Iranian Journal of Seed Research

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 25^th, April 15^th, and May 4^th, 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.

Extended abstract
Introduction: A wide range of deteriorative conditions (especially moisture content and temperature) may affect seed quality during storage which may lead to seed aging. As the most important component of the phenylpropanoids pathway, trans-cinnamic acid, found abundantly in plants and its endogenous levels is influenced by stress conditions. The present study was conducted to investigate germination features, seed reserve mobilization, electrolyte leakage and malondialdehyde content in aged cowpea seeds affected by different concentrations of cinnamic acid.
Materials and Methods: The research has been performed in the laboratory of Faculty of Agriculture, Shahrood University of Technology, Iran. The experiment was designed as a factorial (two factors of the experiment included two levels of seed quality including non-aged and aged seeds and five levels of cinnamic acid concentrations including 0, 15, 30, 45 and 60 µM) based on a completely randomized design. Accelerated aging was applied as an efficient method to mimic storage conditions in the presence of accelerating factors. Cowpea (Vigna unguiculata) seeds (Bastam local variety) were incubated in a relative humidity of 95% and a temperature of 43 °C for 72 h to accelerate aging. Both seed lots were treated with 5 different concentrations of cinnamic acid for 6 h followed by standard germination and vigor tests. Data of germination and vigor tests were processed using the GERMINATOR software. Heterotrophic growth, seed reserves mobilization, electrical conductivity and membrane lipid peroxidation were assessed using the available methods.
Results: In this study, cowpea seeds responded to cinnamic acid differently based on their primary quality. In deteriorated seeds, concentrations of 45 µM and 60 µM could successfully enhance seed germination percentage, as compared with the aged seeds (i.e., control). A concentration of 45 µM also improved the vigor of deteriorated seeds. Seed pretreatment of 15, 30 and 45 µM enhanced seed reserves utilization in non-aged seeds. Aging negatively affected area under curve, germination uniformity and seedling dry weight of the deteriorated seeds. Application of 30 µM cinnamic acid improved germination uniformity. The area under the curve was positively affected by 15µM and 30µM. Concentrations of 45 µM and 60 µM enhanced seedling dry weight. Applying 45 µM cinnamic acid decreased electrolyte leakage by 38% and improved efficiency of seed reserves mobilization. Moreover, seed malondialdehyde content, as an indication of membrane lipid peroxidation, showed a sharp decline by applying increased concentrations of cinnamic acid.  
Conclusions: Based on our results, cowpea seeds respond to cinnamic acid differently based on their primary quality. These results imply that seed pretreatment with 45 µM cinnamic acid may successfully invigorate aged cowpea seeds. We also conclude that cinnamic acid application cannot improve physiological traits and can be regarded as a potent antioxidant in the invigoration of the aged seeds.
 
Highlights:

1. This is the first study focusing on the role of cinnamic acid in alleviating deterioration in aged seeds.
2. Cinnamic acid has been introduced as a robust antioxidant, which is effective in reducing the deleterious effects of seed deterioration.

Extended abstract
 Introduction: Management of agricultural operations in sugarcane fields should be informed by the accurate knowledge of sugarcane growth stages and phenology and is to be reviewed based on variety differences. Given the importance of emergence stage on the establishment of seedling and final quality and quantity of sugarcane yield and given the absence of respective information, a study was conducted to investigate the effect of different planting dates on the phenological characteristics of the seedling stage of sugarcane cultivars in the south of Khuzestan Province during 2016-17 and 2017-18.
 Materials and Methods: The experiment was carried out as a randomized complete block design with three replications. In terms of growth period length, Very premature, Premature, and Semi mature cultivars included CP73-21, CP57-614 and CP69-1062. Planting dates were Aug. 11^th, Aug. 23^rd, Sep. 1^st and Sep 11^th. Planting operation was conducted manually and with 1/3 overlap of grafts. In order to prevent the negative effects brought about by the dispersion and non-uniformity of the experimental field and the special conditions of sugarcane cultivation, each cultivar was cultivated in a separate field and after sampling and the study of different traits, the statistical analysis of each cultivar was performed separately.
 Results: The results showed that sugarcane seedling was not affected by annual conditions and the interaction effect of annual conditions and planting dates. The significant differences of planting dates were observed at the beginning of emergence, its completion and rate of emergence and the number of leaves produced and their area. The fastest rate of the beginning and the completion of emergence was obtained in CP73-21, and on different planting dates, it was more permanent than other cultivars studied, while CP69-1062 had the slowest and more behavioral diversity of emergence on different planting dates. The cultivar CP73-21 did not produce good results in terms of leaf area, but the CP69-1062 cultivar was able to produce the highest level of leaf area due to the extra number of leaves and the mean value of a single leaf area. In addition, the best results were obtained in all characteristics in August, followed by September.
 Conclusions: Based on the results, in order to achieve the best emergence of sugarcane buds, it is necessary to complete the cultivation of most of the fields within the first twenty days of the beginning of the planting season and priority should be given to cultivar CP69-1062 and then cultivars CP57-614 and CP73-21. Due to the differences between sugarcane cultivars, utilizing seedling stage growth data can lead to more scientific management of the crops in terms of the characteristics of each cultivar, which eventually leads to desirable yields.
 
 
Highlights:

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.

Extended Abstract
Introduction: Priming is one of the most commonly used seed enhancement techniques. Events such as increased synthesis of nucleic acids, activation of repair processes, increased respiratory activity, and improved antioxidant capacity during priming lead to advanced metabolism in seeds. The most important effects of priming include increased percentage, speed and uniformity of germination and emergence. However, the longevity of primed seeds in storage is the major concern for researchers as it restricts widespread use of this technique. Some researchers believe that priming reduces the storage capacity of seeds, while others have reported increased seed shelf life after using priming treatments. Therefore, this study sought to investigate the effects of priming on the storage capacity of the seeds of canola cultivars under different storage conditions.
Material and Methods: In this study, the effects of priming on the shelf life of seeds of three canola cultivars including Dk-xpower, Traper and Hayola50 were investigated. For this purpose, the seeds were first treated with hydropriming and osmopriming methods. Then primed and control seeds with 6, 9, 12 and 15% moisture content were stored for 8 months at 15, 25, 35 and 45 °C. Sampling from different seed treatments was carried out at intervals of 1 to 30 days to assess germination. Finally, by fitting a three-parameter logistic model to cumulative germination data versus the day after storage, the time to germination loss to 50% was calculated and used to compare seed storage behavior between the treatments.
Results: The results showed that the storage behavior of canola seed varies greatly depending on the cultivar, and each cultivar showed a distinct behavior. Priming effects on the shelf life of seeds were different depending on the storage conditions, cultivars and also the priming methods. Comparison of the effects of priming on the seeds’ shelf life under different storage conditions showed that priming treatments were more efficient under higher seed moisture content and storage temperatures than those with lower seed moisture content and storage temperatures. In addition, priming treatments in Dk-xpower cultivar often increased the seeds’ shelf life. However, in the Traper and Hayola 50 cultivars, hydropriming often improved the seeds’ shelf life, and in contrast to osmopriming, it led to a decrease in the shelf life of the seeds.
Conclusion: Based on the results of this study, it was shown that priming effects on canola seed viability can be a function of various factors such as cultivar, storage conditions, and also the type of priming treatment. Moreover, in this study, hydropriming often increased seed longevity whereas osmopriming often increased the deterioration rate and reduced seed longevity.
 
 
Highlights:

1. Seed storage behavior of canola cultivars was compared under natural storage conditions.
2. Priming effects on seed longevity of canola cultivars was investigated under different storage conditions.

Extended Abstract
Introduction: Soybean (Glycine max (L.) Merrill) is the primary source of vegetable oil. Even in desirable conditions, soybean seeds lose their viability in long term storage. Many factors contribute to seed deterioration, including genetic factors, mechanical damage, relative humidity, storage temperature, seed moisture content, existence of microflora, and seed maturity, which reduce seed quality and make seeds unfit for cultivation purposes.
Materials and Methods: In order to investigate the effects of seed deterioration on seed germination and also the effects of salicylic acid and ethylene on the improvement of deteriorated seeds of G. max., accelerated aging test for 0, 6 and 10 days and natural aging test for 6 months were conducted. After aging conditions, seeds were imbibed with 50 µM salicylic acid and 10 µM ACC (precursor of ethylene) for 6 hours at 25 °C. In addition, after natural and accelerated aging tests, a bunch of seeds was used without any hormonal treatment (i.e., dry seeds) as control seeds. The seeds’ germination percentage, total sugar, fructose, and glucose were investigated. Moreover, the gene expression of GAI1 and LOX1 was measured on dry seeds and under imbibition of water, salicylic acid and ACC at 6, 12 hours using Q-RT-PCR method.
Results: The germination results showed that increasing number of aging days led to a decrease in germination. Total sugar content in seeds aged for 6 days did not have a significant difference, as compared with non-aged seeds. However, total sugar content in seeds aged for 10 days was significantly higher than non-aged seeds. Increasing accelerated aging levels from 0 days to 10 days led to increases in glucose and fructose contents in dry seeds. In addition, genes exhibited different expressions in different days and hours. Increasing aging from 0 days to 10 days led to increases in GAI1 gene expression. Moreover, LOX2 expression increased in accelerated aging from 0 to 6 days. LOX2 gene expression in naturally dried aged seeds also increased and was higher than that in non-aged seeds. SA and ACC had different effects on measured values.
Conclusion: In general, it can be concluded that the deterioration of seed quality and vigor result from numerous degradation processes and disruption in seeds’ physiological activity. This study showed that aging is associated with an increase in total sugar, glucose and fructose levels. In addition, the expression of the genes involved in the germination is also affected. Increases in LOX2 gene expression were observed in both accelerated aging and natural aging pathways. GAI1 gene expression increased in accelerated aging. However, in normal aging, it decreased.
 

Highlights:

1. Identifying the role of LOX2 and GAL1 genes in soybean seed deterioration.
2. Investigating seeds’ physiological responses under natural and laboratory aging conditions.

Extended abstract
Introduction: Temperature is one of the primary environmental regulators of seed germination. Seed priming technique has been known as a challenge to improving germination and seedling emergence under different environmental stresses. Quantification of germination response to temperature and priming is possible, using non-liner regression models. Therefore, the objective of this study was to evaluate the effect of temperature and priming on germination and determination of cardinal temperatures (base, optimum and maximum) of Brassica napus L.
Material and Methods: Treatments included priming levels (non-priming, priming with water, gibberellin 50 and 100 mg/l) and temperature (5, 10, 15, 20, 30, 35 and 40 °C). Germination percentage and time to 50% maximum seed germination of Brassica napus L. were calculated for different temperatures and priming by fitting 3-parameter logistic functions to cumulative germination data. For the purpose of quantifying the response of germination rate to temperature, use was made of 3 nonlinear regression models (segmented, dent-like and beta). The root mean square of errors (RMSE), coefficient of determination (R²), CV and SE for the relationship between the observed and the predicted germination percentage were used to compare the models and select the superior model from among the methods employed.
Results: The results indicated that temperature and priming were effective in both germination percentage and germination rate. In addition, the results showed that germination percentage and rate increase with increasing temperature to the optimum level and using priming. As for the comparison of the 3 models, according to the root mean square of errors (RMSE) of germination time, the coefficient of determination (R²), CV and SE, the best model for the determination of cardinal temperatures of Brassica napus L. for non-primed seeds was the segmented model. For hydro-priming and hormone-priming with 50 mg/l GA, the best models were segmented and dent-like models and for hormone-priming with 100 mg/l GA,  the dent-like model was the best. The results showed that for non-priming, hydropriming with water, gibberellin 50 and 100 mg/l treatments, the segmented model estimated base temperature as 3.54, 2.57, 2.34 and 2.34 °C and dent-model estimated base temperature as 3.34, 2.45, 2.21 and 2.83 °C, respectively. The segmented model estimated optimum temperature as 24.62, 23.23, 23.69 and 24.38 °C. The dent-model estimated lower limit of optimum temperature and upper limit of optimum temperature as 20.01, 19.62, 16.25, 19.87 and 28.81, 27.38, 29.58 and 27.31 °C.
Conclusion: Utilizing non-liner models (segmented, dent-like and beta) for quantification of germination of Brassica napus L. response to different temperatures and priming produced desirable results. Therefore, utilizing the output of these models at different temperatures can be useful in the prediction of germination rate in different treatments.
 
 
Highlights:
1-The effect of priming on germination of Brassica napuswas investigated.
2-The temperature range of rapeseed germination of Brassica napus changes with the use of seed priming.

Extended abstract
Introduction: Seed germination is a complex and dynamic stage of plant growth, and seed priming is a technique by which the seeds obtain germination potential physiologically and biochemically before being placed on growth media and facing the ecological conditions of the environment. Seed priming increases yield and antioxidant enzymes in plants by increasing germination and seed vigor and as a result, increases percentage of germination. Several studies have investigated the effect of seed priming with organic materials including salicylic acid on improving seed germination in various plant species. Research results have shown that salicylic acid can be used as a growth regulator to increase the germination of plants. Tomato, with scientific name of Lycopersicon esculentum (Mill), belongs to the Solanaceae family and is widely adapted to different climatic and soil conditions. The aim of this study was to evaluate the effect of different concentrations of Salicylic acid on seed germination and some factors of morphophysiologic and biochemical traits of tomato seedlings.
Materials and methods: This research was conducted as factorial in a completely randomized design, including priming treatment in 3 time frames (12, 18 and 24 hours) with three replications. Priming treatments consisted of salicylic acid (2, 2.5 and 3 mg/l) and distilled water. The measured traits were germination parameters including percentage, time, rate, and uniformity of germination and morphological traits including transplant height, crown diameter, root length, leaf number, and leaf area, shoot and root fresh and dry weight and biochemical traits including chlorophyll, peroxidase enzyme, proline, total nitrogen, potassium, calcium, phosphorus, and sodium.
 Results: The favorable effect of salicylic acid was obtained at the concentration of 3 mg/l on mean germination time compared to the distilled water. The positive effect of salicylic acid was observed on transplant height and leaf area (at the concentration of 3 mg/l at 18 and 24 hours’ time frame), shoot and root fresh and dry weight (at 24 hours) compared to the control. Immersion in distilled water for a period of 12 and 24 hours resulted in the highest root length, while salicylic acid treatment reduced root length significantly. The highest transplant height (14.3 cm), leaf number (34), chlorophyll index (59), peroxidase enzyme (10873 unit/g.min^-1), total nitrogen (2.89%), potassium (9.81%), and proline content (14.80 µM/g fresh weight) were observed in 24 hours treatment with concentration of 3 mg / l salicylic acid.

Conclusion: According to the results of this study, salicylic acid at certain concentration improves seeds germination of tomato plants through the regulation of physiologic and biochemical processes. It seems that salicylic acid led to increase in plant growth and improvement of seed germination and morphophysiological parameters of the tomato via affecting cell growth and division. Seed priming with salicylic acid at the concentration of 3 mg/l and in longer time frames had positive effect on most traits, whereas the results for each trait were different in relation to priming time.

 
Highlights:

1-Priming of tomato seed in distilled water for 18 hours reduces the time of seed germination.

2-Salicylic acid can be used as an appropriate pretreatment for producing seedlings with better quantitative and qualitative characteristics by affecting the morpho-physiologic and biochemical properties of tomato seedlings.

Extended Abstract
Introduction: Plants release much of bioactive chemicals from different parts such as leaves, stems and roots through different mechanisms to their surrounding environement. These biologically active chemicals are often referred to as "allelochemicals". Allelopathic compounds play a major role in reducing germination and the growth of crops.
Materials and methods: In this study, the effect of leaching on the reduction of phytotoxicity effect of soybean, black cumin, dragonhead and dill was investigated on the emergence and early growth of canola (Brassica napus L.). The experiment was conducted as factorial based on a completely randomized design with four replications in 2016. Treatments included four previous crop residue (soybean, black cumin, dragonhead, and dill), and three levels of leaching (without leaching, one-time leaching, and two-times leaching). The leaching-free treatment (control) was sub-irrigated to maintain the uniformity of environment moisture. Five days after the first leaching, the two leaching treatment was irrigated again. Five days after the second leaching, when the soil moisture was suitable for seed planting, 10 seeds of canola were cultivated in each pot at a depth of 3 cm of soil. After three weeks seedlings of canola were removed from the pot and the traits were measured.
Results: The results showed that the growth characteristics of canola, except root length, were affected by the residues of the previous crop. In non-leaching conditions, the residue of the four plants reduced the rate and amount of canola emergence, and the greatest reduction in canola emergence was recorded for the application of black cumin residue (7.5%). In the leaching conditions, the length of canola leaves increased, which was higher in the twice leaching treatment. This trend shows that as the amount of leaching frequency increased, it is highly likely that more inhibitiing materials leave the soil and conditions become suitable for canola germination and growth.. The highest dry weight of canola root was observed in one-time leaching treatment. The dry weight of canola leaf grown in dill and soybean residues was increased as a result of one-time leaching, whereas the dry weight of canola grown in black cumin and dragonhead residues showed a higher increase in two-times leaching. Results show that four studied plants have canola growth inhibiting compounds and leaching can ameliorate this effect. The response of canola in the soil containing black cumin and dragonhead residues is higher in two-times leaching, and in the soil containing plant residues dill, one-time leaching is sufficient. In soils containing soybean residue, the response index was almost similar in case of one and two-times leaching.
Conclusion: Generally, the results showed that the application of leaching before planting canola reduced the inhibitory effects of plant residue on germination and growth of canola. Therefore, it is suggested that in the agricultural ecosystems in which canola is present in crop rotation, cultivation of canola must be avoided in presence of soybean, black cumin, dragonhead, and dill residue to eliminate their inhibitory effects on canola growth. In areas with water restriction, autumn rainfall can act as leaching and reduce the effect of allelopathic compounds. In case leaching is not possible, cultivation of canola inside the residue of these plants must be avoided.
 
 
Highlights:
1-Leaching can reduce the effect of allelopathic compounds.
2- Allelopathic compounds of some plants such as black cumin showed better response to two-times leaching.

Extended abstract
Introduction: London rocket is an important winter annual weed of the mustard family (Brassicaceae), which is propagated by seed. Germination of a seed population in response to water potential reduction is modeled using the concept of hydro time. This model has outputs that are physiologically and ecologically meaningful. One of the presumptions of the Hydro time model is the normal distribution of the base water potential among the seed population.
Materials and methods: In order to quantify the germination characteristics and determine the cardinal temperature of germination of London rocket (Sisymbrium irio L.), an experiment was done in 2018 at Science Research Branch, Islamic Azad University, Tehran, Iran. The seeds were placed at constant temperatures (5, 10, 15, 20, 25, 30, 35, 40 and 45 °C). Germination percentage, germination rate, root length, shoot length, seedling length and seedling fresh weight were evaluated. Intersected-lines, dent-like and quadratic polynomial models were used to determine cardinal temperatures. London rocket seed germination was tested across a range of water potential (0, -0.2, -0.4, -0.6 and -0.8 MPa) at the optimal temperature of 22.80 °C. The hydro time model, based on the normal distributions was fitted to data.
Results: Results showed that seed of London rocket did not germinate at temperatures of 5, 35, 40 and 45° C, and 25° C was the best temperature for seed germination (48%). The longest root length (4.49 mm) was observed at 20°C, which did not have significant differences with temperatures of 15 and 25 °C. The longest shoot length (10.19 mm) was obtained at 25 °C and there were not any significant differences among this temperature and temperatures of 15 and 20 °C. Similar trend with the trait of root length was observed for the trait of seedling length. The best model for estimating the cardinal temperatures in London rocket was intersected-line model with respect to coefficient of determination and mean square error. According to the intersected-lines model in London rocket, the minimum, optimum and maximum temperatures were calculated 5.83, 22.80 and 37.91°C. According to the hydro-time model based on normal distribution, the hydro-time constant and the base-water potential (which is a threshold for germination beginning) of London rocket degree were 284.28 (MPa/h) and -1.18 (MPa) at 22.80 °C, respectively.
Conclusions: Knowledge of germination and emergence of weeds also helps to predict the potential distribution to new habitats. The obtained coefficient of determination (0.94) between observed germination and predicted germination showed that the hydro time model based on normal distribution fitted well to germination percentage of London rocket seed. Due to the low hydrotime coefficient of this weed and the drought problem that most provinces face, it is expected that this weed will become more problematic in most provinces of Iran in the future.
 
Highlights:
1- The best temperature for germination of London rocket seed is 25 °C.
2- The best model for estimating the cardinal temperatures in London rocket is intersected-line model
3- The hydro-time constant and the base-water potential of London rocket degree based on normal distribution are 284.28 (MPa/h) and -1.18 (MPa) at 22.80 °C, respectively.

Extended Abstract
Introduction: Germination and seedling establishment are the primary stages of crop growth that are highly sensitive to salinity and drought stresses. On the other hand, seed hardness affects the quality of plant germination. Therefore, the aim of this study was to analyze the effect of seed pre-treatment on germination characteristics of Medicago scutellata var Rabinson.
Material and methods: In the present study, the effects of pre-treatment methods of scarification (sand paper, knife and sand), stratification (0, -5, -10, and -15 ^°C), ultrasonic waves (3, 6, 9, 12, and 15 min), and magnetic field (two intensities of 125 and 250 mT in 4 times exposure by 6, 12, 18, and 24 h) on seed germination of annual medic germination affected by salinity and drought stresses (0, -3, -6, -9, and -12 bar) were investigated with three replications. Twenty seeds per Petri dish were used for each treatment. Seedlings were incubated in the dark at 20/18±0.3^°C in a growth chamber. After ten days, the dry weight of the seedling was obtained after oven drying at 70^°C. Root length, shoot length, seed germination percentage, seedling growth rate (SLGR), the weight of mobilized seed reserve (WMSR), seed reserve depletion (SRDP), and seed reserve utilization efficiency (SRUE) were measured.
Results: Based on the preliminary results using Taguchi method, the -15 °C stratification treatments under salinity and drought, 6 and 9 min of exposure to ultrasonic waves under salinity and drought, and magnetic field intensity of 250 mT for 6 and 9 h were chosen for the experiment of salinity and drought, respectively. In salinity experiment, the maximum root length (23.47 mm), shoot length (15.76 mm), weight of mobilized seed reserve (0.119 mg per seed), and seed reserve depletion percentage (58.9 %) was in scarification treatment; the maximum seed germination (47.2 %) was observed in control treatment; the maximum seedling dry weight (0.195 mg) was identified in magnetic field treatment; and the maximum seed reserves utilization efficiency (0.665 mg.mg.seed^-1) was obtained in ultrasonic waves treatments. In drought experiment, the maximum root length (22.84 mm), shoot length (8.09 mm), seed germination (49.93 %), the weight of mobilized seed reserve (0.096 mg per seed), and seed reserve depletion percentage (43.1 %) was measured in ultrasonic treatment; the maximum seedling dry weight (0.09 mg) was found in magnetic field treatment; and the maximum SRUE (0.516 mg.mg.seed^-1) was observed in control treatment.
Conclusions: According to the results, there is a direct relationship between the decline in seedling dry weight and the decline in the weight of mobilized seed reserve. However, the scarification and ultrasonic waves' treatments had significant effects on seedlings resistance to salinity and drought, respectively. Furthermore, the use of ultrasonic waves and scarification produced higher germination percentage and more vigorous seedlings under drought and saline conditions. In terms of germination and seedling growth, the differences among the treatments increased by the increase in stress intensity. This advantage led to greater seed reserve utilization. Moreover, pre-treatment methods resulted in longer cotyledon length and improvement in vigorous seedlings. Future studies should focus on the study of enzymes activity and/or hormones affecting seed reserve utilization rate in response to drought and salinity stress.

 
Highlights:
1- The most sensitive growth stage of annual medic (seedling production stage) to salinity and drought stress was evaluated.
2- Various pre-treatments to improve the germination of annual medic to enter crop rotation in arid and semi-arid regions due to self-seeding and short growing period were investigated.

Extended Abstract
Introduction: Sweet corn (Zea mays var. saccharata) is a corn variety that is distinguished from other varieties due to the presence of genes that affect starch production in the endosperm. Given that the most of plants including sweet corn face with problems such as non- uniform germination and poor seed emergence in the early stages of germination. Thus, the use of organic stimulants is one of the ways to reduce the harmful effects of non-biological stresses, increase seed germination, uniform appearance and increase their yield and quality. The present study was carried out to investigate the effect of different concentrations of chitosan on seed germination and some biochemical traits of sweet corn under osmotic potential conditions.
 Materials and Methods: To investigate the effect of chitosan and osmotic stress on germination and biochemical parameters of sweet corn, a factorial experiment was conducted in a completely randomized design with four replications at the Seed Technology Laboratory, Faculty of Agriculture, Yasouj University in 2017. The first factor was osmotic stress at 0, -3, -6, and -9 bar osmotic potentials and the second factor was pre-treatment at five levels of chitosan zero, 0.25%, 0.5%, 0.75% and 1% and one level of distilled water. The seeds were immersed in the desired solutions of chitosan for 3 hours at 25 °C and under dark conditions, and then the pre-treated seeds were germinated under standard germination condition. In each petri dish, 25 seeds were placed on a filter paper and osmotic potential was applied using polyethylene glycol 6000. Seed germination was carried out in the germinator at 25 ± 1 ° C for 7 days under dark conditions. The germination traits and biochemical traits were measured according to standard methods.
Results: Osmotic stress reduced germination percentage and germination rate, seedling vigour length index, germination uniformity coefficient, allometric coefficient, and soluble protein content and also increased the mean germination time, proline, soluble sugar content and hydrogen peroxide. Pre-treatment of seeds with a concentration of 0.5% chitosan increased protein, proline, and soluble sugars content at all osmotic stress levels. At the osmotic stress levels, the highest and lowest levels of hydrogen peroxide respectively were observed in 0.5% chitosan treatment and distilled water treatment. The results showed that pre-treatment with 0.5% chitosan increased germination percentage and rate and seedling vigour length index, and also reduced the mean germination time and malondialdehyde. Pre-treatment of seed with zero and 1% chitosan led to reduction in some of the germination and biochemical traits in comparison with 0.25, 0.5, and 0.75% chitosan.
Conclusions: The results showed that seed treatment with 0.5% chitosan could reduce the harmful effects of osmotic potential on some germination and biochemical traits in sweet corn seedlings and improve seedling growth.
 
Highlights:
1-Chitosan increases the germination percentage and germination rate.
2-Chitosan increases soluble sugars, proline, and soluble protein.
3-Chitosan reduces the amount of malondialdehyde and hydrogen peroxide.

Extended abstract
Introduction: Camelthorn (Alhagi maurorum) has a high tolerance to salt and water stresses, and its forage quality is greater than cereal straw and is equal to alfalfa. Seeds of camelthorn do not germinate easily due to the hard seed coat. Therefore, camelthorn cultivation as an agricultural crop needs more research, especially on breaking seed dormancy and increasing germination. Despite numerous studies about camelthorn as a weed, there are few studies on evaluating agronomic factors of camelthorn as a field crop. Hence, in this study, some aspects of germination and salinity tolerance of camelthorn were examined.
Materials and Methods: In this research, different aspects of camelthorn germination were examined at the National Salinity Research Center in 2018. In the first experiment, different pretreatments including control, sandpaper, hydro-priming, hot water, and sulphuric acid were assessed. With the selection of sulphuric acid as the best treatment, varying durations (0, 5, 10, 15, 20, and 25 min) and concentrations (98% and 75%) of sulphuric acid priming were compared in the second and third experiments. In the fourth experiment, the seeds collected in 2018 were compared with the seeds collected in 2017 and 2016. The effect of different salt stress levels (0, 6, 12, 18, 24, 30, and 36 dS m^-1) was evaluated on camelthorn germination and early growth in the fifth experiment. In the sixth experiment, lighting regimes including continuous dark, continuous light, and an alternative period of dark- light were examined and in the seventh experiment sibling factors (together and individual seeds) were evaluated. Seed germination and seedling length were calculated and salinity tolerance threshold levels and 50% reduction threshold were estimated.
Results: The results of the first experiment showed that the highest germination percentage was obtained in sulphuric acid priming (56.6%), which was six folds greater than the control. In the second experiment, it was shown that the highest germination percentage (81.1%) and seedling growth (5.7 cm) was observed in sulphuric acid priming 98% for 25 min. Important note was that these results were related to domestically produced sulphuric acid, and the highest germination and seedling growth were observed in 75% concentration for the imported sulphuric acid. In the fourth experiment, it was found that at least 3 years of seed longevity had no significant effect on seed germination. Considerable losses in germination and growth were observed from 30 dS m^-1 salinity level; however, germination did not completely stop even at 36 dS m^-1 salinity. In the sixth and the seventh experiments, it was found that there were no significant differences between seeds germination in the continuous dark, continuous light, and an alternative period of dark- light as well as between individual and together seeds. So, camelthorn seed is not photoblastic and had no negative sibling factor.
Conclusions: Generally, it was concluded that the best method for improving germination is priming with sulphuric acid 98% (internal) or 75% (imported) for 25 min. According to achievement of high germination in sulphuric acid pre-treatments (chemical scarification), it seems that seed dormancy in camelthorn is presumably physical. Furthermore, although the salinity tolerance threshold of this plant is estimated 14.2 dS m^-1, it can germinate minimally even in very higher salinity. Light salt stress not only decreases the germination of this plant but also is necessary for growth promoting. Based on the high salinity tolerance of camelthorn in the germination stage, its cultivation in haloculture systems is recommended for more investigation.

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

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: Without a doubt, plant hetrotoxicity is one of the important factors in determining the distribution and abundance of some species in plant communities. Thus, the purpose of this experiment was to evaluate the effect of phenolic composition obtained from the methanol extract of Echinochola crus-galli on germination traits and cytogenetic behavior of rice.
Materials and methods: This experiment was done to assess hetrotoxic potential of various concentrations (0, 0.024, 0.048, 0.076 and 0.1 mM) of the phenolic composition obtained from the methanol extract of whole-organ of E. crus-galli on germination traits of rice as well as mitosis division of meristematic cells of radicle in a completely randomized design. To extract thephenolic composition, warm extraction method using a methanol solvent was used. For studying mitosis division, first rice seeds were germinated. Then, each of the steps such as fixation, hydrolysis, staining, squashing and microscopic studies were done on the end of the radicle. Mitosis indices and percentage of mitosis inhibition were calculated and also percentage of each of chromosomal abnormalities at four stages of prophase, metaphase, anaphase and telophase as compared to total cells was calculated.
Results: The lowest percentage and rate of germination and relative germination were found in two concentrations of the 0.076 and 0.1 mM of phenolic composition of E. crus-galli, so that no germination was observed in these treatments. In this study, mitosis division was normal in control samples, so that the rice plant included 12 chromosomes in the metaphase stage. Also the chromosomes were normal in the telophase stage and chromosomal abnormalities were not observed in meristem cells of radicle tip of the control. The lowest value of mitosis indices and the number of dividing cells were related to the concentration of 0.048 mM wuth 30.19 and 385 cells, respectively. In the present study, chromosomal abnormalities in the stages of metaphase, anaphase and telophase were increased with increasing concentration of phenolic composition, and were 28.85 and 16.95% in 0.048 mM concentration of phenolic composition, respectively. The most chromosomal abnormalities were of sticky and laggard type, which were related to the concentration of 0.048 mM of phenolic composition with 39.83 and 32.25%, respectively. The highest number of chromosomal bridges and clumping were obtained in 0.024 mM of phenolic composition with about 19.27 and 29.83%, respectively.
Conclusion: In this study, phenolic composition obtained from the methanol extract of E. crus-galli had asignificant inhibitory effect on germination traits and mitosis division in root tip cells of rice. Thus, the amount of E. crus-galli residues in the field should be considered in direct and indirect cultivation of rice.

Highlights:
1-Difference in impact of the phenolic composition obtained from the methanol extract of Echinochola crus-galli on germination and reduced cytogenetic behavior of rice is related to their threshold concentration.
2- It is advised to cultivate varieties of rice resistant to the remnants of harmful compounds of E. crus-galli as direct cultivation or under nursery condition.

Extended abstract
Introduction: Legumes are the most important source of plant protein and Mung bean has a high nutritional value for humans, as it produces seeds containing high protein percentage. The major problem of salinity in seed germination of higher plants is due to excessive amounts of sodium chloride, osmotic pressure, disruption of nutrient uptake and transport, and direct effects of ionic toxicity on the membrane and enzymatic systems that in turn reduce germination. External use of methyl jasmonate can modulate the effects of various stresses, such as salinity and drought, by increasing the antioxidant activity of the seed. Therefore, the purpose of this research was to evaluate the effect of methyl jasmonate and salinity stress on germination and enzymatic properties of Mung bean.
Material and Method: This study was conducted as factorial based on a completely randomized design with three replications during 2015-16 at the laboratory of Department of Agronomy, Tarbiat Modares University. The experimental treatments included four methyl jasmonate solution (0, 50, 100 and 150 mM) and four salinity stress levels (0, 2, 4 and 6 dS/m salinity from NaCl). Petri dishes were placed in a germinator at 25 ° C and in full darkness for 14 days. In this experiment, germination rate and percentage, time to reach 50% germination, alpha and beta amylase, catalase and peroxidase were measured.
Results: The results of the experiment showed that the lowest rate of slope and final germination percentage were obtained in 50 and 100 mM solutions of methyl jasmonate. In terms of T50, an increase of 4.7 days was observed per one dS/m increase in salinity stress and the lowest T50 was estimated at a methyl jasmonate solution concentration of 78.68 mM. In terms of the activity of germination enzymes, reduction of 0.031 μmol/ml/min per 1 dS.m increase in salinity stress and the highest amount of α-amylase were estimated 72.6 μmol/ml/min at a methyl jasmonate solution concentration of 73.33 mM. Also, the lowest activity of β-amylase enzyme was 0.79 μmol/ml/min at a concentration of 5.6 dS/m salinity stress and the highest activity of β-amylase enzyme was estimated to be 1.7 μmol/ml/min at a methyl jasmonate solution concentration of 86.67 mM. The highest activity of catalase (25.7 ∆A/mg protein/min) was observed at 14.72 dS/m salinity stress and the lowest activity of catalase enzyme (8.9 ∆A/mg protein/min) was estimated at 5.88 mM methyl jasmonate solution. The highest activity of peroxidase enzyme (22.06 ∆A/mg protein/min) was at 24.3 dS/m salinity stress and the lowest activity of the enzyme peroxidase (2.5 ∆A/ mg protein/min) was determined at a methyl jasmonate solution concentration of 266.66 mM.
Conclusions: In general, pre-treatment of methyl jasmonate can reduce the germination time, increase the rate of germination and reduce the oxidative stress in salt stress conditions by improving the activity of germination enzymes, increasing the activity of enzymes, increasing the activity of hydrolyzing enzymes and increasing the easy availability of seedlings to nutrients during germination.

 
Highlights:
1- Germination rate and percentage and morpho-physiological changes of Mung bean seed as affected by methyl jasmonate were investigated.
2- The role of alpha and beta amylase germination enzymes in accelerating the production of Mungbean seedlings under saline conditions were estimated.
3- Methyl jasmonate- induced catalase and peroxidase enzymes activity in resistance to salinity stress were estimated.

Extended Abstract
Introduction: Seeds, like other materials, are hygroscopic and exchange moisture with their surroundings. The changes in the moisture of seeds during storage depend on their hygroscopic nature and this feature plays an important role in determining the seed quality and longevity. Furthermore, studying the hygroscopic characteristics if seeds can be useful in seed storage studies as well as in commercial applications such as drying and seeds processing. Therefore, in this study, the relationship between seed moisture content and relative humidity in seed of rapeseed cultivars was studied.
Material and Methods: In this study, the relationship between the ambient relative humidity and seed moisture content of three rapeseed cultivars at 10, 20 and 30 °C was investigated using hygroscopic equilibrium curves. Therefore, water desorption and absorption curves were studied separately. Water absorption and desorption curves were obtained by drying the seeds at 1% relative humidity and seed hydration at 100% relative humidity, respectively, followed by transferring the seeds to different relative humidities at different temperatures and finally determining the equilibrium moisture content of the seeds. It should be noted that glycerol and sulfuric acid solutions were used to creation different relative humidity. Finally, the relationship between seeds moisture content against the relative humidity was quantified by fitting the D’Arcy-Watt equation.
Results: The results indicated that the seeds moisture content varied in cultivars and temperatures at different relative humidities. Also, there was a difference between water desorption and absorption curves in all cultivars and temperatures; desorption curves were generally higher than water absorption curves. The greatest difference among the cultivars regarding seed moisture content was observed at 100% relative humidity, and this difference was less severe at lower relative humidities. Also, the highest seed moisture content of rapeseed cultivars was observed at 20 °C and 100% relative humidity, and the lowest seed moisture content was recorded at 30 °C and 1% relative humidity.
Conclusions: According to the results, it was found that the relationship between seed moisture content and relative humidity followed a sigmoidal function, and this relationship would also vary depending on cultivar and temperature. There was also a difference between the adsorption and desorption curves, which is called "hysteresis", and showed that the seed moisture content at a constant relative humidity was generally higher in the state of dehydration compared with that in the state of hydration. Due to this event, desorption curve is situated higher than the absorption curve.

Highlights:

1. Response to hygroscopic equilibrium curves in seeds of different rapeseed cultivars was compared.
2. Sulfuric acid and glycerol solutions were used to create different relative humidity.

Extended abstract
 Introduction: One of approaches to reach sustainable agriculture is to exploit crop diversity, especially in legume species. Since Melilotus spp. (sweet clover) is a forage crop with a suitable yield especially in the marginal lands; therefore collection and characterization of this germplasm is the first effective step for its conservation and utilization in the country. Few accessions of Melilotus genetic resources had been collected in the National Plant Gene Bank of Iran, before this study.
Materials and Methods: Sweet clover genetic resources were collected all over the country using standard descriptors during two years. Twenty-six characteristics of collection sites were recorded and their descriptive statistics were estimated. The collected materials were planted in an experimental field to identify their life cycle. The seeds of collected germplasms were conserved in mid (2-4 °C)- and long (-20 °C)-terms conditions for further using.
Results: A total of 258 accessions were collected. The geographical altitude of plant origin differed from -11 m in Babolsar to 3090 m in Noor Abad in Lorestan. The materials were mostly collected from non-saline habitats. However, eight accessions were collected from mid to high salinity locations. Taxonomically, M. albus, M. officinalis, and M. indicus were identified with a number of 21, 201 and 36 accessions, respectively. M. dentatus and M. sulcatus, which have been mentioned in the former researches in Iran, were not collected in the recent study.
Conclusion: The collected germplasms from marginal lands (saline, low drainage and low fertility lands) may be tolerant to such marginal lands, therefore they can be exploited for the future research. All M. indicus species were annual; whereas there were annual as well as facultative and obligate biennial accessions in the two other species. Lack of access to M. dentatus and M. sulcatus may be an alarm that they may be threatened species in the country. Collected materials in this study along with the former collection in the Iranian National Plant Gene Bank (80 accessions) have provided high potentials of Melilotus genetic resources for exploitation in the further.

Highlights:
1- The three-fold increase in the Melilotus germplasms in the ex-situ conservation system.
2- Alarm for M. dentatus and M. sulcatus which may be threatened with extinction in the country.

Extended Abstract
Introduction: Guar (Cyamopsis tetragonoloba L.) is a plant from the legumes family. Guar gum is obtained from endosperm in guar seeds. Guar gum is used in many industries such as pharmaceutical and food industries, paper, mining, oil and drilling, textiles, and explosives industries. Modeling is a method that is widely used in predicting plant growth stages and determining the required thermal units in each growing stage, especially germination.
Considering the important therapeutic and industrial uses of guar and the lack of sufficient information and reports to determine the cardinal temperatures of this plant, this study aimed to investigate the effect of temperature on germination traits and early seedling growth and predict the cardinal temperatures (minimum, optimal and maximum) of germination for this plant.
Materials and Methods: This research was carried out at the Seed Sciences and Technology Laboratory of Agricultural College of Sarayan, the University of Birjand in 2017. Experiments were carried out in a completely randomized design with 8 levels of temperature treatments (5, 10, 15, 20, 25, 30, 35, and 40°C), with 5 replications. Germination percentage, daily germination speed, mean daily germination, plumule length, root length, and seedling length were calculated. Cardinal temperatures of germination were calculated using regression analysis with the aid of the proposed models (logistic, two-way, quadratic, and third-order polynomials) using germination speed. The data were analyzed using SAS software and the comparison means were done by Duncan's test at a probability level of 5%. Sigma Plot software was used to plot the germination rate against temperature graphs (for fitting different models).
Results:  The results showed that the effect of different temperature levels on the percentage, speed and mean seed germination was significant (P <0.05). According to the results, the lowest values for percentage, speed, and average germination were obtained at 5, 10, and 40°C, and the highest germination speed was observed at 15 °C and also the highest percentage of germination and average germination was observed at 35°C. The results of the effect of different temperature levels on seedling growth showed that the effect of temperature on the seedling length, stem, and root length was significant (P <0.01), so that the lowest values related to seedling length, plumule, and radicle was found at 5, 10 and 40°C, and the maximum seedling and plumule length were 30°C.
Conclusion: Quantification of the gauge seed germination reaction to different temperature levels was carried out using four dual-functions, logistic, quadratic and triple polynomials. The second-order multitasking regression model, based on the coefficient of explanation (R²) and the amount of deviation, had a suitable and significant fit with the data related to germination rate against the independent temperature variable. Based on the parameters of the model, the optimum temperature was obtained at 26.05°C and the minimum and maximum temperature of guar germination were calculated to be 6.09 and 40°C.

Highlights:

1. Cardinal temperatures of guar seed germination were predicted.
2. Based on cardinal germination temperatures, the planting date of guar became predictable.