farshid ghaderi far

The use of medicinal plants has been done since ancient times and may even be considered the origin of modern medicine. Medicinal plants are a source of biomolecules with therapeutic potential and as a lead to develop new drugs. Black cumin (*Nigella sativa* L.), often referred to as a "miracle herb," is a medicinal plant that has been used worldwide for centuries in the treatment and prevention of diseases such as cancer and diabetes. Additionally, it has been valued as a spice and flavoring agent in products like bread and sweets. Various factors influence the growth and yield of black cumin per unit area, with planting date being particularly significant. The timing of planting affects environmental conditions during the plant's growth stages, influencing the rates of vegetative and reproductive growth, and ultimately impacting yield. Therefore, selecting the appropriate planting time is crucial for the successful cultivation of any crop, including black cumin. The aim of this research is to determine the most suitable planting date of black cumin for this plant and the response of different ecotypes of this medicinal plant to the planting date in the weather conditions of Gorgan city.

In order to evaluate different ecotypes of black cumin in response to planting date in Gorgan, a field experiment with four planting dates was carried out in the cropping year of 2020-2021 at the research farm of Gorgan University of Agricultural Sciences and Natural Resources, Iran. The experiment was carried out in the form of split plots based on completely randomized block statistical design with three replication, in which four planting dates were 18th December, 17th January, 16th February and 18th March as the main plot and thirteen ecotypes (Such as Tafaresh, Gardmiran, Razan, Hamedan, Arak, Esfahan, Semirom, Eqlid, Ashkazar, Zabol, Bajestan, Sarayan and Khaf) with 3 replication were considered as sub-plot. In this research, the attributes of plant height, number of branches per plant, number of follicles per plant, number of grain per follicle, weight of 1000 grains and grain yield were measured. After harvesting, measurements were taken and then the data were analyzed with SAS 9.4 statistical software and means comparison was done with LSD’s test in significance at 5% probability level. Graphs were prepared using Excel software.

The results showed that the interaction effects of planting date and ecotype on plant height, number of branches per plant, number of capsules per plant, number of grains per capsule and 1000- grain weight were significant. However, the main effects of planting date and ecotype on grain yield were significant, and the interaction effects were not significant. With the delay in planting, all measured traits decreased. The highest grain yield was obtained from the first planting date (December 18) with 1245 kg per ha. The highest grain yield was obtained from Khaf (1245 kg.ha-1), Sarayan (1179 kg.ha-1), Bajestan (1156 kg.ha-1), Zabol (1141 kg.ha-1) and Esfahan (1117 kg.ha-1) ecotypes. In contrast, the lowest grain yield was obtained from the fourth (March 18) planting date with 694 kg.ha-1. The lowest grain yield was obtained from Arak and Gardmiran ecotypes with 903 and 890 kg.ha, respectively. With the delay in planting, the grain yield of high-yield ecotypes decreased linearly (8-9 kg.ha for each day of delay in planting), with the difference that the decrease in grain yield in the Bajestan ecotype (5.8 kg.ha for each day of delay in planting) was less than other ecotypes, which indicates the high adaptability of this ecotype to the planting date and environmental conditions of Gorgan. Also, there is a positive and significant correlation between grain yield and traits of plant height (0.73**), number of branches per plant (0.56**), number of follicles per plant (0.83**), number of grains per follicle (0.84**) and 1000- grain weight (0.55**).

In general, the results of this research showed that planting date and ecotype have a significant effect on black cumin yield, and it is recommended to plant high-yield ecotypes in December to obtain higher grain yield in Gorgan and additional tests should be done in this area for final confirmation.

Considering the nutritional value of pea (Pisum sativum L.) and its seed generations in crop yield, this study was conducted to investigate the effects of various generations of pea on yield and yield components in the Gorgan region of Iran. The treatments included three generations: F1, F2, and F3. Planting was carried out with a row spacing of 33 cm and an intra-row distance of 10 cm. This experiment was designed as a randomized complete block design with three replications. Sampling occurred during the flowering, green pod, and ripening stages. The following traits were measured: the number of plants with red flowers, leaf area index, stem height, number of pods per plant, weight of green pods, number of seeds per pod, weight of one hundred grains, dry biomass weight, yield of green pods, seed yield, and the harvest index. The data were analyzed using Excel and SAS software. Based on the findings of this study, it can be concluded that the green pod yield and several other traits measured in the second generation of pea did not exhibit a statistically significant difference compared to the first generation; any observed differences were minimal. However, the use of seeds from the third generation resulted in a significant decrease in yield (3,088.99 kg/ha, 2,873.71 kg/ha, and 2,095.44 kg/ha in the F1, F2, and F3 generations, respectively.) and yield components when compared to both the first and second generations. It was concluded that uilizing second-generation pea seeds from the Wolf variety can help reduce planting costs while achieving the desired yield of green pods.

Long-term storage of seeds under unfavorable conditions leads to their deterioration associated with decreased germination. Several studies have shown increased lipolysis in deteriorating seeds, but little is known about the role of protease activity during deterioration. In the present study, the effect of the controlled deterioration (CD) on the mobilization of storage proteins and the effects of pretreatment with protease inhibitor (PMSF) on the germination percentage of walnut kernels after CD were investigated.

Kernels were adjusted to 15% and 20% MC with water (control) or PMSF solution and then incubated for 3 and 6 days at 45°C for CD.

CD increased soluble proteins, solubility of 19-24 kDa glutelins, increased activity of a 80 kDa protease, accumulation of total amino acid, proline and increased protein carbonylation. Although aging-dependent decrease of germination was similar in both control and PMSF pretreatment, the aged kernels in PMSF pretreatment had lower proline, amino acid and carbonyl groups contents compared to the control.

These results suggest that CD causes increased solubility of protein reserves, but the inhibition of serine protease(s), unlike lipase, has no effect on improving the adverse physiological effects of CD including germination loss, and only at the biochemical level, it partially improved kernel response to stress. Identification of different metabolic pathways operating during CD of kernels can draw a picture of deterioration mechanism and also leads to introducing protocols for the quality and viability maintenance of kernels during storage.

White morning glory (Ipomoea lacunose L.) is one of the weeds that have recently spread in the fields of Golestan province and has become a serious challenge for farmers. In this study, the effect of different environmental conditions, including constant temperature, alternating temperature, water stress, salinity, high temperature, and burial depth on the germination and emergence of three seed populations of this plant collected in 2018, 2019, and 2020 (at the time of the experiment, these seeds were after-ripped 15, 3, and 0 months, respectively) were investigated. All experiments were conducted based on a completely randomized design with three replications. The results showed that the response of germination to the studied environmental factors was different in seed populations. Germination percentage started at 10°C and increased with increasing temperature. Although the germination percentage was significant at 40°C, it was completely stopped at 45°C. Alternating temperature compared to constant temperature increased the germination in the range of low temperatures; however, there was no difference with the constant temperature in the high-temperature range. The water potential required to reduce 50% of germination in the seeds of 2018, 2019, and 2020 was -0.83, -0.82, and -0.43 MPa, respectively. The tolerance of this species to salt stress was much higher than to water stress, and the increase of salinity up to the potential of -1.1 to -1.4 MPa reduced its maximum germination by 50%. Increasing the high temperature to 80 and 100 °C stimulated the germination, and no seeds survived at 120°C. In the populations of 2018 and 2020, the emergence percentage of seeds increased with the increase of burial depth; so that it reached its maximum value at a depth of 3 cm. By increasing the burial depth, the percentage of seedlings emergence of these populations decreased and stopped at a depth of 9 cm. The seedlings emergence of 2019 population also happened with the same process (but in smaller numbers), but no seedlings emergence occurred at a depth of 5 cm. In general, the results of this study showed that the reaction of white morning glory germination to environmental factors is different. Knowing the germination response of this species against the mentioned factors can help predict the germination and emergence of this plant to design suitable management strategies.

 Safflower seeds are rich in unsaturated fatty acids with a high capacity for peroxidation, which have a high potential to reduce germination and seed vigor during the storage period. Therefore, Introducing appropriate methods to preserve or improve their germplasm during storage would be advantageous. The aim of this study was to investigate the effects of seed priming on germination and vigor of safflower seeds (Sofeh and Sina cultivars).

A three-factor experiment was conducted in a completely randomized design with three replications before and after artificial deterioration. The experimental factors included controlled deterioration of seeds at 45°C in six levels (no deterioration, 1, 2, 3, 4, and 6 days) and priming in four levels (no prime, hydropriming, salicylic acid 50 mg/l and sodium chloride 5 percent).

 Artificial aging strongly and linearly reduced the germination ability of safflower seeds, and germinability and seed vigor reach zero in a time interval which lasts between 2.5 to 4.5 days (depending on the treatment and the investigated trait). The use of priming prior to artificial aging was more advantageous than priming after artificial aging. In addition, priming with salicylic acid was more useful compared to other priming treatments.

 Priming of safflower seeds before storage would result in the extended shelf-life of the stored seeds while also preserving the seed germination potential. 

With regard to the ever-growing water deficit in the world, the adoption of the direct-seeded rice cultivation system has been suggested as an alternative to the transplanting method. One of the disadvantages of the direct-seeded method is low and non-uniform germination and emergence due to low seed vigor in rice. Priming is a technique which improves the rate and uniformity of seed germination under these conditions. Thus, this study aimed to investigate the effects of priming treatments on seed germination of different rice cultivars under different temperature conditions using the thermal time model.

This study was conducted in 2019 at the seed research laboratory of Gorgan University of Agricultural Sciences and Natural Resources. In this experiment, germination of primed and non-primed seeds in three rice cultivars (Nada, Anam, and Tolo) was investigated under different temperatures (15, 20, 25, 30, and 35°C). The priming treatments which consisted of control, hydropriming, and osmopriming with different chemicals (potassium chloride 2%, potassium nitrate 1%, calcium chloride 4%, glycine betaine 10 ppm, salicylic acid 10 ppm, and ascorbic acid 10 ppm) were investigated under different temperatures.

The results showed that priming treatments had no significant effect on the seed germination percentage of rice cultivars at different temperatures. The thermal time model based on binomial distribution fitted well to cumulative germination percentages in all priming treatments. Among the parameters of the thermal time model, the greatest priming effect was on the reduction of the thermal coefficient, followed by the reduction of the sigma coefficient, which resulted in the increased rate and uniformity of germination. Priming treatments had no significant effect on base temperature. Also, the responses of rice cultivars to seed priming treatments varied so that in Anam and Neda, priming with calcium chloride but in Tolo, hydropriming was more effective on the model parameters, especially thermal time to 50% of germination.

In general, priming treatments did not affect the base temperature of germination in rice cultivars, but they significantly affected the rate and uniformity of seed germination. As the latter issue is one of the main problems in the direct-seeded rice system, suitable priming treatments for each cultivar can be adopted to increase the rate and uniformity of seed germination and emergence in this system.

In seed research, germination percentage data is the result of counting and has a binomial distribution. Therefore, seed researchers use data transformation, especially square root transformation, to stabilize the variance and normalize the data before performing analysis of variance and comparison of treatments. Despite the use of data transformation, this method has fundamental issues in the structure that misleads the test results. Therefore, it is important to introduce and replace a method that preserves the research assumptions and provides acceptable results for researchers without using data transformation. The use of generalized linear model is an alternative method for analyzing germination data with binomial distribution. In this research, the generalized linear model will be introduced first. Then, the efficiency of this method will be illustrated using simulated and actual germination data.

In this research, first the simulated data was generated by the Monte Carlo method. Based on the simulated data, the significance level and the power of test of generalized linear model were computed. Then the actual data related to three experiments including the effect of acidity on germination of wheat varieties, the effect of water stress and salinity on germination of yellow sweet clover seeds, and the effect of alternating temperatures on germination of three lavender populations were used and the results of the generalized linear model were compared with the square root transformation method based on the data of three experiments.

The simulation results showed that the generalized linear model has a high efficiency to preserve the predetermined significance level and a high power in detecting significant differences in germination of the treatments. Moreover, the results of the comparison of the generalized linear model with the square root transformation method illustrated that the generalized linear model had a higher capability to detect significant differences between various treatments, especially in the treatments with unequal seeds in the Petri dish, and in the treatments in which the square root transformation method resulted in no significant difference among treatments, the generalized linear method showed a significant difference.

Generally, the results of this research demonstrated that the generalized linear model can be used as an alternative method to square root transformation in studies on the germination percentage of seeds with binomial distribution, without having the problems of the square root transformation method. Moreover, this model outperforms the square root transformation in detecting significant differences in germination of treatments with fixed and different seeds.

Wild rye (Secale cereale) is considered one of the most important winter cereal weeds in the world. The damage resulting from the interference of this weed with wheat is more than other species of weed. This species is known as the most important wheat weed in the southern highlands of Golestan province (Shahkouh region). Since the area under wheat cultivation in the southern highlands of Golestan province (Shahkoh region) is much lower compared to the plains and low-altitude areas, no attention has been paid to the problems of wheat production, including the presence of Wild rye in the mentioned region.

This experiment was designed and carried out as a survey method in 30 wheat fields at Alvand and Omid cultivars in Shahkoh region of Golestan province. Sampling was done from each field in the wheat harvest stage at ten points in quadrats measuring 1 x 1 square meter. All wheat and wild rye plants were harvested at each point and transferred to the Plant Physiology Laboratory of Gorgan University of Agricultural Sciences and Natural Resources to determine plant density, yield and yield components.

The results showed that the number of wild rye plants in the fields varied from 0 to 9 plants per square meter. The number of spikes. m-2, grain yield and biomass yield of wild rye in all densities were higher in interference with Alvand cultivar than Omid cultivar. With increasing the density of rye, the studied traits decreased in wheat cultivars. With the introduce of each rye plant, the number of spikes.m-2, number of seeds per spike, 1000-seed weight, seed yield, biological yield and harvest index were 6.64%, 3.50%, 2.47%, 9.28%, 5.38% and 9.43% in Omid cultivar and 4.74%, 4.19%, 2.93%, 7.30%, 3.77% and 7.15% in Alvand cultivar, respectively. A lower decrease in the number of spikes.m-2 and 1000-seed weight in the Alvand cultivar can indicate its higher competitive power compared to the Omid. On the other hand, the seed yield of these cultivars in terms of non-interference with wild rye in fields under self-consumption seeds was almost similar to fields under certified seeds (without contamination with rye).

These findings showed that wild rye has an important role in reducing the yield of wheat cultivars in Shahkooh region; Alvand cultivar is considered as a more suitable cultivar due to its higher yield potential in both interference and non-interference conditions; The use of certified seeds may be the main strategy to control wild rye in Shahkuh region.

The different species of Amaranthus species are among the most important damaging weeds in the world. Due to the importance of studying the effect of management factors on seed dynamics of different weed species, this experiment aimed to investigate the effect of burial depth and high temperatures on the seed dynamic of different species of Amaranthus in Golestan province including white pigweed (A. albus), prostrate pigweed (A. belitoides), hybrid Amaranthus (A. chlorostachys), redroot pigweed (A. retrofelexus) and green Amaranthus (A. viridis) were performed.

This research was conducted on five amaranthus species of white pigweed, prostrate pigweed, hybrid Amaranthus, redroot pigweed, and green Amaranthus at the seed laboratory and greenhouse of Gorgan University of Agricultural Sciences and Natural Resources. In the first experiment, seed emergence of different species of Amaranthus was studied in eight burial depths including 0, 1, 2, 3, 4, 5, 7, and 10 cm. In the second experiment, seeds were exposed to 50, 60, 70, 80, 90, 100, and 110 °C temperatures for 5, 10, and 15 minutes

All seeds of A. blitoides and A. viridis germinated in the topsoil (zero depth); But, in A. albus, A. retroflexus, A. chlorostachys, 93%, 83%, and 3% of the seeds were emergence at the soil surface, respectively. By increasing the burial depth to one centimeter, the percentage of seeds emergence in different species of Amaranthus decreased significantly and was negligible at ≥ 2 cm depth. Germination test performed on retrieved seeds showed that zero to 16% of the seeds were able to germinate in petri dish, and most of the non-germinated seeds were viable. In all species except for A. chlorostachys high temperatures reduced the germination percentage.

Due to the reduction of seed germination percentage of different species of Amaranthus from a depth of more than one centimeter of soil, it seems that the use of conservation and conventional tillage methods has a good potential to reduce infestation of fields by these weeds. Also, although high temperatures reduce weed infestation in fields, they do not have a significant effect on depleting the seed bank of these species.

Highlights:

1- Seed dynamics of different species of Amaranthus were affected by burial depth and high temperature
2- Deep burial of seeds of different species of Amaranthus causes the stability of their seeds in the soil seed bank.

The wild species of safflower have different degrees of non-deep physiological dormancy, which affects the seeds germinability under different environmental conditions. Afterripening (dry storage) of seeds with non-deep physiological dormancy can increase their germination by releasing of seed dormancy. Also, it has been found that according to the afterripening period, the germination response of some species changes to temperature and water potential. Wild species of plants are of great importance due to their use as genetic resources in breeding programs. On the other hand, knowing the characteristics and needs of their germination under different environmental conditions leads to facilitating the reproduction and preservation of these valuable genetic resources. Therefore, the present study was conducted to investigate the germination response of safflower wild species to temperature and water potential during different afterripening period.

In this study, the seeds of two wild species, C. oxycanthus and C. glaucus, were Afterripened for 0, 2, 4, 6, and 12 months at 25°C. After each afterripening period, the percentage and rate of seed germination at temperatures of 5, 10, 15, 20, 25, 30 and 35 ℃ were checked and the cardinal temperatures of germination were calculated. Also, the response of germination to different water potential levels including zero, -0.2, -0.4, -0.6 and -0.8 MPa was investigated.

The results showed that afterripening the seeds for 2-6 months increased the germination percentage of the seeds compared to the control, while the germination percentage decreased in the treatment of 12 months afterripening. In addition, the seeds of C. oxycanthus and C. glaucus species were sensitive to light and gibberellic acid application, and in the presence of these treatments, the germination percentage increased. These findings showed that both species have different degrees of non-deep physiological dormancy. However, the species C. glaucus had higher dormancy. Also, different afterripening periods led to an increase in basic, optimum and germination ceiling temperatures compared to fresh seeds. Examination of the germination response of the seeds of the two studied species showed that in both species, with the increase in the duration of the afterripening period, the base water potential for 50% germination (ψb50) became more negative, and hence, tolerance to drought stress increased during the afterripening period. Nevertheless, afterripening for 12 months significantly increased the hydrotime coefficient (θH) and actually decreased the germination rate compared to other treatments.

In summary, afterripening of seeds in safflower wild species during a suitable period of time (2-6 months) can lead to the improvement of their germination characteristics under different temperature and humidity conditions. In addition, it should be noted that long-term storage of seeds can lead to a decrease in the quality of seeds.

Weeds reduce crop growth and yield through interference and competition with the crop. Polygonum convolvulus L. is an annual weed from the Polygonaceae family. In order to investigate the effect of different treatments in breaking the P. convolvulus seed dormancy, a study was conducted in the weed research laboratory of Gorgan University of Agricultural Sciences and Natural Resources in 2020. The treatments included after-ripening (for seven months), different concentrations of gibberellic acid and potassium nitrate, hot water treatment, mechanical scarification with sandpaper, sulfuric acid (98%), chilling at 4 °C and cutting the seed coat. The results showed that after-ripening, gibberellic acid and potassium nitrate, immersion of seeds in hot water and scarification with sandpaper had no effect on seed germination. Treatment of P. convolvulus seeds with sulfuric acid as well as chilling caused germination in the seeds. Also, scarification the P. convolvulus seed coat around the embryo caused maximum seed germination (87%). The highest germination percentage of P. convolvulus seeds was observed in combined treatment of sulfuric acid treatment (20 minutes) and chilling (15 day) (91.66%) and scarified the seed coat (87%), which were not significantly different. According to the obtained results, it can be stated that the mechanical resistance of seed coat against embryonic growth is the main cause of dormancy in P. convolvulus seeds.

Azivash (Corchorus olitorius L.) is an edible and medicinal plant that can be cooked either fresh or dried. It is cultivated in different regions including Asia and Africa. In the cultivation of wild okra, the possibility of obtaining herbage yield for fresh leaf consumption without negative consequence on seed yield can provide an alternative economic return. In addition, selecting a suitable sowing date to achieve the highest seed yield, can help seed producers maximize their yield per unit of land area during seed production.

To determine the effect of repeated cutting and sowing date on herbage and seed yield of Azivash (Corchorus olitorius L.), an experiment was conducted using a split-plot design based on a randomized complete block design with three sowing dates as the main plots, and three cutting treatments as sub-plots.

The sowing date and repeated cutting had a significant effect on herbage yield, pod number per plant, seed number per pod, pod length, pod dry weight, and seed yield. In general, the treatment of not cutting (Control) on June 9th sowing date produced the highest seed yield (2,895 kg/ha). Conversely, the treatment of cutting twice on July 9th sowing date had the lowest seed yield (290 kg/ha).

Based on the results, it appears that the most suitable sowing date for achieving a seed yield of 2895 kg/ha is June 9th. However, if producers aim for higher income from agricultural land through dual-purpose herbage and seed production, sowing on June 9th with once cutting would result in a herbage yield of 33,467 kg/ha and a seed yield of 2,630 kg/ha in Gorgan region.

Detection of resistance to an herbicide in a putatively resistant accession requires a series of experiments which are capable of illustrating the response of the accession to various herbicide doses. Whole plant bioassay in pots usually takes approx. 2 months to obtain the results, thus, rapid tests were developed to accelerate the process. Although determination of discriminating concentration as well as conduction of rapid test for some ACCase inhibitors has been performed by various researchers, no reports are available in this regard for in clodinafop propargyl herbicide in rigid ryegrass from wheat field of Golestan province. Thus, the following study was conducted with the objective of rapid detection of resistance to the mentioned herbicide in this weed using the rapid test.

The experiments were conducted using the seeds of 30 putatively resistant rigid ryegrass accessions and a susceptible biotype gathered from wheat field of Golestan province in 2019. Rapid test in petri dishes was conducted as a completely randomized design with three replications, with each petri dish as one replicate. To determine the discriminating concentration, various concentrations of clodinafop propargyl was applied on the susceptible accession and then, all putative accessions were screened using this concentrations. The biotypes of the studied weed were exposed to various doses of the herbicide in the petri dish bioassay to determine the resistance factor. Also, another experiment based on a completely randomized design with three replications was conducted for screening of putative accessions in the greenhouse. Accessions which maintained their survival and dry weight respectively 50 and 80 percent compared to the unsprayed control were selected. A whole plant dose-response bioassay was also done separately for each biotype. Checking the distribution map of resistant biotypes indicated that these biotypes were not uniform in the wheat fields of Golestan province. During sampling, geographical coordinates of infected areas were recorded using GPS Map60 device and weed distribution map was prepared using ArcGIS software.

Discriminating concentration of clodinafop propargyl for rigid ryegrass was obtained 0.0196 mg ai. L-1. According to the results, 25 out of 30 accessions were detected as resistant and underwent the concentration- response assay in petri dishes. Resistant factors of the biotypes in the rapid test ranged from 38.75 to 1756.20. According to the results of the greenhouse, 25 accessions were detected as resistant with resistance factors of 11.58 to 24.05. There was a positive and significant correlation between the results obtained from the rapid test with the greenhouse assay (%93). Investigation of distribution map of resistant biotypes indicated non-even distribution of these biotypes across wheat fields of Golestan province, with resistant and susceptible biotypes often observed in the west and east of the province, respectively.

Putative rigid ryegrass accessions collected from the region may be screened using 0.0196 mg ai. L-1 concentration and resistant biotypes may be detected more rapidly compared to greenhouse assays. Also, the results of the rapid test are in accordance with those of the whole plant assay in pots. Due to the swift development phenomenon of herbicide resistance issue, rapid detection of resistance is essential. Thus, using methods such as rapid test may be very feasible.

Numerous studies are being carried out to reveal the effects of different treatments on the germination of seeds from various plants. The most commonly used method of analysis is the nonlinear regression which estimates germination parameters. Although the nonlinear regression has been performed based on different models, some serious problems in its structure and results motivated researchers to investigate alternative approaches with higher accuracy and precision. The main purpose of the present research is to introduce the alternative parametric time to event model and comparing its reliability to the nonlinear regression in experiments carried out under different conditions.

  The results of four different experiments were used here including the effect of Potassium cyanide on walnut seed germination, the effect of salinity on wheat seed germination, the effect of water potential on corn seed germination and the effect of temperature on cotton seed germination. The nonlinear regression and time to event methods were applied based on the Gompertz model. The obtained standard errors from the two models were further assessed using the Monte-Carlo method.

Both methods provided well-fitting models according to the MSE and R2   criteria. Although the germination parameters were approximately identical in both models, the standard error of parameters in nonlinear regression was significantly less than those of time to event method except for the experiments in which all tested seeds germinated within the time frame of study so that in the latter case the estimated standard errors in both models were identical. The Monte-Carlo method confirmed the results of the time to event model and reveals the underestimation of the nonlinear regression method in estimating the standard error of parameters.

Generally, the results of this research showed that the time to event model can be trustfully utilized in seed germination studies under different conditions and treatments. This model, not only provides precise estimates of the germination parameters but also provides the precise standard error of parameters that have important roles in making inferences for parameters. The drc package in R software enables researchers to fit the different time to event models.

In order to investigate the variation in germination rate, cardinal temperature and hydrothermal time parameters of wild mustard seed in different water potentials were designed and implemented during the study in gorgan university of agricultural sciences and natural resources, in 2017 as a split plot done in a completely randomized design with three replications of the municipality. In this research, germination modeling was performed well. To describe the germination rate response to temperature in different potentials of water 0, -0.2, -0.4, -0.6, -0.8 MPa were used from the dent-like function. By applying different concentrations of gibberellic acid (100, 300, 500, 1000, 1500 and 2000 ppm), the process of germination changes in the studied temperatures was incremental, so that the highest germination percentage was related to gibberellic acid 2000 ppm. By reducing the potential at each level of gibberellic acid, the base temperature increased and the lower and upper optimum temperature and the ceiling temperature decreased. The hydrotime coefficient in control seeds decreased significantly with increasing temperature and the water potential was increased. The hydrotime coefficient and base water potential increased with decreasing gibberellic acid. The results showed that the coefficients obtained by the hydrothermal time model were of relatively high precision and the constant value of hydrothermal time, base water potential and base temperature in control seeds were 1173.83 MPa ºC h-1, -0.09 MPa and 3.07 °C and for gibberellic acid with concentration of 2000 ppm were 315.57 MPa ºC h-1, -0.50 MPa and -1.22 ºC, respectively. Changes in the base water potential for 50% of germination in gibberellic acid 1500 and 2000 ppm treatments had a two segmented trend up to 20 °C so that it -0.7 to -0.6 MPa and increased above 20 °C the maximum value at 30 °C.

Persian rose or Varak (Rosa persica) is a thorny shrub belongs to Rosaceae family. This small scented plant due to the having a yellow-flower with a distinct reddish-brown spot in petals base and tremendous resistance to heat and drought has a great potential for modern rose breeding. Since there are not any available reports on germination habit of this aforementioned species, therefore the goal of this experiment is to evaluate the seed viability and type of dormancy in this anomalous species.

To increase the germination percentage of R. persica, collected seeds were exposed to 96% of sulfuric acid for 0, 10 and 30 min. whereupon sulfuric acid-exposed seeds were sown on MS (Murashige and Skoog) media supplemented with 0, 0.1, 1 and 10 mg/l gibberellic acid. This combination was evaluated under ex vitro (Petri dish) and in vitro (in MS media) condition at 4 and 24°C in incubator. Data collected from many traits related to the root and stem after 6 weeks of the experiments.

Despite confirmation of seed viability via Tetrazolium test, standard germination test was failed under ex vitro condition and a few weeks after the beginning of the experiment all specimens became infected with fungus. However, under in vitro condition, treatment of seeds with sulfuric acid for 10 min and then 1 mg/l gibberellic acid, were significantly effective on germination percentage and more than 60% germination frequency was observed in 10-minute sulfuric acid treatment in a hormone-free medium while no seeds have germinated in the control. The maximum root and stem length, hypocotyl length, epicotyl length, seedling length and the number of leaves has achieved when seeds exposed to sulfuric acid for 30 min. However, 10 min treatment of seeds with sulfuric acid was more effective in increasing the length and number of lateral roots and stem diameter. Root and stem length, hypocotyl length and seedling length has increased when gibberellic acid augmented. Stem diameter, length and number of lateral roots were higher in hormone free medium while the number of leaves and epicotyl was higher in medium supplemented with 0.1 mg/l gibberellic acid.

The effect of sulfuric acid on improving germination indicates physical dormancy of Iranian rose seeds. Application of whole treatments did not result to germination at 4°C. Seeds respond to germination treatments only at 24°C. The result of our study on temperature unlike other rose species reveals no need for stratification treatment.

Due to drought, water crisis and increasing soil salinity in Jiroft region in recent years, it seems necessary to cultivate alternative crops for the cold season with low water requirements, high economic efficiency and compatibility with the region and short growth period. Quinoa (Chenopodium quinoa Willd.) is a good choice for this due to its low water requirement and high salinity resistance. Therefore, this study aimed to investigate the protein and saponin contents as well as yield and yield components of quinoa genotypes during autumn and winter cultivation.

This experiment was performed as a split plot in the form of a randomized complete block design with 4 replications, in the research farm and laboratory of the Agricultural Research and Training Center and Natural Resources in the south of Kerman province in the two cropping years of 2018-2019. Planting date (autumn and winter) was the main factor and the genotypes Titicaca, Redcarina, Gza1, Q12, Q18, Q21, Q22, Q26, Q29, Q31 were the second factors. In this experiment, traits such as stem length, the length of growth period, seed protein and saponin contents, 1000-seed weight and grain yield were determined.

Combined analysis of variance of the data showed that the traits measured in this experiment (stem length, length of growth period, percentage of seed protein and saponin) were significantly affected by genotype, planting date and their interactions. Inflorescence length was only significantly affected by genotype. Stem length was very different in autumn and winter cultivation so that in autumn cultivation the highest stem length occurred in Q22 and Q12 genotypes but in winter cultivation the highest stem length was related to Q26 and Q29 genotypes. In all studied genotypes, the percentage of saponin and protein in autumn cultivation was less than winter cultivation, the range of changes in grain saponin and protein percentage was between 4.52 to 5.56 and 10.78-13.89 percent, respectively. Also, grain yield and 1000-seed weight of quinoa were significantly affected by genotype, planting date and their interactions. The range of grain yield changes varied between 1.91 (autumn cultivation treatment and GZA1 genotype) to 3.99 tons per hectare (autumn cultivation treatment Q12).

The results of this study also showed that it is possible to cultivate this crop twice a year in Jiroft region, provided that appropriate cultivars are used. Therefore, Q12 and Q31 cultivars are recommended for autumn cultivation while Q29 and Q26 cultivars are recommended for winter cultivation.

Common morning-glory (Ipomoea purpurea L.) is one of the most important harmful weeds in summer crops in Golestan province. Germination is one of the most important stages of plant life and the study of environmental factors affecting the germination of weeds is necessary for their proper management.

In order to investigate the effect of some environmental and management factors on seed germination and emergence of common morning-glory, experiments were conducted in the laboratovar and research greenhouses of the Gorgan University of Agricultural Sciences and Natural Resources in 2017. In this study, common morning-glory response to constant temperature (5, 10, 15, 20, 25, 30, 35, 40 and 45 ° C), alternating temperature (5:15, 10:20, 15:25, 20:30) , 25:35), high temperature (temperatures of 50, 80 and 100 ° C for 5 and 10 minutes), drought (0, -0.2, -0.4, -0.6, -0.8, -1 MPa), salinity (0, -0.2, -0.4, -0.6, -0.8, -1, -1.2 and -1.4 MPa), pH (4, 5, 6, 7, 8, 9), burial depth (0, 1, 2, 3, 5, 7, 9, 11, 13, 15 and 17 cm) and flooding duration (0, 3, 5 and 7 days) were examined.

Constant and alternating temperatures had a significant effect on the germination percentage of common morning-glory. The highest germination percentage were observed at constant temperatures of 30 and 35 °C and at alternating temperatures of 15: 25 and 20: 30 °C (day / night). Based on the Dent model, Cardinal temperatures of seed germination of this plant including base, optimum upper and lower and ceiling temperatures were 7, 30, 35 and 44 °C, respectively. Germination of of common morning-glory seeds decreased with increasing salinity and drought. The concentrations of sodium chloride and polyethylene glycol, which reduced the germination of this plant by 50%, were equal to -1.06 and -0.45 MPa, respectively. This indicates that this plant is resistant to salinity and there is a possibility of its development in saline lands of the country. Germination of this plant in pHs of neutral and alkaline were significantly higher than acidic pHs. At high temperatures, the percentage of germination and seed viability decreased significantly. The percentage of common morning-glory seed emergence at burial depths of 1 to 7cm were not significantly different (92 to 100%). With increasing depth from 9 to 13 cm, the percentage of emergence decreased significantly and no seeds emerged from a depth of 15 cm. Therefore, the use of non-tillage and low tillage methods can not have much effect on the management of this weed; Unless deeper plowing is used. Results showed that seed germination of this plant is very sensitive to flooding stress.

The results of the present study showed that environmental factors have a significant effect on the germination and emergence of common morning-glory and they can be used in designing effective management scenarios to control of this weed.

Germination is the most vital period in the plant life cycle that is influenced by various environmental and genetic factors. Among environmental factors, drought stress can greatly affect the germination and emergence of seedlings. The tolerance to this stress in the early stages of plant development is very important and seeds that can germinate in these conditions will have a successful establishment, proper density and high yield. Therefore, knowing the drought tolerance threshold in different genotypes of a plant can be very useful in recommending their cultivation in different regions. The hydrotime model is one of the common experimental models in studying the effects of drought stress on seed germination. This model has three parameters including base water potential, hydrotime coefficient and sigma, which indicate drought tolerance, germination rate and germination uniformity, respectively. These coefficients, especially the base water potential, can be used to introduce genotypes for cultivation in areas with different drought levels. Therefore, this study was conducted to investigate the response of different quinoa genotypes to drought stress at the germination stage with the help of hydrotime model coefficients.

To investigate the effect of drought stress on seed germination of different quinoa (Chenopodium quinoa Willd) genotypes, a factorial experiment was designed and conducted in a completely randomized design with four replications in the seed laboratory of Gorgan University of Agricultural Sciences and Natural Resources in 2019. For the germination test, 4 replicates of 25 seeds of each genotype were placed in a petri dish with a diameter of 8 cm on a layer of filter paper which added 3 ml of solutions prepared in different water potentials (0, -0.4, -0.8, -1.2 and -1.6 MPa) in an incubator at 25 °C. Depending on the germination rate, in the first days after the onset of germination, the number of germinated seeds was counted three to five times per day; with decreasing the germination rate, the number of counts was reduced to two times per day. The germination criterion was the radicle existence of one millimeter or more. The hydrotime model was used to investigate the germination response of quinoa genotypes to drought stress.

The results showed that all genotypes had high germination up to -0.4 MPa and their average germination percentage was above 90%; But as the water potential became more negative, the difference between the germination percentage of genotypes increased. According to the hydrotime model, there was a significant difference between different quinoa genotypes in terms of base water potential for 50% germination (ψb50), hydrotime coefficient (θH) and germination uniformity (σψb). The value of the ψb50 parameter ranged from -1.58 in genotype2 to -1.95 in genotype3. This indicates that quinoa is drought tolerant at the germination stage compared to sunflower, barley, wheat, safflower and canola. The lowest and highest hydrotime coefficients were observed in genotypes2 and 3 with 16.83 and 26.08 MPa/h, respectively (with an average of 20.93 MPa/h). Quinoa hydrotime coefficient is lower than rapeseed, wheat and safflower; In other words, the germination rate of the seeds of this plant is higher compared to the mentioned crops. The reason for this may be related to the size of the seed. The lowest germination uniformity was in genotype 3 (0.68 MPa) and the highest value observed in genotype 7 (0.46 MPa). The hydrotime and sigma coefficients are considered as indicators of germination rate and uniformity. The lower values of these coefficients are indicated the higher the germination rate and uniformity of the genotype, the faster the canopy closure and the higher yield.

In general, the results of this study show that the seeds have a high germination rate and with a high tolerance to drought stress at the germination stage; This increases the chances of faster establishment in the water shortage conditions. Also, the ability to tolerate drought in the germination stage of quinoa reduces the need for water consumption in this stage, which can be very useful and practical in developing management plans that lead to increased water use efficiency.

Seeds need successful germination at the optimal time and conditions to survive. Sometimes, even in the best environmental and genetic conditions of the seed, they do not germinate or germinate with a delay, which are called dormant seeds. Seed dormancy can have positive effects on avoiding adverse conditions and ensuring survival in the environment. However, dormancy in crop plants reduces emergence and yield by preventing germination. A combination of environmental and seed genetic factors are involved in seed dormancy formation. In general, seed dormancy includes: physical dormancy, physiological dormancy, morphological dormancy, morphophysiological dormancy and combinational dormancy, and physical / chemical scarification treatments, hot and cold stratification, leaching, hormonal treatments, after-ripening, light and combination treatments can be used to eliminate dormancy depending on its type. Therefore, in this study, using domestic studies conducted in the field of seed dormancy in different plant species, identification of dormancy in different plant species and its types have been discussed, and general and practical information in this regard has been provided.

In this study, 168 reports published on 250 plant species in the last 20 years, which were published in the seed dormancy of medicinal plants, weeds, rangelands, ornamentals and crops were investigated. Then, the percentage of plants studied and their families, as well as the share of different types of seed dormancy and appropriate treatments to for its eliminate were determined.

Among the plant species studied, the most freuqent type of dormancy was related to physiological dormancy (50%), followed by physical dormancy, combinational dormancy, morphophysiological dormancy and the lowest share of dormancy in the studied plant species was related to morphological dormancy (1.61%). The most effective treatments to eliminate physiological dormancy were the use of cold stratification, gibberellic acid, and potassium nitrate. Also, the most effective treatments for the removal of physical dormancy were the use of physical / mechanical scarification treatments, chemical scarification and potassium nitrate treatment. According to the results, temperature treatments and then gibberellic acid and potassium nitrate treatments are recommendedt eliminate morphological dormancy. To eliminate morphophysiological dormancy, it is recommended to use treatments to maturate differentiated small or undifferentiated seeds (removal of morphological dormancy) as well as treatments to counteract the germination inhibitory factors or to compensate the were applied the most to eliminate morphophysiological dormancy.

By identifying the type of dormancy and applying the appropriate treatments, the germination of economical and valuable plants can be improved.

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.

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.

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.

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.

The exposure of seeds to undesirable soil conditions induces secondary dormancy and this causes many problems for seed producers. Assessing seed secondary dormancy potential is an important factor in developing rapeseed lines and cultivars. A relatively rapid, precise, and reproducible method derived from the Hohenheim standard dormancy test (HSDT) has been developed for secondary dormancy evaluation of 41 rapeseeds (Brassica napus L.) lines and 5 cultivars. The two previous methods, HSDT and rapid secondary dormancy (RDT) were compared with our suggested fast-reproducible dormancy test (FRDT) method. All three methods consider three stages for seeds i.e. dormancy induction, germination in darkness, and breaking secondary dormancy. In the FRDT method, time to germination in darkness and seed dormancy breakage duration decreased to 7 and 4 days, respectively, whereas the corresponding figures in the HSDT were 14 and 7 days. Meanwhile, the duration of the three stages in sum decreased from 35 to 25 days. The obtained ranges of seed dormancy in different lines and cultivars as assessed by HSDT, FRDT, and RDT varied from 6 to 98.75, 7.5 to 99, and 0 to 36%, respectively. Positive relationships were found between data of the seed secondary dormancy testing by HSDT and FRDT methods. Owe to the precise and reproducible estimates, both HSDT and FRDT methods can be used for testing seed secondary dormancy in different rapeseed lines and cultivars. This method helps seed breeders to improve the screening of new rapeseed lines and cultivars with lower potential for secondary dormancy and as a result reduce the risk of volunteer rapeseed emergence in the field, which compromises yield in the next growing season.

Seeds deteriorate and become aged during storage so that the rate of this process depends on the temperature and seed moisture content. This experiment was conducted to study changes in the activity of antioxidant system of cottonseeds during deterioration. An Accelerated aging test was used to create different levels of deterioration. Cottonseeds were incubated at 43 ℃ for 0, 48, 96, 144, and 192 hours and 100% relative humidity. Results showed that the membrane electrical conductivity, lipid peroxidation, and hydrogen peroxide increased with lengthening of deterioration periods. Increase in hydrogen peroxide was accompanied with decreased activity of catalase and the increased activity and content of peroxidase and ascorbic acid, respectively, which indicates declined activity of catalase due to aging as compared with peroxidase activity and ascorbic acid content. Also, with an increase in the period of deterioration, percent, rate, and uniformity of germination reduced. In general, the study indicated that the oxidative stress due to the accumulation of reactive oxygen species and the reduction of the antioxidant system is one of the main reasons for cottonseed viability loss during storage.

Cotton is the most important fiber crop in Iran and as well as the world. The acreage of cotton is about 80,000 ha in Iran. The present study aims to determine the parameters of the SSM-iCrop2 model and evaluate the ability of the model to simulate cotton growth and yield in different regions and environmental conditions of Iran. Different aspects of crop growth are organized as sub-programs including phenological development, leaf area changes and dry matter production and distribution. Soil water balance sub-program is entered in the model to simulate changes in soil water and determination of stress severity. Simulation by the model is done on a daily basis and requires data related to atmosphere, soil and crop management. The model was tested for Iran conditions. To estimate the coefficients and evaluation of the model, data obtained from experiments conducted in various areas of the country were used. The model was evaluated using independent data following estimation of genetic parameters. The results indicated acceptable efficiency of the model in prediction of daily simulation including days to maturity (RMSE=8.4 day, CV=6.5 %) and seed cotton yield (RMSE=56.6 g/m2 and CV=13.9 %) for parameterization and seed cotton yield (RMSE=50.4 g/m2, CV=12.8 %) for evaluation. Also, the results showed that RMSE and CV values for simulation of yield, Evapotranspiration, and used water were respectively (77.6, 12.9%), (150.3 and 16%) and (178.5 and 19.6%) in major cotton production areas of Iran. These results indicate that estimates for variables are acceptable.

In order to investigate the resistance of short spike canarygrass (Phalaris brachystachys) biotypes to acetyl coenzyme A carboxylase inhibiting herbicides wheat fields of Golestan province, 43 suspected resistance were collected from a different area in 2018. The susceptible biotype was also collected from regions with no chemical control record. The study was carried out in three steps including determination of discriminating concentration for susceptible biotype, screening P. brachystachys biotypes with the discriminating concentrations, and concentration-response experiment for suspected resistant biotypes at Gorgan University of Agricultural Sciences and Natural Resources in 2018. According to the seed bioassay test, the discriminating concentration of sensitive biotype for clodinafop propargyl, diclofop methyl, haloxyfop-r-methyl, cycloxydim and pinoxaden were 0.02, 1.36, 0.03, 0.06 and 0.08 mg a.i.L-1, respectively. In the screening test using the discriminating concentration, 36 (84%), 36 (84%), 19 (44%), 23 (53%), 21 (48%) out of 43 biotypes were identified as suspected resistant to clodinafop propargyl, diclofop methyl, haloxyfop-R-methyl, cycloxydim and pinoxaden, respectively. In general, the results showed that the studied biotypes had different patterns in terms of resistance to different groups of ACCase-inhibiting herbicides. The results of the concentration-response test also showed that among 43 suspected resistance suspected of resistance, 19 biotypes were resistant to all five herbicides.