Iranian Journal of Seed Research

In order to investigate the seed vigor of corn hybrid 704 after maternal plant foliar application with methanol, some micro and macro-nutrients an experiment was conducted in a factorial form based on RCBD with three replications during growing seasons of 2010-2011. Treatments were four growth stages (the 8-10 leaves, the tasseling, the seed-filling, all the stages), seven levels of foliar application (Methanol, Zn, B, Mg, N, Mn, a mixture of all combinations) and control. The analysis of the data showed a significant effect of the combination type of foliar application in different stages on the germination percent, mean daily germination, germination speed, seedling vigor index, radical length, plumule length and seedling dry weight. The detailed results of the study showed that foliar application with N, Mg, Zn, Mn and B in grain-filling stage, foliar application with N, Mg and Mn in tasseling and foliar application with N, Mg and B in all stages had the highest germination percent (100%) and mean daily germination (14.29%). Also, Mg-foliar application in grain-filling and all stages, B-foliar application in grain-filling stage had the highest germination seed (12.33). In addition, Mg-foliar application in grain-filling stage had the vigor index, radical length, plumule length and seedling dry weight.

The effect of seed rate of alfalfa (Medicago sativa L.) and efficiency of plant growth promoting bacteria (PGPR) that facilitates phosphorus uptake with different doses of phosphate fertilizer was evaluated on seed quality. For this purpose, the germination and seed vigor tests before and after accelerated aging were performed in a split split plot experiment based on randomized complete block design with three replications in 2010 in the field of education and research in the College of Agriculture and Natural Resources, Tehran University, Karaj. Phosphorus factor at 4 levels (0, 30, 60 and 90 kg Phosphorus.ha-1) in main plots, PGPR (Pseudomonas) in three levels (no bacteria, bacterial strains, No. 9 and bacterial strains No. 41) in subplots and rate of seed factors on three levels (2, 6, and 10 kg of seed per hectare) were the sub-subplots. The results showed the highest rate of germination and seed vigor obtained by use of 6 kg seeds per hectare, PGPR No.41 strains with 30 kg Phosphorus per hectare and after accelerated aging. The highest rate of germination and seed vigor at 10 kg of seed per hectare were found for PGPR No.41 strains, with 60 kg Phosphorus ha-1 treatments. After accelerated aging practices to achieve maximum germination index and vigor, seed rates and phosphorus requirement were more than standard conditions. Based on obtained results for the storage conditions, bacterial strains No. 41 had a better effect on increasing seed vigor than bacterial strains No. 9. To produce alfalfa seed with high vigor and obtain better results, use of optimum seed rates and phosphorus (6 and 30 kg.ha-1, respectively) along with PGPR (strain No. 41) could be considered in crop plants.

Osmotic stress is the most important of the abiotic stresses that lead to limitation of growth and yield in rapeseed. This study was conducted to examine the effect of cycocel seed priming on osmotic stress tolerance in germination and early growth stages of rapeseed, as a factorial experiment based on completely randomized design at Agriculture College of Shiraz University in 2012. The treatments included seed priming in three cycocel concentrations: 0 (without priming as control), 2.5 and 3.5 g L-1 and osmotic stress in five levels: 0 (as control), -0.3, -0.6, -0.9 and -1.2 MPa using polyethylene glycol. The results showed that osmotic stress was significantly reduced germination percentage (15.1%), germination rate (15.3%), radicle length (29.5%), plumule length (31.6%), radicle fresh weight (22.4%), plumule fresh weight (37.6%) and vigor index (39.9%). Furthermore, osmotic stress leads to increase radicle to plumule fresh weight and radicle to plumule length ratio as 6.8 and 24.3 percent, respectively. Seed priming with cycocel reduced the adverse effects of osmotic stress on measured parameters. Although, there was no positive effect on germination percentage and rate under osmotic and nonosmotic conditions for cycocel in both concentrations, but cycocel at 3.5 g L-1 appeared to have a greater positive effect than 2.5 g L-1. Considering positive impact of cycocel seed priming on the reduction adverse effects of osmotic stress further research on cycocel seed priming and osmotic stress tolerance is recommended under field conditions.

Bilhar or Mountain Kandall (Dorema aucheri) belongs to Apiacea family that contains flavonoid and coumarine compounds. Since propagation of this plant in natural habitats occurs through seed and due to deep dormancy, the identification of different seed dormancy breaking methods is necessary for the preservation of this species. In this respect, different methods, including chilling, washing and gibberellic acid was studied, on the seeds gathered from Kohgiloyeh and Boyerahmad province. For this reason, a factorial experiment with three factors was done based on a completely randomized design in three replications, in the faculty of agriculture, Yasouj University, in 2012. Experimental factors were included, chilling period (stratification periods of 3 and 4 weeks), gibberellic acid (zero and 1500 ppm) and washing (washing with distilled water and non-washable). Results showed that 4 weeks chilling treatment had maximum germination percentage and germination rate and seedling vigor. Also, maximum root and shoot dry weight were obtained from the seeds of this treatment. Whereas, double and triple interaction effects for germination percentage, epicotyl and hypocotyl length were not significant. Germination percentage was better in 4 weeks prechilled seed than 3 weeks. Obtained results from this research showed that Bilhar seeds have the physiological dormancy.

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

In order to study, the effects of hydropriming and osmopriming on germination characteristics of Nigella sativa L. under salt stress an experiment was conducted in factorial laid out in completely randomized design with four replications at Research Laboratory, Faculty of Agriculture, Mashhad Branch, Islamic Azad University-Mashhad Iran, in 2014. Factors were included of priming treatment in six levels [control (Non-priming), hydropriming with distilled water, osmopriming with KNO3, KCl, CaCl2 and NaCl] and salinity treatment in four levels [0, 50, 100 and 150 Mmol]. Analysis of variance showed that the effects of salinity and seed priming on all measured indices and interaction between two factors on germination percentage and rate, radicle and plumule length and seed vigor were significant at the probability level of 1%. The results showed that with increasing salt concentration all measured traits were decreased. This decreasing started from the 50 Mmol concentration. Under salt stress condition, osmopriming with KNO3 and then hydropriming and osmopriming with KCl improved all germination indices compared with control.

Germination rate and percentage are maximal at optimum temperatures and then reach to zero at the base and ceiling temperatures. An experiment was conducted at the Gonbad Kavous University laboratory as a completely randomized design with 4 replications, to study germination response to temperature and evaluation of cardinal temperature on germination rate and percentage of hibiscus tea. Seeds germinated at 0 to 45 ⁰C by 5 ⁰C intervals. Results indicated that the response of germination percentage and rate adequately fitted with dent like and segmented functions, continually. Base and ceiling temperatures were 1.66 and 43.33 ⁰C for germination percentage and 4.53 and 42.95 ⁰C for germination rate. Optimum temperatures were 30 ⁰C for germination rate and 11.56 and 33.63 ⁰C for germination percentage. In conclusion, base and favorable temperatures for hibiscus tea seeds were 11 and 35 ⁰C. Therefore it is recommended to cultivate at Gonbad kavous weather condition.

The effect of spermidine on seed germination of three different cucumber cultivars under cold stress was studied as a 4×2 factorial experiment by using a completely randomized design with 4 replications. The first factor was 4 concentrations of spermidine consisted of 0 (control), 0.1, 0.5 and 1 mM and the second one was three cucumber cultivars consisted of ‘Emperator’, ‘Amiran’ and ‘Rashid’. For this purpose, 50 seeds of each cultivar were placed on filter papers inside sterilized Petry dishes and spermidine solutions were added to them according to each treatment. All petry dishes were placed at a 13°C temperature of the incubator until end of the experiment and germinated seeds were counted daily. The measured traits were the percentage of germination, plumule length, radicle length, the dry and fresh weight of the plumule and radicle. The results showed that treating seeds of ‘Rashid’ cultivar with 0.1 mM spermidine increased the percentage of germination, plumule and radicle length, fresh and dry weights of radical compared with control. Treating ‘Rashid’ seeds with high concentration (1 mM) of spermidine showed inhibitory effects on all measured characteristics, but in ‘Amiran’ cultivar only decreased the percentage of germination, plumule and radicle length, the fresh and dry weight of radicle.

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

In order to study the effect of alkaline stress on seed germination and seedling biochemical characteristics of two safflower cultivars, a laboratory experiment was conducted based on a completely randomized design with three replications in the Vali-e-Asr University of Rafsanjan. Experimental factors included the levels of alkaline with sodium bicarbonate (0, 10, 20, 30, 40, 50 and 60 mM) and two cultivars of safflower (Soffeh and 411). The result showed that alkaline stress had significant effects on seed germination characteristics. Increasing alkaline stress reduced percentage and rate of germination, length and dry weights of shoots and roots, K+ concentration and K+/Na+. However, alkaline increased malondialdehyde content, proline, total carbohydrate and Na+ concentration. In alkaline stress condition, there was a significant difference between cultivars in length of shoots and roots, proline content and K+ concentration. 411 cultivar showed notable superiority compared to Soffeh cultivar. Both cultivars had the highest malondialdehyde at 60 mM alkalinity and the lowest malondialdehyde obtained in Soffeh cultivar and control. The result of this research showed that 411 cultivar was better than Soffeh cultivar in proline and soluble sugar content, but these two cultivars had no significant differences in other traits.

Rapid germination is an important factor determining the final yield. This study was performed to investigate the effects of different levels of methanol and drought stress on germination characteristics of lentil seedlings. The experiment was conducted in completely randomized design with three replications in summer 2014 at the Khatam Alanbia University of Behbahan. The first factor was different levels of methanol equal to 0 (control), 5, 10 and 15 volumetric percentage (v/v), and the second factor we negative water potential in four levels 0, -3, -6 and -9 bar by PEG. Results showed that there was a significant difference between different methanol concentrations regarding germination percentage, germination speed index, plumule and radical length, plumule and radical dry weight, radical area, radical diameter and consumed endosperm (P 0.01). Different levels of methanol caused a significant decrease in germination characteristics compared with to control. Drought stress with -9 bar level significantly decreased germination percentage, germination speed index, plumule and radical length, plumule and radical dry weight, radical area, radical diameter and consumed endosperm compared to other levels. Effects of drought and methanol were significant differences regarding the germination speed index, plumule length, plumule dry weight and consumed endosperm (P 0.05).

In order to investigate the effect of an electromagnetic field and ultrasonic waves on the seed germination of Cuminum cyminum that two separate experiments using a completely randomized design with four replications was conducted at Seed Science and Technology Laboratory of Faculty Agricultural Sciences, the Shahed University of Tehran in 2012. In the first experiment, for the seeds of zero, 10 and 30 min exposure to electromagnetic field intensity was 88 microTesla. In the second test (ultrasonic waves), seeds for zero, 2, 4, 6, 8 and 10 min exposure ultrasonic waves’ intensity were 40 and 59 kHz. The interaction between the electromagnetic field and the length had a significant effect on the traits of length, fresh weight and dry weight of root and shoot, length and weight of root to shoot ratio, percent and rate germination and mean germination time. In most of the studied traits showed that electromagnetic field causes a significant decrease in the number of traits so that the control (zero M.T) had the highest value. The interaction of Ultrasonic waves at the time had a significant effect of on the most traits. Maximum germination percentage (100%) for the treatment of 40 kHz with duration of 4 and 6 minutes and mean germination time was highest in control (10.76 days) and 59 kHz treatment duration of 2 and 4 min (respectively 11.01 and 10.75 days). Generally, Cuminum cyminum seeds responded positively to the use of ultrasonic waves (In contrast field) and germination index was significantly increased in this case.

In order to evaluate the effect of priming on some germination and seedling growth characteristics of safflower (Carthamus tinctorius L.) under drought stress, an experiment was conducted base on completely randomized design with four replications at the Seed Technology Laboratory of Yasouj University, in 2011. Treatments were included of five priming levels (control or no prime, hydro priming, potassium nitrate 3% (KNO3), PEG and Urea -4 bar) as the first factor and three levels of drought stress (0, -4 and -8 bar) as the second factor. The results showed that the interactions of drought stress and seed priming on germination percentage and the germination rate was not significant. But the main impact of priming and drought stress on them was so significant at 1% probability. The highest germination percentage and germination rate (75.66% and 3.62 seed.day-1, respectively) were shown in urea priming and the lowest (52% and 2.31 seed.day-1 respectively) in the control treatment (no prime). Drought stress was caused a significant decrease in germination traits. In general, the results obtained in this study showed that treatment with urea and potassium nitrate compared with PEG improved germination and seedling growth of safflower.