جستجوی مقالات مرتبط با کلیدواژه « Seedling emergence » در نشریات گروه « زراعت »

The use of seed priming technology to accelerate the germination and seedling emergence of multi-purpose plants such as halophytes (Alhagi) with the ability to produce medicine and forage under environmental stress conditions or use of saline water (such as seawater of Persian Gulf) has received much attention today. Therefore, the present study was conducted to investigate seed priming methods and different salinity levels on germination, seedling emergence, and some growth responses of Alhagi plant.

Two separate split-factorial experiments were conducted based on a randomized complete block design with four replications as a petri dish culture (first experiment) and a pot experiment in the field was performed in the Department of Plant Production and Genetics, Faculty of Agriculture, Shahid Chamran University (Ahwaz, Iran) during 2020-21. In both experiments, different levels of salinity (municipal water source with EC=0.96 dS.m-1, 8 and 16 dS.m-1 using seawater of Persian Gulf) were assigned as the main plot, and different methods of seed priming (non-priming, hydro priming, hormonal priming with 50 ppm gibberellin and hydro priming+hormonal priming with 50 ppm gibberellin) and species (A. maurorum and A. graecorum) were assigned as sub-factors.

The results showed the significance of salinity × species × priming interaction on all studied traits. According to the mean comparison results, the highest values of germination percentage, seed vigor index, seedling emergence, plant height, number of branches, total dry matter and stomatal conductance were obtained from a municipal water source with EC=0.96 dS.m-1 and hydro priming+hormonal priming with 50 ppm gibberellin for A. graecorum (29.1, 90.2, 24.0, 32.3, 52.5, 52.1 and 32.4% increase compared to non-priming and control salinity stress on this species, respectively). The output of the fitted logistic model to seedling emergence percentage showed that this model well explained the relationship between seedling emergence of two Alhagi species in responses to salinity and seed priming (R2 adj≥0.98 and RMSE≤3.38). Therefore, in both studied species, the decline in seedling emergence started from the 8 dS/m salinity level. However, at the 16 dS/m salinity level, the slope of increase in seedling emergence percentage was slower per time unit.

To cultivate and exploit the saline coastal lands and also to restore the pastures in the country, A. graecorum species under the combined treatment of hydro priming + hormonal priming with 50 ppm gibberellin are recommended in comparison with other treatment levels.

Highlights:

1- Germination and growth responses of two Iranian Alhagi species and the possibility of production by irrigation of seawater of Persian Gulf were investigated.
2- Seed priming technique was used to accelerate seedling emergence and improve some traits in two Alhagi species.

Aging seed can be defined as loss of seed quality, viability and vigor. This process is irreversible over time and its intensity increases with increasing temperature and humidity. Aging seed is one of the major factors reducing quality and quantity in the agricultural sector, especially oilseeds. The use of antioxidants can reduce the damaging effects of aging. Ellagic acid is a natural plant antioxidant that can play a role in reducing the effects of stress on plants. This substance is a phenolic compound and among different antioxidants, due to its polyphenolic properties, it is one of the best scavengers for oxygen free radicals.

To investigate the effect of ellagic acid on improving the quality of plants obtained from normal and aged soybean seeds, an experiment was conducted in the research farm of Shahroud University of Technology during the two cropping years 2019 and 2020. In this study two sets of seeds including control seeds (un-aged) and aged seed were used and ellagic acid (50 mg. l-1) was applied for control, seed pretreatment, foliar spray and seed pretreatment+foliar spray. Farm research was conducted a factorial experiment based on a randomized complete block design (RCBD) in three replications. Soybean seeds var. DPX were collected from Mazandaran agricultural research center. The water content of seeds was 12%. The seeds were those that harvested in the same year and kept in a controlled storage room at the temperature between 14 to 17 °C and relative humidity of 30 to 40% at the Agricultural Research and Training Center and Natural Resources of Mazandaran Province. To prepare aged seeds in the laboratory, the seeds were incubated at 41°C and 95% relative humidity for 72 hours. Seed pretreatment with a concentration of 50 mg.L-1 ellagic acid was performed under ventilation condition for 6 hours. The seeds were then dried in the shade and used to continue testing and measuring traits compared to normal seeds. Foliar application was done early in the morning at the beginning of flowering (R1) and in favorable environmental conditions.

The results showed that aging reduced the mean daily seedling field emergence by 61.39% compared to normal seeds. The ratio of chlorophyll a to b, total chlorophyll, stomatal conductance and membrane stability index in the leaves of plants from aged seeds decreased by 9.9, 6.3, 7.0 and 28.9%, respectively, compared to the control. The amount of free amino acids and soluble sugars in the leaves of plants from aged seeds increased compared to normal seeds. Pretreatment of normal and aged seeds with ellagic acid increased the mean daily seedling field emergence by 23.1% and 19. 7%, respectively. The content of insoluble sugars were increased with application of both pretreatment and foliar spray of ellagic acid 32.0% respectively. The highest oil yield in both conditions was observed with application of both pretreatment and foliar spray of ellagic aicd. The yield seed increased with ellagic acid compared to the control 23.6%. Grain yield was higher than 23.2% in the plants that had received ellagic acid in a form foliar spray. In the end, the pretreatment+foliar spray of ellagic acid had the highest grain yield, which increased to control 55.5%.

However, in this study, the application of ellagic acid as a seed pretreatment and foliar spray had a positive effect under normal and aging conditions, but in the scope of the research, the combined application of ellagic acid as seed pretreatment and foliar spraying can be recommended to increase seed yield and seed oil yield in soybean. In general, ellagic acid can be introduced as a powerful antioxidant in aging conditions to reduce some of the destructive effects of the reactions involved in aging.

Spotted spurge is a summer annual weed in row crops that can reduce their yield. Thus, in order to evaluate the effect of different management practices on the emergence time of spotted spurge, a split-split plot experiment was conducted in a completely randomized block design with three replications in Dasht-e-Naz Sari in 2016 and 2017. Two tillage systems (Conventional tillage and no-till), three soybean densities (200,000; 300,000 and 400,000 seeds ha-1), and three doses of imazethapyr (0, 50, and 100 g ai ha-1) were considered as experimental factors. The spotted spurge emergence was significantly affected by management practices including tillage system, soybean seeding rate, and imazethapyr dose. Conventional tillage, 400,000 seeds ha-1 of soybean and a 100 g a.i. ha-1 imazethapyr resulted not only the lowest spotted spurge seedling density m-2 but also caused the longest delay in the time to reach 50% of seedling emergence (T50), thus resulting in a long lag phase of spotted spurge emergence early in the season. This condition provided more time for soybeans to establish better and improve their competitive ability, which resulted in higher soybean yield per unit area at the end of the growing season in these treatments. The results of our study could help to develop effective management strategies for this species.

An important step in weeds control are to identify the ecophysiological characteristics of the seeds of these plants. In order to investigate different methods of dormancy breaking of wild mustard seed (Sinapis arvensis L.) an experiment was conducted on a completely randomized design with three replications in 2019 in the Faculty of Agriculture and Natural Resources of Mohaghegh Ardabili University. Experimental treatments included control, chilling, placing in gibberellic acid solutions with four concentrations of 500, 1000, 1500 and 2000 parts per million for 24 hours, placing in concentrated sulfuric acid solution (98 Percent) for 1, 2 and 3 minutes and placing the seeds in ultrasonic for 10, 20 and 30 minutes. The results showed that the measured traits were affected by experimental treatments. Gibberellic acid 1500 parts per million (ppm) was measured at with the greatest effect on germination and growth components. Compared with the control treatment, gibberellic acid 1500 parts per million (ppm) increased 80 percent of wild mustard seed germination. However, in most of the studied traits, sulfuric acid had a negative effect on germination and growth components. The results suggest that despite the positive effect of gibberellic acid on germination of wild mustard seed, concentrated sulfuric acid has a detrimental effect on their and can be used as one of the methods for effective in controlling weeds.

Hyparrhenia hirta L. is a drought tolerant herbaceous species and one of the valuable genetic reserves. Poor seed production has caused some problems related to natural regeneration of this plant and micro-propagation and the production of artificial seeds through somatic embryos in this plant is necessity and especially important. A factorial experiment based on a completely randomized design with three replications was performed to consider the effect of encapsulation of somatic embryos with different concentration of sodium alginate and calcium chloride as well as different duration of ion exchange on seedling emergence percentage from encapsulated embryos. Single adult embryos derived from suspension cultures were placed in different sodium alginate concentrations of two, three and four percent. Single embryos in sodium alginate solution were injected by syringes in various calcium chloride complex at concentrations of 50, 75 and 100 mM, and were coated in different times of 20, 30, 40 and 50 minutes. The encapsulated seeds were cultured on MS 1​​/2 without any growth regulator and kept in a growth chamber at 22 °C and the period of 16/8 h (light/darkness) for two weeks and the emerged seedlings from the alginate coating were measured. The highest germination percentage and seedling emergence (60%) was obtained from 3% sodium alginate and 100 mg calcium chloride during 40 minutes of ion exchange time.

This research was done to evaluate the ability of standard germination test to predict emergence and establishment of barley seedlings in farm. The experiment was conducted under both laboratory and farm conditions at Razi University during 2013-14. In laboratory, eight seed lots of dryland barley were compared in a standard germination test based on completely randomized design and different indices related to seed and seedling vigor were measured. These seed lots were also planted under farm condition as a randomized complete block design and percentage and rate of seedling emergence were evaluated. The results of laboratory test showed that the seed lots were significantly different in final germination percentage, normal seedlings percentage, daily germination rate, root length, root dry weight, shoot dry weight and seedling vigor index. Orthogonal comparisons of data from the laboratory and the farm experiments showed that the new seed lots had higher germination and vigor characteristics than the old seed lots. In the correlation analysis between the measured traits in the farm with the laboratory conditions showed that the percentage and rate of seedling emergence in the farm test had higher correlations with final germination percentage, normal seedling percentage and daily germination rate in the laboratory test. So, it seems that we can recommend standard germination test with high trust to predict the seedling emergence and establishment of dryland barley in the farm.

Determination of sugar beet planting date is one of the important factors influencing field management. The occurrence of frost damage after seedling emergence has been considered as a limiting factor for early sugar beet planting. This study was conducted to determine the proper sugar beet planting date in Islamabad Gharb, Kangavar and Kermanshah (including Sahne, Bisotun, and Mahidasht cities). A model was designed based on meteorological data collected from 1993 to 2008. After running a normality test for soil and meteorological data (Shapiro-Wilk test), the probability of temperature decrease (less than -2 oC) under different months (from March to May) was determined using normal distribution function. Then, according to the required base-temperature and thermal units from planting to emergence as well as collected temperature data at the depth of 5 cm in each region, the plausible planting and emergence time was predicted. Through combining the probability of frost occurrence (less than 20%) at -2 oC and proposed planting date and field emergence, a plating-time model was developed for each region. Results showed that the average thermal units required from planting to seedling emergence was 173 growing degree days for all regions. Based on the results, the earliest planting date with minimum frost damage for Kermanshah, Islamabad Gharb, and Kangavar are 17th March, 22nd March, and 9th April, respectively.

Determination of response function of seed germination and seedling emergence to temperature and obtaining cardinal temperatures (base, optimal and maximum) and biological day requirement (minimum day number for seed germination and seedling emergence under optimal temperature and moisture conditions) for emergence is important for crop simulation modeling. This study was carried out to survey seedling emergence response to temperature in five rapeseed cultivars that were sown on 12 sowing dates under Gorgan environmental conditions (2013-2014). Three regression models including beta, segmented and dent-like were used to describe the response of seedling emergence rate to temperature. Root mean square of error, coefficient of determination, correlation coefficient and regression of predicted versus observed values were used to develop the appropriate model. Segmented model was superior compared to beta and dent-like models to achieve the objective of this study. Estimated cardinal temperatures using appropriate model were 3.2, 26.8 and 40˚C for base, optimum and maximum temperatures, respectively. Estimation of biological day requirement in sowing depth of 2 cm showed 4.5 days. The result showed that there is no significant difference for cardinal temperatures and biological day requirement among cultivars. It was concluded that segmented model can be used to quantify the response of rapeseed sedling emergence to temperature and to obtain cardinal temperatures of emergence and thermal time or time to emergence. These parameters are required to develop prediction models for rapeseed seedling emergence under diverse temperature conditions.

According to the effect of seed size on seed quality, this study was conducted in the Seed and Plant Certification and Registration Institute (SPCRI) in 2009-10, based on completely randomized design and with three replications. Studied factors(16 treatments) consisted of two canola cultivars (Okapi and Talaye), four separated seed sizes (1.4, 1.6, 1.8 and 2 mm) and two levels of using and none using of gravity separator tool. Based on the results using of 1.6 mm sieve size accompanied to gravity separator tool is recommended for cleaning these two varieties seed while germination percent and seedling emergence was improved and also higher seed loss percent was attained by using of sieves with 1.8 and 2 mm size. Whatever lower seed loss percent was attained using 1.4 mm sieve size but percentage of seed purity was decreased and also number of weed seeds increased which resulted in rejection at standard seed certification process. So the best treatment was related to the sieve with 1.6 mm size that was standard in the aspect of physical purity and germination percent.

International Seed Testing Association (ISTA) defined seed vigour as "the sum of those properties of the seed which determine the level of activity and performance of the seed or seed lot during germination and seedling emergence". In any seed lot, losses of seed vigour results in the reduction of the ability of seeds to carry out all the physiological functions that allow them to perform. This process, called physiological ageing, starts before harvest and continues during harvest, processing and storage. Any given seed vigour test must be able to provide a more sensitive index of seed quality than the germination test and provide a consistent ranking of seed lots in terms of their potential performance. It must also be objective, rapid, simple and economically practical, reproducible and interpretable. Internationally, many vigour tests have been proposed such as standard germination test, cold test, electrical conductivity test, hiltner test, tetrazolium test, controlled deterioration test, accelerated aging test, etc. The accelerated aging test provides valuable information on storage and seedling field emergence po¬tentials. In the accelerated aging test, seeds are hydrated to a specific level when ex¬posed to relatively high temperature (40 to 45 oC) and humidity (around 100 % relative Humidity). Following this aging treatment, seeds are subjected to a germination test and higher vigor seed lots tolerate this aging condition better than lower vigor seed lots and produce a higher percentage of normal seedlings. In this study, chickpea seed lots were exposed to different temperatures and durations in order to calibration of accelerated aging test to predict the seedling emergence under field conditions.
This research was conducted as two laboratory and field tests at Campus of Agriculture and Natural Resources, Razi University, Kermanshah, Iran, in 2012. In the laboratory test, accelerated aging treatments (temperature and duration) including 41, 43, and 45 oC and duration 0 (control), 48, 72, 96, 120, and 144 h were performed on 13 chickpea seed lots. Following this aging treatment, seeds were subjected to standard germination test and different traits (including final germination percentage, mean daily germination, daily germination speed, germination rate, germination index, seedling vigor index, and efficiency of seed storage usage) were evaluated. Theses 13 seed lots belonged to both kabloli (Hashem, Azad, ILC-482, Bivanij, Arman cultivars) and desi (Kaka and Pirooz cultivars) types. In the field tests, these 13 chickpea seed lots were planted as a randomized complete block design with four replications. In field test, different seedling traits (including final emergence percentage, mean time to emergence, mean daily emergence, daily emergence speed, emergence rate, and field emergency index) were evaluated. Finally, correlation of different traits related to seed vigor in the laboratory test was determined with percentage and rate of seedling emergence in the field.
Analysis of variance in the laboratory test showed that the effects of seed lots, accelerated aging treatments and their interaction were significant on all above mentioned traits except for efficiency of seed storage usage. Different levels of accelerated aging treatments had significant effects on germination characteristics, so that germination characteristics were decreased with increasing of temperature and duration in accelerated aging test. In the field test, chickpea seed lots were different significantly in most seedling traits. Means comparison of laboratory and field experiments showed that the new seed lots had higher germination and vigor characteristics than the old seed lots. Correlation analysis showed that, shoot dry weight in the accelerated aging test under 43 oC , 48 h and root length under 43 oC, 72 h had the highest correlation with seedling emergence percentage in the field test. Root length under 41 oC, 72 h and shoot dry weight under 43 oC, 72 h had the highest correlation with seedling emergence rate in the field test, too.
It seems that accelerated aging test is recommendable to predict the seedling emergence of chickpea in field conditions. The accelerated aging test under 41 oC, 72 h and 43 oC, 48 h had the highest correlation with both percentage and rate of seedling emergence in the field test.

To understand germination and emergence characteristics of black henbane, ground cherry and curly dock a laboratory experiment, based on randomized complete block design with four replications, was carried out at the Faculty of Agriculture, Ferdowsi University of Mashhad in 2012. Treatments were temperature ranges (5/15, 10/20, 15/25, 15/30 and 20/35 ° C night / day) and different levels of salinity (0, 10, 20, 40, 80, 160 and 320 mM of NaCl). The effect of pH adjusted to 5-9 by using acid buffer solution. Seeds were planted at different depth (0, 1, 2, 3 and 4 cm) to study their effects on seedling emergence. Results showed that black henbane exhibited highest germination percentage at 25/15 diurnal tempratures, with 86.50 and 60.50 respectivly for daylight and complete darkness. Germination of ground cherry was highest (93%) at 10/20 diurnal temprature and 41% in complete darkness. Highest germination percentage for curly dock at diurnal temperatures of 20/10, 25/15 and 30/20 with light / dark regime of constant darkness was abserved. The seeds at diurnal temprature of 35/25 in both light regimes did not germinate. Increasing salinity reduced germination. Increasing the osmotic potential, also reduced germination significantly. Highest germination percentage of black henbane (97%) was observed at pH 7, and lowest germination (17%) at pH 9. Increasing planting depth reduced seedling emergence significantly. Germination percentages of ground cherry and curly dock at pH 6 and 7 were highest (97% and 96% respectively) and lowest 26 and 25 % respectively at pH 9.

In order to investigate factors affecting on seed germinating of London rocket (Sisymbrium irio)، lab experiments were set up in 2011 at the Payamenoor University، Mashhad، Khorasan Razavi province. Effect of different concentrations of Gibberellic acid (GA3) and Cytokinin، wet and dry prechilling duration، hydrogen peroxide duration، ethanol، salt and osmotic stress and burial depth on seed germination and seedling emergence were investigated. Increasing concentration of GA3 from 50 ppm to 100 ppm enhanced germination of London rocket، but higher concentration of GA3 had inhibition effect. Wet prechilling was more effective than dry prechilling in seed germinating of London rocket. Increasing concentration of cytokinin decreased seed germination. Seed germination of London rocket was reduced by increase in duration of soaking in hydrogen peroxide. Ethanol had inhibition effect on germination Osmotic and salt stress decreased seed germination. Seed germination decreased with increase in burial depth. Results from the study could be used for integrated weed management programs.

In order to investigate the effects of on-farm seed priming and sowing dates on seedling emergence, yield and yield components of a local genotype bean called Pach Baghala-Red strain (Phaseolous vulgaris L.) as a double crop after rice, an experiment carried out in the Rice Research Institute of Rasht. Experimental design was laid out in a split plot based on a randomized complete block with three replications. Sowing date was set out as the main plots including 11th, 21st and 31st August and priming treatments including four levels (no primed, priming using zinc sulfate, urea solutions and tap water) used as sub-plots. Time for priming was 5 hours soaking in each treatment. Results showed that primed seeds had higher speed and percentage of emergence especially by zinc sulfate solution. Also emergence percentage in the third planting date was decreased by 16% compared to other dates. In the first sowing date, all priming treatments and in the second sowing date, zinc sulfate solution led to higher grain yield while priming had no effect on the yield in the third sowing date because of severe reduction in growing season. Also harvest index was reduced significantly in the third sowing date. Priming with zinc sulfate solution significantly increased the 100 seeds weight but delay in planting decreased it. 100 seeds weight and number of seed per pod had the highest correlation with grain yield, meanwhile no correlation was detected between grain yield and pod number per square meter.

To evaluate the effects of on-farm seed priming treatments and sowing dates on rate and percentage of seedling emergence, biological yield and some physiological indices of corn hybrid (SC. 260) an experiment was conducted in Hamedan, Iran in 2010. A split plot in a randomized complete block design with three replications was conducted. Main plots include three sowing dates (early, on-time and late seeding time) and subplots were representative of four on-farm seed priming treatments (priming with tap water, urea, and zinc solutions and non-priming). Results showed that priming with zinc and urea solutions in the first date increased emergence rate. Percentage of emergence was increased by zinc solution and tap water at the first sowing date, while in the second sowing date using urea and zinc solutions increased percentage of emergence. However, in the third sowing date only urea solution was effective. The highest of maximum crop growth rate was achieved in the first and third sowing dates with tap water and zinc solution. All priming treatments were higher in maximum leaf area index than the non-primed treatment. In the first sowing date, all priming treatments exhibited higher biological yield especially in tap water and urea solution. Finally, the SPAD numbers in all priming treatments in the first and third sowing dates were higher than non-primed treatment. Generally, it was concluded that in Hamadan, seed priming especially with tap water and urea solution could help early seeding of corn plant and to avoid early chilling damage in autumn

In order to evaluation the allelopathic effects of cool season crops stubble on seedling emergence and early growth of sorghum، soybean and corn، an experiment was conducted in seed library research and greenhouse of College of Agriculture، University of Tehran in 2006. The experiment consisted of cool season crops as main plots، four stubble concentrations (5/3، 7/93، 10/55 and 0 (control) g/kg) and three crops (sorghum، soybean and corn) which were factorially assigned to the main plots. The experiment was arranged as a split plot factorial in a completely randomized block design with three replications. All traits (seedling emergence rate، plant height، shoot dry weight، root dry weight and shoot/root ratio) were affected by experimental treatments. By an increase in stubble concentration to 20 g/pot germination، percent of the studied crops significantly reduced. Germination of soybean was the most susceptible trait to allelopathic mater. Rye had the highest allelopathic effects on plant height of the studied crops. Root dry weight of soybean was significantly affected compared with that of corn and sorghum. The increase of stubble concentration led to the highest shoot/root ratio in soybean.

Seed samples of three oil-seed rape cultivars SLMO46, Orient and Zarfam (Regent×Cobra) with 35, 25 and 15% moisture contents were provided from seed production fields. Cortrolled deterioration test was conducted in laboratory by maintaining seeds at 40, 45 and 50°C for durations of 12, 24 and 48 hours. Analysis of data on different seed quality assessment parameters showed that except coefficient of velocity of germination, other traits were affected by deterioration treatments. Seeds of cultivar Orient had the lowest viability, seedling vigour and other related traits at 50°C for 48 hours treatment. The dioriorated seed were sown in field and some characteristics such as seedling emergence speed, field emergence index, seedling height, seedling fresh and dry weight and seedling vigour index were assessed. Analysis of data showed that only seedling fresh weight and seedling vigour index were not affected by the effect of year. Interaction effects of cultivar, temperature and duration of seed deterioration were significant for all measured characters. Seeds of Orient cultivar deteriorated at 50°C for 48 hours had the lowest field emergence speed and field emergence index. Study of correlation between different traits assessed in laboratory and field indicated that except seedling fresh weight, other field traits correlated to the final germination percent and other laboratory traits. The results of the present study revealed that application of controlled deterioration test has the potential to evaluate seed quality and seedling emergence and establishment of oil-seed cultivars in field