Iranian Journal of Seed Research

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.

Medicinal barberry plants, belong to Berberidaceae family. Seeds of barberry have long period dormancy. Therefore, overcome to seed dormancy and increasing germination rate of seeds due to different methods will be useful. In this regard, two separate experiments were designed. In the first experiment, effect of different levels of Gibberellic acid (0, 600 and 900 mg.l^-1 at 8˚C) and temperatures (25 (control), 10 and 5 °C at 50 days) in a factorial experiment based on the completely randomized design with three replications and in the second experiment, effect of different nutrition concentrations of MS medium (full strength MS, 1/2MS and 1/4 MS) in a completely randomized design with three replications on embryo culture of four native species of barberry (Berberis integrima, B. vulgaris, B. crataegina and B. orthootrys) were investigated. Based on the results obtained from the first experiment, chilling treated seeds showed the greatest effect (88%) on seed germination in comparison with gibberellic acid treatment. The results of the second experiment showed that the best MS concentration for embryo culture was full strength MS medium with%100 seed germination in four above mentioned barberry species after 2-3 days. In general, the best method to overcome barberry seed dormancy was an embryo culture in full-strength MS nutrition.

Asafetida (Ferula assa- foetida L.) is an important medicinal plant belonging to Apiaceae family and has long dormancy. In this research, vernalization, washing time, GA3, medium strength, harvesting time and interaction of these treatments were studied to optimize condition of germination. The results showed that vernalization at 4-5°C for two weeks increased germination by 50%, as compared with the control. Maximum and minimum germinations were obtained for 6 and 2 hours’ washing, which was 42% and 20.47%, respectively. Germination of Ferula was increased (41.5%) by using 10 mg/l of GA3, as compared with the control. In addition, using half strength MS media led to a 25% increase in germination. Moreover, germination mean increased by applying these treatments to one-year-old seeds, in comparison with fresh ones (61% and 36%, respectively). By running factorial experiments in the CRD, the best combination of treatments which could significantly increase germination was a combination of vernalization (4-5°C for two weeks), half strength MS media, GA3 (10 mg/l) and washing time (6h). Given the results of the study, for the purpose of breaking the dormancy of Asafetida, it is suggested that use is made of one-year-old seeds, and half strength MS media, along with right combinations of vernalization, washing time and GA3.
 

In order to study the seed germination behavior and dormancy breaking methods of three weed species (i.e., Chenopodium album, Convolvulus arvensis and Setariaviridis) of pistachio orchards in Rafsanjan, Iran, three separate factorial experiments (with 2 factors) were conducted based on a completely randomized design with four replications, at the Faculty of Agriculture, Vali-E-Asr University of Rafsanjan, Iran, in 2014. Weed seeds were collected from five different regions of Rafsanjan, such as Markazi, Anar, Koshkoiyeh, Kabotarkhan and Nogh. Dormancy breaking treatments for Chenopodium album involved distilled water (control), KNO₃ (at 500 and 1000 ppm), chemical scarification by sulfuric acid (for 5 and 10 min), and cold stratification (for 1, 3 and 5 weeks). Treatments for Convolvulus arvensis involved distilled water (control), scarification by sandpaper, chemical scarification by sulfuric acid (20 and 30 min), and boiling water (for 15 and 30 min). Treatments for Setaria viridis involved distilled water (control), gibberellic acid (250, 500 and 1000 ppm), KNO₃ (500 and 1000 ppm), and cold stratification (for 1, 3 and 5 weeks). The results showed that seed germination percentage (SGP) and mean germination time (MGT) of three weed species were significantly different among weed populations and dormancy breaking methods. For Chenopodium album, cold stratification of 5 weeks resulted in highest SGP (97%) in Nogh population. For Convolvulus arvensis and Setaria viridis, the highest SGP was obtained after scarification by sandpaper (98% in Kabotarkhan population) and using 1000 ppm gibberellic acid (60% in Kabotarkhan population), respectively. In addition, increasing the weight of 1000 seeds in the three weed species in question increased SGP.
 
 

Given the medicinal and ornamental properties of Hawthorn (Crataegus spp.), and given that there are some problems in its propagation, which is due to the hard cover of the seeds and immature embryo, working out techniques that can facilitate the process of seeds’ germination is of great import. Thus, the present study sought to identify the best method for the purpose of breaking the seed dormancy of 8 species of native hawthorn of Iran. The study was carried out as factorial with a completely randomized design and had three replications. The first, second and third factors were, respectively species of Hawthorn in eight levels, sulfuric acid in three levels (half and an hour versus non-treated (control) and chilling treatment in three levels (90, 105 and 120 days, respectively). The results showed that the highest percentage of germination (32%) and germination rate (9.1 day^-1) were obtained under the interaction of sulfuric acid treatment for one hour, followed by a 120-day chilling period in C.turkestanica, which had a significant difference with other treatments. It is concluded that hawthorn seeds have deep endocarp and physiological dormancy. The interaction of Sulfuric acid treatment and moist chilling play an important role in increasing the percentage and speed of germination of Hawthorn seeds.

Highlights:

1.  Achieving the best way to break the dormancy of Hawthorn seeds in different species and genotypes.
2. Shortening the seeds’ germination time.

Extended Abstract
Introduction: Weeds, as the most important biological stress, reduce the efficiency of water use, waste of food, shading and secretion of toxic substances, leads to a 10 to 100 percent reduction in crop yields. The first step of the weed control understands the biology and life cycle of the weed particularly seed Eco physiological characteristics. Dormancy in weed seeds, including Redroot Pigweed seeds, is common. So, due to the importance of dormancy breaking and germination studies of weed seeds, the present study was designed to identify the methods for dormancy breaking and the germination of Redroot Pigweed seeds.
Materials and Methods: This research started in autumn 2013 by collecting Redroot Pigweed seeds from fields of Alajujeh village, Khoda Afrin County, East Azerbaijan Province, and then it was carried out at the Laboratory of the Faculty of Agriculture of the University of Maragheh in 2014 and 2015. For data analysis, the GenStat 12.1 program was used and the Duncan test was used at 5% probability level to compare the averages. Excel 2013 was also employed for drawing the diagrams.
Results and discussion: Analysis of variance demonstrated that the effect of treatments on germination percentage and germination rate in Redroot Pigweed seeds at 1% probability level and the mean germination time at 5% probability level was significant. The results showed that among studied treatments, seeds holding for 18 months were most efficient seeds dormancy breaking at Redroot Pigweed. So that the highest germination percentage (92%), germination rate (29.18 seed/day) and lowest the mean germination (4.2 day) time were obtained in seeds holding treatment. Pre-chilling treatment also had significant effects in stimulating germination. As regards treatments of seed holding in low temperature and Pre-chilling accelerate the germination process and increase germination percentage, so, having precise information of these traits enables to study, a better management and control of this troublesome weed.
Conclusions: In general, the results of this study show that among the treatments, holding seeds for 18 months at 6 ° C is the best method for solving Redroot Pigweed seeds weeds.

 
Highlights:
1- Seed holding in low temperature and Pre-chilling accelerates the germination process.
2- Seed holding in low temperature increases germination percentage.

Extended Abstract
 Introduction: Seed dormancy, as a technique to avoid environmental stress, is important in preserving plant species and could be of various types including physiological, physical, morphological and morph-physiological dormancy. Seed testa hardness is one of the main causes of dormancy in leguminous family plants. A common method for breaking seed dormancy in leguminous plants is the use of scarification treatments. Given that oxygen deficiency is a factor that induces dormancy, scarification treatments through acceleration of gas exchanges, especially oxygen and carbon dioxide, can reduce seed dormancy and finally increase germination percentages. In addition, priming with gibberellic acid can help dormancy breaking in plant species that have physiological dormancy, finally leading to germination. Therefore, the present study investigated seed dormancy and germination to find the most appropriate treatment for the elimination of seed dormancy in three ecotypes of Astragalus cyclophyllus.
Materials and Methods: A factorial experiment based on a completely randomized design with three replications was carried out at Agriculture Laboratory of Lorestan University in 2013. The first factor was three ecotypes of Astragalus Semirom, Damavand and Zanjan, and the second factor was seed dormancy breaking treatments. The applied treatments were: control, (mechanical scarification plus chilling time with 10, 20 and 30 days prechilling at 4^°C, mechanical scarification + gibberellic acid at concentrations of 400 and 500 ppm for 48 hours, scarification with sulfuric acid 96% for 2 and 4 min, mechanical scarification and 2% potassium nitrate for 72 h, mechanical scarification and gibberellic acid 400 ppm for 48 h and 20 days prechilling. The measured indices included germination percentage, mean germination time, seedling length, seedling fresh weight, seedling dry weight and alpha-amylase activity.
Results: The results showed that the interactions between seed dormancy breaking treatments and ecotype were significant for all the traits. Based on the results of mean comparison, Damavand ecotype exhibited better performance in terms of most of the traits studied, as compared with Semirom and Zanjan ecotypes. Compared with the treatments applied, mechanical scarification plus gibberellic acid 400 ppm was more effective in germination parameters and seedling vigor index. Mechanical scarification and gibberellic acid 400 ppm for 48 h along with 20 days prechilling increased total germination percentage by an average of 67.68% in Semirom ecotype and was more effective in increasing the activity of α-amylase enzyme.
Conclusion: It seems that seed dormancy of Astragalus cyclophyllus is not of physiological type and increased germination can be due to mechanical scarification in physical dormancy breaking and priming effect of prechilling and gibberellic acid.
 
 
Highlights:

1. The effect of different dormancy breaking treatments on seed germination was investigated.
2. Alpha-amylase activity of Astragalus Seed increased under dormancy breaking treatments.