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Effects of Foliar Application of Salicylic Acid and Spermine on Maternal Plant under Drought Stress on Germination Indices of Purple Coneflower (Echinacea purpurea)
Hakimeh Darvizheh, Mortez Zahedi, Bohlul Abbaszadeh, Jamshid Razmjoo,
Volume 5, Issue 1 (9-2018)
Abstract


Extended abstract
Introduction: Echinacea purpurea, a member of Asteraceae family, is a herbal medicine which is effective for promoting human immune system. Enviromental stresses including water defecit, which limit maternal plant growth, can also affect their seed quality and germination. Various compounds such as salicylic acid and spermin are known to be useful in the alleviation of harmful effects of drought on plants and their seed production.
Materials and Methods: In order to investigate the seed vigor of Purple Coneflower after foliar  application of salicylic acid (SA) and spermine (SPM) on maternal plant (no spray,75 mg/l SA, 150 mg/L SA, 75 mg/L SPM, 75 mg/l SA+75 mg/L SPM and 150 mg/L SA+75 mg/L SPM) under three irrigation regimes (irrigation after 20, 40 and 60% depletion of soil available water), a split plot experiment was conducted based on a completely randomized block design with three replications during 2016- 2017 growing seasons at research field of Institute of Forests and Rangelands, Iran.
Results: Water stress decreased the percentage and rate of germination, shoot and seedling length, shoot dry weight, germination energy and seed germination vigour. The results showed that foliar application had a significant effect on shoot, root and seedling length, shoot, root and seedling dry weight, germination rate, allometric factor, and germination vigour. The interaction effect of drought stress and foliar application indicated that non-stress and 150 SA+70 SPM mg/L had the highest radicle length (28.8 mm), radicle dry weight (1.81mg), seedling dry weight (6.20 mg) and Allometric factor (0.412).
Conclusions: Based on the results of the current experiment, the foliar application of salicylic acid and spermine improved the seed germination of coneflower plants under both normal and water stress conditions and the highest values of these parameters were obtained under combained application of high concentrations of salicylic acid (150 mg/L) and spermine (75 mg/L).
 
 
Highlights:
1- Investigating the foliar application of salicylic acid and spermine in maternal Echinacea purpurea plant under drought stress in germination of seed.
2- The foliar application of salicylic acid and spermine on maternal plants of Echinacea improved germination quality under water stress.
Effect of Magnetic Field on Seed Germination of Guizotia abyssinica under Drought Stress Conditions
Samaneh Hosseini, Mohammad Rafieolhossaini, Parto Roshandel,
Volume 5, Issue 1 (9-2018)
Abstract
Extended abstract
Introduction: Niger with the scientific name of Guizotia abyssinica (L.F.) Cass. belongs to the Asteraceae family. Niger seed contains 50-75 percentage of oil which is used in the treatment of rheumatism and burns, and as a substitute for olive oil. Its meal is also used for animal feeding. Environmental crises sustained by living systems are considered as stress. Drought stress is one of the non-biological stresses. Yield reduction due to this type of stress is reported to be higher than that related to other stresses. Since plant development starts from germination and for survival, the seeds should germinate to adapt themselves to the environmental conditions and establish themselves in the soil, the success of passing the germination stage will play an important role in other stages of plant establishment. Different studies have shown the positive effect of magnetic field on increasing germination characteristics. In this regard, applying a magnetic field before planting is a safe and inexpensive method for increasing germination and seedling growth. Seed priming is useful for a faster and more powerful response to drought stress and among different types of priming, physical priming is of particular importance for ecological reasons and for not having a negative impact on the environment.
Materials and Methods: In order to study the effect of seed physical pre-treatment and drought stress on seed germination characteristics of Niger, an experiment was conducted as factorial in a completely randomized design with three replications at the Research Laboratory of Seed Science and Technology at Shahrekord University. Different magnetic field intensities at five levels including (0, 50, 100, 150 and 200 mT (at 5 minutes period)) as the first factor and drought stress at five levels (0, -4, -5, -6 and -7 bar Polyethylene Glycol6000) as the second factor were considered.
Results: The results of variance analysis showed that the effect of drought stress, magnetic field intensity and their interaction were significant on all of the evaluated characteristics. The maximum germination percentage and rate and the minimum of T10 and T50 were observed in 50 mT field intensity under normal conditions. The minimum germination index under normal conditions and the maximum length and shoot dry weight under non-treatment conditions and the maximum root and shoot fresh weight in 200 mT field intensity under normal conditions were obtained. The maximum root length and dry weight were observed in 50 and 100 mT field intensity under normal conditions, respectively. 
Conclusions: Seeds which cross through a magnetic field, become swollen and probably as a result, the activity of auxin hormone in these seeds increases. In addition, the respiration level also increases in them and they have higher levels of energy and activity, which results in faster and more uniform germination and the creation of stress-resistant plants. In this study, although by increasing drought stress intensity, negative effects were observed on germination characteristics, the magnetic field under these conditions improved some germination characteristics. In general, for the purpose of improving germination and alleviating drought stress conditions, for 0, -5 and -7 bar potentials, the field intensity of 50 mT and for -4 and -6 bar potentials, the field intensity of 150 mT are recommended.
 
Highlights:
  1. The effect of magnetic field on germination of multipurpose seed of Niger plant.
  2. The effect of drought stress on germination of multipurpose seed of Niger plant, given Iran’s being located in dry belt.
  3. The positive effect of magnetic field on germination of Niger seed to improve the negative effects of drought stress.

Effect of Stratification and Its Combination with Gibberellic Acid on Seed Dormancy Breaking of Echinophora platyloba
Ali Abbasi Sourki, Zahra Hosseni, Sina Fallah,
Volume 5, Issue 2 (3-2019)
Abstract



Extended Abstract
Introduction: Seeds are a good option for propagation and protection of medicinal plants. Although Seed dormancy is an adaptive strategy for wild medicinal plants, but it is considered as an undesirable trait in domestication and cultivation of them, need to be solved. Echinophora platyloba seed has dormancy despite its remarkable medicinal properties.
Materials and Methods: In order to break seed dormancy, three separate experiment including stratification, hormonal treatment and combination of both were performed. For stratification 10 samples of were placed in a wet bed at 5 ° C for 2, 4, 6, 8, 10, 12, 14 and 16 Week and were compared using a completely randomized design with three replications. For hormonal treatment, the seeds were placed in GA concentrations of 0, 500 and 1000 ppm for 24 hours and then transferred to germination conditions. However, since the breaking of dormancy did not occur, this experiment was not discussed any more. For combined application of hormone and stratification, seeds were placed at mentioned concentrations of gibberellin for 24 hours at 20 ° C and then gibberellin solutions were removed and the seed transmitted to 5 ° C and compared for 2, 4, 6, 8 weeks with a CRD factorial experiment with three replications. The first factor was concentration of gibberellin in three levels and the second factor was the duration of stratification in 4 levels.
Results: Stratification had a positive effect on seed dormancy breaking and 16 week chilling lead to highest germination percentage and rate and vigor indices. The combined application of hormonal treatments accelerated dormancy release and improved seed germination characteristics, which peaked at 8 weeks. 8-week stratification treatment at 5 ° C with 1000 ppm gibberellic acid was the best treatment to overcoming of dormancy in Echinophora-platyloba seeds.
Conclusion: It seems that seed dormancy of Echinophora seeds is physiological, which broke down by moist chilling and simultaneous application of stratification and gibberellin successfully. Although Gibberellin had no effect on dormancy break, it reduced the need for stratification. Combined application of them showed synergistic effects on dormancy release.
 
 
Highlights:

  1. Echinophora seed’s dormancy was broken under stratification conditions, but GA had no effect on it lonely.
  2. The application of gibberellin reduced the chilling demands of Echinophora seeds and the combined application of them had a synergistic effect on dormancy break

Evaluation of Different Methods in Seed Dormancy Breaking and germination of Redroot Pigweed (Amaranthus retroflexus)
Vaghef Enayati, Ezatollah Esfandiari, Alireza Pourmohammad, Kamal Haj Mohammadnia Ghalibaf,
Volume 5, Issue 2 (3-2019)
Abstract



Extended Abstract
Introduction: Weeds, as the most important biological stress, reduce the efficiency of water use, waste of food, shading and secretion of toxic substances, leads to a 10 to 100 percent reduction in crop yields. The first step of the weed control understands the biology and life cycle of the weed particularly seed Eco physiological characteristics. Dormancy in weed seeds, including Redroot Pigweed seeds, is common. So, due to the importance of dormancy breaking and germination studies of weed seeds, the present study was designed to identify the methods for dormancy breaking and the germination of Redroot Pigweed seeds.
Materials and Methods: This research started in autumn 2013 by collecting Redroot Pigweed seeds from fields of Alajujeh village, Khoda Afrin County, East Azerbaijan Province, and then it was carried out at the Laboratory of the Faculty of Agriculture of the University of Maragheh in 2014 and 2015. For data analysis, the GenStat 12.1 program was used and the Duncan test was used at 5% probability level to compare the averages. Excel 2013 was also employed for drawing the diagrams.
Results and discussion: Analysis of variance demonstrated that the effect of treatments on germination percentage and germination rate in Redroot Pigweed seeds at 1% probability level and the mean germination time at 5% probability level was significant. The results showed that among studied treatments, seeds holding for 18 months were most efficient seeds dormancy breaking at Redroot Pigweed. So that the highest germination percentage (92%), germination rate (29.18 seed/day) and lowest the mean germination (4.2 day) time were obtained in seeds holding treatment. Pre-chilling treatment also had significant effects in stimulating germination. As regards treatments of seed holding in low temperature and Pre-chilling accelerate the germination process and increase germination percentage, so, having precise information of these traits enables to study, a better management and control of this troublesome weed.
Conclusions: In general, the results of this study show that among the treatments, holding seeds for 18 months at 6 ° C is the best method for solving Redroot Pigweed seeds weeds.

 
Highlights:
1- Seed holding in low temperature and Pre-chilling accelerates the germination process.
2- Seed holding in low temperature increases germination percentage.


Allelopathic Effects of Mustard (Sinapis arvensis) on Germination, Morphological and Biochemical Characteristics of Barley (Hordeum vulgare)
Yaser Alizadeh, Ehsan Zeidali, Hamid Hassaneian Khoshro,
Volume 5, Issue 2 (3-2019)
Abstract



Extended abstract
Introduction: Crop rotations are practiced to eliminate the effect of monoculture, but the succeeding crop may be influenced by the phytotoxins released by the preceding crop. Among plants, Brassica species contain allelochemical compounds as glucosinolate that is, under special conditions, released to environment and affects seed germination and plant growth. Wild mustard (Sinapis arvensis L.) as a weed of 30 crops in 52 countries which has a series of allelopathic effects that prevent germination of other plants. Products of glucosinolate- like ionic thiocyanate (SCN-) inhibited the root or shoot growth of many crop species. Also volatile compounds like isoprenoid and benzenoid released from Brassica tissue degradation may suppress many crops growth. It was also found in many studies that allelochemicals, which inhibited the growth of some species at certain concentrations, might stimulate the growth of same or different species at lower concentrations. The present research was conducted to evaluate the effects of aqueous extract concentration of various mustard parts on barley seed germination and seedling growth.
Materials and Methods: In order to evaluate the allelopathic effect of mustard in agro ecosystems, a factorial experiment based on completely randomized design with three replications was carried out in botany laboratory of agriculture faculty, Illam University in 2014. Experimental treatments included five concentrations of mustards foliage and root aqueous extract (0, 10, 30, 50, and 70 percent) that were studied at germination and early growth stage of barley (cv. Abidar) in two separate experiments. In the seed germination section, the effects of aqueous extract of mustard on germination rate and germination percentage of barley seed were measured. In the study of the effect of aqueous extract of mustard on barley seedlings, weight and length of root and shoot, leaf chlorophyll content, proline and soluble sugars content were measured.
Results: Results showed that the highest amount of barley seed germination percentage and germination rate (100 and 19.5, respectively) were observed in control and the lowest amount (40 and 9.5, respectively) belonged to mustard root aqueous treatment with 70 percent concentration. The most decrease in barley seedlings length and weight were observed at the highest concentration of aqueous extract. The amount of chlorophyll a decreased from 2.39 in control to 1.66 mg per fresh weight in 70 percent concentration of aqueous extract treatment. The highest amount of proline (66.8 μM per fresh weight) in barley foliage was observed in 70 percent aqueous extract treatment. The results from this study showed that mustard allelopathic effect may be a possible mechanism controlling the barley germination and early growth stage in agro ecosystems.
Conclusion: Generally, we were able to demonstrate short term auto toxicity and possible short-term allelopathy due to mustard has harmful effects on barley including reduced seed germination and emergence of barley seedling. Depending on the concentrations of Mustard extract, allelopathic activity will vary Mustard. Further investigations are also needed to determine the influence of cultivar variations, and to identify the active compounds involved in mustard auto toxicity and Allelopathy.
  
Highlights:
1-Mustards aqueous extract reduced seed germination percentage and plant growth in barley.
2-Mustards aqueous extract increased proline and soluble sugars in barley, but it reduced amount of chlorophyll in this plant.


Investigation of Seed Germination Indices and Anthocyanin Content of Niger (Guizotia abyssinica) Seedling under the Effect of Three Nanoparticles
Moazzameh Eskandarinasab, Mohammad Rafieiolhossaini, Parto Roshandel, Mahmoud Reza Tadayon,
Volume 5, Issue 2 (3-2019)
Abstract


Extended abstract
Introduction: The use of nanotechnology as a diverse and applied discipline is ongoing in almost all areas of science. Fertilizers and nano-nutrients have the effective properties which help the production of plants depending on their needs to regulate the plant growth. Plants under stress conditions are willing to produce natural nanoparticles to continue their growth. Nano TiO2 has a high photocatalytic effect and as a catalyst, it is mainly used in water, electronic devices, conversion and storage equipment of Energy as suspension. Sources of SiO2 are very diverse, including natural nanoparticles, anthropogenic particles and engineering nanoparticles. Although, silicon in many crops is not an essential element for growth, it has beneficial effects on plants growth and development. Today, carbon nanotubes are one of the most important materials in industrial programs. These materials, with different methods and specific properties, can play an important role in the production of composite materials, application in medicine, electronic and energy storage. The Niger plant, with the scientific name of Goizotia abyssinica (L.F) Cass, belongs to the Asteraceae family. Its seed, are used in pharmacy, food industry, green manure and for feeding birds and cows. Therefore, the purpose of this experiment was to investigate the effect of type and concentration of three nanoparticles on some of germination characteristics and anthocyanins content in Niger medicinal-oily plant.
 Materials and Methods: In order to evaluate the effect of three nanoparticles on seed germination of Niger, an experiment was conducted as factorial in a completely randomized design with four replications. The treatments of TiO2, SiO2, and CNT were as the first factor while their concentrations in four levels (zero, 10, 30 and 60 mg/l) were as the second factor. In this study the traits of germination percentage, germination rate and mean of daily germination, germination and vigour index, length, fresh and dry weight of radicle and plumule, anthocyanin content and radicle resistance percentage were measured. 
 Results: The germination percentage, germination rate and mean of daily germination decreased by increasing of nanoparticles concentration. The favorable effect of TiO2 on germination index at the concentration of 30 mg/l and radicle dry weight at the concentration of 10 mg/l, was gained compared to control. The positive effect SiO2 on germination index and radicle dry weight at the concentrations of 10 and 60 mg/l, the anthocyanin content and the fresh and dry weight of plumule at the concentration of 60 mg/l was obtained compared to control. Also, the appropriate effect of CNT on germination index at the concentration of 10 and 30 mg/l, the anthocyanin content and radicle dry weight at the concentration of 60 mg/l and plumule fresh weight at the concentration of 30 mg/l, was observed.
Conclusions: According to the results of this study, it seems that the effect of nanoparticles in plants, in addition to the plant, species, type and concentration of nanoparticles, varies depending on the growth stage and physiology of the plant. It seems that nanoparticles at some concentrations can increase the water absorption of seeds and increase seedling growth with their positive effects. Anthocyanins are produced by exposure to stress due to their antioxidant activity. In general, it can be stated that increasing the concentration of nanoparticles caused and increased the oxidative stress in plant. Therefore, it is recommended by investigating the bad effects of nanoparticles on plants, if necessary, use nanoparticles at low concentrations (less than 60 mg/l) to increase the plant's efficiency.
 
Highlights:
  1. The effect of nanoparticles kind and concentration on seed germination indices and anthocyanin content of Niger seedling.
  2. Investigating the interaction of nanoparticle type and concentration as the physical priming factor of seeds on seed germination of multi-purpose Niger plant.

Comparison of Different Models for Determining Time up to 50% Maximum Germination: A Case Study of Cottonseeds (Gossypium hirsutum)
Farnaz Porali, Farshid Ghaderi-Far, Elias Soltani, Mohammad Hadi Palevani,
Volume 5, Issue 2 (3-2019)
Abstract


Extended abstract
Introduction: Germination speed is one of the most important germination indices, used in most studies to compare the effects of different treatments on seed germination. Researchers use the reverse time up to 50% maximum germination (1/D50) to calculate the germination rate. One of the methods used for calculating the D50 is the utilization of nonlinear regression models such as Logestic, Gompertz, Richard, Weibull and Hill. In addition, for the purpose of calculating this parameter, simple empirical models such as the model presented by Farooq et al. and Ellis and Roberts are used. The question which arises is which of these methods has more precision predicting D50. The purpose of this study was to calculate D50, using different methods in seed germination of cotton.
Material and Methods: In this experiment, cottonseeds were placed at three temperatures of 15, 25 and 40°C with three replications, and germinated seeds were counted daily several times. To calculate D50, several nonlinear regression models including Gompertze, Logestic, Hill (the four-parameter), Richard and Weibull models were used. Moreover, for the purpose of calculating D50, the models presented by Farooq et al. and Ellis and Roberts were used.
Results: The results showed that all nonlinear regression models exhibited suitable fit to germination data. However, logestic, Hill and Weibull showed better predictability of D50, compared with other models. Besides, D50 calculated by the Farooq model was similar to that estimated by nonlinear regression models, whereas D50 estimated by the Ellis and Roberts model was higher than that estimated by other models.
Conclusions: The results of this study showed that both non-linear regression models and the model developed by Farooq could be used to calculate D50 of cottonseed. In general, the results of this study showed that nonlinear regression models could be used to calculate D50. In this research, Logestic, Hill, and Weibull showed good fit for cumulative seed germination data of cotton seeds versus time at different temperatures. These models have coefficients that have a biological concept that includes maximum germination percentage, time to 50% maximum germination and time to start germination. Moreover, when researchers only seek to measure D50 and are not familiar with the statistical software, they can use the empirical formula presented in this research.
 
Highlights:
  1. Calculating D50 in cottonseeds, using different methods.
  2. Using nonlinear regression models to calculate D50 in cottonseeds.
  3. Developing a proper method which is more accurate, and better lends itself to calculating D50 of cottonseeds.

Effect of Seed Aging and Water Potential on Seed Germination and Biochemical Indices of Fenugreek (Trigonella foenum-graecum) at Different Temperatures
Hasan Teimori, Hamidreza Balouchi, Ali Moradi, Elias Soltani,
Volume 5, Issue 2 (3-2019)
Abstract


Extended abstract
Introduction: Seed germination is one of the first important and complex stages in the plant life cycle and is affected by many hereditary and environmental factors. Various factors affect germination and seedling establishment. Among these factors are the characteristics of the maternal plant (nutrition, genetics), seed treatment stage at harvest time, as well as environmental factors (temperature, water potential, and ventilation and soil compaction). Also, under the influence of seed loss during storage, seed vigor, which is known as the first component of seed quality, decrease. The aim of this study was investigation of germination and biochemichal responses of the aged seed of Fenugreek to different temperature and humidity ranges.
Materials and Methods: This experiment was conducted as a factorial based on a completely randomized design with four replications in the Laboratory of Seed Science and Technology, Faculty of Agriculture, Yasouj University in 2016. The experimental treatments consisted of nine levels of temperature (5, 10, 15, 20, 25, 30, 35, 40 and 45 degrees Celsius), water potential included seven levels (zero (control), -0.2, -0.4, -0.6, -0.8, -1 and -1.2 MPa) and seed aging at two levels (no aged (control) and aged seed).
Results: In this experiment, the effect of seed aging, water potential and their interactions on each environment on germination indices (germination percentage and germination rate, length and weight vigor index) and biochemical indices (soluble sugar, proline, soluble protein and catalase enzymes) of Fenugreek seeds were significant. The results showed that in the aged seed the germination percentage and rate and seedling vigor index tended to decrease with water potential reduce in temperature lower and higher than 20 degrees Celsius, and the amount of biochemical components of the seed (soluble sugar, soluble protein, proline, and catalase enzyme) also increase.
Conclusion: In general, germination and biochemical indices of seed of Fenugreek are sensitive to water potentials, aging, and seed germination temperatures, respectively. In terms of osmotic potential decrese, the germination temperature of less than 20 ° C resulted in increased germination resistance of fenugreek seed to a more negative water potential.
 
Highlights:
  1. Study of germination and biochemical properties of fenugreek seed aged under different level of osmotic potantials and temperatures.
  2. In areas with a lower osmotic potential it is better to cultivate Fenugreek seed at temperatures below 20 °C.

The Effect of Seed Pre-treatments on Germination of Astragalus gossypinus Seed
Ali Asharf Mehrabi, Somayeh Hajinia,
Volume 6, Issue 1 (9-2019)
Abstract


Extended Abstract
Introduction: White Astragalus (Astragalus gossypinus Fisherr.) is one of the valuable plants for producing gum, which is of critical importance in soil conservation and the economy of the country. This plant is propagated by seed; its seeds are in the natural state of dormancy. Therefore, recognizing the factors affecting dormancy and creating optimal conditions for seed germination of this plant is necessary for the cultivation and reclamation of rangelands. This study was conducted with the aim of finding the best treatment for breaking the dormancy and improving seed germination under various chemical and physical treatments.
Materials and Methods: The experiment was carried out as a factorial based on a completely randomized design with four replications at the gene bank of cereal and legume Lab of Ilam University, 2017. The factors included two levels of scarification chemical (with and without sulfuric acid (H2SO4) for 10 minutes), three levels of stratification (control, moist chilling at +4 °C and dry chilling -20 °C), potassium nitrate in two levels (zero and 1% KNO3) and gibberellic acid in two levels (zero and 5 ppm GA3). Germination indices including germination percentage, germination rate, seedling and radicle length, seedling fresh weight and vigor index were measured.
Results: Initial assessment of vital indices in seed such as germination and primary growth showed that the simultaneous application of scarification by sulfuric acid and moist chilling at +4 °C has the most impact on removing dormancy and increasing germination percentage. The highest germination rate was observed in moist chilling at +4 °C, which was 32.19 percent more than that of the control treatment. Scarification by sulfuric acid reduced the mean germination time in moist chilling at +4 °C. Scarification by sulfuric acid increased the fresh weight of the seedling by 55.25 percent, compared with the control. Pre-treatments with potassium nitrate undre control conditions, moist chilling at +4 °C and dry chilling at -20 °C increased the fresh weight of seedlings, at 52.66, 30.94 and 17.18 percent, respectively. Application of potassium nitrate increased root length by about 60.7 percent, compared with control. The highest radicle length (78.71 mm) was obtained when the seed was treated with sulphuric acid with wet chilling at 4 ° C for two weeks, which was 30 percent higher than control. The highest seedling length (84.88 mm) was obtained in scarification with sulfuric acid, wet chilling, and potassium nitrate and gibberellic acid. The highest seed vigor index (61.85 %) was observed in the treatment of scarification with sulfuric acid under moist chilling, and pre-treatments of gibberellic acid and potassium nitrate.
Conclusions: In general, it can be concluded that seed dormancy of Astraglus gossypinus involves both physical and physiological dormancy. The best treatment for removing the dormancy of this species seems to be scarification with sulfuric acid for 10 minutes puls concentrated stratification in moist chilling at +4 °C for two weeks.
 
 
Highlights:
  1. Determination of the optimal seed dormancy techniques of white Astragalus for the purpose of increasing seed germination percentage.
  2. Comparison of the efficiency of different dormancy breaking techniques.
  3. The combined effect of sulfuric acid, chilling and priming with gibberellic acid and potassium nitrate on germination indices.

The Effect of Seed Inoculation with Organic and Biologic Fertilizers on Germination and Heterotrophic Seedling Indices in Rainfed Wheat (Triticum aestivum) Cultivar
Narjes Hojati Fahim, Mohamad Sedghi, Mehrdad Chaeichi, Rraouf Seyed Sharifi,
Volume 6, Issue 1 (9-2019)
Abstract


Extended Abstract
Introduction: Iran is located in the arid and semi-arid regions of the world with an average rainfall of 240 mm per year, which requires rethinking of the adoption of methods. One of the alternative ways is to use organic and biological fertilizers. Biological fertilizers are considered as the main and the most important factor in the integrated management of plant foods for sustainable agriculture as they play an important role in product improvement and efficiency. Therefore, this research was carried out with the aim of investigating the effect of seed pre-treatment with some organic and biological fertilizers in rainfed wheat.
Materials and Methods: A factorial experiment with three replications was conducted at the Laboratory of Seed and Plant Certification and Registration of the Center of Agriculture and Natural Resources Research located in Hamedan. Seed inoculation was considered in 5 levels (Seafull, Disper Root Gs., Bio-Health, Trichodermin and control) on 8 different rainfed wheat cultivars (Azar-2, Hashtrood, Baran, Rasad, Owhadi, Sardari, Takab and Homa). First, the seeds were disinfected with sodium hypochlorite, and were then cultured in special containers and were placed in the germinator at 20 ° C. After 4 and 8 days, the number of germinated seeds was counted. Germination seeds were counted in each treatment and germination indices such as germination rate, average daily germination, coefficient germination rate, longitudinal vigor index, weight vigor index, seedling fresh weight, root length/shoot ratio, shoot fresh weight, root fresh weight, seed reserve utilization rate, seed reserve utilization efficiency, fraction utilization seed reserve, seed dry weight were calculated.
Results: With application of different levels of fertilizer, the rate of germination treatment Homa×Bio-Health (155%), average daily germination treatment Hashtrood×Bio-Health (69%), coefficient germination rate treatment Owhadi×Disper Root Gs (60%), longitudinal vigor index treatment Owhadi×Bio-Health (108%), weight vigor index treatment Homa×Bio-Health (64%), root fresh weight treatment Hashtrood×Disper Root Gs (106%), shoot fresh weight treatment Hashtrood×Seafull (23%), seedling fresh weight treatment Homa×Bio-Health (42%), root length/shoot ratio treatment Owhadi×Trichodermin (75%), seed reserve utilization rate treatment Homa×Bio-Health (118%), and fraction utilization seed reserve treatment Homa×Bio-Health (119%) increased, compared with the control. In addition, the application of Bio-Health fertilizer and Hashtrood cultivar had the highest amount in almost all the mentioned attributes
Conclusion: Investigation of the different levels of fertilization showed that in most of the indices related to germination and heterotrophic growth of seedling, pretreatment with Bio-Health biofertilizer had a significant difference with other fertilizer levels.
 
 
Highlights:
  1. Evaluation of germination indices for recent cultivars of rainfed wheat, released by rainfed Research Institute of Iran.
  2. Investigating and comparing fertilizers with various multifactorial compounds (fungi and bacteria) and with each other.
  3. Conducting research on commercial compounds and comparison of live biochemical and non-organic matters in a single experiment.

Study of Germination and Seedling Growth Parameters of Three Clover Species (Trifolium spp.) under Drought and Salinity Stresses
Forough Hajivand Ghasemabadi, Hamid Reza Eisvand, Naser Akbari, Omid Ali Akbarpour,
Volume 6, Issue 1 (9-2019)
Abstract


Extended Abstract
Introduction: Agriculture has been influenced by different abiotic stresses such as temperature, drought and salinity, which reduces roughly half of the yield of crops. In many forage plants, germination and early seedling growth are the most sensitive stages of their growth in the face of environmental stresses. Current research was conducted to study the effects of drought and salinity iso-osmosis stresses on germination indices and growth parameters of three clover species, including Trifolium resupinatum, T. alexandrinum and T. incarnatum.
Material and Methods: Two separate experiments (drought and salinity) were conducted as a factorial experiment based on a completely randomized design with three replications. The test factors included clover species with three levels, including T. resupinatum, T. alexandrinum and T. incarnatum and different levels of drought and salinity potentials (0, -2, -4, -6, -8, -10 and -12 bar) due to polyethylene glycol 6000 (PEG 6000) and sodium chloride (NaCl), respectively. Sterile disposable petri dishes with a diameter of 10 cm were used, in each of which, 27 seeds were placed on filter paper and then 5 ml of the desired treatment solution was added to each. Petri dishes were then placed in a germinator at 20°C and relative humidity of 75%. After the end of the desired time germination (About 14 days), from each petri, germination percentage and rate, number of secondary roots, time to get 50% germination (D50), root to shoot ratio and the number of abnormal seedlings were recorded.
Results: Inhibitory effects of salinity and drought stresses affected all germination indices. Germination percentage, rate of germination, root and shoot length all decreased with increasing stress levels, while time to get 50% germination (D50) increased with the increase in stress levels. Under both drought and salinity, all growth parameters of Trifolium resupinatum were higher than the other two species. Germination percentage of T. incarnatum was 0% at -12 bar of drought, but germination of T. resupinatum and T. alexandrinum was 70.33% and 7.33% at -12 bar of these stresses, respectively. Under salinity conditions, all the seeds of the three species germinated at -12 bar. Root to shoot ratio increased with increasing stress levels and at high stress levels, it decreased. The decreases were 41.39% and 0% in drought and salinity, respectively. The number of secondary roots increased with increasing stress levels and the maximum number was observed in Trifolium alexandrinum which was 5.42 and 1 in drought and salinity, respectively. The number of abnormal seedling increased with increasing salinity levels, while under drought conditions there was no abnormal seedling.
Conclusion: Comparison of the effects of sodium chloride and polyethylene glycol showed that sodium chloride reduced germination index due to toxic effects or osmotic effects more than polyethylene glycol solution. ­­­­­­­­­­­­­­­­­­­It seems that Trifolium resupinatum has the best yield in both drought and salinity stresses, and that in drought condition, Trifolium alexandrinum, and in salinity stress, Trifolium incarnatum have the best performance.
                                                                                                                           
 
Highlights:
  1. Introduction of clover species with more tolerance to drought and salinity in germination stage.
  2. Evaluation of germination indices of clover species under drought and salinity iso-osmotic conditions.

Quantification of the Best Harvest Time of Guar (Cyamopsis tetragonoloba) Seed with High Quality in Golestan Province
Mahsa Nazer, Seyed Mohammadreza Ehteshami, Masoumeh Salehi, Ali Kafighasemi,
Volume 6, Issue 1 (9-2019)
Abstract

Extended Abstract
Introduction: Guar (Cyamopsis tetragonolob) which belongs to fabaceae and leguminosae families is self-pollinating and is indigenous to India and Pakistan. This plant is suitable for growth in dry, damp and sandy soils, and can tolerate saline and relatively alkaline soils. Determining the best time for harvesting seeds and its timing with maximum quality is one of the important issues in the field of seed production management. The changes in the physiological quality of seeds occur during development until seed treatment. The use of high-quality seeds plays an important role in the final yield of crops. The purpose of this study was to determine the most suitable time for harvesting seeds because seed moisture content at harvest time is one of the most important factors affecting seed quality.
Materials and Methods: This research was carried out in July 2013 at Iraqi Research Station in Gorgan, Golestan, Iran in a split-plot design with four replications. The treatments consisted of the time of harvesting the seeds from the mother's base in six stages (with different moisture content) and harvesting places (upper, middle, and bottom pods) so that, starting from the podding, every 7 days, the seeds were removed from the base. The mother was harvested and such traits as germination rate, germination percentage, seedling vigor, seed moisture content, and alpha-amylase activity were calculated. In this research, a logistic model was used to study the changes in germination percentage, germination rate, seedling vigor index and straw index during seed dressing on Guar.
Results: The results of this study showed that the hypothesis that seed reaches its maximum quality at the end of the period of seed filling is confirmed, suggesting that with a moisture content of 30 and 14% in late seed filling period, Guar seeds have the highest quality. In general, the results of the present study confirm that the stages of development and management of Guar seeds on maternal basis have an impact on its quality. In the early stages of growth (humidity 85, 80 and 62 percent), due to prematurity and lack of essential seed structures, the qualitative traits of germination percentage, germination rate, seedling vigor, and strawberry index were low, and with the evolution of essential structures and reduced seed moisture content (58, 30 and 14%), the quality traits increased.
Conclusions: In general, it can be concluded that the best timing for harvesting Guar seeds with the highest quality in Golestan province is when seed moisture reaches 14% or 100 days after planting, and the pods formed at the bottom are the ones with the highest quality.
 
 
Highlights:
  1. To investigate the qualitative indices of Guar seed on the mother plant during seed filling period
  2. To determine the best harvest time and its adaptation with the highest quality of Guar seed

Impact of Storage Fungi on Soybean Seed Deterioration in Different Storage Conditions and Seed Moisture Content
Saman Sheidaei, Aidin Hamidi, Hossein Sadeghi, Bita Oskouei, Leila Zare,
Volume 6, Issue 1 (9-2019)
Abstract


Extended Abstract
Introduction: Understanding the complex characteristics that control the life span of the seed has ecological, agricultural and economic importance. Inappropriate storage conditions after harvesting destroy a large part of annual yield partly due to microbial activity in the storage. Damage from storage fungi varies based on the climatic conditions, crops and storage facilities. This study was carried out to investigate the effect of storage conditions and initial seed moisture content on the growth of storage fungi and also the relationship between the degree of contamination with fungi and the quality and biochemical changes of the seeds.
Materials and Methods: The present study was carried out as a factorial experiment based on a completely randomized design to assess the impact of storage fungi on soybean seed deterioration at different storage conditions. The treatment included three degrees of initial seed moisture content including low moisture content (10%), medium moisture content (12%) and high moisture content (14%) as the first factor. Moreover, two storage conditions including the seed storage in Moghan and controlled seed storage in Seed and Plant Certification and Registration Institute were considered as the second factor. Soybean seeds of Williams's cultivar were investigated for the infection of Aspergillus flavus, Aspergillus niger, Fusarium and Penicillium fungi and also related biochemical traits and seed quality such as germination percent, seedling vigor index, soluble sugar and total protein.
Results: The results of this experiment showed that the increase of the seed moisture content by 14% can significantly decrease the seed quality. Therefore, the seed moisture content of 14% was identified as unsuitable moisture for the storage of soybean seeds. In addition, the infection with storage fungi has a direct relationship with the degree of seed moisture and seeds with high moisture content are rapidly attacked by the storage fungi which can decrease seed quality and viability. Moreover, the Aspergillus niger infection increased from 27.5 to 43.75 and the germination percent decreased from 52.5 to 23 percent in seeds with a moisture content of 14% in Moghan storage, as compared with the controlled storage. Furthermore, this study showed that when the percentage of storage fungi increases, the soybean seed deterioration increases. Studying the biochemical changes of deteriorated seeds during the storage showed that as the aging of the seeds increases, soluble sugars and protein percentage decrease. The amounts of soluble sugars and total protein of the seed were significantly lower in seeds maintained under unsuitable conditions. Furthermore, the content of soluble sugars and total protein decreased significantly by the increase of the seed moisture, which resulted in the increase in seed deterioration.
Conclusions: Based on the obtained results, initial seed moisture and storage conditions are two important determinants of fungi infestation during storage, which can affect the content of soluble sugars and total protein causing seed deterioration, seed vigor and viability. It can be concluded that the soybean seed moisture content of 12%, which is the standard moisture content of soybean seed production in Iran, is regarded as suitable moisture for seed storage.
 
 
Highlights:
  1. Introduction of proper storage conditions and initial seed moisture in order to decrease fungal damage and soybean seed deterioration.
  2. Determination of different fungal damages during the storage of soybean seeds.
  3. Determination of relationship between the degree of soybean seed infection of storage fungi and the seed’s quality, its amount of protein and soluble sugars.

Investigation of the Effect of Salinity and Drought Stress on Germination Characteristics of Strangle Wort (Cynanchum acutum) Seeds
Habib Nejadgharebaghi, Esfandiar Fateh, Amir Aynehband,
Volume 6, Issue 1 (9-2019)
Abstract


Extended Abstract
Introduction: Strangle wort (Cynanchum acutum) is a perennial weed that could be propagated by seeds and vegetative organs. This brings about harvesting problems for some crops such as cotton, sugar beet, wheat and maize. In recent years, this weed has caused huge losses in sugar cane fields. The role of environmental conditions in weed management is highly important. Given this, the present study seeks to investigate the effects of environmental conditions (salinity and drought stress) on germination characteristics of strangle wort weed.
Materials and Methods: In order to investe the effect of different salinity and drought levels on strangle wort (Cynanchum acutum), two seperate experiments were conducted at Hakim Farabi Khuzestan Sugar Cane Research Institute in 2014-2015. The experimental design was completely randomized, with four replications. The treatments were different salinity levels at 8 levels (0, 2.5, 4.5, 6.5, 8.5, 12.5, 16.5 and 20.5ds/m) and the second experiment involved different drought stresses (osmotic potential) at 7 levels (0, -1, -3, -6, -9, -12 and -15 bar).
Results: The results of salinity stress experiment showed that with increases in salinity levels from 0 to 20.5 ds/m, germination, radicle length, plumule length and seedling weight decreased by 61, 80, 91 and 99%, respectively. The results of drought stress experiment showed that with increases in salinity levels from 0 to -15 bar, all studied traits, i.e., germination, radicle length, plumule length and seedling weight all decreased by 100%.
The analysis of variance results showed that in all the traits, there were significant differences between salinity and drought stress in 1% probability level. In this research, in the salinity experiment, in most of traits, especially radicle length quickly decreased after 8.5 ds/m salinity to higher levels and in drought stress experiment, after -3 bar to higher levels.
Conclusion: On the whole, it seems that sufficient information about this weed is vital for the adoption of the best control method, and gaining insights into how strangle wort responds to environmental stress, especially salinity stress, could help us to come up with new control approaches for this invasive weed. This can present a proper ecological approach that could be adopted in sustainable agriculture programs, which is environmentally sound as it decreases the use of chemical inputs. In addition, in order to lower the tolerance of this weed to salinity and especially drought stress, it is suggested that it be used for weed management programs. According to the results of this study, soil salinity higher than 8.5 ds/m and drought tension above than -3 bar can cause sizeable reduction in most traits (growth parameters) especially in root length. In most of the traits scrutinized, the tolerance of the weed to salinity and drought stress was 12.5 ds/m and -6 bar, respectively.
 

 
Highlights:

  1. Evaluation of germination characteristics of strangles wort under salinity and drought stress conditions.
  2. Determination of tolerance threshold of strangles wort germination seed to salinity and drought stress.

Aqueous Extract Effect of Different Organs of Malva sylvestris Weed on Germination Characteristics and Photosynthetic Pigments of Echinochloa crus-galli
Mahnaz Tatari, Ebrahim Gholamalipour Alamdari, Zeinab Avarseji, Mehdi Zarei,
Volume 6, Issue 2 (3-2020)
Abstract



Extended abstract
Introduction: Due to their aggressive and competitive habits, weeds inhibit the growth of valuable plants. Interference in plants includes environmental competition and allelopathy (Autotoxicity and hetrotoxicity). In hetrotoxicity, chemical compounds released from plants are able to effect the neighboring plants. Proper management of weeds and the exploitation of their hetrotoxicity potential can reduce losses caused by weeds. This could also represent an effective step towards the reduction of the use of herbicides. Therefore, the purpose of this study was to evaluate the effect of hetrotoxicity potential of aqueous extract of various organs of Malva sylvestris L. weed on traits of germination and photosynthetic pigments of Echinochloa crus-galli L.
Material and Methods: An experiment was conducted to evaluate the effect of hetrotoxicity potential of aqueous extract of Malva sylvestris  L. weed including the stem, leaf and flower as well as their mixture on traits of germination and photosynthetic pigments of Echinochloa crus-galli L. as a completely randomized design in three replications in Weeds Science Laboratory of Gonbad Kavous University in 2017. For this experiment, aerial parts of M. sylvestris were first collected at the flowering stage from Ramian field. They were subsequently separated with great care and were powdered. Then from them, 5% suspensions (weight/volume) were prepared, using distilled water. Finally, the extract of each organ of M. sylvestris was added to Petri dishes containing E. crus-galli seeds. After the 7th day, traits such as rate and percentage of germination, radical and shoot elongation, vigor index, total content of chlorophyll a and b and carotenoids were measured.

Results: The results showed that various organs of M. sylvestris and their mixture had different inhibitory effects on traits of germination and seedling length of E. crus-galli weed. The highest inhibition effects on rate and germination percentage and elongation of radical and shoot of E. crus-galli were obtained using leaf extract of M. sylvestris about 64.04, 64.37, 87.69, 62.81%. In this study, radical length is more affected under hetrotoxic compounds of various organs of M. sylvestris, as compared with shoot length. Based on the results, various organs of M. sylvestris and their mixture also have different inhibitory effects on chlorophyll and carotenoid content of E. crus-galli weed. It seems that the differential effects among different organs of M. sylvestris are a function of the threshold concentration of allelochemicals to hetrotoxic compounds of the organs, which causes various response by E. crus-galli.
Conclusion: Given the evidence for the effect of hetrotoxicity potential of various organs of M. sylvestris on traits of germination and pigments of chlorophyll and carotenoid of E. crus-galli and huge biomass generated, it is advisable to exploit allelochemical compounds of this plant as bio-herbicides.
 

 
Highlights:
1- Study of the the effect of hetrotoxic potential of Malva sylvestris weed on germination characteristics and photosynthetic pigments of Echinochloa crus-galli in Ramian field.
2- E. crus-galli weed exhibits great sensitivity to hetrotoxic compounds of various organs of M. sylvestris,  especially the leaves.
3- Allelopathic characteristics of M. sylvestris weed have huge potentials for the production of bio-herbicides.


Effect of Stevia (Stevia rebaudiana) Seed Priming Treatments with Salicylic Acid, Iron, and Zinc on Some Germination Traits and Photosynthetic Pigments under Drought Stress
Alireza Gorzi, Heshmat Omidi, Abdolamir Bostani,
Volume 6, Issue 2 (3-2020)
Abstract


Extended abstract
Introduction: Stevia (Stevia rebaudiana Bert.) is a herbaceous perennial plant that belongs to the family of Asteraceae. Stevia is a self-incompatible herb and the seeds resulting from this plant have low germination ability. Steviol glycosides found in this plant are 250-300 times sweeter than sucrose and despite their sweet flavor; they are not absorbed by the body. In general, the poor germination capacity of Stevia seeds is a major impediment for its large-scale cultivation. Priming is one of the seed enhancement techniques that could lead to an increase of germination percentage and germination rate under stress conditions. Therefore, the present study was conducted to evaluate the impact of priming with salicylic acid (SA), iron (Fe) and zinc (Zn) on some germination indices, seedling growth as well as the content of photosynthetic pigments in Stevia under normal and drought stress conditions.
Materials and methods: A factorial experiment using a completely randomized design was carried out in the Seed Science and Technology Laboratory of Agricultural College, Shahed University, in 2017. The factors studied comprised four levels of drought stress (0, –0.3, –0.6 and –0.9 MPa) and seven priming combinations with SA, Fe and Zn. Non-primed seeds (dry seeds) were also considered as control. In this experiment, Fe and Zn were supplied by sources of iron (II) sulfate heptahydrate (FeSO4.7H2O, 0.5%) and Zinc sulfate heptahydrate (ZnSO4.7H2O, 0.5%), respectively. The traits examined in this study included germination percentage, radicle length, plumule length, seedling weight vigor index and the content of photosynthetic pigments and carotenoid.
Results: The results of this experiment indicated that the plumule length was more sensitive to drought stress, as compared with the root length. With increased intensity of drought stress from 0 to – 0.9 MPa, the content of photosynthetic pigments in Stevia significantly decreased in all the priming treatments, so that the lowest amounts of chlorophyll a, b and carotenoid were observed at the potential of – 0.9 MPa. Priming with SA + Fe + Zn was found to be more effective than other treatments in improving the germination characteristics and the chlorophyll content of Stevia under normal and drought stress conditions. At the highest level of drought stress, germination percentage, radicle length, plumule length, seedling vigor index and total chlorophyll content increased by 55.7, 50.5, 74.3, 90.3 and 85.5%, compared with the control in the concurrent application of Fe, Zn, and SA.
Conclusion: In general, seed priming by micronutrient elements (Fe and Zn) and salicylic acid, and particularly their integrated application, could be recommended to increase the resistance of Stevia to drought stress in the germination phase.
 
 
Highlights:
  1. Drought stress at the germination stage has a significant effect on the seedling growth and the content of photosynthetic pigments in Stevia.
  2. Seed priming increases drought tolerance of Stevia at the germination stage.
  3. The integrated application of SA, Fe, and Zn is more effective than their separate application to alleviate the drought-induced damaging effects.

Effects of Plant Growth-Promoting Rhizobacteria on Germination and Early Growth of Alfalfa (Medicago sativa) under Salt Stress Conditions
Marzie Soltani Alikooyi, Ali Abbasi Surki, Mohsen Mobini Dehkordi, Shahram Kiyani,
Volume 6, Issue 2 (3-2020)
Abstract



Extended Abstract
Introduction: Salinity is one of the most serious abiotic stresses, causing instability in germination and seed emergence due to low osmotic potential and ionic toxicity. Development of simple and low-cost biologic methods is essential for short-term management of salt stress. The use of plant growth-promoting rhizobacteria increases the rate and uniformity of germination. This research aimed to investigate the effect of bacterial growth-promoting bacteria on the germination and seedling growth indices of alfalfa c.v. Hamedani in different salinity levels.
Materials and Methods: A CRD factorial experiment with four replications was conducted in Seed Science and Technology Laboratory of Shahrekord University in 2016. The first factor consisted of 6 salinity levels 0, 2.5, 5, 7.5, 10 and 12.5 dS/m created with sodium chloride, and the second was four levels of bacterial pre-treatment: no inoculation with bacteria and biopriming, inoculation of alfalfa seeds with Acinetrobacter calcoaceticus PTCC 1318, Bacillus megaterium PTCC 1250 and Enterobacter aerogenes PTCC 1221. The seeds were treated with bacteria and placed at a 20 °C growth chamber. They were then irrigated with desired solutions depending on the salinity treatment. Germinated seeds were counted daily and the parameters of germination percentage and rate, seedling length, seedling dry weight, vigour index I, II and allometric coefficient were calculated after 10 days.
Results: Salinity levels higher than 10 dS/m reduced germination indices and seedling growth of alfalfa. The highest reductions were obtained for 12.5 ds/m salinity level versus control for germination percentage (10.81%), germination rate (49.48%), plumule and radicle length (13.30% and 28.88% respectively) and vigor index I and II, which were 30.27% and 6.28%, respectively. The seed treated with A. calcoaceticus was able to tolerate salinity stresses more than others. For example, the reduction for the seed treated with A. calcoaceticus was only 4%, compared with non-stressed control. In salinity conditions 2.5 and 5 dS/m, the highest rate of germination was obtained, using A. calcoaceticus bacteria. In addition, the seeds treated with E. aerogenes showed higher stability at different levels of salinity for seedling length traits. The highest vigour index related to the use of A. calcoaceticus in salinity was 7.5 ds/m.
Conclusions: A. calcoaceticus had a significant role in reducing the negative effects of salinity on germination percentage and rate, vigour index I and II and allometric coefficient while E. aerogenes bacteria were more effective in reducing negative effects of salinity on seedling length and dry weight.
 
 
Highlights:

  1. Acinetrobacter calcoaceticus bacterium increased the percentage and rate of germination of alfalfa seeds under salt stress.
  2. Enterobacter aerogenes bacteria efficiently adjusted the negative effects of salinity on alfalfa seedlings length and dry weight.

Evaluation of Seed Germination and Seedling Growth Characteristics of Sweet Pepper (Capsicum annuum) Under Salinity and Drought Treatment
Mohammad Hossein Aminifard, Hassan Bayat,
Volume 6, Issue 2 (3-2020)
Abstract


Extended abstract
Introduction: Pepper (Capsicum annum L.), which belongs to the solanaceae family, is one of the most important vegetable and garden products. Due to its nutritional value, its use tends to rise all over the world. Germination and seed emergence are strongly influenced by environmental stresses such as salinity and drought. Drought stress affects various aspects of plant growth. It reduces germination, delays vegetative growth and reduces dry matter in the plant. Salinity stress, as an environmental stress, is a limiting factor for the growth and development of crops and garden production.
Materials and Methods: The present study was conducted to evaluate the impact of drought and salinity stress on seed germination characteristics of sweet pepper (Capsicum annuum L.) in two separate experiments, using a completely randomized design with three replications in the Faculty of Agriculture, University of Birjand in 2016. PEG 6000 was used for drought stress and NaCl, for salinity stress. The treatments included drought and salinity stress levels (0, -2, -4, -6, -8, -10 and -12 bars). Seeds were disinfected with sodium hypochlorite (2%) solution for 1 minute, and were then washed with distilled water. The medium was petri dishes with a diameter of 9 cm.  25 seeds were placed on two layers of filter papers in each dish. 5 ml of distilled water or solution was added to each petri dish. The measured traits were germination percentage, germination rate, seed vigor index, radicle length, plumule length, ratio of radicle length to plumule length and dry weight of radical and plumule.
Results: The results indicated that salinity and drought stress had significant effects on seed germination characteristics of sweet pepper so that salinity stress with osmotic potential of -10 and -12 bar decreased the germination of sweet pepper and reached zero. Increasing salinity stress from zero to -12 bar decreased germination percentage, germination rate and seedling dry weight by 43.75, 41.67 and 93.46%, respectively. The results indicated that with increases in both salinity and drought stress, seed vigor index decreased significantly. The results showed that with increasing drought and salinity stress from 0 to -12 bar, seed vigor index decreased 96.58 and 100 percent, respectively.
Conclusions: The results of this study showed that the tolerance of sweet pepper to salinity stress was higher than its tolerance to drought stress at the germination stage, but for more accurate evaluation, it is necessary to conduct additional experiments in the field and in the greenhouse.
 
 
Highlights:
1- Investigation and comparison of germination and seedling growth of sweet peppers under salinity and drought stress.
2- Salinity and drought stress reduce germination indicators of Capsicum annuum.

Effect of Early Planting Dates and Different Treatments of Seed Priming on Germination and Seedling Establishment of Roselle (Hibiscus sabdariffa)
Mohammad Ghayour, Majid Taherian, Sadegh Baghban, Saeed Khavari,
Volume 6, Issue 2 (3-2020)
Abstract


Extended Abstract
Introduction: The effect of environmental factors on the developmental stages of a plant causes the planting date to vary from one region to another. Temperature is a very important factor in the maximum percentage germination and germination rate. Priming improves germination rate, brings about the uniformity of germination and reduces seed susceptibility to environmental factors. The purposes of this experiment were to study the effects of priming treatments at different temperatures on the germination characteristics of Hibiscus sabdariffa under laboratory conditions,  to investigate priming treatments on different planting dates and to compare early planting dates on the farms.
Materials and Methods: The experimental study was carried out as a factorial experiment in a completely randomized design with four replications in the Laboratory of Seed Technology of Kashmar University Jihad. The first factor is five primings (Concentrations of ZnSO4 (10 mM), Humic acid (2.5 cc) and the combination of Humic acid and Zinc sulfate, Biological materials (Pota Barvar 2), no treatment (control) and the second factor is five levels of temperature: 10, 12, 14, 16 and 18 °C. Field studies were carried out in Agricultural and Natural Resources Research Center of Kashmar in three separate experiments in 2018. The research was carried out in a completely randomized block design with three replications on three planting dates (March 25th, April 15th, and May 4th, 2018). In each experiment, priming treatments were applied similarly to field experiments. 
Results: The results of the current experimental study showed that temperature, priming and temperature interaction with priming had a significant effect on all the traits studied. The highest percentage and rate of germination were observed at 18 °C and priming with Pota Barvar 2. The results also showed that planting date had a significant effect on all the traits studied in the field experiment. Priming showed a significant difference only in stem fresh weight. The interaction effect of priming and planting date was not significant for the traits studied. The highest germination percentage was obtained on April 15’s planting date. By planting later than March 25 to 15 April, a decrease of 74% was observed in the rate of germination. Among priming treatments, the combination of Zinc Sulfate and Humic acid showed a significant superiority, compared with other treatments. 
Conclusion: The findigns suggest that due to the high sensitivity of seed germination of sour tea at low temperatures, the planting date in each area should be carefully chosen so that it does not coincide with temperatures below 18 °C.
 
Highlights:
  1. Evaluation of the effect of seed priming treatment at different temperatures on germination characteristics of Roselle under laboratory conditions.
  2. A different priming treatment leads to increases in germination characteristics of Roselle.

Evaluation of Primary Conditional Dormancy in Seeds of Oilseed Rape (Brassica napus) Produced in Golestan and Mazandaran Provinces
Keyvan Maleki, Elias Soltani, Iraj Alahdadi, Majid Ghorbani Javid,
Volume 6, Issue 2 (3-2020)
Abstract


Extended abstract
Introduction: Conditional dormancy (CD) is a dynamic state between dormancy (D) and nondormancy (ND). Seeds at the conditional dormancy stage germinate over a narrower range of temporal conditions. Conditional dormancy is usually observed in seeds with physiological dormancy. However, primary conditional dormancy has also been seen in some freshly harvested seeds. The purpose of the present study was to investigate whether freshly harvested oilseeds have non-dormancy or conditional dormancy.
Materials and Methods: A factorial experiment was conducted based on a completely randomized design with four replications at Seed Technology Laboratory of Aburaihan Campus, University of Tehran, Iran, in 2018. In this experiment, seeds of rapeseed were collected from 20 different locations in Golestan and Mazandaran provinces. Following that, a germination test was carried out at different temperatures (5, 15, 20, 30, 35°C), and the germination percentage and seed germination rate were recorded. In order to break seed dormancy, two treatments were used: gibberellic acid and after-ripening. For after-ripening treatment, seeds were stored in a paper bag in a dry and dark environment for 6 months. For gibberellic acid treatment, a solution of 100 parts per million (PPM) of gibberellic acid was prepared and added to the Petri dishes. Subsequently, the percentage and rate of germination were recorded.
Results: The results showed that freshly harvested seeds had primary conditional dormancy and germinated in a narrow range of temporal conditions. In addition, cardinal temperatures for freshly harvested seeds were 4.45 and 27.8 for bases and ceilings, respectively. Following gibberellic acid and after-ripening treatments, seeds germinated in a wider range of temperatures and base and ceiling temperatures reached 1.74 and about 40°C, respectively. Thus, germination percentage of seeds treated with gibberellic acid and after-ripening increased at both high and low temperatures. However, the increase in germination percentage was higher at high temperatures than low temperatures. In addition, the effect of gibberellic acid treatment was more than that of after-ripening treatment on the release of dormancy, and after-ripening treatment had an intermediate effect between the gibberellic acid and freshly harvested seeds.
Conclusion: Based on the results of this experiment, the application of gibberellic acid and after-ripening treatments resulted in breaking the dormancy of freshly harvested seeds and increased germination temperature range at high and low temperatures.  Of the two treatments, gibberellic acid had the greatest effect on breaking dormancy and increasing temperature range. Among the cultivars, these changes were maximum in the germination capacity of Hyola 50 and Trapar cultivars and Trapar cultivar had minimum changes.
 
 
Highlights:
1-Conditional dormancy of oilseed cultivars was investigated under different environmental conditions.
2-Application of gibberellic acid and after-ripening treatments resulted in breaking primary conditional dormancy in oilseed cultivars.

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