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Showing 20 results for Germination Rate

Asad Masoumi Asl, Rreza Amiri Fahliani, Hamidreza Balouchi,
Volume 1, Issue 1 (6-2014)
Abstract

Salinity is one of the most extensive environmental stresses and is a limiting factor for the growth and development of crops, such as rice. Then, an experiment based upon completely randomized design with four low levels (0, 7.5, 15, 22.5) and four high of salinity (75, 150, 225 and 300 mM) with control as the first factor and nine cultivars of rice (dollars, Hasan Saraii, Mousa Tarom, Kamfiruz, Lenjan Askari, Gharib, Domsiah Mamassani, 304, Champa Yasouj) as the second factor with three replications was conducted in 2012 in the Yasouj University. Results showed that Hasan Saraii had salinity tolerance with the most germination percentage, germination rate and shoot length at high salinity levels (more than 75 mM), and Domsiah Mamassani with the minimum of that traits had not any salinity tolerance. But in the low salinity (less than 22.5 mM), Hasan Saraii, Lenjan and Mousa Tarom had the highest percentage of germination. The maximum germination rate was due to Mousa Tarom and the maximum shoot length observed in Gharib variety. So it seems, if we would only consider the germination percentage, Hasan Saraii is the best variety and if the maximum germination percentage and rate are considered, the variety that would be considered is Mousa Tarom. Therefore, high salinity we should not just rely on the germination but the germination rate should also be noted and in lower salinity due to different cultivars germination percentage, germination rate and dry weight of root should be paid much more attention.

Jalal Jalilian, Nabi Khaliliaqdam,
Volume 2, Issue 1 (9-2015)
Abstract

Rocket (Eruca sativa) is an important medicinal plant which not be done any experiment about its germination quantification response to temperature. Thus, an experiment base on CRD performed in seed research laboratory of Urmia University with four replications with ten levels of temperatures includes 1, 3, 5, 10, 15, 20, 25, 30, 35 and 40 0C. Results revealed that the temperature had significant effects on the rate and germination percent and Dent-like model estimated greatly cardinal temperature (base, upper and bottom optimum and ceiling temperatures). Germination rate stopped at equal and less than 0.79 and equal and higher than 47.6 0C and Rmax were 0.066 in 16.9-32.6 0C. Also, results emphasized that Rocket seed needs low temperature for germination but, germination rate and percent of Rocket increased by temperature increment. Therefore, the Rocket can germinate and emerge in dispersal spans of an environmental thermal from 0.79 to 47.6 0C and thus recognized as a crop with allowable production for various seasons and climate.


Zeinab Alipoor, Sohrab Mahmodi,
Volume 2, Issue 1 (9-2015)
Abstract

Due to the importance of medicinal plants, understanding the seed germination response to temperature is agronomically important. A laboratory study was conducted to investigate the effect of different temperatures on seed germination of fennel, cannabis and sesame in a completely randomized design with four replications. Various constant temperatures (5, 10, 15, 20, 25, 30, 35 and 40°C) were considered. According to the results, the effect of temperature on germination rate and percentage in all species was significant. The seeds of fennel were not germinated in 5, 35 and 40 0C and seeds of sesame germinated only in 5 0C. The maximum rate of germination obtained in 30 °C for fennel and 25 °C for sesame and cannabis. The highest germination percentage of fennel and cannabis and sesame were in 20, 25 and 30 0C respectively. The lowest of germination uniformity (GU) were observed in 20 0C for fennel and in 15 0C for cannabis and sesame. Amount of seedling vigor maximized for fennel and cannabis in 250C and for sesame in the 300C. The values of length and weight of radical and plumule were enhanced with the increase of temperature and record on maximum in special temperature and then reduced slowly. The quantitative information provided by this study can be used in prediction of emergence under diverse temperature conditions. Germination of cannabis seeds occurred in a wide range of temperatures and this seed are less sensitive to temperature compared to the other two plants. Germination of fennel seeds was less, except at 200C. The sesame seeds had good germination at 15-35 0C.


Khadijeh Badpa, Mohsen Movahhedi Dehnavi, Alireza Yadavi,
Volume 2, Issue 2 (3-2016)
Abstract

To evaluate the interaction of Cd and SA on seed germination of Safflower (Carthamus tinctorius L. cv. Soffe), this experiment was carried out as a factorial based on CRD with four replications in 2012, in Yasouj University seed lab. Factors included of four levels of seed priming with SA (0, 0.3, 0.6, and 0.9 mM) and eight levels of cadmium nitrate (0, 5, 10, 15, 20, 25, 30 and 35 mM). In all Cd treatments, SA 0.9 mM had maximum germination percentage (84% in 0 mM Cd) and rate (6.58 seed day-1 in 5 mM Cd), radical length (4.21 cm in 0 mM Cd) and stem (3.29 cm in 0 mM Cd), radical dry mater (2.25 mg in 0 mM Cd), shoot dry matter (0.94 mg in 0 mM Cd) and seed vigor index (6.30 in 0 mM Cd). Generally, seed priming with SA decreased the impact of Cd on seed germination and SA 0.9 mM was the best treatment.


Maryam Janalizadeh, Ahmad Nezami, Hamidreza Khazaie, Hassan Feizi, Morteza Goldani,
Volume 3, Issue 1 (9-2016)
Abstract

Priming of seeds by magnetic fields (magneto priming) is proposed as an ecological, useful and low-priced method for improvement of seed germination and plant emergence. In order to evaluate the germination behavior of sesame seeds affected by magnetic fields, an experiment was conducted as a completely randomized design with 22 treatments (non-exposure to magnetic fields (control) and 21 magneto priming treatments) with three replications at the college of agriculture, the Ferdowsi University of Mashhad in 2014. the seed of sesame put into a plastic bag bulky and was treated with different intensity of magnetic fields (25, 50, 75 and 100 mT) for several times (10, 20, 30, 60 and 120 minutes). For assessment of germination traits of sesame under constant magnetic field conditions, magnetic tapes with three mT strength were used in each Petri dish throughout the experiment. Results showed that magnetic fields had no significant effects on final germination percentage and mean germination time and all magnetic treatments except for 75 mT at 60 minutes indicated reducing effects on germination percentage in comparison to control. Priming of seeds with magnetic fields in 50 mT strength for 20 minutes led to the increment of germination rate compared to control treatment but all levels of 100mT treatment caused a reduction in germination rate than control. The most radicle length, seedling length and seedling vigor length index belong to 75 mT at 60 minutes treatment and the most seedling dry weight and seedling vigor weight index related to 100 mT for 20 minutes treatment. Ranking of treatments showed that exposure of seeds for one hour in 75 mT and 10 minutes in 25 mT magnetic fields strength had the best outcomes.


Shahram Nazari, Mohammad Ali Aboutalbian, Farid Golzardi,
Volume 3, Issue 1 (9-2016)
Abstract

Seed priming is a method which is a quite effective method for improving germination and seedling establishment. Two separate experiments were performed to determine the best hydro and osmopriming treatments effects on canola‘s seed germination. The experiments were performed in seed technology laboratory of Islamic Azad University, Karaj, Iran, 2014. The first experiment contained three canola varieties seeds hydropriming (Okapi, Zarfam and Talayeh) using tap water over time interval 0. 2, 6, 10, 14, 18, 20 and 24 hours. The second experiment included, tree canola cultivars in accompany with six concentrations of ZnS04 (0, 0.035, 0.1, 0.4, 1 and 4 gr.Lit-1) over priming time interval of 0, 6, 10 14 and 18 hours. Both experiments were conducted as a factorial experiment in the context of completely randomized design (CRD) with four replications. The results revealed that the maximum germination percentage across all cultivars e.g. Okapi (99%), Zarfam (95%) and Talayeh (80%) is achieved at 10 hours hydropriming interval. Also concerning to germination rate, the best performance was observed for Talayeh cultivar at 10 hydropriming hour’s interval. The most vigor longitudinal and vigor weighted indices (1050.55 and 4.56) were observed in the Okapi cultivar in the fourth hydropriming level. The interaction between the cultivars, the concentration of ZnS04 and osmopriming time was significant for all characters except for shoot dry weight and vigor weighted Index. The three-way interaction showed that the highest shoots dry weight (0.11, 0.057 and 0.055) and also vigor weighted index observed in Okapi, Zarfam and Talayeh cultivar in 0.035 concentration of ZnS04 (gr.lit-1) at the time was 10 hours, respectively. The results of this study showed that hydropriming and ZnS04 might improve the performance of rapeseed Cultivars seed.


Marjan Diyanat, Seyyed Meisam Hosseini,
Volume 3, Issue 1 (9-2016)
Abstract

In order to study the responses of redstem filaree (Erodium cicutarium L.) seed germination to temperature levels, an experiment was carried out in a completely randomized design with four replications and twelve levels of temperature (0, 3, 5, 7, 10, 12, 15, 20, 25, 30, 35, 40 0C). Results showed that the effect of treatments on germination properties of redstem was significant, so the highest percentage of germination was achieved at 150C and reduced with increasing temperature and was totally inhibited at 40ºC. Based on a linear regression between germination rate and temperature, the cardinal temperatures: minimum (Tmin), optimum (To) and maximum (Tmax) were determined: 0, 15.20 and 37.18 ºC, respectively. A significant difference was not observed in plumule length at a range of 5-30°C that showed that it is less sensitive to temperature in comparison with root length. Highest wet-dry weight was achieved at 20 °C that was not different by 10, 12 and 20°C. Above results suggest that redstem failure could grow in a wide range of growing conditions, but prefers temperate zones. The results of this study are important to understanding thermal requirements and improvement of management strategies of redstem filaree.


Almas Nemati, Hamid Sharifi, Mohammad Gerdakaneh, Zeynab Sharifi,
Volume 3, Issue 1 (9-2016)
Abstract

The seeds of two species (Citrulus colocynthis) and (Silybum mrianum) gathered from natural habitat located in the Koohdasht city (Lorestan province) and transferred to Kermanshah Agricultural and Natural Resources Research and Education Center in the summer of 2014. For each species, separate experiments in a completely randomized design with 14 treatments and 4 replications were done. Treatments included moist-chilling time (control, 10, 20, 30, 40, 50, 70 and 90 days at 4 °C), gibberellic acid concentration (200, 400, 600 and 800 PPM) and integrated treatment of gibberellic acid 400 ppm with moist-chilling for 30 days and 70 days. The results showed that for both species increasing of moist-chilling duration and concentration of gibberellic acid significantly increased germination percentage, germination rate and seed vigor index. The best breaking seed dormancy treatment was moist-chilling of 90 days for seeds of (Citruluus colocynthis) and gibberellic acid 800 ppm for (Silybum mrianum). The result showed that seeds of two species had the combination of physiological (related to seed inside inhibitors) and physical dormancy (related to hard coat).


Seyyed Mahdi Javadzadeh, Parviz Rezvani Moghaddam, Mohammad Banayan-Aval, Javad Asili,
Volume 3, Issue 2 (3-2017)
Abstract

Roselle is an important medicinal and industrial plant of the family of Malvaceae, and is planted in vast areas of Sistan and Baluchestan. In a laboratory study, the effect of varying temperatures on seed germination of Hibiscus sabdariffa was investigated and minimum, optimum and maximum temperatures for its germination were determined in a completely randomized design with four replications.  For this purpose, temperatures 5, 10, 15, 20, 25, 30, 35, 40, 45 and 50°C were considered in each treatment. Cardinal temperatures for germination were determined consistent with three models (i.e., Intersected-lines Model, Five-Parameters Beta Model and Quadratic Polynomial Model). The traits measured were germination percentage, the speed of germination and mean germination time. The temperature effect on all the measured traits was significant. The results of the regression analysis showed that the best model in terms of cardinal point of this plant is the Five-Parameters Beta Model. Given the results of this model, the minimum and the optimal temperatures for the germination of Roselle are 4.04°C, and 29.83° C, respectively.
 


Shahram Nazari, Reza Deihimfard, Javad Faraji,
Volume 3, Issue 2 (3-2017)
Abstract

Gaining insights into the germination and emergence patterns of weeds as well as the factors which have an impact on these patterns is beneficial for weeds management programs. In order to investigate the effect of temperature, waterlogging and salinity on germination and emergence of common lambsquarters, three separate experiments were conducted, adopting a completely randomized design with four replications. The results of the temperature experiment showed that the highest germination percentages, which were 87, 93 and 88%, were obtained in the temperature range of 15, 20 and 25°C, respectively. Maximum values of germination rate, radicle length, plumule length, and seedling dry weight were obtained at 20°C. In addition, optimum seed vigor index of 796.29 was observed at 20°C. The results of the Regression Model showed that germination percentage decreased with an increase in waterlogging duration and halted after 8 and 10 days of consecutive waterlogging. Mean comparisons revealed that radicle and plumule length, seedling dry weight and vigor index decreased significantly by increasing the period of waterlogging. Salinity adversely affected germination percentage, germination rate and seedling dry weight of common lambsquarters. These factors were at their highest amounts in the control and 50 mM NaCl treatments. A downward trend was observed in these factors as NaCl concentrations increased and finally the germination process stopped in concentrations ranging from 300 to 400 mM NaCl. Radicle and plumule length also decreased from 10.51 and 9.23 cm in the control treatment to 3.57 and 2.47 cm at 250 mM NaCl. Overall, the results revealed that the maximum seed vigor index of 851.84 was obtained in the control treatment and seed vigor halted when the salinity level increased to more than 250 mM NaCl. Finally, the results showed that optimum temperature for germination of common lamsquarters was 20 °C and the existence of salinity and waterlogging stress can decrease growth indices of this weed at germination and seedling stages.


Mehri Khesht Zar, Mehran Sharafi Zad, Jafar Ghasemi Ranjbar,
Volume 4, Issue 1 (9-2017)
Abstract

To investigate the role of seed size on maize germination characteristics, an experiment was conducted in 2014 in the Laboratory of Registration and Certification of Seeds and Plants, Khuzestan Branch. Treatments included three levels of seed size (control (mixed), large and small) and hybrids at three levels (KSC704, Karun and Mobin). The results of these experiments showed that the hybrid had a significant impact on germination percentage, the rate of germination, vigor index, root and shoot length and dry weight of seedling. In addition, the highest germination (94.3%), the rate of germination (8.4 seeds per day), vigor index (37.6), shoot length (21 cm), root fresh weight (3.1 gr) and dry weight of seedlings (0.59 g) affected by seed size belonged to the Karun hybrid. Generally speaking, in terms of germination and seedling growth, there were differences among the three groups of maize seeds. Out of the hybrids scrutinized, Karun hybrid was a better one in terms of germination and growth of seedlings.

Highlights:
  1.  Due to higher storage capacity, the use of large seeds brings about increases in the seedling germination rate and their establishment in the field
  2. The use of large seeds with more seed vigor decreases competition between seedlings and reduces vapor from the field.

Samira Parsaei, Mohsen Movahhedi Dehnavi, Hamidreza Balouchi,
Volume 4, Issue 1 (9-2017)
Abstract

Micronutrients play a great role in the production of high quality seeds, especially in terms of germination. Therefore, providing seeds with sufficient amounts of these is an important consideration in seed production. The present study was conducted as two separate experiments in the Seed Laboratory of Yasouj University in 2015. In the first experiment, the sesame seeds (cv. Darab 1) obtained from a previous split plot experiment based on RCBD, consisting of three irrigation levels (after 75, 110 and 145 mm evaporation from class A pan) and four foliar applications comprising water, zinc sulfate, boric acid and mixture of zinc sulfate and boric acid, were investigated in germination experiments in the minimum temperature (i.e., 15°C). The second experiment was a factorial based on RCD with three replications. The first factor in the eight levels included seeds soaked in water, ZnSo4, H3Bo3 and ZnSo4 + H3Bo3 and seeds with high contents of Zn (159 m Kg-1), B (15.3 m Kg-1) and Zn (139.5 m Kg-1)+ B (14 m Kg-1) and dry see as the control. The second factor was accelerated aging periods at three levels (0, 2 and 4 days) at 45°c and RH = 100%. The results showed that with a delay in irrigation time, compared with water foliar application, foliar application of micronutrients (Zn, B, Zn+B), and significantly increased germination traits. The results also suggested that, compared with seeds soaked in nutrients, seeds with high Zn and B contents significantly increased germination indices and antioxidant (catalase and peroxidase) activities, especially under accelerated seed aging.

Highlights:
  1.  The role of maternal sesame plant (cv. Darab 1) foliar application by zinc and boron elements in germination, vigour and storage capability of seeds was studied.
  2. The effect of seeds soaked in solutions enriched with zinc and boron elements on germination, vigour and storage capability of seeds was examined.

Zakia Ibrahim Quchi, Gholamreza Mohsenabadi , Hamed Hassanpour ,
Volume 4, Issue 2 (3-2018)
Abstract

In order to investigate the effect of different levels of temperature and drought stress on seed germination parameters of nettle roman (Urtica pilulifera L.), an experiment was conducted as factorial in a completely randomized design with three replications at the Department of Agronomy, College of Agriculture, University of Guilan, in 2014. Treatments included different temperature levels (5, 10, 15, 20 and 25 °C) and drought stress levels (0 (control), -2, -4,-6 and -8 bars). The results showed that treatments and their interactions had a significant effect on germination percentage (GP), germination rate (GR), root length and root dry weight. The highest GP (88%), GR (1.8 seed/day) and root dry weight (0.06 g) were obtained as the result of the interaction between the temperature of 25°C and no-stress condition. In this study, with an increase in drought stress and a decrease in temperature, GP, GR, root dry weight, root length and shoot length decreased. The impact of drought stress on GR and GP was lower at 20°C, compared with the temperature of 25°C. A decrease in water potential from -4 to -6 bars at 20°C caused a reduction of 50% and 30% in GP and GR, respectively. However, these reductions at 25°C were 75% and 70%, respectively. According to the results, it could be stated that the significant reduction threshold of seed germination parameters was -2 bars.

 
Highlights:

  1. The germination characteristics of Roman nettle were studied under drought stress and temperature.
  2. In drought stress of -4 bars, germination percentage and germination rate decreased significantly.

Farzad Mondani, Ashkan Jalilian, Atusa Olfati,
Volume 5, Issue 1 (9-2018)
Abstract

DOR: 98.1000/2383-1251.1397.5.55.9.1.1603.41

Extended abstract
Introduction: Malva (Malva neglecta) is one of perennial plants of the Malvaceae family. One of the most important mechanisms for survival of the plants is dormancy, rest or distance in germination and growth; in this case, despite favorable conditions for germination, the seed remains at rest for an indefinite period of time. Seed dormancy is a consistent feature in some seeds, especially weed seeds to optimize distribution of germination over time. Seed dormancy has a very important role in ecological management. The cause of the physical dormancy lies in skin cells outside tier structure that is impermeable to water. In physical dormancy, the seed coat is so hard that it does not allow the embryo to grow during germination. The chemical dormancy of the plants seeds is caused by the presence of inhibitor substances in the outer shell of many fruits and seeds and may also be due to an Enamel layer that blocks the exchange of oxygen. It goes without saying that understanding the ecology of weed germination and dormancy can contribute to long-term management. Therefore, this study was conducted to determine the effects of breaking seed dormancy and the impact of chemical and mechanical treatments on the germination of the Mallow seeds.
Materials and Methods: In order to recognize the effects of chemical and mechanical treatments on breaking seed dormancy and some of the most important features of seed germination of Malva, the experiment was conducted based on a completely randomized design with 4 replications at Crop Physiology Lab, Razi University, during 2016. Treatments were distilled water (control), sulfuric acid 98% (for 2, 3 and 4 minutes), potassium nitrate 3% (for 3, 4 and 7 days), hydrogen peroxide 30% (for 2, 3 and 4 minutes) and scarification with sandpaper and prechilling (for 1, 2 and 3 weeks). Germination percentage, germination rate, length and dry weight of hypocotyl, length and dry weight of radicle, seedling total dry weight and vigor index were evaluated. Group comparisons, analysis of variance and comparison of means were run based on LSD at 5% level, using SAS software (version 9.4).
Results: The results showed that the highest and the lowest germination percentage were 82% and 5% in scarification with a chilling for 3 weeks and control treatments, respectively. The results of treatment group comparisons also showed that using scarification with a chilling had the greatest impact on seed dormancy breaking. The most hypocotyl length (34.92 mm), hypocotyl dry weight (2.60 g), seedling dry weight (3.29 g) and seed vigor index (58.13) were observed in scarification with a chilling for 3 weeks. The highest germination rate (5.21 in day), radicle length (34.92 mm) and radicle dry weight (0.85 g) also belonged to sulfuric acid 98% for 2 minutes. It seems that seed dormancy of Malva was a combination of physiological and physical dormancy, because the effectiveness of the treatments evaluated in both metabolic and physical processes brought about the increase in the seed germination percentage.
Conclusion: Out of the treatments examined and given the results of group comparisons, scarification with sandpaper and prechilling had the most effect on breaking Malva’s seed dormancy. As scarification with chilling had the main role in breaking seed dormancy, it could be said that the dormancy is physiological and factors contributing to this dormancy are the embryo, the existence of inhibiting factors or both. The results indicated that the germination of Malva (Malva neglcta) seeds mechanically scratched with scarification increased. Therefore, seed dormancy is due to hard coated seeds. The seed coat is as one physical barrier against growth of embryo or radicle that inhibits absorption of water and gas exchanges.
 
 
Highlights:
1- Investigating dormancy breaking and germination traits of neglcta species of Malva.
2- Evaluation of efficiency of different chemical and mechanical treatments in the germination traits of Malva.

Hakimeh Darvizheh, Mortez Zahedi, Bohlul Abbaszadeh, Jamshid Razmjoo,
Volume 5, Issue 1 (9-2018)
Abstract

DOR: 98.1000/2383-1251.1397.5.1.9.1.1578.32

Extended abstract
Introduction: Echinacea purpurea, a member of Asteraceae family, is a herbal medicine which is effective for promoting human immune system. Enviromental stresses including water defecit, which limit maternal plant growth, can also affect their seed quality and germination. Various compounds such as salicylic acid and spermin are known to be useful in the alleviation of harmful effects of drought on plants and their seed production.
Materials and Methods: In order to investigate the seed vigor of Purple Coneflower after foliar  application of salicylic acid (SA) and spermine (SPM) on maternal plant (no spray,75 mg/l SA, 150 mg/L SA, 75 mg/L SPM, 75 mg/l SA+75 mg/L SPM and 150 mg/L SA+75 mg/L SPM) under three irrigation regimes (irrigation after 20, 40 and 60% depletion of soil available water), a split plot experiment was conducted based on a completely randomized block design with three replications during 2016- 2017 growing seasons at research field of Institute of Forests and Rangelands, Iran.
Results: Water stress decreased the percentage and rate of germination, shoot and seedling length, shoot dry weight, germination energy and seed germination vigour. The results showed that foliar application had a significant effect on shoot, root and seedling length, shoot, root and seedling dry weight, germination rate, allometric factor, and germination vigour. The interaction effect of drought stress and foliar application indicated that non-stress and 150 SA+70 SPM mg/L had the highest radicle length (28.8 mm), radicle dry weight (1.81mg), seedling dry weight (6.20 mg) and Allometric factor (0.412).
Conclusions: Based on the results of the current experiment, the foliar application of salicylic acid and spermine improved the seed germination of coneflower plants under both normal and water stress conditions and the highest values of these parameters were obtained under combained application of high concentrations of salicylic acid (150 mg/L) and spermine (75 mg/L).
 
 
Highlights:
1- Investigating the foliar application of salicylic acid and spermine in maternal Echinacea purpurea plant under drought stress in germination of seed.
2- The foliar application of salicylic acid and spermine on maternal plants of Echinacea improved germination quality under water stress.
Farnaz Porali, Farshid Ghaderi-Far, Elias Soltani, Mohammad Hadi Palevani,
Volume 5, Issue 2 (3-2019)
Abstract

DOR: 98.1000/2383-1251.1397.5. 1.10.2.1605.41

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

Narjes Hojati Fahim, Mohamad Sedghi, Mehrdad Chaeichi, Rraouf Seyed Sharifi,
Volume 6, Issue 1 (9-2019)
Abstract

DOR: 98.1000/2383-1251.1398.6.77.11.1. 1575.1605

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

Mohammad Hossein Aminifard, Hassan Bayat,
Volume 6, Issue 2 (3-2020)
Abstract

DOR: 98.1000/2383-1251.1398.6.137.12.2.1576.1610

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


Mohammad Ghayour, Majid Taherian, Sadegh Baghban, Saeed Khavari,
Volume 6, Issue 2 (3-2020)
Abstract

DOR: 98.1000/2383-1251.1398. 6.95.12.2.1575.41

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

Keyvan Maleki, Elias Soltani, Iraj Alahdadi, Majid Ghorbani Javid,
Volume 6, Issue 2 (3-2020)
Abstract

DOR: 98.1000/2383-1251.1398. 6.31.12.2.1575.1606

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


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