leaf area, shoot fresh and dry weight and root length and dry weight in all genotypes and increased chlorophyll index only in MS-89-12 genotype. Narin as well as MS-90-15 and MS-90-13 genotypes with the lowest reduction percentage due to salinity stress were determined as the most tolerant genotypes. The results of field experiment also indicated that salinity stress, depending on its severity, significantly reduced plant height, ear length, fertile spikelet number in ear, grain number per spike and thousand grain weight, which led to considerable decrease in grain and biological yield. Under control conditions (2 dS.m-1), the highest and lowest grain yield were obtained from MS-90-13 and Narin (6.91 and 5.81 t.ha-1, respectively), and under 14 dS.m-1 salinity conditions, Narin and MS-90-15 genotypes had the highest and lowest grain yield (3.23 and 1.51 t.ha-1, respectively). The threshold levels of salinity tolerance for MS-89-13, MS-90-13, MS-90-15, Narin and Ms-89-12 were evaluated to be7.41, 6.30, 4.92, 4.84 and 4.20 dS.m-1, respectively. The results showed that MS-89-13 had the higher salinity tolerance at salinity of less than 8 dS.m-1, but at higher salinity levels, Narin and MS-90-13 genotypes similar to greenhouse experiment were more tolerant than the other genotypes. According to the relatively similar results of greenhouse and field experiments, MS-90-13 line for lower salinity levels and Narin variety and MS-90-15 line for higher salinity levels were the more suitable genotypes, which could be recommended with due to considerations.

This study was conducted in two separated experiments in the National Salinity Research Center in 2016. In the first experiment, the effect of 12 priming treatments consisted of potassium nitrate, sodium chloride, calcium chloride, and GA3 with control were investigated on seed germination of Salicornia (Salicornia bigelovii var. LVYUAN no.1) in order to select the best priming for the second experiment. In the second experiment, the effects of different salinity levels (12.5, 25.0, 37.5 and 50.0 dS m-1) and GA3 concentrations including 500 and 1000 mg L-1 were also evaluated on seed germination of the Salicornia genotype. The salinity treatments were prepared by different percentage of Persian Gulf water. The results showed that all the priming treatments increased germination percentage compared to the control, and the highest effect belonged to the concentrations of 500 and 1000 mg l-1 of GA3,by 142.3% and 119.1%, respectively. It was revealed in the second experiment that salt stress significantly reduced percentage and rate of seed germination, so that salinity treatments as 12.5, 25.0, 37.5 and 50.0 dS m-1 could reduce germination percentage by 11.8%, 40.3%, 63.3% and germination rate by 81.4% and 21.3%, 40.0%, 62.3% and 70.1%, respectively. However, GA3 priming could improve the salt tolerance and compensate a part of this loss, especially at 500 mg L-1. Application of GA3 increased salt tolerance threshold of Salicornia at germination stage. In no prim and GA3-priming treatments at 500 and 1000 mg L-1, salinity tolerance thresholds were 4.15, 9.31 and 6.56 dS m-1 and the threshold of 50% reduction was 20.36, 35.97 and 31.39 dS m-1, respectively. In general, the results indicated that seed germination and rate of Salicornia were improved using GA3.

Intensification salinization of water and soil resources requires more attentions to halophytes species cultivation. In this research, the effect of salt stress as varied percentage (control, 15%, 30%, 45%, 60%, 75%, 90% and 100%.) of Persian Gulf water (58 dS m-1) was examined on germination and seedling growth of different Salicornia species, in order to determine salinity tolerance threshold and threshold of 50% reduction in germination at National Salinity Research Center, Yazd in 2017. Species consisted of Salicornia europaea, S. bigelovii along with three local populations: Khor-e-Mozain (Bushehr province), Ilkhchi (East Azerbaijan province) and Markazi (Iran central regions). The results showed that the mean germination of the species were significantly reduced from 25% Persian Gulf water, however germination of all species did not stopped even at 100% Persian Gulf water. However, seedling length in Khor-e-Mozain, S. europaea and S. bigelovii was decreased as salinity was intensified, while in Ilkhchi and Markazi were increased up to 45% and 60% Persian Gulf water, respectively and then was reduced. In general, all Salicornia species had high salinity tolerance, however there were considerable variations between different species, so that salinity tolerance threshold of Khor-e-Mozain, Ilkhchi, Markazi, S. europaea and S. bigelovii were 14.36, 5.01, 14.46, 11.91 and 7.54 dS m-1 and their threshold of 50% reduction were 56.25, 51.60, 61.15, 32.69 and 27.01 dS m-1, respectively.

In this research, the effect of concentration and time of seed priming with salicylic acid on germination and early growth and it’s application methods under salinity stress conditions on phenology characteristics of barley, variety Reyhan, was studied in two separate experiments. The effect of concentration (in five levels, control, 0.5, 0.75, 1.0 and 1.5 mM) and time (in three levels, 6, 12 and 24 h) of seed priming by salicylic acid (SA) in the first experiment and different application methods of SA (no application, priming and spraying at the stages of establishment, double ridges and anthesis) under different salinity conditions (no stress and salinity of 6 and 12 dS.m-1)in the second experiment was evaluated. Both experiments were conducted as completely randomized design with four replications at College of Agriculture, Shiraz University, Iran, in 2014. The results of the first experiment showed that SA-priming with 1.5 mM for 12 h had the highest positive effect on germination and early growth, which was selected for the second experiment. The results of the second experiment showed that salinity stress of 6 dS.m-1 reduced the planting to anthesis period as well as planting to physiological ripening and 12 dS.m-1salinity stress also reduced the planting to booting, planting to anthesis and planting to physiological ripeningperiods. Seed priming with SA prolonged the growth periods, whereas the delay in SA application decreased its positive effect. Foliar application at establishment increased planting to booting, planting to anthesis as well as planting to physiological ripening periods,however foliar application at anthesis had no significant effect on phenology of barley plants. In total, seed priming or foliar application at establishment at early growth stages ameliorated the acceleration of the developmental stages due to salinity stress and early application of SA was found to be more important with increasing salinity stress.

In a 2-year field study, soil moisture and EC of soil extract (ECe) during growing season as well as grain and biological yield and water productivity of barley plant cv. Nosrat were monitored as affected by two salinity levels of irrigation water. Salinity levels of irrigation water were 2 and 12 dS.m-1. The results showed that salinity stress reduced grain, biological yield, and water productivity by, respectively, 36.0%, 52.1%, and 23.0% in the first year, and 48.4%, 69.1% and 31.7% in the second year. Higher losses in the second year were due to lower precipitation. Two-year averages of water productivity in terms of grain yields were 0.87 and 0.64 kg/m3, for 2 and 12 dS.m-1 water, respectively. In all days after imposing salinity treatment, soil moisture in control plots was significantly lower than saline plots. This difference was more distinct in the first depth and continued until the end of the growing season. On average, soil moisture levels in saline plots were higher than the control plots by 16.8% and 22.4% in the first and second years, respectively. In both years, ECe was also affected by salinity treatment, and this effect became more over time. The 2 and 12 dS m-1 salinity treatments decreased and increased ECe, respectively. The highest ECe values were observed at 160 days after planting in all three soil depths. Overall, in this condition, irrigation with saline water increased ECe about twice at the end of season compared to early growth, and increased ECe by 20% over EC of irrigation water. Greater soil moisture in saline conditions is not useful for crops because it is not easily available and has low quality, however, halophytes such as Panicum antidotale, Kochia spp., Salicornia spp. in rotation with barley might use this higher soil moisture and produce acceptable yield with less water.

IntroductionDrought stress is most important abiotic stress reducing growth and production of wheat worldwide. Protective role of plant growth regulators (PGRs) against drought stress has been accepted in general, however, comparison of PGRs types to determine the optimum one is crucial. Many PGRs are known to alleviate the negative effects of drought stress in plants. However, limited research has been conducted to investigate the potential benefits of exogenous application of different PGRs in wheat plants grown under drought stress. Chlormequat chloride (CCC), salicylic acid (SA) and jasmonic acid (JA) could consider as three major PGRs using in cereals.
Materials and MethodsTo examine the effect of three PGRs consisted of CCC, SA and JA on yield components and grain yield of wheat cv. Roshan under different water stress conditions (a range of light to severe drought levels) two separated experiments were conducted at controlled and field conditions at College of Agriculture, Shiraz University during 2012-2013 growing seasons. Concentration of CCC, SA and JA were 19.0, 1.0 and 0.1 mM, respectively. Drought stress levels were 100%, 80%, 60% and 40% of field capacity in greenhouse and were 100%, 2/3 and 1/5 of field capacity in the field experiment. Field capacity was determined as 25% (g g-1) for the experimental field. Greenhouse and field researches were carried out in factorial experiment based on completely randomized design and in split plot experiment based on randomized complete block design, respectively. Four and three replications were used greenhouse and field experiments, respectively. Roshan as a bread wheat cultivar with standard height was used. Foliar application of 3 PGRs was done at double ridges stage in both experiments; however, irrigation treatments were applied at double ridges stage and early anthesis at greenhouse and field experiment, respectively. For plot irrigation a tape system was used and amount of irrigation was measured by a water meter.
Results and DiscussionThe results showed that water stress decreased flag leaf area, ear length, grain number per ear, biological yield and grain yield in the greenhouse and biological yield and grain yield in the field experiment. The maximum of flag leaf area was obtained at anthesis and after that there was no increase in green area. In the other hand, ear length and grain number per ear were fixed at anthesis and so drought stress had less negative impact on flag leaf area, ear length and grain number per ear under field conditions. Increasing the level of drought stress was considerably associated with greater reduction in grain yield and yield components. However, PGRS application improved yield components and consequently enhanced the grain yield. The higher flag leaf area in PGRs-treated plants might be due to lowering developmental rate or delaying plant maturity and senescence. So, by improving leaf area, PGR application resulted in increased photosynthetic rate leading to a higher yield. Although all PGRs had positive effect on growth and yield of wheat nevertheless, the effect of chlormequat chloride followed by salicylic acid was greater than jasmonic acid; so that foliar applications of chlormequat chloride, salicylic acid and jasmonic acid were associated with 20.7%, 13.8% and 7.24% increase in grain yield, respectively, under controlled conditions. These values were 18.3%, 12.2% and 8.1% for the field experiment. Such compensatory effects of PGRs could be due to various reasons. Chlormequat chloride can stimulate root growth, reduce transpiration, increase water use efficiency, and prevent chlorophyll destruction. Similarly, SA application may result in stomatal closure, increased WUE, increased chlorophyll content, increased respiratory-pathways and intercellular CO2 concentration, and stimulatory changes in other physiological and biochemical attributes. Jasmonic acid is also essential components for the signaling pathway triggering the expression of plant defense genes in response to abiotic stresses. This PGR had a significant role in osmotic adjustment under drought stress conditions.
ConclusionsOverall, drought stress depending on time and severity of application had several adverse effects on wheat cultivar including decreased flag leaf area, ear length and grain number which led to reduced biological yield and grain yield. However, exogenous application of SA, CCC or JA reduced at least some of the harmful impacts of drought stress and in some cases compensated losses or damages caused by the drought, resulting in purging of differences between the control and drought stress conditions. Furthermore, chlormequat chloride might have a wide scope for further investigations as an approach to increase grain yield under limited water conditions.

Although role of salicylic acid (SA) in enhancement of salinity tolerance of plants has been well shown, more researches are needed for better understanding of its physiological mechanisms. In this experiment, the effect of different SA concentrations (0, 0.5, 1.0, 1.5 and 2.0 mM) was examined on biochemical attributes and grain yield of barley cv. Nosrat under non-saline and saline conditions (2 and 12 dS.m-1, respectively) during 2012-13 and 2013-14 growing seasons at the National Salinity Research Center, Yazd, Iran. Salt stress enhanced soluble proteins content, free proline, malondialdehyde and electrolyte leakage by 22.1%, 147.7%, 87.2% and 102.9%, respectively. However, membrane stability index as well as concentrations of chlorophyll a and b reduced by 33.2%, 31.4% and 59.3%, respectively. Salt stress also decreased grain yield by 34.2% and 40.9% in the first and second year, respectively. Salicylic acid reduced the negative effect of salt stress on grain yield, therefore, SA foliar application decreased the rate of grain yield reduction under saline condition from 42.1 in no-SA to 27.3% in 1.5 mM in the first year and from 43.7% in no-SA to 33.8% in 1.0 mM in the second year. This mitigation could be related to biochemical attributes, as SA at different concentration levels enhanced soluble proteins content, free proline, concentration of chlorophyll a and b and carotenoids as well as membrane stability index, and reduced malondialdehyde and electrolyte leakage. It can be concluded that SA had better effect up to 2.0 and 1.0 mM under non-saline and saline conditions, respectively. In Genral, SA with reducing negative impact of salt stress on biochemical attributes could improve salinity tolerance and increase grain yield of barely cv. Nosrat.

In a five years experiment, the effect of crop rotation was examined on yield and soil physico-chemical properties in 200 hectares land of College of Agriculture- during 2010-2015 growing seasons Shiraz University, Shiraz, Iran,. Eight rotation systems consisted of 1: complete fallow (no planting), 2: continuous maize-wheat, 3: wheat rotation with alfalfa, 4: maize rotation with alfalfa, 5, 6, 7 and 8: fallow in one, two, three and four of ten growing seasons during five years using randomized complete block design with four replications. Shiraz wheat cultivar and SC704 maize hybrid were used. Results showed that the highest wheat grain yield (7706 kg.ha-1) and maize fresh forage (82100 kg.ha-1) obtained when sown in rotation with alfalfa. Fallow had positive effect on yield of both crops, up to four seasons for wheat and up to two seasons for maize. Continuous maize-wheat with higher soil salinity and lower amount of nitrogen (N), phosphorous (P), zinc (Zn), iron (Fe), copper (Cu) and manganese (Mn) led to significant reduction in yield compared to rotations with alfalfa or fallow for more than two seasons. Wheat and maize in rotations with alfalfa had higher soil nitrogen, phosphorous, iron and manganese which were associated with greater wheat grain yield and maize fresh forage. Micronutrients were greater in fallow systems and this might led to greater and stable wheat grain yield and maize fresh forage yield. It was concluded that rotation with alfalfa or 2-3 seasons fallow for maize and 4 seasons for wheat improved soil chemical conditions, and consequently had higher economical yield of wheat and maize.

Chlormequat chloride (CCC) as one of the most important growth retardants has been used for manipulation of growth and yield of cereal crops; however, the effect of CCC has not yet been well understood under drought stress conditions. Therefore, one greenhouse and a field experiment were conducted to examine the effects of CCC on yield and yield components of wheat in drought conditions at College of Agriculture, Shiraz University during 2012-2014 growing seasons. The treatments in greenhouse were application and no-application of CCC, wheat cultivar (Marvdasht, Shiraz and Chamran) and irrigation regimes (100%, 75% and 50% of FC); while the treatments in filed were different CCC concentrations (0, 3 and 5 g L-1) and drought stress levels (no-, light-, moderate- and severe-drought). The results showed that under both greenhouse and field conditions, drought stress at different levels decreased yield and yield components of wheat cultivars. However, CCC improved drought tolerance in wheat with increasing yield and yield components; under field conditions, positive effects of CCC were enhanced with increasing its concentration up to 5 g L-1. The positive effect of CCC was greater under control and light stress compared to under severe stress conditions. In the greenhouse study where Marvdasht, Shiraz, and Chamran cultivars were evaluated, Chamran cultivar produced the highest grain yield under both normal and drought conditions; although Shiraz cultivar was found more responsive to CCC. Overall; drought stress reduced growth and grain yield of wheat crop; however, CCC could compensate, at least in part (i.e. 30% to 60%) for the latter reductions.

Although sink-source relation could be differed under drought tension conditions compared to optimum conditions, there are limited research with focus on this topic. In the present research, sink-source relation under drought tension conditions was investigated in a field experiment based on statistical randomized complete blocks design at College of Agriculture of Shiraz University during 2013-2014 cropping year. The treatments included irrigation regime at two levels normal irrigation and cutting off irrigation at flowering in main plots, Pishtaz, Chamran and Marvdasht wheat cultivars in sub plots and treatment of no defoliation and defoliation of all leaves except flag leaf at stem elongation and in flowering sub sub plots. The results showed that drought tension and defoliation decreased significantly ear length, grain number per ear, one-thousand grain weight, biological yield and grain yield as well as water productivity in all three cultivars. Delaying in leaf defoliation, reduced its negative impact on yield and yield components of wheat cultivars, so that defoliation at stem elongation and flowering stages was associated with 68.4 and 31.4 percent reduction in average of grain yield cultivars, respectively. Grain yield reduction in defoliation treatment at the time of stem elongation was due to reduction in grain number and in defoliation treatment at the time of flowering was due to grain weight reduction. Defoliation treatment, could compensate some losses in yield and yield components due to drought tension, in the other side, Chamran cultivar had the most tolerance to drought tension and defoliation; therefore, Chamran cultivar had better performance in such conditions. Due to higher tolerance of Chamran cultivar to drought tension and defoliation, use of this cultivar in the regions with wet limitations deserves long term explorations with more details.

Environmental stresses represent a major constraint to meeting the world food demand. The estimation of potential yield losses by individual environmetnal stresses are estimated 17% by drought, 20% by salinity, 40% by high temperature and 15% by low temperature. Salt stress is among the most important abiotic stress, depended to severity and stage, reducing growth and changing accumulation and distribution of ions in rapeseed (Brassica napus). Rapeseed sensitivity to soil salinity continually changes during the growing season. Most crops are tolerant during germination, but the young developing seedlings are susceptible to injury during emergence from the soil and during early juvenile development. Once established, plants generally become increasingly tolerant during later stages of growth. Althought effect of salt stress was well docucmented on rapseed growth; however, sensitivity of different growth stages of this plant has not fully studied. So, the main objective of this research was to examine salinity tolerance at different growth stages in rapeseed.
In this research the effect of different saline waterat different growth stageswas evaluated on some morpho-physiological traits on rapeseed (cv. Talaye) in controlled greenhouse in College of Agriculture, Shiraz University at 2014. The treatments included 0.4 (tap water as control), 4, 7 and 10 dS.m-1imposed at different growth stages consisted of 5 leaves, stem elongation and flowering. The pots (5 L size) were filled with field soil, sand and humus as 2:1:1 ratio. The used soil texture was sandy clay with pH = 7.05 and EC= 0.52 dS m-1.Saline solutions were achieved using 1:1 weight ratio of NaCl: CaCl2 and controlled by a portable EC-meter.In this research, plant height, leaf number per plant, leaf area index, chlorophyll content index, dry weight of shoot and root, water content of shoot and root, sodium concentration of shoot and root as well as potassium concentration of shoot and root were measuered. Relative salinity tolerance at different growth stage of rapeseed for dry matter production also was assessed based on Van Genuchten and Hoffman method.
The result generally showed that salt stress reduced plant height, leaf number, leaf area index, shoot and root dry weight, shoot and root water content and shoot and root potassium concentration. On the other hand, chlorophyll content index and shoot and root sodium concentrations were enhanced as affected by salinity. These changes were intensified in parallel with increased salinity levels. In the most cases, the negative effects of salt stress in all levels were more at 5 leavesstage, and delay in salinity impose decreased these negative effects. For example, salt stress in the highest level (i.e. 10 dS.m-1)imposed at 5 leaves, stem elongation and flowering stages were associated with 78.0%, 50.7% and 26.5% reductions in shoot dry weight and with 61.8%, 41.2% and 21.0% reductions in root dry weight, respectively. Salinity thresholds (50% reduction) for rapeseed cv. Talaye were determined by 1.2, 2.8 and 7.5 dS m-1 for 5 leaves, stem elongation and flowering stages, respectively. Therefore, it could be concluded that this plant was sensitive, mild tolerance and tolerance at 5 leaves, stem elongation and flowering stages, respectively.
The results of this experiment revealed that salt stress limited growth of shoot and root as well as changed potassium and sodium accumulation and distribution to the detriment of rapseed plants. It was also showed more sensitivity of rapeseed to salinity at early growth; which salt stress tolerance was enhanced with plant aging.