جستجوی مقالات مرتبط با کلیدواژه « ظهور گیاهچه » 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.

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.

This study was done to evaluate different linear and nonlinear regression models to determination of cardinal temperatures and biological day's requirement for emergence of lentil. Therefore, a split plot experiment was conducted based on three replications. Seeds of lentil (Gacgsaran, Kimia and Bilehsovar) were sown in field at 12 different dates. Beta, dent-like and segmented models were applied to evaluate the relationship between germination rate and temperature. Root mean square deviation (RMSD), coefficient of determination (R2), variation coefficient (CV (and linear regression coefficients (a and b) were used to select the perfect model. Results of models fitting indicated that the response of lentil emergence to temperature is best described by a segmented model. Cardinal temperatures estimated by this model were -1.27 to -1.62°C for base temperature, 23.15 to 25.92°C for optimum temperature and 30°C for ceiling temperature based on air temperature. There was not any significant difference among cultivars in view of in base temperature and optimum temperature but cultivars had significant difference in biological days. The biological day’s requirement was 6.99, 8.56 and 8.78 for Bilehsovar, Gacgsaran, and Kimia, respectively. The quantitative information provided in the present study can be used to predict the emergence of lentil cultivars.The main applicable result of this study was that reaction of seedling of the lentil is describable best by the use of segmented model, so this model and its derived parameters are applicable in predicting emergence in some given lentil cultivars.

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.

Emergence of saffron buds is sensitive to soil compaction and structure. Soil bulk density is introduced as the most important index of soil physical quality. Accordingly, this study was done to evaluate the effect of compost and compost-biochar in planting bed on the emergence and early seedling growth of saffron ecotypes and its relationship to soil bulk density. Experimental treatments consisted of planting beds (without any organic amendment (control), incorporation of 20 t.ha-1 compost and 10 t.ha-1 compost 8 t.ha-1 biochar (cellulosic material of hardwood)) and different ecotypes of saffron (Bajestan, Estahban, Ferdows, Gonabad, Natanz, Qaen, Sarayan, Torbate-Heydarieh and Zarand). Data obtained from experiment were subjected to combined analysis of variance among planting beds based on randomized complete block design. The results showed that application of compost and compost渪ᲅ, improved emergence of the main and lateral buds as well as leaf growth parameters compared to the control. Zarand, Torbate-Heydarieh and Estahban ecotypes responded differently to the planting bed types in terms of emergence percent and rate of main bud compared to other ecotypes. Considerable variation was observed among the ecotypes in terms of all studied parameters, which indicated the adaptability of ecotypes to climatic conditions of corm provenance. Generally, the Bajestan, Ferdows and Qaen ecotypes showed superiority in terms of leaf area and dry weight. Compost and compost-biochar significantly (12%) reduced the soil bulk density compared to the control. Linear regression analysis indicated that there was a negative relationship between soil bulk density and the studied parameters, and significant decrease in all parameters was observed with increasing of soil bulk density.

In order to investigate the effect of magnetic field and irrigation with different salinity levels on cotton seedling emergence, a study was conducted as factorial experiment in a randomized complete block design with three replications in the Kashmar Higher Education Institute during 2016. In this experiment, different levels of irrigation water salinity were considered i.e.0.5: (S1); 3: (S2); 7: (S3); 10: (S4); and 13: (S5) ds/m as a main plots and magnetic field (M1) and non-magnetic (M2) as sub-plots. Six Neodymium-iron-boron magnets with the power of 1500 mT and dimensions of 4×2×1 cm were used to produce magnetized water. were included Determination of percentage and duration of seedling emergence under irrigation by magnetic and no magnetic were evaluated parameters The results showed that by increasing of salinity, germination of cotton reduced so that the ratio of reduction were as 46, 60, 83 and 100 % for salinities treatments i.e. 3, 7, 10 and 13 ds/m, respectively, under non-magnetic condition and also under magnetic condition were at the rates of 21, 46, 36 and 50 %, respectively. According to the results, it was evident that more than 67 % of the buds were appeared in all salinity levels under magnetic conditions before the fourth day after the appearance of the first seedling, while for non-magnetic conditions were obtained sixth day for low salinity and for high salinity 15day after the appearance of the first seedling. The results showed that magnetic water effect was significant at 1 and 5% on number of seedling and accelerate germination time, respectively. Therefore, it can be conclude that magnetic effect was positive on the number of buds and accelerate germination time under various irrigation water salinities.

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.

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.

In order to evaluate the response of emergence rate of oil seed rape seedlings to temperature, a pot experiment was conducted to assess the relationship between emergence rate of three rape seed cultivars (apetalous flower, RGS003 and Syn3) by using a non-linear regression against temperature variation. Six models (tooth shape, segmented, beta, curve, quadratic and cubic) were used and the superior model was selected according to square root of MSE, coefficient of determination, coefficient of correlation and simple linear regression coefficients (a, b) between observed and predicted emergence rates. Results showed that the seedling emergence response to temperature explained by beta function in RGS003, by beta and cure functions in Syn3, and by segmented function in apetalous flower cultivar. Prediction of cardinal temperatures by using the best models showed that the base temperature varied between 7.89 and 10.94, the optimum temperature was between 20.1 and 24 and the ceiling temperature was between 36 and 37.19°C for rape seed cultivars. The biological day estimation for seedling emergence by using segmented and beta models showed that there were significant differences between rape seed cultivars. According to the results of this experiment, beta and segmented models could be used for quantification of seedling emergence response of rape seed cultivars to temperature. It seems that these models and parameters (base, optimum and ceiling temperatures) could be used for prediction of seedling emergence in the field. Cardinal temperatures and its related model could be used for modeling of seedling emergence of rape seed cultivars.

In order to evaluate seedling growth characteristics، of seeds produced under deficit irrigation and seed inoculation with rhizobacteria on soybean [Glycine max (L.) Merr] seed. An experiment was conducted based on split factorial in form of randomized completely block design with three replication. Treatments are include water stress [irrigation after 50 (normal irrigation)، 100 (mild stress)، 150 mm (severe stress) evaporation from pan of class A]، Cultivars [Manokin، Williams and SRF×T3 Line] and seed inoculation [Bradyrhizobium japonicum، Bradyrhizobium japonicum co-inoculated with Azotobacter chroococcum، control]. Bacteria factor was in main plot and placed cultivars and drought stress seeds condition in subplot. The result showed that water deficit had significant effect on seedling number، rate and length. Severe stress seeds condition had lower number and emergence rate compared to normal irrigation. Maximum seedling characteristics were for co inoculation treatment than no inoculation. Mild stress seeds inoculation with Bradyrhizobium japonicum had highest seedling length، dry weight and vigor was for normal and mild stress condition.

To study the root allelopathic effects of cool season crops on germination and early growth of three crops (sorghum, corn, and soybean), an experiment was conducted in seed research laboratory and greenhouse of College of Agriculture, University of Tehran. The experiment consisted of four cool season crops (wheat, barley, rye and pea) and control as the main plots, three spring-crops (corn, soybean and sorghum) as sub-plots and three sowing times (sowing immediately after physiological maturity, 2 and 4 weeks past physiological maturity) as sub-sub plots. The experiment was arranged as a split-split plot in a completely randomized design of three replications. All traits (seedling emergence percent, seedling emergence rate, as well as plant height and biomass weight) were affected by experimental treatments. Rye had the highest allelopathy effect on the evaluated crops. Soybean had the greatest susceptibility to root allelopathism as compared with corn and sorghum. Delay in sowing time decreased the root allelopathic effects in a way that 4 weeks of delay in sowing time exerted a significant influence on growth traits. Mean germination percent and mean germination rate of the evaluated crops increased with a 4 weeks delay in sowing time. Also, an increased trend of biomass weight was observed with delay in sowing time.

Poor wheat stand establishment is a major cause of yield loss, particularly in rainfed and poorly irrigated environments. Seeds of eight wheat cultivars (Triticum aestivum L.) including irrigated and rainfed varieties, belonging to three different climates of Iran (Hamedan as cold, Karaj as temperate and Sarpolzohab as warm climates) were primed using osmoprimig treatments through use of Urea, NaCl and PEG6000 as well as hydropriming treatments through tap and distilled water. In each climate while employing the related cultivars, a separate experiment was conducted using a split plot factorial in a randomized complete block design of three replications. Main plots were representatives of two sowing dates (timely, and late), while subplots included combinations of cultivar and priming treatments. Results showed that Urea and PEG osmopriming treatments as well as tap water hydropriming treatments caused an increase in emergence rate (both two sowing dates) in all rainfed cultivars of all climates as well as in Alvand irrigated cultivar of cold climate (Hamedan) zone. In addition, NaCl and Urea osmopriming increased flowering speed in first sowing date of Azar2 (rainfed cultivar of Hamedan) and Chenab (rainfed cultivar of Sarpolzohab) respectively. In rainfed cultivars of cold climate zones, PEG and Urea osmopriming significantly increased leaf area index. Number of spikes per unit area was the most important factor among yield components that was significantly increased by osmopriming treatments in Hamedan cultivars (both irrigated and rainfed cultivars) as well as in Karaj rainfed cultivar and for both sowing dates. This resulted in an increase in yield. Meanwhile harvest index was not affected by priming treatments. It seems that the desired effects of osmopriming would be on the increase in the presence of such environmental growth limiting factors as low temperatures and water deficit.