نشریه علوم و فناوری بذر ایران
سال نهم شماره 2 (پیاپی 18، تابستان 1399)

Seed deterioration is an important factor in reducing of physiological seed quality that it increased the severity of damage in adverse environmental conditions. The effects of hydrogen peroxide to improve physiological and antioxidant enzyme activities in aged groundnut seeds under drought stress were studied. A factorial experiment based on completely randomized design with three replications was done. Priming of different concentrations of hydrogen peroxide (0, 50, 100 and 150 µM) under 0, -0.4, -0.6 and -0.8MPa drought stress levels were evaluated. The results showed that seed priming with hydrogen peroxide in different drought levels increased some traits such as germination percentage, germination rate, vigour index, plumule and radicle length, soluble carbohydrates and protein contents and antioxidant enzymes activities (catalase, ascorbate peroxidase and superoxide dismutase). While it decreased mean germination time, electrical conductivity and malondialdehyde content in comparison to nonprime seeds. So seed priming with 50 and 100 µM of hydrogen peroxide in -0.8MPa level increased germination rate, vigor index , soluble carbohydrates and proteins, respectively by 27.89, 93.24, 71.42, 46.12, 27.06, 76.73, 30.26 and 51.04% compared to nonprimed seeds. Also, it increased activity of catalase, superoxide dismutase and ascorbate peroxidase, respectively by 26.37, 8.79, 39.07, 15.43, 5.28 and 21.51% compared to non-primed seeds. Therefore, the use of 50 mM hydrogen peroxide to reduce the negative effects caused by deterioration in drought stress is recommended.

Germination is one of the most sensitive stages of plant life, which is affected by various environmental factors such as temperature and humidity. Because seed standard germination test alone cannot accurately describe seedling emergence in field conditions, seed strain tests such as accelerated aging test (seed deterioration) are used. In this research, germination and biochemical indices of linseed (‌Linum usitatissimum Var. Norman) in moisture potential of 0, -0.2, -0.4, -0.6, -0.8, -1.2 and -1.2 MPa under accelerated aging conditions at temperatures 10, 15, 20, 25, 30 and 35°c were evaluated. The results showed that the percentage and rate of germination and seedling vigor index in accelerated aging and non-accelerated aging respectively were increased by increasing temperature up to 20 and 25 ° C, , then decreasing to 35 ° C. And with decreasing potential water, in terms of accelerated aging, showed its lowest level at any temperature. The amount of soluble protein, catalase activity and proline content of seeds increased with decreasing water potential and accelerated aging effects at each temperature. Also, with increasing temperature, protein content and catalase enzyme activity of Linum usitatissimum seed are increased; proline content of the seed decreased.The results of this study showed that Linum usitatissimumis resistant to high and low temperatures in the early stages of germination under favorable temperature conditions of plants resistant to dehydration and under stress-free conditions.

To evaluate the effect of salinity stress on seed germination and screening of sugar beet genotypes, 20 polygerm and 15 sugar beet drought tolerant genotypes were separately tested in between paper and rapid germination test in Erlen under control and 20 dSm-1. Also they were tested in rapid germination test in Erlen and green house experiment under control and 16 dSm-1 in factorial experiments based on completely randomized designs with four replicates. Salinity stress in rapid germination test decreased germination index over drought tolerant and polygerm sugar beet genotypes about 80 and 90%, respectively in comparison to normal. Rapid germination test in Erlen was found to be better and more suitable in comparison of sugar beet genotypes under salinity in comparison to between paper tests. Genotypes which had more field emergence potential in laboratory had more total dry weights in green house under salinity condition. There was positive and significant correlation between fast germination tests in EC=20 and 16 dSm-1, so it seems that the rapid germination method in Erlen in EC=16 dSm-1 is more efficient to evaluate sugar beet genotypes under saline conditions

In order to study the effect of accelerated aging and priming with gibberellic acid on germination characteristics, lipids peroxidation, soluble protein, total phenol and electrical conductivity of wheat seed (Pishtaz Cultivar) an experiment in factorial laid out completely randomized design with three replications was conducted at Seed Technology Laboratory, Department of Agronomy, Faculty of Agriculture, Ferdowsi University, Mashhad, Iran, in 2016. Factors were included of seed aging(100% relative humidity at 40°C) in three levels [low deterioration (4 days), medium deterioration (6 days) and high deterioration (7 days)] and priming with gibberellic acid in four levels (0, 25, 50 and 100 ppm). Analysis of variance showed that the effect of seed aging, priming with gibberellic acid and interaction between two factors on all traits were significant. Based on the means comparison of the traits germination percentage, germination rate, soluble protein and total phenol decreased with increasing aging time. But, the level of malondyaldeid and electrical conductivity increased due to damage to cell membrane with increasing aging time. Investigation of interaction between two factors showed that the priming with gibberellic acid reduced the negative effects of seed aging on all traits.

In order to quantifying cardinal temperature and hydro time germination of Cuminum cyminum seeds, an experiment was conducted as completely randomized design with three replications in laboratory of Faculty of Agriculture and Natural Resources of University of Mohaghegh Ardabili in 2017. Experimental treatments were included: temperatures as, 0, 5, 10, 15, 20, 25, 30, 35 and 40 ˚C and osmotic potential as 0, -0.2, -0.4, -0.6, -0.8, -1 and -1.2 MPa. Quantifying of cardinal temperature for germination fraction of 10, 50 and 90 % were evaluated from four models as: beta, modified beta, dent-like and segmented. In this study, RMSE and R2 and AICc were used for comparison between models. Result indicted that beta model showed better responses description for germination rate of Cuminum cyminum to temperature compared with others models. However basic temperature of Cuminum cyminum was between 0.7 to 0.9 ˚C, optimum temperature about 20 to 21 ˚C and maximum temperature was 35 ˚C. In addition based on hydro time models results, θH and Ψb(50) of Cuminum cyminum were estimated 97.5 and -0.46 MPa respectively.

This experiment was conducted at Mehrgan Agricultural Research Station, Kermansha, Iran, in 2012. The maize parents of hybrid 704 cultivar was cultivated in a randomized complete block design with three replications. The treatments includes: 1-ammonium nitrate (1/3 before planting and 2/3 after planting) 2-solupotas 3-iron chelate, 4-zinc sulfate, 5-manganes sulfate 6- boric acid, 7- Combine treatments 1 to 6 with each other. 8- Combine treatments 1 and 2 with each other. 9- Combine treatments 3 to 6 with each other. 10- Control (without spraying). The applied treatments were sprayed in three stages: 1- growth stage from 6 to 8 leaves 2- maximum leaf area index 3- after pollination. The length of plots was 7 meters and width was 4.5 meters (including 4 mother line and 2 father line) with spacing rows of 75 cm and plant spacing on the 18 cm row. The cultivation was carried out on May 1 and irrigation system was sprinkler. The treats measured was include macro and micro elements in seed, germination percentage, seedling vigor index (SVI), germination rate and Seedling growth rate (SGR) for each treatment. The results showed that foliar application did not significantly differ in the amount of nutrients in corn seed. Despite the lack of significant difference in the amount of nutrients in the seed, seedling growth and germination rate were superior in some treatments, so that the highest seedling growth was observed in potassium spraying treatment. The highest rate of germination was also due to spraying with high consumption elements.

In order to quantify the germination characteristics and determine the cardinal temperature of germination of Euphorbia maculata, seeds were placed at constant temperatures (2- 45 °C). Results showed that seed of E.maculata had no germination at temperatures of 2, 5, 10 and 45 ° C, and the temperature of 30° C was the best temperature for germination seeds (91% Germination percentage). Three models of intersected-line, dent-like segmented and quadratic polynomials were used to estimate the cardinal temperatures. The best model for estimating the cardinal temperatures in E.maculata was intersected-line model with respect to coefficient of determination and mean square error. According to the intersected-line the minimum, optimum and maximum temperatures were calculated 9.8, 28.33 and 43.16 °C. In order to investigate water potential on germination percentage, seeds treated with water potentials (0, -0.2, -0.4, -0.6 and -0.8 MPa) at optimum temperature of 28°C. Baesd on the three-parameter sigmoid method, the value of speed, root length, stem length, seedling fresh weight and dry weight were estimated to be -0.53, -0.48, -0.51, -0.48, -0.52Mpa respectively. According to the hydro-time model based on normal distribution, the hydro-time constant and the base-water potential (which is a threshold for germination beginning) of E.maculata degree were 291.32 (MPa/h) and -1/2 (MPa) at 28 °C, respectively. Thus, this weed species has a great potential for distribution to other areas such as provinces with a dryer climate than Golestan, and the necessary measures to prevent its distribution is necessary.

A factorial experiment was conducted to evaluate the biochemical changes during the soybean seed deterioration based on a completely randomized design. The treatments consisted of germination in two levels of minimum and high quality, three initial seed moisture content (low, medium and high moisture), and two storage conditions were considered including the common storage in Moghan and the controlled storage condition. Indices of germination percentage, vigor and biochemical changes including protein content, soluble sugars, malondialdehyde, catalase and peroxidase enzymes were evaluated. The study of biochemical changes of deteriorated seeds during the storage showed that, with the increase of seeds’ deterioration, the soluble sugars and protein percentage decreased, as well. Moreover, seeds’ storage in poor condition caused a significant decrease in seeds’ soluble sugar and total protein content. Also, the increase of seed moisture was followed by further seed deterioration that significantly decreased the content of soluble sugars and total protein. Significant differences were observed between seeds with different initial germinations and they had significantly higher content of soluble sugars and protein percentages. Furthermore, measuring the amount of malondialdehyde and the activity of catalase and peroxidase enzymes indicated that there exists a significant correlation between the degree of seed deterioration with the level of malondialdehyde and the activity of scavenging enzymes. Overall, along with the decrease of germination and the quality of soybean seeds after the storage, the amount of lipids peroxidation increased and the seed deterioration decreased the activity of catalase and peroxidase enzymes during the storage.

Present study was conducted to evaluate the effects of chemical scarification (Sulphuric acid 97% for 0, 3, 6 and 9 h at 25°C), removal of endocarp and cold stratification (0, 21 and 31 days at 10°C) treatments on percentage and rate of seed germination of olive cultivars (Koroneiki, Zard and Shenghe). A factorial experiment was used based on a completely randomized design with three replications. Results indicated that the chemical scarification treatments and removal endocarp followed by an adequate stratification period can increase seed germination significantly. The best results obtained by removal endocarp treatments. The highest germination percentage of cv. Koroneiki obtained after Cold stratification treatments for 21 days (up to 93%). The best result for cv. Shenghe and cv. Zard observed following Cold stratification treatments for 31 days (85.55% and 84.44 respectively). The highest germination percentage of cv. Koroneiki obtained after 97% sulfuric acid solution treatments for 6 h (49.67%). Treating seeds of this cultivar by 97% sulfuric acid for longer period resulted in damage to embryo and no seedlings emerged after these treatments. The best result for cv. Shenghe observed following 97% sulfuric acid treatment for 9 h (42.34%) cv. Zard observed following 97% sulfuric acid treatment for 6 h (40.23%). The least germination rate and percentage was observed in control treatments. Growth of olive seedlings also increased by scarification, removal endocarp Cold stratification treatments significantly. Results suggested that removal endocarp and chemical mechanical scarification treatments can improve germination percentage and seedling growth of olive cultivars.

The production of cereal seeds including wheat and barley as one of the most important strategic products is the largest seed production cycle in the country. One of the most important goals in the agricultural sector is the production and distribution of standardized and certified grain crops in a wide range. In this regard, the Agricultural Jihad organization and the private sector in Khorasan Razavi province have signed contract with the contractors who have the necessary conditions for the production of cereal seeds. During the growth period, the relevant technical experts conducted alternate visits to the farms to confirm seed propagation farms. The important problem with this is that around 30% of these farms do not endorse for many reasons, despite the high cost. Therefore, the purpose of this research is to investigate the economic and management factors affecting the confirmation of wheat and barley seed producers' farms. In the present study, by using cross-sectional data of 1391-92 and using Logit model, the factors affecting the confirmation of wheat and barley fields were investigated. The results showed that the variables of education level, total cropping area, use of technical experts, satisfaction of seed price and satisfaction of payment method by seed purchase companies had a positive and significant relationship, and the number of cultivars had a negative and significant relationship With dependent variable, confirmation of seed farms.