Iranian Journal of Seed Research

Extended abstract
Introduction: Soybean is a plant that has a moderate tolerance to drought stress. Drought stress is one of the most important abiotic stresses affecting soybean production by about 40%. In addition, drought stress reduces seed vigor as a result of stress conditions. Positive effects of mycorrhizal fungi on the increment of dry matter and plant biomass, especially in low-irrigated conditions and in dry areas have been proven. The reason for the increase in crop yield in mycorrhizal inoculated plants is their water balance in water deficit stress conditions and as a result, absorption of water and mineral elements. Rhizobium bacteria, carbohydrates, and other foods are catched from the phloem vessels and the received energy is used to convert nitrogen to ammonium ion and eventually amino acids. Japonicum rhizobium bacterium is not naturally found in soils of Iran and the bacteria should be added to the soil along with seeds.
Materials and Methods: This experiment was carried out to determine the germination characteristics, seed vigor and its related traits in soybean Kosar cultivar grown under drought stress conditions and inoculation with mycorrhiza and bacteria with three replications during 2018. In the field experiment, drought stress included optimal irrigation (irrigation after 70 mm evaporation), moderate stress (irrigation after 110 mm evaporation) and severe drought stress (irrigation after 150 mm evaporation from class A evaporation pan), mycorrhizal fungus in three levels, mycorrhiza-free, and inoculation with glomus mosseae, Glomus intraradices and Rhizobium bacterium in two levels, including no inoculation and inoculation with Rhizobium japonicum.
Results: The mean comparison showed that the seeds obtained under normal irrigation, inoculation with mycorrhiza and bacteria had the highest dry weight of radicle, plumule and seedling, percentage and germination rate. The lowest electrical conductivity of the seeds and the mean time of germination were obtained under these condition. Severe and moderate drought stress reduced stress tolerance index, root tolerance index and stem tolerance index, seedling vigor index and seed vigor index compared to optimum irrigation about 42-23, 38-18, 30-18, 50-26 and 41-21) percent, respectively. Inoculation with Glomus mosseae and Glomus intraradices increased the seed vigor index, radicle lentgh, plumule lentgh and seedling length compared to non-inoculation with mycorhizal fungi by 48-42, 27-26, 41-37 and 35-33 percent, respectively. Inoculation with Rhizobium japonicum increased radicle lentgh, plumule lentgh and seedling lentgh compared to non-inoculation with bacterium by 21%, 16% and 18%, respectively. The highest water percentage in seedling tissue was obtained under optimum irrigation conditions, inoculation with mycorrhizal fungi and inoculation with rhizobium bacteria.
Conclusion: According to the results of this study, in all three different irrigation conditions to improve germination and increase seed vigor, the use of mycorrhiza fungi is effective especially glomus mosseae and inoculation with Rhizobium bacteria.

Highlights:

1. Germination characteristics, germination rate and duration of soybean Kosar cultivar on seeds obtained under different irrigation conditions were investigated.
2. The effect of mycorrhiza and bacteria on seed vigor and related traits were evaluated under different levels of drought stress.
3. The damage done to the seed membranes due to the interaction of irrigation and inoculation with mycorrhiza and bacterium was investigated.

Extended Abstract
Introduction: Seed germination and seedling emergence depend on the genetics of plant species and are also influenced by environmental factors. Genetics and nutritional status of the maternal plant, maturity stage at a time of harvest, and environmental factors such as temperature, salinity, drought, and soil fertility influence seed germination. Seed vigor as the main parameter of seed quality decreases due to accelerated aging and storage. The objective of this study was to evaluate the response of accelerated aged Chia seed to different levels of salinity stress.
Material and Methods: Two-way factorial experiment with experimental factors, including five levels of seed accelerated aging durations (0, 24, 48, 72, 96 h) and six levels of salinity stress (0, 50, 100, 150, 200, and 250 mM) was arranged based on a complete randomized block design with three replications. The experiment was conducted at seed technology laboratory Khuzestan Agricultural Sciences and Natural Resources, University of Khuzestan, in 2019.
Results: Results of analysis of variance revealed that the effect of seed accelerating aging, salinity stress, and interaction effects of both factors on all measured germination traits were significant (p<0.01). The best pattern of seed germination was evaluated using three-parameter sigmoid models (logistic, Gompertz, and sigmoidal) and two polynomial models (quadratic and cubic), then the performance of all models was compared using (R²_adj), root square of the mean (RMSE) and corrected Akaike index (AICc). Results showed that at accelerated aging duration, models' performance to describe Chia seed germination response varied at different levels of salinity stress. At no aging and 72h of accelerated aging treatments, the sigmoidal model exhibited the best fit on final seed germination, whereas for the other levels of accelerated aging, Gompertz exhibited the best fit. Based on the output of the sigmoidal model, for no aging and 72 hours of accelerated aging, 50% of seed germination was declined at 171.7 and 76.9 mM, respectively, and based on the results of the Gompertz model, after 24 and 48 h of accelerated aging, seed germination declined to 50% at 163.8 and 129.6 mM. Results obtained from fitting polynomial models on seed germination showed that the cubic model provides reasonable descriptions for studied traits such as seed vigor.
Conclusion: Chia seed germination was sensitive to salinity and accelerated aging treatments. At no aging condition, Chia seeds tolerate salinity stress up to 200 mM and were able to germinate. By increasing aging durations, seed germination declined dramatically at all salinity levels and after 96 hours of aging, there was no seed germination at 150 mM.

 
Highlights:
1- The best nonlinear model to study accelerated Chia seed response to salinity stress was selected using the model selection criterion.
2- Chia seed germination threshold to salinity stress was determined for not- aged and aged seeds.

 

Extended Abstract

Introduction: Syrian mesquite is introduced as a weed in wheat and barley fields, saffron, cotton and vegetables, and in orchards. The spread of this weed in different climates raises the question of how much native plant conditions can affect germination characteristics. Therefore, the purpose of this study was to evaluate the effect of native plant conditions on germination characteristics in response to environmental stresses (temperature, salinity, and drought).

Materials and Methods: To investigate dormancy elimination and germination response thresholds of two Syrian mesquite ecotypes (Khuzestan and Fars) to environmental factors (temperature, salinity, and drought), four separate experiments were carried out as factorial based on completely block design with three replications at Agricultural Sciences and Natural Resources University of Khuzestan. Treatments included immersion the seeds with concentrated sulfuric acid (96%) (0, 10, 15, 20, 25, and 30 min), different temperature (0, 5, 10, 15, 20, 25, 30, 35, 40, and 45 °C), salinity levels (0, 100, 200, 300, 400, 500, and 600 mM), and different levels of drought stress (0, 0.2, 0.4, 0.6, 0.8, 1 and 1.2 MPa).

Results: The time required for immersion of seeds in sulfuric acid to dormancy breaking for two ecotypes was different. The estimated parameters indicated time of immersion in sulfuric acid to reach 50% germination in the Khuzestan ecotype (11.38 min) was longer than the Fars ecotype (8.10 min). The Khuzestan ecotype was also able to germinate (45%) at 40 ° C, whereas germination in the Fars ecotype was stopped at this temperature. Germination rate and cumulative germination percentage at temperatures below 25 ° C were higher in Fars ecotype than in the Khuzestan ecotype. The results of the salinity experiment showed that 50% reduction in seed vigor index, final germination percentage, and germination rate in the Fars ecotype were 167.48, 404.46, and 307.02 mM respectively and in the Khuzestan ecotype were 0.89. 229, 380.16, and 299.57 mM, respectively. For drought treatments, 50% reduction in final germination percentage, seed vigor index, and germination rate in Fars ecotype were -0.50, -0.38, and -0.39 MPa, respectively, and in Khuzestan ecotype were -0.46, -0.46, and -0.50 MPa, respectively.

Conclusion: Overall, the results showed that native plant climatic conditions (latitude and longitude, elevation, rainfall, and temperature) can affect the degree of seed dormancy, resistance to environmental stresses such as temperature, salinity, and drought.

 
Highlights:
1- Seed germination response thresholds of two ecotypes of Fars and Khuzestan for exposure to temperature and drought and salinity stresses were compared.

Highlights:

1. Goharan barley cultivar responds more positively to foliar application under late season drought stress conditions.
2. Foliar application of potassium sulfate, zinc sulfate and super oxidase superoxide on Goharan cultivar maternal plant under late season drought stress condition led to the highest seedling root length, root dry weight and shoot dry weight.

Extended Abstract
Introduction: Providing important and effective elements such as zinc and boron- especially in areas where the soil for some reason cannot meet the needs of the plant- will be a good solution to improve seed and seedling quality and nutrition, and community health status. A considerable part of the wheat producing regions in the country are faced with late season haet during seed development stages. Thus, the present study will investigate the effect of heat stress and mother plant nutrition with zinc and boron micronutrients on seed deterioration and physiological quality of wheat seedlings.
Material and Methods: In a field experiment, wheat seeds were planted on two suitable planting dates (November 20) and late (January 5) to apply late-season heat stress during the seed development stage with three replications in Ramhormoz, Iran. The nutrition of mother plants with zinc and boron elements was done at three levels (nutrient-free and application of zinc and boron) as a foliar application. After harvest, the seeds were transferred to the laboratory and membrane integrity of seed cells was investigated using an electrical conductivity test as an indicator of deterioration. Another part of the seeds was planted in a factorial pot experiment based on RCBD with three replications to evaluate the quality of seeds and seedlings in the greenhouse.
Results: The results showed that exposure of seeds to heat stress during development reduced seed quality as well as seedlings so that the cell membrane in the seeds produced under heat stress conditions was damaged and their electrical conductivity increased by 19%. Also, these seeds showed more sensitivity to deterioration. The percentage of seedling emergence in the stressed seeds decreased by 21.66%. Heat stress also reduced seedling quality indices such as chlorophyll content, shoot dry weight, and root dry weight. Application of zinc and boron on the mother plant not only led to improved quality of seeds and seedlings under normal conditions but also the negative effects of heat stress on seed and seedling quality were reduced. There was a significant negative correlation between the seed electrical conductivity test and qualitative parameters. Therefore, the use of this test is recommended to determine the quality of seeds, especially seeds produced under late-season heat stress conditions.
Conclusion: Noting the negative effect of heat during seed development on seed quality, planting dates should be adjusted as much as possible so that the seed development stage does not coincide with the late-season heat stress. Due to the beneficial effects of using zinc and boron in the mother plant on many traits related to the quality of seeds and seedlings, their application- especially zinc- in soils with deficiency or the possibility of heat stress at the end of the season is recommended.

Highlights:

1. Zinc and boron micronutrients were used to mitigate the harmful effects of heat stress on seed quality.
2.  Physiological characteristics of seedlings obtained from seeds produced in the field under late-season heat stress conditions were investigated.

Extended Abstract
 Introduction: Germination is considered the first and most important stage of establishment and consequently, successful competition which is influenced by genetic and environmental factors. Among the environmental factors influencing the germination, temperature and light are the most important ones. Using different models, the germination response of seeds to temperature can be quantified; therefore, this study was performed to investigate the effect of temperature on germination and to quantify the germination response of Buckwheat seed (Fagopyrum esculentum Moenc) to temperature using nonlinear regression models and thermal-time model.
Materials and methods: The seeds were germinated in 4 replications of 25 seeds under 8 constant temperature treatments (5, 10, 15, 20, 25, 30, 35 and 40 ° C). Using a three-parameter logistic model, Buckwheat seed germination was quantified at different temperature levels and the percentage and time to reach 50% germination were obtained. Four nonlinear regression models and a thermal-time model were used to quantify the response of Buckwheat seed germination rate to temperature. To compare the models and determine the most appropriate model, the root mean square error index (RMSE), coefficient of determination (R²), coefficient of variation (CV) and standard error (SE) were used for the observed germination rate versus the predicted germination rate.
Results: The results indicated that temperature affected the seedling length, normal seedling percentage, seed vigor and the germination rate as well as germination percentage. Also, the results showed that germination characteristics increased with increasing temperature up to 20 and 25 °C. Comparison of the three models based on the root mean square error (RMSE) of germination time, the coefficient of determination (R²), CV and SE, the best model to determine the cardinal temperatures of Fagopyrum esculentum was the dent-like model. The results of thermal-time model showed that the base temperature of Fagopyrum esculentum seeds was 4.01 ° C and the thermal-time coefficient was 1242.6 h° C.
Conclusion: Utilization of non-linear regression models (segmented, dent-like and beta) and thermal-time model to quantify the germination response of Fagopyrum esculentum response to different temperatures led to acceptable results. Therefore, germination rate and percentage may be predicted using the outputs of these models at different temperatures.

Highlights:

Extended Abstract
Introduction: Drought stress, as abiotic and multidimensional stress, has severe effects on plant growth. One of the new approaches in the management of drought stress is the use of nanoparticles. Nanoparticles infilterate the seeds and increase nutrient and water uptake and ultimately, improve germination. The present research was conducted to evaluate the effects of titanium dioxide nanoparticles on chickpea plant germination factors to modify the negative effects of drought stress.
Materials and Methods: A factorial experiment was conducted in a completely randomized design with four replications on chickpea seeds of Arman cultivar in the Plant Sciences Research Institute of the Ferdowsi University of Mashhad in 2019. Seeds were primed with concentrations of 0, 5, 10, 15, and 20 mg L^-1 titanium dioxide for 24 hours. The seeds were cultured in sterilized Petri dishes. Drought stress was applied using polyethylene glycol 6000 with 0, -2, -4 and -8 bar osmotic potentials.
Results: The analysis of variance results showed that the interaction effect of drought stress and titanium dioxide nanoparticles was significant on germination rate, the number of normal seedlings, seed vigor index, germination index, length of seedling, radicle length, and radicle dry weight. All germination traits were inhibited as a result of drought stress. On the other hand, the presence of titanium dioxide nanoparticles partially decreased this inhibition in some traits. Germination percentage, germination rate, normal seedling percentage, seed vigor index, germination index, epicotyl length, radicle length and radicle dry weight decreased as a result of stress.
Conclusion: At all drought stress levels, the concentration of titanium dioxide nanoparticles up to 20 mg L^-1 significantly improved traits such as germination percentage, seed vigor index, epicotyl length, and epicotyl dry weight. It seems that nanoparticles can stimulate cell activity and increase the transformation of reserves to translocatable material and consequently, improve germination characteristics. Thus, the application of titanium dioxide nanoparticles up to a concentration of 20 mg L^-1 can partially reduce the negative effects of drought stress on the germination characteristics of chickpeas.

Highlights:
1- Germination percentage and seed vigor index of chickpea increased with the application of titanium dioxide nanoparticles up to 20 mg l^-1 at all drought stress levels.
2- The radicle length and dry weight of chickpea increased by titanium dioxide nanoparticles.
3- The negative effects of drought stress on chickpea seed germination decreased by titanium dioxide nanoparticles.

Extended abstract
Introduction: Safflower (Carthamus tinctorius L.) is an annual oilseed crop that is adapted to arid and semi-arid regions and is considered an indigenous plant of Iran. Germination and seedling stage in the soil is one of the most important stages in the life cycle of plants. High germination rate and percentage increase the number of seedlings and the rapid successful establishment of seedlings in the soil also contributes to the suitable vegetative growth of the seedlings in later stages of life. Therefore, evaluation of germination indices and seedling establishment in the soil and finding more suitable conditions to improve these indices can have a direct impact on more successful plant cultivation. One of the methods used in this regard is priming.
Materials and Methods: In order to study the effect of plant growth-promoting bacteria and temperature treatments on germination indices and seedling growth of the safflower, this investigation was conducted based on a completely randomized block design with three replications at the Agricultural Research Laboratory of Yasouj University in 2016. Experimental factors were seven levels of temperature treatments (5, 10, 15, 20, 25, 30, 35°C) and seed priming with three strains of Pseudomonas fluorescens such as Pf 2, Pf 25 and CHA 0 and one strain of Bacillus subtilis and control (without inoculation).
Results: The results showed that 20°C temperature caused the highest germination percentage, germination rate and vigor length. Also, seeds inoculated with Pseudomonas fluorescens growth-promoting bacteria strain CHA0 had the highest germination percentage (68.74), germination rate (3.49 seeds per day) and vigor length vigor (6.22). Seedling length, dry weight and vigor weight were the other parameters that showed the best results at 20 and 25°C. Also, germination and seedling growth indices decreased by an increase or decrease in the optimum temperature. The use of plant growth-promoting bacteria causes increased activity of ascorbate and catalase enzymes, which leads to a decrease in injuries related to non-optimum temperature and improved germination indices.
Conclusion: According to our results, to accelerate the germination rate and other parameters, it is better to inoculate seeds with bacteria strains CHA0 and 25 in the temperature range of 20-25°C.

Highlights:

1. The germination behaviour of safflower primed with bacteria varies at different temperatures.
2. Seeds inoculated with Pseudomonas fluorescens growth-promoting bacteria of CHA0 strain had better germination conditions.

Using the 20-25°C temperature improves germination indices.

Extended Abstract
Introduction: The application of different physical, chemical, and hormonal treatments mainly improves the germination of plants such as Dracocephalum kotschyi Boiss that have a seed dormancy mechanism. However, the interaction effects of germination, temperature, pretreatment with sulfuric acid, treatment with gibberellic acid and mycorrhiza on D. kotschyi germination have not been studied. Therefore, this experiment was performed in vitro to study the effect of seed pretreatment on improvement of germination characteristics of D. kotschyi seed.
Materials and Methods: The treatments studied in this experiment included (1) pretreatment of seed coat with sulfuric acid (97-95 %, for 10 min) and non-pretreatment (distilled water); (2) different treatments including treatments with concentrations of 0, 250, and 500 mg L^-1 gibberellic acid (GA) or inoculation with mycorrhiza suspension in two separate experiments; and (3) two temperature treatments; room and refrigerator (about 4 °C) temperatures. The experiment was performed as a factorial based on a completely randomized design with four replications and different germination and initial seedling growth indices were examined.
Results: Gibberellic acid application at room temperature resulted in a significant increase in germination percentage and rate, whereas there was no significant difference between different levels of gibberellic acid and control at 4 °C. Similarly, the application of 250 mg L^-1 GA improved seedling length and seedling vigor index at room temperature. While pretreatment with sulfuric acid significantly reduced germination and seedling growth indices compared to non-pretreatment, inoculation with mycorrhiza suspension in both pretreatment conditions compensated the germination reduction caused by sulfuric acid pretreatment by improving germination. Similarly, while the highest seedling length and vigor were obtained from mycorrhizal treatment at room temperature in non-pretreatment with sulfuric acid, at 4 ° C, inoculation with mycorrhiza also significantly reduced the loss in seedling length and seedling vigor index caused by sulfuric acid application.
Conclusion: According to the findings, it seems that the application of 250 mg L^-1 GA at room temperature can be considered to improve the germination trend of D. kotschyi. Also, according to the results, treatment with mycorrhiza in sulfuric acid-free treatment at room temperature can be recommended as optimal conditions to improve the germination of D. kotschyi.

Highlights:
1- The interaction effect of chemical pretreatment with biological and hormonal treatments on the germination of Dracocephalum kotschyi was investigated.
2- The application of gibberellic acid at room temperature improved germination compared to the control, whereas it had no effect on germination at 4 °C.
3- Application of mycorrhiza reduced germination loss caused by pretreatment with sulfuric acid and led to maximum germination and seedling growth.

Extended Abstract:
 Introduction: Production of high-quality seeds to stabilize crop yield is an important challenge for breeders. One of the most important answers to this challenge is to clarify the molecular mechanisms associated with seed vigor characteristics. Functional proteins of Cupin superfamily are among the molecules in signaling pathway. Previous research has shown that in maize, a storage protein similar to the functional Cupin superfamily protein called ZmGLP is effective in seed germination. However, in the previous experiments, suitable indicators were not used to assess seed vigor and its relationship with field establishment. So, it is needed to study the performance of ZmGLP in predicting field emergence to complete the previous research.
 Materials and Methods: An experiment was performed on 14 samples of commercial inbred maize lines. In this experiment, in addition to the laboratory evaluation of seed germination, field indices of physiological seed quality including the percentage of seedling emergence in the field, time to 50% seedling emergence, time to 90% seedling emergence, seedling dry weight, seedling height and coefficient of variation of seedling height was also assessed. In the polymerase chain reaction, two pairs of primers (CF / CR primers and IDF / IDR primers) were used to identify the DNA sequence of the Cupin.
Results: The results show that the seeds were different in terms of physiological quality. The lowest percentage of germination in laboratory was related to K1264/1, while the lowest physiological quality of seeds in field indices was observed in K1263/17. The molecular test confirmed the presence of the desired allele at the InDel9 site of vigor-related genes in the three samples of B73, K1264/1, and K1264/5-1, but no amplification band of the InDel9 site was observed in all K1263/17 seed samples. Due to the fact that line K1264/1, which had the lowest germination percentage in the laboratory, had an amplification band at this related site to vigor, it is not enough to rely on the results of the laboratory germination test to investigate the relationship between this gene and seed vigor. The field emergence test and seed vigor test that have a good prediction of field emergence must be used in these studies.
Conclusions: According to the results of this experiment, molecular tests with functional markers based on Indel9 can be used to accelerate the evaluation of vigor, especially when the breeder is breeding a new line or hybrid. It is a useful, rapid, and effective molecular method to predict seed emergence in the field and screen the lines to ensure the genetic strength of the germination of the lines, especially in the temperate germplasms of corn. Finally, it is necessary to determine the threshold of low vigor during seed quality investigation in different cultivars, and relationship between the presence or absence InDel9 site should be considered in future research.

Highlights:
1- The feasibility of using molecular markers to determine the seed vigor of corn lines in the field was studied and optimized for the first time.
2- The results of physiological quality assessment of seeds in the field for the studies related to the relationship between molecular markers and seed vigor were exploited for the first time.
3- The Indel9 site and molecular markers related to seed vigor in the field were introduced.

Extended abstract
Introduction: With regard to the ever-growing water deficit in the world, the adoption of the direct-seeded rice cultivation system has been suggested as an alternative to the transplanting method. One of the disadvantages of the direct-seeded method is low and non-uniform germination and emergence due to low seed vigor in rice. Priming is a technique which improves the rate and uniformity of seed germination under these conditions. Thus, this study aimed to investigate the effects of priming treatments on seed germination of different rice cultivars under different temperature conditions using the thermal time model.
Materials and methods: This study was conducted in 2019 at the seed research laboratory of Gorgan University of Agricultural Sciences and Natural Resources. In this experiment, germination of primed and non-primed seeds in three rice cultivars (Nada, Anam, and Tolo) was investigated under different temperatures (15, 20, 25, 30, and 35°C). The priming treatments which consisted of control, hydropriming, and osmopriming with different chemicals (potassium chloride 2%, potassium nitrate 1%, calcium chloride 4%, glycine betaine 10 ppm, salicylic acid 10 ppm, and ascorbic acid 10 ppm) were investigated under different temperatures.
Results: The results showed that priming treatments had no significant effect on the seed germination percentage of rice cultivars at different temperatures. The thermal time model based on binomial distribution fitted well to cumulative germination percentages in all priming treatments. Among the parameters of the thermal time model, the greatest priming effect was on the reduction of the thermal coefficient, followed by the reduction of the sigma coefficient, which resulted in the increased rate and uniformity of germination. Priming treatments had no significant effect on base temperature. Also, the responses of rice cultivars to seed priming treatments varied so that in Anam and Neda, priming with calcium chloride but in Tolo, hydropriming was more effective on the model parameters, especially thermal time to 50% of germination.
Conclusion: In general, priming treatments did not affect the base temperature of germination in rice cultivars, but they significantly affected the rate and uniformity of seed germination. As the latter issue is one of the main problems in the direct-seeded rice system, suitable priming treatments for each cultivar can be adopted to increase the rate and uniformity of seed germination and emergence in this system.

Highlights:

1. The thermal time model can be used to select the appropriate priming treatment for improving seed germination components of rice cultivars.
2. The responses of rice cultivars to different seed priming treatments were different.
3. Priming treatments did not improve the base temperature of seed germination in rice cultivars, but they significantly affected seed germination rate and uniformity.

Extended Abstract
Introduction: Safflower seeds are rich in unsaturated fatty acids with a high capacity for peroxidation, which have a high potential to reduce germination and seed vigor during the storage period. Therefore, Introducing appropriate methods to preserve or improve their germplasm during storage would be advantageous. The aim of this study was to investigate the effects of seed priming on germination and vigor of safflower seeds (Sofeh and Sina cultivars).
Materials and Methods: A three-factor experiment was conducted in a completely randomized design with three replications before and after artificial deterioration. The experimental factors included controlled deterioration of seeds at 45°C in six levels (no deterioration, 1, 2, 3, 4, and 6 days) and priming in four levels (no prime, hydropriming, salicylic acid 50 mg/l and sodium chloride 5 percent).
Results: Artificial aging strongly and linearly reduced the germination ability of safflower seeds, and germinability and seed vigor reach zero in a time interval which lasts between 2.5 to 4.5 days (depending on the treatment and the investigated trait). The use of priming prior to artificial aging was more advantageous than priming after artificial aging. In addition, priming with salicylic acid was more useful compared to other priming treatments.
Conclusion: Priming of safflower seeds before storage would result in the extended shelf-life of the stored seeds while also preserving the seed germination potential. 

Highlights:

1. The effect of priming on germination and vigor of safflower seeds before and after artificial deterioration was compared and investigated.
2. The effect of priming before and after artificial deterioration on the improvement of safflower seed quality varied in different cultivars.

Extended abstract
Introduction: Growth, development, and ultimately production of plants are affected by several environmental factors. Drought and salinity are major environmental stresses that have irreparable effects on all stages of germination, plant growth, and the structure and activity of organs. The germination stage and seedling establishment are more sensitive to osmotic and salinity stresses, so it is important to evaluate the germination indices under stress conditions for plant cultivation in dry and saline environments.
Materials and Methods: To investigate the effect of different levels of osmotic and salinity on germination and early growth of camelina (Camelina sativa L.), two experiments were conducted separately in a completely randomized design in the laboratory of Bardsir Faculty of Agriculture, Shahid Bahonar University of Kerman in 2023. In the first experiment, polyethylene glycol solution (PEG 6000) at -0.2, -0.4, and -0.6 MPa levels was applied to generate the osmotic potential. In the second experiment, NaCl at 50, 100, and 150 mM concentrations was used. In both experiments, distilled water was used to create zero stress (control).
Results: The results showed that mild osmotic (-0.2 MPa) and salinity (50 mM) stresses had no significant adverse effect on seedling establishment. However, increased intensity of osmotic and salinity stresses significantly reduced germination percentage and rate, seedling vigor length index, seedling dry weight, radicle length and dry weight, and plumule length and dry weight, so that drought stress at -0.6 MPa reduced the length and dry weight of the root and the length and dry weight of the plumule by approximately 40.40%, 57.4%, 49.2%, and 53.3% compared with the control, respectively. The highest level of salinity stress (150 mM) caused a decrease of 37.8%, 56.8%, 45.3%, and 55.4% in the length and dry weight of the root and the length and dry weight of the plumule compared with the control, respectively. An increment of MDA content, soluble carbohydrates, and the amount of free amino acids was observed at moderate (-0.4 MPa) and severe (-0.6 MPa) osmotic stress and 100 and 150 mM salinity stress levels.
Conclusions: Since camelina is a new plant in Iran, evaluating the response of this plant to different levels of osmotic and salinity stress during germination and early growth stages of the seedling provides the possibility of its cultivation and development in the dry lands of different regions of the country. It seems that mild drought (-0.2 MPa) and salinity (50 mM) stresses did not have a significant adverse effect on camelina germination indicators, but if the stress level exceeds the plant's tolerance range, it leads to decreased germination traits. Recommending the cultivation of this species requires studying its stability, compatibility, and agroecological characteristics.

Highlights:

Extended abstract
Introduction: Currently, temperature and salinity stresses are spreading globally, which have a detrimental impact on the performance of various plants, particularly during seed germination and seedling growth stages. Therefore, the objective of this laboratory study was to examine the influence of temperature treatments and salinity levels on germination characteristics and initial seedling growth of kochia.
Materials and Methods: In the first experiment, temperature at nine levels (1, 5, 10, 15, 20, 25, 30, 35, and 40°C), and in the second experiment, salinity (osmotic potential at six levels (no stress, -0.4, -0.8, -1.2, -1.6, and -1.8 MPa) were considered as experimental treatments. In order to determine the cardinal temperatures (base, optimal, and ceiling) of germination in kochia seeds, non-linear regression models including the segmented, dent-like, and modified beta models were used.
Results: In the first experiment, the response of kochia germination rate was predicted by a segmented function with R², RMSE, and AIC (Akaike) values of 0.92, 1.32, and 65.69, respectively, which indicates the high accuracy and precision of this model in predicting the cardinal temperatures of kochia seed germination compared with the other two models. In this model, the estimated base temperature for germination was 0.7°C, the optimal temperature was 20°C, and the ceiling temperature was 44.3°C. In the second experiment, salinity stress negatively affected the characteristics of seed germination in kochia, including germination percentage, germination rate, percentage of normal seedlings, seedling length, and seedling vigor index. The highest germination percentage of kochia seeds was observed under salt-free conditions with 88.66%, which decreased to 13% under -1.8 MPa salinity conditions.
Conclusions: In general, the results showed that the segmented model is more efficient and accurate than the other two models in predicting germination of kochia seeds under different temperature treatments. Also, increasing levels of salinity stress significantly reduced germination potential and seedling growth of kochia seeds, so that at a stress level of -1.8 MPa, germination rate decreased by 75% compared with stress-free condition.

Highlights:

1. The cardinal temperatures (base, optimum, and ceiling temperatures) of kochia seed germination were determined.
2. This research introduced 1°C temperature and -1.8 MPa of salinity level as low temperature stress and critical salinity, respectively.

Extended abstract
Introduction: This study investigated the effects of storage temperature, humidity, and storage duration on the germination indices of German chamomile seeds. Given the significant impact of storage conditions on seed quality, the primary objective was to standardize optimal storage methods for this medicinal plant. The research aimed to evaluate the influence of seed moisture content, storage temperature, and storage periods on the germination performance of German chamomile seeds.
Materials and Methods: The experiment was conducted in 2019 at the Faculty of Agriculture, Yasouj University. It was designed as a split-split plot arrangement within a completely randomized design, with four storage temperature levels (15, 25, 35, and 45°C), three seed moisture content levels (8, 12, and 16%), and six storage durations (30, 60, 90, 120, 150, and 180 days). Initial seed moisture content was measured, and the desired moisture levels were adjusted using specific formulas. Germination tests and related indices, such as germination percentage and germination rate, were conducted. Data were analyzed using SAS software.
Results: The results from the mean comparison of the interaction between storage duration and seed moisture content at temperatures of 15, 25, 35, and 45°C revealed that germination percentage significantly decreased as storage duration increased. The lowest germination percentage was observed after 180 days of storage at 16% seed moisture content. Similarly, germination rate decreased significantly across all temperatures with prolonged storage. Seedling growth analysis under different storage conditions showed a significant reduction in root, shoot, and seedling length at all temperatures as storage duration increased. The shortest lengths of these components were observed after 180 days of storage at 16% seed moisture content, attributed to seed aging and reduced germination capacity. Increasing seed moisture content from 8% to 12% resulted in an average decrease of 9% in germination percentage and 5% in germination rate. Further increasing moisture content from 8% to 16% led to a more substantial average reduction of 73% in germination percentage and 72% in germination rate. Raising storage temperature from 15°C to 25°C, 35°C, and 45°C resulted in average decreases in germination percentage of 9%, 25%, and 42%, respectively. Similarly, germination rate decreased by 14%, 33%, and 43% at this respective temperature.
Conclusions: Overall, the results indicate a decline in the germination indices of German chamomile seeds with increasing seed moisture content and storage temperature. The optimal seed moisture content of 8% and a storage temperature of 15°C were identified as the most suitable conditions for maintaining seed quality.

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