Iranian Journal of Seed Research

Extended Abstract
 Introduction: Seed is the fundamental input of crop production and tobacco is cultivated as transplanting and its transplant produced as float system. Therefore, seed germination and produced seedling health and diseases and pests management have high importance. So, evaluation of seeds dressing effect on germination and important pests and diseases management in the nursery for healthy transplantable seedling production is important. The study aims to investigate the effect of disinfectant of K326 tobacco seed on germination and percentage of transmissible transplants and management of contamination of sciaridae fly, aphid, and collar rot in a float system tray.
 Material and method: This study was conducted as a completely randomized design in 3 replications at Tirtash Research and Education Center in 2014. seeds dressed by pelleting apparatus disinfected with Metalaxyl (Ridomil) and Thiophanate–methyl (TopsinM) fungicides and Imidacloprid (Gaucho), Thiamethoxam (Confidor) and Thiodicarb (Larvin) insecticide and seeds heating by 60ºC temperature warm air during 1 hour, seeds treatment by 50ºC heat water for 10 minutes and treatment by 0.5 percent concentration sodium hypochlorite for 4 minutes. Then normal seedlings percent by standard germination test, seedling emergence percent in float system, transplantable seedling of float system and infected to Sciarid fly, aphid and stem rot seedlings determined.
 Results: Results showed that K326 Tobacco Seeds Disinfected by 2.5 g/kg metallaxyl + 2.5 g/kg thiophane-methyl (70% wettable powder) + 10 g/kg imidacloprid + 6 cm3/kg Thiodicarb had the highest percentage of normal seedlings, percentage of seedling emergence in the float system tray and percentage of removable transplants and the least seedling contaminated with sciaridae, aphid and collar rot.
 Conclusion: Results of this study showed that all seed disinfection treatments improved seed germination, seedling emergence percentage, and removable seedlings in the float system tray as well as infected seedlings compared to control decreased collar rot, sciaridae fly, and aphids. Also, the mentioned traits were superior to the non-chemical disinfectant treatments in seed disinfection treatments with the studied fungicides and insecticides.

Highlights:
1- The effects of chemical disinfectant treatments (different insecticides and fungicides permitted and common) as coatings on seed germination and percentage of tobacco seedling emergence were evaluated and compared.
ed The effect of non-chemical disinfectant treatments on seed germination and percentage of tobacco seedling emergence and management of pests and diseases seedbed were evaluated and compared.

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: Tubers are considered as the most important vegetative organs in reproduction of purple nutsedge, as one of the most troublesome weeds worldwide. Therefore, it is great of importance to investigate the properties of the tuber response to the surrounding environment such as absorption and loss of water. Water uptake is the first step in the sprouting process, though the pattern of water uptake by purple nutsedge tubers has not been documented. Loss of water in tubers is one of the potent factors in reducing their ability to sprouting. Three separate experiments were carried out to investigate the absorption and loss of water content of purple nutsedge tubers.
Material and Methods: In the first experiment, the tubers were placed in a water bath at temperatures of 10, 20, 30, and 40 ° C. Then, the weight of the tubers was measured at different times (24 till 3600 minutes). The water uptake percentage of tubers at different temperatures was studied by fitting the Peleg model. In the second experiment, the initiation day of sprouting was investigated at constant temperatures of 10, 20, 30, and 40 ° C. In the third experiment, water loss and sprouting percentage of tubers were evaluated in two conditions refrigerator (4° C) and room (22 to 25 ° C).
Results: The results showed that the initial water content of tubers was 42% and absorbed 10% extra water after being immersed in water. The water uptake behavior was based on the Peleg model at two stages: (1) rapid uptake (less than 420 minutes (7 hours), and (2) a low uptake with a gentle slope afterward. In the Peleg model, the parameters K₁ (minutes *.%weight ^-1) and K₂ (%^-1) are water absorption rate and water absorption capacity, respectively. The K₁ parameter was negatively against temperature. The highest and lowest values were 49.56 and 28.55 at 10 and 40 ° C, respectively. On the other hand, the trend of the K₂ was constant (0.1) at 10-30 °C but was 0.08 at 40 °C. The two-parameter Hyperbola model was superior to the Peleg and predicts the highest water absorption and time to 50 percent water absorption parameters. The results showed that sprouting of purple nutsedge tubers at 10, 20, 30, and 40 °C occurred after 14.44, 6.57, 3.24, and 3.12 days, respectively. Keeping the tubers in the room (22-25 °C) and refrigerator (4 °C), sprouting stopped after 3 and 9 months, respectively. The time required for 50% reduction of sprouting in the room and refrigerator was estimated to be 1.3 months (39 days) and 5.12 months (154 days), respectively. The time required for 50% loss weight of tubers in the room and refrigerator was 1.981 months (59 days) and about 6 months (180 days), respectively. Overall, weight loss (water loss) up 11.85%, resulted in 50% reduction in tuber sprouting.
Conclusion: Maximum water uptake in tubers occurred in less than 420 minutes (seven hours) at all temperatures. Slow sprouting in tubers at low temperatures is not associated with an obstacle in water absorption. Tubers lost half of their sprouting ability by losing water about 12%. On the other hand, the results show that the tubers at cool temperatures (4 °C) lose their water and sprouting capacity less than the ambient temperature (22 to 25 °C).

Highlights:
1- Determination of water absorption pattern on purple nutsedge tubers.
2- Effect of storage location in reducing water and sprouting ability of purple nutsedge tubers.

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

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

 

Extended Abstract

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

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

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

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

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

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: Since the maximum percentage and rate of germination of rapeseed occur at a certain temperature, finding these temperatures can play an important role in determining the appropriate time and place for the cultivation of different cultivars. Also, light can affect the germination percentage of rapeseed at different temperatures, but the response of rapeseed to light, especially at lower and higher temperatures, has not been studied. Therefore, this study aimed to investigate the changes in the germination of rapeseed cultivars at different temperatures and determine cardinal germination temperatures based on germination percentage and rate under both the presence and absence of light conditions.
Materials and methods: In this study, germination tests were carried out at 5, 10, 15, 20, 25, 30, 35, 37, and 40°C temperatures in two light conditions (12 h light / 12 h dark) and darkness on nine spring cultivars (Traper, Agamax, Hayola-50, Hayola-420, RGS, Mahtab, Hayola-61, Zafar, and Zarfam) and one winter cultivar (Garo). The four-parameter Hill model was used to describe germination changes over time and the dent model was used to calculate cardinal temperatures. Seed viability at lower and higher temperatures was evaluated by the tetrazolium test.
Results: The evaluation of the trend of cumulative germination percentage over time in different cultivars showed that maximum germination percentage of all cultivars happened in the temperature range between 15-30 °C, some in the temperature range of 10-30 °C (Hyola-61) and others even in the temperature range of 5-30 °C (RGS, Mahtab, Garo, Zafar, and Zarfam) had the highest germination percentage. The highest germination rate in all cultivars was observed at the temperature range of 22-35 °C. Light only had an effect on the germination percentage of the seeds at sub and super optimal temperatures. At these temperatures, light increased the germination percentage. The remaining seed of 5, 10, 35, 37, and 40 °C temperature after transfer to 20 °C did not germinate, whereas most of them were viable based on the tetrazolium test.
Conclusion: The difference in the optimum temperature range for germination percentage and rate showed that to optimize seed performance, the optimal temperature range between the germination percentage and germination rate should be considered as the optimum temperature for germination. At sub and supra optimal temperatures, light leads to improved germination in some cultivars. The effect of light on germination at supra optimal temperatures was far higher than that of sub-optimal ones. Survival of the remaining seeds at the sub and supra optimal temperatures in some cultivars provided evidence of thermo-dormancy in these cultivars, this issue needs further investigation in the future.

Highlights:
1- The cardinal temperatures were studied based on both the percentage and rate of germination and the effect of light on them.
2- Some new varieties such as Traper and Agamax that little information about their characteristics is available were examined.
3- In this study, the reason for the lack of germination of rapeseed at the sub and supra optimal temperatures especially in the darkness has been mentioned.

Extended abstract
Introduction: Purple nutsedge (Cyperus rotundus L.) is one of the problematic weeds worldwide prevalent in tropical and subtropical regions. Tubers are major tools through which purple nutsedge is propagated, whereas its seeds have a low ability to germinate. Therefore, evaluation of the response of tubers against environmental agents is great of importance to know the germination and emergence time. Germination, in turn, is mostly affected by temperature, among other environmental factors. Various models that are recognized as the Thermal Time model have been introduced to describe the seed germination pattern against temperature. Since predicting the emergence of reproductive organs through the modeling is great of importance for improving the control strategies; the present study was carried out to investigate the response of tuber sprouting of purple nutsedge (Cyperus rotundus) against temperature using thermal time models.
Material and methods: The experiment was carried out as a randomized complete block design with three replications in a germinator. Each replicate was placed on a separate shelf. For each replicate, 15 tubers were placed inside a 20 cm Petri dish on a filter paper and then 100 ml of water was added. The experiment was performed separately for constant temperatures of 10, 15, 20, 25, 30, 35, and 40 °C in absolute darkness. To analyze the data as modeling, five thermal time models were evaluated based on the statistical distributions of normal, Weibull, Gumble, logistic and log logistic. Indices such as R², RMSE, RMSE%, and AICc were used to evaluate the models.
Results: The results showed that all models predicted the germination response of purple nutsedge tuber with high accuracy (R² = 0.95). A comparison of models based on AICc values showed significant superiority of the Gumble model over other models. According to this index, there was no difference between logistic and log logistic models with normal. Among the models, Weibull was identified as the most inappropriate model. Different models estimated the final germination (Gmax) between 0.93 to 0.94 (93 to 94%). The base temperature was estimated through different models from 7.10 to 7.47 °C. Among the models, the model based on the Gumble distribution proved the skew to the right of the thermal time and Tm. According to the Gumble model, the thermal time parameters required to reach 50% germination (θT (50)) equals 123.8 ° C day and the maximum temperature for germination at 50% probability (Tc (50)) was estimated to be 46.10 ° C.
Conclusion: the thermal time model based on the Gumble probability distribution was most plausible among the models. Also, a distributed right skewness related to the thermal time and Tm was proved through the Gumble model. The parameters obtained from the Gumble model can be used to predict the sprouting of purple nutsedge tubers.
 
Highlights:

Extended Abstract
Introduction: Seed dormancy is the most important factor that prevents weed seed germination. Lack of simultaneous germination of weed seeds causes a number of problems in their control due to seed dormancy in the fields; therefore, weed seed dormancy is considered to be an undesirable trait for farmers. The aim of this study was to investigate the effect of magnetic field on seed dormancy elimination in some weed species.
Material and Methods: In order to study the effect of Magnetic field on germination and seedling growth of redroot pigweed (Amaranthus retroflexus), spring wild oat (Avena fatua) and common purslane (Portulaca oleraceae), a factorial experiment based on completely randomized design was conducted at the Ecology laboratory of Science Research Branch, Islamic Azad University in 2019. Factors consisted of dormancy breaking treatment at 8 levels (gibberellic acid 1000 mg/l for 20 minutes, gibberellic acid 2000 mg/l for 20 minutes, sulfuric acid for 5 minutes, sulfuric acid for 10 minutes, sulfuric acid for 20 minutes, nitrate potassium at 0.01 g/L, nitrate potassium at 0.05 g/L and control) and magnetic field at 4 levels (0, 25, 50 and 100 mT).
Results: Results showed that responses of three weed species to magnetic field were different. Magnetic field increased percentage of germination, fresh weight of plumule and length of plumule of redroot pigweed, so magnetic field at 100 mT was the best treatment for dormancy breaking. The highest germination percentage of wild oat was obtained in 0.01 mM potassium nitrate at 50 mT. The length plumule of wild oat increased significantly at 2000 mg/l gibberellic acid with increasing magnetic field level from zero to 25 mM. Nitrate potassium at 0.05 g/L was the best treatment for breaking the dormancy of common purslane. Magnetic field at 100 mT could increase percentage of germination of this weed.
Conclusion: In general, the results of this study showed that sulfuric acid treatment was not a suitable option for the removal of dormancy in the three weed species because of the elimination of seed embryos. Magnetic field treatment significantly increased the studied traits in all three species of redroot pigweed, spring wild oat and purslane. The interaction between dormancy breaking treatment and magnetic field was significant in many of the studied traits and the effect of dormancy breaking treatment was intensified by magnetic field. Therefore, the use of magnetic field treatment is recommended to increase the germination of these three species.
 
Highlights:
1- There is a positive and significant interaction between seed dormancy elimination treatments and magnetic field.
2- Sulfuric acid treatment is not a suitable option for breaking the dormancy of redroot pigweed, spring wild oat and purslane.

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.