Iranian Journal of Seed Research

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: 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: 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: Seed deterioration is a physiological phenomenon that affects all germination, biochemical, cytological, and growth characteristics of plants. So it is necessary to use seed vigor enhancement methods to resolve these problems. One of these methods is the application of seed priming techniques to reduce deterioration effects. Therefore, the present study aimed to investigate the effect of different pre-treatments by using Nano-zinc, ascorbic acid, humic acid, gibberellin and KNO₃ on germination indices and chromosomal aberration of aged onion seeds.
Material and Methods: This experiment was performed as factorial based on a completely randomized design with 3 replications (100 seeds per replicate) in the faculty of agriculture at Urmia University. The first factor was the level of aging at 4 levels (control, 12h, 24h, and 48h) and the second factor was seed pre-treatments at 6 levels (control, Nano-zinc (30 mg), ascorbic acid (100 mg), humic acid (150 mg), gibberellin (200 mg/l) and KNO₃ (0.1%). Given that the germination was not similar at different levels of aging, the seeds were germinated at control and 12h of aging after 6 days, at 24 and 48h of aging after 8 and 9 days, respectively. Hence, germination percentage, germination rate, normal seedling, mean germination time, and seed vigor were evaluated after the mentioned times. Chromosomal aberrations were also examined.
Results and Discussion: The results showed that the interaction effect of aging and seed pre-treatments on germination indices were significant at %1 probability level. By increasing the period of aging, all germination characters decreased significantly. The highest germination percentage (80%, 70%, 50%) and germination rate (5.350, 3. 316, 1.525 seed/day) were obtained by using Nano-zinc At 12h, 24h and 48h ageing levels. Nano-zinc and gibberellin had the highest effect on seedling vigor and normal seedlings. Seedling vigor increased significantly by using Nano-zinc and gibberellin at 12h (1133, 933.9), 24h (742.9, 692), and 48h (369.9, 323.3). The chromosomal aberration was reduced by using pre-treatment.
Conclusion: In this study, the most effective pre-treatments to improve germination characteristics and reduce chromosomal aberrations were gibberellin (200 mg/l) and Nano-zinc (30 mg). Therefore, it can be stated that the use of Nano-zinc and gibberellin as seed pre-treatments can significantly reduce the effects of deterioration on onion seeds.

Highlights:
1- Nano-Zinc and gibberellin were the most effective priming treatments on seed germination and growth characteristics of the aged onion seeds.
2- Priming treatment reduced the percentage of chromosomal aberration in the onion and the highest effect was obtained using Nano-zinc and gibberellin.

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.

Extended Abstract
Introduction: Salinity is one of the most harmful factors in the arid and semi-arid regions in the world that influences crop production. Micro-organisms can play an important role in adaptation strategies of plants to stress and by producing of plant growth promotion hormones such as cytokinin, gibberellic acid, auxin, amino acids, and vitamins of B groups help to more growth of the plant and have an important role in increasing of tolerant in plants in unsuitable environments.
Material and Methods: This experiment was established as factorial in a completely randomized design with three replicates at Shahed University of Tehran. The treatments included salinity in four levels (0, 40, 80, and 120 mM NaCl) and biological pre-treatment at eight levels (control: non-inoculation), inoculation with Trichoderma harzianum fungus strain BI, with inoculation with azotobacter bio-fertilizer, inoculation with phosphate bio-fertilizer, inoculation with both bio-fertilizer, a combination of fungus and azotobacter bio-fertilizer, a combination of fungus and phosphate bio-fertilizer, inoculation with fungus and both bio-fertilizer). In this experiment, germination indices, photosynthetic pigments, proline, sodium, and potassium amount, starch, carbohydrate, electrical conductivity, and soluble protein were studied.
Results: The result showed that the interaction effect of biological pre-treatment and salinity was significant on all indices except chlorophyll b and anthocyanin. Treatment of phosphate bio-fertilizer had maximum positive effect on germination percent with increasing salinity. In the co-application of fungus and azotobacter bio-fertilizer treatment, the amounts of chlorophyll a, b, and total chlorophyll in different levels of salinity were more than the other treatments and were incremental with further increasing of salinity level. The highest amount of potassium (4.10 mg/g FW) obtained in the co-application of a fungus with azotobacter bio-fertilizer under 40 mM of salinity and showed 22.02 percent increase in comparison to control. With rising salinity, fungus treatments were the most effective in preventing more increasing sodium amount and azotobacter bio-fertilizer in preventing more reducing potassium. The number of soluble proteins was the highest amount (13.09 mg/g FW) in the co-application of fungus and both bio-fertilizer and showed 38% increase compared to control at the same level of salinity.
Conclusion: The uses of microorganisms reduced the negative effect of salinity and led to the increase of potassium in shoots. Also, utilization of microorganism led to lower electrical conductivity at the highest salinity level compared to control and thus, positively affected germination.
 

Highlights:
1- The effect of bio- primed bacteria and fungus on physiological traits of Pumpkin was investigated seedlings under salinity.
2- Threshold of tolerance of pumpkin seedlings to salinity was improved by increasing K content and reducing Na under bio- primed treatments.
3- Osmolite components of pumpkin seedlings increased under bio- primed treatments.

Extended Abstract
Introduction: Water deficit stress is one of the important factors affecting seed germination. This stress decrease germination rate and affects germination percentage under high levels as well. Seed priming improves germination by changing metabolic activities before radicle emergence. This investigation was conducted to evaluate the effect of seed priming by salicylic acid on the emergence index and grain weight of spring wheat under water deficit stress.
 Material and Method: These experiments were conducted as factorial based on the completely randomized design with three replicates in the greenhouse of the Faculty of the Agriculture Sciences University of Mohaghegh Ardabili. Experiment treatments included different salicylic acid concentrations (0, 1, 2 mM) and water deficit stresses (25%, 45%, 65% and 85% Field capacity).
Result: According to results, emergence index (emergence percentage and emergence rate, uniformity emergence, and times to 10, 50, and 90% emergence) was influenced at 1% by water deficit stress. The effect of salicylic acid was significant on the emergence index. The interactions of water deficit stress and salicylic acid were effective at 1% on emergence uniformity and time to 90% emergence. Changes in plant height and heading rate were lower under water deficit stress. Also, both slope (b) and maximum content (a) decreased by water stress (22% and 7%). Priming by salicylic acid at 2 mM had the highest effect on both traits and resulted in a decrease in their slopes (17% and 13%) and an increase in their maximum content (34 and 10%). Plant dry weight was influenced by the interactions of water deficit stress and salicylic acid at 5% level. The plant's final height and grain weight was influenced by water deficit stress and salicylic acid. The highest grain weight was obtained at 80% and 60% field capacity with means of 0.79 and 0.75 g, which had no significant differences with eachother. The heights grain weight (0.72 g) was obtained by application of  2 mM salicylic acid which led to an increase of 250% compared to control.
Conclusions: Overall, we showed that water deficit stress resulted in decreased emergence rate and emergence percentage of wheat and finally declined plant growth and grain weight. Application of salicylic acid in seed priming resulted in improvement in the emergence index, growth, and grain weight of wheat. Also, the highest grain weight was observed at 2 mM concentration and it can be considered as the enhancing treatment.

Highlights:
1- Response of plant growth stage to stress was quantified using nonlinear regression
2- Relationship between emergence and grain weight was investigated under stress and priming by salicylic acid.

Extended Abstract
Introduction: It is obvious that all plants adopt mechanisms to control NaCl accumulation because sodium chloride is the most soluble and most abundant salt. Binweed (Convolvulus arvensis L.) is among the ten widespread noxious weeds in the world that it is reproduced by seed, horizontal lateral root, and rhizome. Because of the extensive underground root system of the bindweed with abundant buds and established root reserves, binweed competes more tolerant than crops under salinity and drought stress. More information on morphophysiological traits of binweed under salinity conditions and comparison of salinity tolerance index between germination and seedling can also be contributed to the most effective management. In order to investigate the germination and seedling growth characteristics of binweed two experiments were conducted separately under salinity stress.
Materials and Methods: Germination experiment was done in a completely randomized design with 9 levels of salinity stresses include 0 (control), 5, 10, 15, 20, 25, 30, 35, and 40 dS.m^-1, with four replications in the lab. The seedling experiment was performed in a random complete block design consisted of five levels of salinity (tap water, 10, 20, 30, and 40 dS.m^-1) with three replications as the pot in a non-shade greenhouse of Agricultural College of Shahid Chamran University of Ahvaz.
Results: The results showed that with raising salinity, percentage germination and vigure index of seed declined, but Radicle/ Plumule ratio rose. After two weeks, in response to salinity a decrease in root and shoot characteristics of the seedling was observed. Salinity stress data were fitted to a three-parameter logistic for seedling stage showed that the salinity levels higher than 7.86 dS.m^-1 led to 50 percent reduction in tolerance index. It was found that 19.84 dS.m^-1 caused 50% decrease in the tolerance index at germination stage. Sufficient tolerance index –growth stage variation in response to salinity was found which suggests that bindweed tolerance to salinity at germination stage is about 3 times more than that of seedling stage.
Conclusions: Radicle/ plumule ratio at germination stage and root lateral branches at seedling stage increased in concentrations of up to 25  and 20 dS.m^-1, respectively. It seems the maintenance of root area and branches in response to increased salinity provide an acceptable mechanism of salinity tolerance for binweed. According to the three-parameter logistic model, the salinity tolerance of bindweed at germination and seedling stages was estimated at 20 and 8 dS.m^-1, respectively.
Keywords: Logistic model, Root lateral branches, Relative water content, Salinity tolerance index
Highlights:
1 Salinity tolerance of bindweed was investigated in germination and seedling growth.
2- Salinity tolerance index was compared between germination and seedling of bindweed and was introduced a proper trait which is more effective to pointing salinity tolerance.
3- The best sigmoidal model based on salinity criterion was introduced for salt tolerance index of bindweed.

Extended Abstract
Introduction: One of the biological methods of weed control is the use of allelopathic substances or herbal secretions that have the potential to inhibit growth weeds. Wheat allelopathic studies include the study of wheat allelopathy against other crops, weeds, pests and diseases, isolation and identification of allelopathic compounds, the effects of wheat toxicity on self-storage and management of wheat residues. Wild mustard (Sinapis arvensis) is a problematic weed in the country, especially in Golestan province. The present study was conducted to investigate the allelopathic potential of four wheat cultivars to use those cultivars in integrated weed management system to reduction growth mustard weed.
Materials and methods: A factorial experiment was conducted in completely randomized design with three replications at Physiology Laboratory of Golestan Agricultural Research Center. Treatments included concentrations of 0, 2.5, 5, and 7.5% aqueous extract of aerial and underground organs of four wheat cultivars (Morvarid, Moghan, Tajan, and Arta) with 6000 polyethylene glycol treatment in four concentration (zero, 2.5, 5, and 7.5 percent). Three-parameter logistic model was used to evaluate the allelopathic potential of wheat genotypes for reducing the percentage of wild mustard germination and liquid chromatography (HPLC) was used to determine the phenolic acids composition in wheat cultivar extract.
Results: Extract of shoot of all wheat cultivars reduced root length of wild mustard in comparison of control. Wheat cultivars reduced shoot length of wild mustard by 28% to 51% compared to control. The highest reduction in mustard shoot length was obtained from the Morvarid extract. Increase in shoot extract concentration of Arta to 7.5%, reduced root and shoot dry weight as 47 and 29% in compare of control treatment and Moghan cultivar in the same concentration (7.5%) caused reduction in root and shoot dry weight with 68 and 41% respectively. The highest reduction in germination indices of wild mustard was obtained from high concentrations of Morvarid and Moghan wheat extract. It was also found that with increasing concentration of polyethylene glycol (PEG) growth indices and germination components of wild mustard seed decreased, but this decrease was not significant. This confirms that the osmotic potential of the extract concentration is not involved in the exacerbation of the allelochemical effect and the likelihood of osmotic effect seems poor. In total, Morvarid cultivar with 25.34 mg phenolic acid content had the highest phenolic acid concentration, which was approximately three times more than that of Tajan, 1.5 times Moghan and three times of Arta cultivar. Morvarid cultivar had higher concentration of vanillic acid and ferulic acid than the other three cultivars. Overall, the least allelopathic effect was observed in Tajan cultivar and the most allelopathic effect was in Morvarid cultivar.
Conclusion: Among the cultivars studied, the highest inhibition was related to Morvarid cultivar. The results also showed that the highest amount of inhibition was related to shoot extract so that the root extract inhibition was less than the shoot on studied traits. In general, the results of the present study showed that some wheat cultivars have greater inhibitory potential against wild mustard weed, which can be used in breeding programs to produce cultivar with high allelopathic potential. Awareness of this issue is more important, especially in sustainable weed-management. Therefore, it is suitable to perform comprehensive studies on their allelopathic potential so that they can be used in agriculture, including combating with weeds, pests and plant diseases, breeding crop and horticulture, design herbicides and pesticides that is provide environmentally friendly, safe, and biodegradable.

 
Highlights:

Extended Abstract
Introduction: Germination is one of the most important stages of plant growth that determines the durability, establishment and final yield of crops and in regions that due to drought conditions the growth of plant encounters with problem, improving germination traits count as one of the important breeding strategies. The present study was designed to determine the effect of different levels of osmotic stress on germination and seedling traits of some bread wheat cultivars cultivated in cold regions of Iran.
Materials and Methods: In order to investigate the effect of different levels of osmotic stress on germination characteristics of bread wheat cultivars cultivated in cold regions of Iran, a factorial experiment was conducted based on a completely randomized design with 3 replications in which, the first factor consisted of 20 bread wheat cultivars (including rain fed cultivars as well as end-of-season water stress tolerant varieties) and the second factor consisted of 3 levels of osmotic stress (non-stress, -3 and -6 bar stress). Seedling traits such as coleoptile length, shoot length, shoot weight, root length, root weight, root / shoot ratio, root growth angle, germination speed and the germination stress index (GSI) were evaluated. For the experiment concerning the yield comparison, 20 cultivars mentioned above were compared under non-stress and terminal drought stress conditions.
 
Results: The results showed that the ratio of root/shoot length and weight and shoot weight had the highest sensitivity and the lowest number of roots to osmotic stress. Increasing root length as root weight decreased with increasing stress showed that roots became longer and thinner due to stress. Among the genotypes, Saein, Zare, Pishgam, Sadra, Baran and Mihan had desirable traits and CrossMV17, Homa, Orum and Cross Azar2 had no desirable germination traits. In non-stress conditions, 11 genotypes had high coleoptile length including Hashtrood, Azar 2, Saein, CD62-6, CD91-12, Mihan, Baran, Heydari, Homa, Cross Azar 2 and Zare genotypes. At 3 bar stress, 11 genotypes had the highest coleoptile length, with the highest values being assigned to Hashtrood, Heidari and Saein. At 6 bar stress, CD91-12 and CD62-6 lines, Hashtrood, Homa, Pishgam, and Zare had the highest coleoptile length. At 3 bar stress cross Azar 2, Saein, CD62-6, Gascogen and HD2985 demonstrated the highest germination rate. Furthermore, Cross Azar2, HD2985, Gascogen, CD62-6 and Saein led to the best results, respectively. However, in both 3 and 6 bar stress conditions Saein, Cross Azar2, CD62-6 and HD2985 were superior for germination stress index (GSI). For grain yield under normal conditions, Gascogen, Heidari, Pishgam, Orum and Zarrineh had the highest yield and Baran, HD2985, C-88-4, C-9011 and Cross Azar2 were placed next. Under stress conditions Baran, Gascogen, HD2985, Cross Azar2, Heidari and Zarrineh consisted the highest performance. According to STI index Gascogen, Heidari, HD2985 and Zarrineh were the most tolerant genotypes to drought stress. Cluster analysis grouped the studied genotypes into 2 clusters, the first cluster comprising 13 genotypes Heidari, Mihan, HD2985, Baran, Pishgam, Hashtrood, Cross Azar 2, CD62-6, Gascogen, Azar 2, Saein, Sadra and Zare. The second cluster consisted of 7 genotypes C-88-4, Zarineh, C-90-11, Orum, CD91-12, CrossMV17 and Homa. Genotypes of cluster 1 were superior in terms of germination traits such as shoot length, coleoptile length, root length and root weight and reduced root/shoot ratio.
Conclusion: Significant differences in all studied traits among genotypes indicated sufficient genetic variation for selection in germination traits. Results showed that Saein, Zare, Pishgam, Sadra, Baran and Mihan cultivars had desirable germination traits and were superior to other genotypes.

Highlights:
1- The tested genotypes are either newly named or advanced lines and have not been studied for germination traits.
2-The growth angle trait of seed roots through filter paper has received little attention in studies.

Extended Abstract
Introduction: Catharanthus roseus is regarded as a medicinal ornamental plant. This plant has anti-cancer, anti-hypertensive, anti-diabetes, and antimicrobial properties. Catharanthus has a fairly long vegetative period due to its slow initial growth. The long growth period of the plant is considered one of the limitations in its cultivation on a larger scale. By using plant growth regulators such as salicylic acid (SA) in the imbibition phase and pre-treatment, an increase in seed activity and the seedling growth of many crops is observable. Also, jasmonic acid (JA) plant growth regulators play an important role in seed germination and plant growth. Regarding the long growth period of this plant, the small size of the seed, and poor establishment in the field with semi-heavy and heavy textured soils, the present study aimed to evaluate the effect of seed priming with SA and JA in different concentrations and periods on improving Catharanthus roseus seed germination indices.
Materials and Methods: The studies were conducted as a factorial experiment based on a completely randomized design with three replications at the Laboratory of Seed Science and Technology of Shahed University, Tehran, in 2017. Treatments included five different concentrations of SA (0, 0.01, 0.1, 0.5, and 1 mM), concentrations of JA (0, 1, 10, and 100 µM) and five periods of time (0, 6, 12, 24, and 48 hours). At the end of the experiment (10 days) traits such as germination percentage, germination rate, mean germination time, mean daily germination, germination value, seed length vigor index, seed weight vigor index, seedling dry weight, shoot dry weight, radicle dry weight, radicle length, shoot length, and seedling length were measured.
Results: The results indicated that the effect SA, JA, and time were significant on germination percentage, germination speed, mean germination time, mean daily germination, germination value, seedling length, seedling length vigor index, seedling weight vigor index, and radicle dry weight. The best times for pre-treatment with SA were 24 and 48 hours. Among the applied concentrations of SA, 0.5 and 1 mM concentrations showed the best results. Also, the best time and concentration for pre-treatment with JA were 12 and 24 hours and 10 µM.
Conclusions: The results of this study showed that using SA and JA for seed priming improved seed germination components. In addition to the pre-treatment concentrations of SA and JA, the duration of seed contact with growth regulators is important. It was observed that there was a significant difference among the different priming times, therefore, it can be stated that seed pre-treatment time is one of the important factors of seed priming, and the determination of proper priming time prevented the negative effect of pretreatment on germination and seedling growth in primed seeds.

Highlights:
1- The optimum concentrations of salicylic acid and the priming time of the seed were determined.
2- The appropriate concentrations of jasmonic acid and the optimum time for pretreatment of seed were determined.
3- The effect of growth regulators of salicylic acid and jasmonic acid on seed germination indices was evaluated.

Extended Abstract
Introduction: The weed invasion is one of the main yield-reducing factors in crops. They are potent competitors on vital resources which limits the availability of the resources for crops. Allelopathy is one of the weeds' abilities that commonly with inhibitory influences, affects plant communities' behavior. Therefore, the evaluation of these compounds' effects is important on crop plants. Also, the identification of allelopathic plants and their bioactive compounds can be a suitable approach to weed management. Thus, the aim of this study was the evaluation of the allelopathic potential of C. falcate on germination indices of wheat seeds and the mode of action of the extract on some enzyme activities. Furthermore, secondary metabolites in methanolic root extract were identified and reported.
Materials and methods: Germination and seedling experiments of Triticum aestivum var. Sardary seeds were tested by 0, 5%, 10%, 15%, and 20% concentrations of C. falcata root extracts based on CRD with four replications at the research laboratory of Maragheh University during 2018-19. Also, the influence of the extract was studied on enzyme activities of alpha-amylase, catalase, peroxidase, superoxide dismutase, and polyphenol oxidase. Furthermore, chemical compounds of the root methanolic extract identified by GC/MS instruments.
Results: Germination percentage and germination rate decreased significantly with the increase in the concentration of the extract, and germination stopped at concentrations above 15%. The results of seedling growth showed severe inhibitory effects of the extract on radicle and shoot organs of wheat seedlings that associated with reducing of the lengths and weights of the organs, and consequently, the vigor of seedling declined. The extract significantly reduced the activity of alpha-amylase, however, the activities of antioxidant enzymes first increased at low and medium concentrations but at high concentrations, the activities declined. The phytochemical analysis identified 62 compounds in the root of this plant that Octadecatrienal, Dihydro-4H-pyrazolo [3, 4-d] pyrimidin-4-one, Hexadecanoic acid, Hexadecanoic acid, 2-hydroxy-1 (hydroxymethyl) ethyl ester, Isopropyl isothiocyanate, and Cyclohexanone could be effective compounds on seed germination.

Conclusion: C. falcata had a very strong inhibitory effect on the seed viability and seed vigor of the wheat seeds. According to the results, the mode of action of the allelopathic compounds is induced by induction of oxidative stress and inhibition of seed reserves remobilization during germination. The high sensitivity of alpha-amylase activity to allelochemicals was detected in this experiment. The decrease in the activity of all studied enzymes at high concentrations of C. falcata root extract was also significant. Stearic acid and palmitic acid derivatives accounted for about 30% of the compounds, which are very likely to interfere with the activity of the enzymes.

 Highlights:

1. Allelopathy effects of C. falcata root extract on germination indices of wheat were studied.
2. Chemical compounds identified were in methanol extract of the plant roots of C. falcate.
3. Oxidative stress is induced by the allelochemicals of C. falcata.

Extended Abstract
Introduction: Salinity stress is one of the most important factors in decreasing crop yield. Crossing between cultivars and wild relatives is one of the methods to creating salinity tolerant plants that has led to the creation of new Tritipyrum cereals. Investigation of the effect of salinity stress at the germination stage is a reliable test in assessing salinity tolerance of many species; it reduces percentage and rate germination as well as decreases of root and shoots growth. This research aims to investigate the effects of different levels of salinity stress on germination of promising non-Iranian Tritipyrum lines and two wheat cultivars, Alvand (salinity tolerant) and Ghods (salinity sensitive).
Materials and Methods: The experiment was conducted in factorial based on the completely randomized design at the Faculty of Agriculture, Yasouj University. The first factor consisted of 13 Tritipyrum lines and two wheat cultivars and the second factor consisted of different salinity levels (240, 160, 80, 0 mM NaCl). After surface disinfection and seed culture in a petri dish, germination-related traits were measured until the 14^th day.
Results: The results showed that by increasing salinity level, germination rate and percentage, root length, shoot length, dry and fresh root weight, and shoot dry weight decreased. The highest percentage (79.79%) and rate (75.74 seed per day) of germination in stress and non-stress conditions were related to the Az/b line. The germination percentage of the Alvand tolerant cultivar (55.59%) was higher than 5 Tritipyrum lines but less than the other 7 lines, its germination rate (53.69 seed per day) was higher than 10 Tritipyrum lines. The percentage and germination rate of sensitive cultivar Ghods (40.98 and 36.87 seed per day, respectively) were lower than all Tritipyrum lines. Under salinity stress, the La/b line had the highest root length (7.77 cm) which was even longer than the root length of the Alvand tolerant cultivar (4.9 cm). The highest root dry weight (0.027 g) under stress conditions was related to the Ka/b line and the lowest root dry weight (0.013 cm) was related to the Ghods cultivar. Among germination traits, the highest and the lowest heritability were related to shoot length under stress and non-stress conditions and root fresh weight (under non-stress conditions) and root length (under stress conditions), respectively. Genetic variance of shoot length and germination percentage in non-stress conditions was higher than stress conditions and selection under non-stress conditions had a higher yield than stress conditions. Clustering of genotypes by cluster analysis divided the genotypes into four groups under normal and salinity conditions. Under salinity stress, the salt-tolerant cultivar was placed alone in the fourth cluster. The salinity-sensitive cultivar was also in the third cluster with the St/b line. The rest of the Tritipyrum lines were clustered in the first and second clusters, with (Ka/b)(Cr/b)F₆ hybrid line in the first cluster. Salt stress condition seems to have separated Qods from all Tritipyrum lines (except St/b), but under normal conditions, it did not indicate clustering accuracy of the studied genotypes.
Conclusion: The results of this study demonstrated salinity tolerance in the most simple and hybrid lines of this plant at the germination stage, among them (St/b)(Cr/b)F₃, (Ka/b)(Cr/b)F_6, and (Ka/b)(Cr/b)F₃ and La(4B/4D)×(b) and the simple lines La/b, Az/b and St/b were better than others. Therefore, these selected lines can be considered in further complementary studies.
 

Highlights:
1. The studied plant is new and needs to be examined at the germination level before introducing.
2. Simple lines with the hybrid lines of this new plant have been studied that can show the effect of crosses.
3. Grouping of lines for tolerance or susceptibility is done solely based on germination traits.

Extended Abstract
Introduction: Coneflower herbal medicinal plant is from the Asteraceae family, native to North America. Because of its immune-boosting properties, it is used to treat a variety of pathogens. The seed germination stage is one of the crucial and crucial stages in the growth cycle of plant species that can play an important role in the production process by optimal establishment of seedlings. Seed of Coneflower germinates and grows very slowly and weakly. Therefore, the use of some plant growth regulators, such as the gibberellin hormone, can play an important role in improving seed germination. The aim of this study was investigate the effect of hormone seed priming using gibberellin on seed germination quality of Coneflower.
Material and Methods: A factorial experiment was conducted based on the complete randomized design arranged with three replications. The experiment was conducted at the seed technology laboratory of Agricultural Sciences and Natural Resources University of Khuzestan, 2018. Experimental treatments were different concentrations of gibberellin (0, 50, 100, 200, 400, and 800 mg/l) as the first factor and the durations of seed priming (12, 24, and 48 hour) as the second factor.
Results: Results of in vitro studies showed that the interaction of gibberellin in priming time on percentage, rate and mean germination time, root and shoot length, seed vigor index, peroxidase activity at 1% and Seed soluble protein content was significant at 5% level. Seed germination quality and protein content increased by the application of 200 mg/l gibberellin for the 24 hours, whereas at the concentrations of 400 and 800 mg/l, gibberellin reduced germination quality and antioxidant enzymes activities. Results of stepwise regression models of antioxidant enzymes activity and protein content with germination indices showed that these traits were significantly entered into the prediction model. It was observed that in all traits except for the rate and the mean germination time, the amount of protein entered the prediction equation. In general, stepwise regression models predicted stem length and power index better than other traits and showed the highest coefficients in these traits with values of 0.85 and 0.83. Also, catalase and peroxidase activities were significantly correlated with rate and mean germination time only. The amount of soluble protein had a positive and significant correlation with all studied traits except germination rate and mean germination time. The highest correlation coefficients for protein content were obtained from longitudinal power index with correlation coefficient (r = 0.856).
Conclusion: Based on the obtained results, the best hormone priming treatment was 200 mg/l gibberellin for the durations of 24 hour.
 
Highlights:
1- The role of gibberellin hormone on seed germination traits Coneflower was evaluated
2- The effect of gibberellin hormone on the activity of antioxidant enzymes and soluble proteins during seed germination was investigated.

Extended abstract
Introduction: Seed is the most important sexual reproductive factor in plants that plays an important role in transmitting hereditary characteristics, plant distribution, and establishment in different regions. Seed germination as one of the most important and complex stages in the life cycle of plants is affected by genetic and environmental factors. Drought stress is one of the main barriers of crop plants and trees, production in many parts of the world, especially in arid and semi-arid regions such as Iran. The purpose of this study was to investigate the effect of drought stress on biochemical and seed germination indices of different seed lot of Ziziphus spina–christi as suitable medicinal species for controlling soil erosion in arid regions.
Materials and Methods: This experiment was conducted as a factorial based on a completely randomized design with four replications at the Seed Science and Technology Laboratory of Yasouj University in 2018. Experimental factors included Ziziphus spina–Christi seeds collected from the regions of Minab, Kazeroon, Masjed Soleiman, and Dehdasht and five water potentials including zero, -2, -4, -6, and -8 bar.
Results: In the present study, the effect of osmotic potential, seed lot, and their interaction were significant in each seed lot on germination (germination percentage, germination rate, seedling length, allometric index, longitudinal vigor) and biochemical (hydrogen peroxide, soluble protein content, Proline, catalase, and ascorbate peroxidase) indices of Ziziphus spina–christi. The results showed that except for allometric index response of all studied germination traits to osmotic potential was decreasing, Also with increasing osmotic potential, seed soluble protein was decreased and the amount of proline and activity of catalase and ascorbate peroxidase increased. With increasing osmotic stress, the root length was significantly increased, which increased the allometric coefficient of the seedling.
Conclusion: Germination and biochemical indices of seeds of all seedlots had significant changes with the reduction of osmotic potential and the reduction of osmotic potential was associated with reduced germination and plant establishment capability. These results can help us to recognize the prerequisites of germination and the development of the forests.

Highlights:
1- Germination indices of seeds related to several Ziziphus spina–christi seed lots were investigated under different water potentials.
2- Biochemical aspects related to seed dormancy in several Ziziphus spina–christi seed lots were evaluated.

Extended Abstract
Introduction: Medicinal herbs are of particular importance in the treatment and prevention of diseases. Indian Cheese Maker has strengthening, liver repair, anti-inflammatory properties and is useful in the treatment of bronchitis, asthma, wounds, neurological disorders such as Parkinson's and Alzheimer's. Evaluation of seed quality as a propagating organ and the most important input for crop production and medicinal products has a special place in seed production, control and certification. Studying germination and biological properties of seeds of medicinal plants and methods of breaking dormancy in them are among basic and primary studies of domestication of medicinal plants. In the meantime, scrubbing with abrasives changes the integrity of the seed shell and allows the seeds to be permeable to water and gases. The researchers stated that the dormancy of seeds containing inhibitory metabolic materials can be reduced by removing the seed shell through mechanical scarification and osmopriming. For this purpose, the effect of scarification and potassium nitrate on germination and enzymatic properties of Indian Cheese Maker was evaluated.
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. Potassium nitrate solution (0, 0.5, 1 and 1.5 mg.l^-1 from KNO₃), scarification (un-use and scarification with soft sanding) and osmopriming durations (8, 16, 24 and 32 hour) were experimental factors. The experiment was performed on Indian Cheese Maker seeds, landrace of Khash. Petri dishes were placed in a germinator at 25 ° C and in full lighting for 14 days. In this experiment, germination rate and percentage of germination, mean of germination time and daily germination, seed vigority, alpha and beta amylase were measured.
Results: The results of the experiment showed that in scarification, the highest germination percentage (69.47%) was obtained by seed priming at a concentration of 1.5 mg.l^-1 potassium nitrate for 19 hours under abrasion. In scarification, germination rate increased at 16 and 32 hour, 0.62 and 1.17 No.day^-1 for each mg.l^-1 of potassium nitrate. The highest daily mean germination (0.15) was observed at 1.5 mg.l^-1 potassium nitrate and 24 hour time and decreased to 8 hours mean germination time (7.39 days) by reducing pretreatment time. Also, the highest mean germination time (9.35 days) was observed in 32 hours pretreatment with potassium nitrate and the highest mean germination time in non-scarification condition (9.13 days) and in scarification condition decreased with mean of germination time (8.04 days). The activity of alpha and beta-amylase germination enzymes was affected by different concentrations of potassium nitrate and scarification and at high concentrations of potassium nitrate the activity of these enzymes decreased.
Conclusions: In general, application of potassium nitrate osmopriming, by improving the activity of germination enzymes and increasing seed germination properties of Indian Cheese Maker, increased the activity of hydrolyzing enzymes in the endosperm of germinated seeds, which reduced the mean germination time, increased germination rate and germination percentage. In general, seed scarification with low concentrations of potassium nitrate at 16 to 24 hours is recommended for breaking seed dormancy of Indian Cheese Maker.

 
Highlights:

1. Germination rate and percentage of Indian Cheese Maker seed were monitored by osmopriming and scarification.
2. The role of α and β amylase germination enzymes in accelerating dormancy breaking of Indian Cheese Maker was studied.
3. Mean time and mean daily germination during the dormancy breaking process of Indian Cheese Maker were estimated.

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: Cotton is the most important fiber-oil seed crop. Seed germination, vigour and health are the most important aspects of cotton seed quality. In Iran, annual cotton seed requirement is near 4000 tones, half of which is delinted and half is provided as fuzzy seed and therefore infection of fuzzy seeds to seed borne disease pathogens is possible. Every year a part of produced cotton seed does not possess standard quality and is not certify for various reasons including infection with seed borne disease pathogens. Thereafter, this research was conducted in order to study the relationship among cotton commercial cultivars seed germination, vigour and health.
Materials and Methods: Fuzzy seeds lots samples of Sahel, Varamin, Bakhtegan and Mehr cotton commercial cultivars with of 80, 90, and 95 percent intial germination ability (normal seedlings percent) produced at Golestan, Khorasan Razavi, Fars, and Ardabil provinces respectively underwent Standard germination and accelerated ageing tests. Final germination percent before and after accelerated ageing, normal seedlings percent after accelerated ageing, decayed seeds percent before and after accelerated ageing, mean germination time, seedling length, dry weight, seedling length and weight vigour indices after accelerated ageing were measured and  the fungus on decayed seeds were determined by blotter test. Then, their average frequency was determined.
 Results: Sahel and Bakhtegan cultivars and seeds having the highest primary germination ability had the most final germination percent before accelerated ageing and Sahel cultivar seed with the highest and moderate initial germination had the highest final germination percent after accelerated ageing. Sahel cultivar seeds had the highest normal seedlings percent after accelerated ageing. The highest decayed seeds percent before accelerated ageing belonged to Varamin and Mehr cultivars with moderate and low intial germination ability, and the highest decayed seeds percent after accelerated ageing belonged to Varamin and Mehr cultivars with low intial germination ability. Seeds having the lowest primary germination ability had the highest mean germination time and Sahel cultivar seeds had the highest seedling length and weight vigour indices. All studied cultivars seeds had been contaminated with Fusarium spp., Alternaria spp., Aspergillus spp. and Trichothecium roseum. Also, Varamin and Mehr cultivars seeds had the highest and Sahel cultivar seeds had the lowest average frequency of fungus on decayed seeds. Final germination percent before and after accelerated ageing and seedling length and weight vigour indices had significant negative correlation with decayed seeds percent before and after accelerated ageing.
Conclusion: Seeds decay was the most important factor of studied cotton cultivars seed deterioration and germination and seedling vigour decrease. Sahel and Mehr cultivars seeds and seeds with the highest (95 percent) and lowest (80 percent) intial germination ability seeds respectively had the highest (91 percent) and lowest (58 percent) seed final germination percent and seedling vigour. Alternaria spp., Aspergillus spp. on Mehr cultivar seeds, Fusarium spp. on Varamin cultivar seeds and Trichothecium roseum on Bakhtegan cultivars seeds with average frequency on decayed seeds after accelerated ageing of respectively 100, 99, 80.70 and 63 percent were the fungus that led to the most seeds germination and seedlings vigour decrease.

Highlights:

The relationship of cotton commercial cultivars seeds germination percent and seedling vigour with contamination to seed borne fungi were determined

Extended abstract
Introduction: Small size of Satureja (Satureja hortensis L.) seed causes many problems in mechanized cultivation and its seed consumption is increased significantly.  The approach discussed in the present study is the seed coating of Satureja by several matters and selecting the suitable method as well as investigation of adding hormonal and nutritional substances to the selected coating material for better emergence and the elimination of problem arise as a result of coating.
Materials and Methods: Purified Satureja seeds (97%) were prepared and poured into the coating machine at a specified amount. First, 1% solution of benomyl fungicide was sprayed on the seeds. Then some coating powder was sprayed on the spinning wet seeds inside the machine. Then some of the adhesive solution was sprayed on it and again the coating powder was added and this was repeated several times to create a suitable form for the coated seeds. This was repeated using different materials and among these coatings powder, vermiculite and perlite provided better coating on Satureja seed. Then, different materials including gibberellin, BAP, cytokinin, thiourea (CH₄N₂S) and potassium nitrate (KNO₃), phosphorus from H₂PO₄ source and manganese sulfate (MnSO₄) were used to the emergence of the enlarged seeds and also, the emergence of these seeds were evaluated in the greenhouse.
Results: Initial results showed that vermiculite and perlite provided better cover for Satureja compared with the other coating materials. Investigating the emergence of perlite-coated seeds in the greenhouse showed that gibberellin (all concentrations) and kinetin (500 mg/l) present in the seed coat improved the Satureja seed emergence under greenhouse condition. Also, it was found that Thiourea (700 and 7000 mg/l), potassium nitrate (7, 70, 700 mg/l), phosphorous (9 kg/100 kg seed) and manganese sulphate (2 and 4 mg/l) present in the coat significantly increased the Satureja seed emergence and led to improved seedling growth.
Conclusion: Perlite for the purpose of seed pelleting of Satureja showed good results and the use of gibberellin (at all concentrations) and quintine (500 mg/l) in the seed pelleting improved germination of pelleted Satureja seed.
 

Highlights:
1- Technical knowledge of Satureja seed pelleting was obtained.
2- The suitable material to improve the emergence of pelleted Satureja seed was introduced.