Iranian Journal of Seed Research

The present study was conducted to investigate the efficiency of hormonal pretreatment on increasing germination and early growth of seedling in the Seed Technology Laboratory of Shahed University in 2015 as a factorial experiment, adopting a completely randomized design with 4 replications. The treatments were: 5 levels of IAA (indole-3-acetic acid) namely, zero, 0.1, 0.5, 1 and 1.5 mg/L and 5 levels of PBA (Tetrahydro pyranyl ­benzyl­ adenine), which were zero, 0.5, 1, 1.5 and 2 mg/L. Analysis of variance showed that the use of the two hormones and their interactions had a significant effect on all traits such as seed germination, biomass, leaf relative water content and photosynthetic pigments. The highest percentage of germination (66.66%) was obtained in 1.5 mg/L IAA with 1 mg/L PBA. 0.5 mg/L PBA and in 0.1 mg/L IAA the longest shoot (1.28 and 1.17 cm, respectively) was obtained. Germination coefficient decreased by about 12.5% by increasing IAA from 0.1 to 1.5 mg/L. The greatest relative water content (42.73% and 37.38%) was obtained with 0.5 mg/L PBA and 1.5 mg/L IAA, respectively. Combination of IAA+PBA (0.1+0 mg/L) had a positive effect on both the length of the root and seedling. The high concentration of PBA and the lowest amount of IAA had similar results in terms of plant biomass. The highest plant biomass (4.33 mg) was obtained in seeds treated with 2 mg/L of cytokinin and 0.1 mg/L of auxin. Photosynthetic pigments were also affected by these two hormones through the IAA was more effective than PBA. The finding was that auxin and cytokinin increase germination and improve the morpho-physiological indicators and thus increase the yield of Stevia.
 

Gaining insights into the germination and emergence patterns of weeds as well as the factors which have an impact on these patterns is beneficial for weeds management programs. In order to investigate the effect of temperature, waterlogging and salinity on germination and emergence of common lambsquarters, three separate experiments were conducted, adopting a completely randomized design with four replications. The results of the temperature experiment showed that the highest germination percentages, which were 87, 93 and 88%, were obtained in the temperature range of 15, 20 and 25°C, respectively. Maximum values of germination rate, radicle length, plumule length, and seedling dry weight were obtained at 20°C. In addition, optimum seed vigor index of 796.29 was observed at 20°C. The results of the Regression Model showed that germination percentage decreased with an increase in waterlogging duration and halted after 8 and 10 days of consecutive waterlogging. Mean comparisons revealed that radicle and plumule length, seedling dry weight and vigor index decreased significantly by increasing the period of waterlogging. Salinity adversely affected germination percentage, germination rate and seedling dry weight of common lambsquarters. These factors were at their highest amounts in the control and 50 mM NaCl treatments. A downward trend was observed in these factors as NaCl concentrations increased and finally the germination process stopped in concentrations ranging from 300 to 400 mM NaCl. Radicle and plumule length also decreased from 10.51 and 9.23 cm in the control treatment to 3.57 and 2.47 cm at 250 mM NaCl. Overall, the results revealed that the maximum seed vigor index of 851.84 was obtained in the control treatment and seed vigor halted when the salinity level increased to more than 250 mM NaCl. Finally, the results showed that optimum temperature for germination of common lamsquarters was 20 °C and the existence of salinity and waterlogging stress can decrease growth indices of this weed at germination and seedling stages.

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.
 

1.  The role of maternal sesame plant (cv. Darab 1) foliar application by zinc and boron elements in germination, vigour and storage capability of seeds was studied.
2. The effect of seeds soaked in solutions enriched with zinc and boron elements on germination, vigour and storage capability of seeds was examined.

1.  Due to higher storage capacity, the use of large seeds brings about increases in the seedling germination rate and their establishment in the field
2. The use of large seeds with more seed vigor decreases competition between seedlings and reduces vapor from the field.

To study the effect of production region and seed size on germination indices and heterotrophic growth components of peanut seedling, a study was performed in three peanut fields in Astaneh Ashrafieh and Agronomy Laboratory of Rasht Islamic Azad University from 2010 to 2012. This research was carried out using the standard germination, cold and accelerated aging tests. Tests were performed using factorial experiment with a completely randomized block design in 3 replications. The first factor was seed production region in 3 levels (Noghredeh, Amshal and Bandar-Kiyashahr) and the second factor was seed weight in 3 levels [large, medium and small]. The results indicated that the effect of production region on the germination speed (p<0.01) and coefficient of uniformity of germination (p<0.05) was significant so that the maximum means (6.17 and 18.11 day^-1, respectively) were achieved in seeds produced in Amshal. The effect of the interaction of the region and seed size on the mean germination speed was significant so that the maximum mean (282.22) was achieved in large seeds produced in Amshal. The effect of production region on the seed reserve use rate was significant in standard germination (p<0.01) and cold tests (p<0.05). The effect of seed size on the seed reserve use rate and seed use reserve fraction were significant (P<0.01) in all the three germination tests. The maximum amount of seed reserve use rate was achieved in seeds produced in the Amshal region (in standard and cold tests with averages of 0.562 and 0.440, respectively). In addition, the maximum amount of seed reserve use rate was achieved in large seeds (with averages of 0.541, 0.470 and 0.277 mg per seed in standard, cold and aging tests, respectively). The maximum seed use reserve fraction was achieved in small seeds (with averages of 1.371, 1.310 and 1.664 in standard, cold and aging tests, respectively).

 

Highlights:

1. Peanut seed germination tests were performed based on seed production regions and seed sizes.
2. Three different vigour tests (standard, aging, cold) were used to identify higher quality seeds.
3. Germination indices indicated high quality in large seeds produced in different environmental conditions.
4. Large seeds had the maximum seed reserve use rate and minimum seed use reserve fraction at the germination stage of peanuts.

In order to investigate the effect of different levels of temperature and drought stress on seed germination parameters of nettle roman (Urtica pilulifera L.), an experiment was conducted as factorial in a completely randomized design with three replications at the Department of Agronomy, College of Agriculture, University of Guilan, in 2014. Treatments included different temperature levels (5, 10, 15, 20 and 25 °C) and drought stress levels (0 (control), -2, -4,-6 and -8 bars). The results showed that treatments and their interactions had a significant effect on germination percentage (GP), germination rate (GR), root length and root dry weight. The highest GP (88%), GR (1.8 seed/day) and root dry weight (0.06 g) were obtained as the result of the interaction between the temperature of 25°C and no-stress condition. In this study, with an increase in drought stress and a decrease in temperature, GP, GR, root dry weight, root length and shoot length decreased. The impact of drought stress on GR and GP was lower at 20°C, compared with the temperature of 25°C. A decrease in water potential from -4 to -6 bars at 20°C caused a reduction of 50% and 30% in GP and GR, respectively. However, these reductions at 25°C were 75% and 70%, respectively. According to the results, it could be stated that the significant reduction threshold of seed germination parameters was -2 bars.

 
Highlights:

1. The germination characteristics of Roman nettle were studied under drought stress and temperature.
2. In drought stress of -4 bars, germination percentage and germination rate decreased significantly.

1. The reaction of the cotton cultivars studied was different to levels of salinity stress.
2. An increase in salt stress caused a significant reduction in the germination characteristics of cultivars of cotton studied.
3. Bi-plot analysis and clustering based on STI and SSI indices turned out to be a suitable method for clustering cotton cultivars.

Salt and drought are two major environmental stresses that affect growth and development of plants. In order to study the effects of sodium chloride and polyethylene glycol (6000) on germination characteristics and early seedling growth of redroot pigweed (Amaranthus retroflexus), two completely randomized designs with 4 replications were conducted at Weed Research Laboratory of Bu-Ali Sina University, Hamedan in 2015. The treatments were salt and drought stress as osmotic potential at six levels (zero (control), -2, -4, -6, -8 and -10 bar). The results showed that when stress increased, germination percentage, germination speed, radicle and plumule length, seedling length and seedling vigor index decreased significantly (p≤ 0.05). With an increase in the intensity of salt and drought stress from zero to -10 bars, redroot pigweed seed germination reduced about 96 and 100 percent, respectively, compared with the control. The highest seedling length in both stresses was observed in the control (7.71 cm) and by increasing stress intensity to -10 bars in both salinity and drought stresses, seedling length was reduced to 1.52 cm and 0 cm, respectively. Fitting of the three-parameter logistic model provided a successful estimation of the relationship between salt and drought stress levels and germination percentage of redroot pigweed as well as germination speed. This model showed that salinity and drought stress at -3.58 and -3.75 bars caused a 50% reduction in maximum germination percentage of redroot pigweed. In addition, 50% decrease in germination speed caused by salinity and drought stress was observed in -2.58 and -2.88 bars, respectively.

 
Highlights:

1. The germination characteristics of redroot pigweed were studied under salt and drought stresses.
2. Drought stress reduced germination percentage of redroot pigweed.

1. The effect of hydropriming on recovering the power of seed germination of pinto bean has been studied under the salinity condition.
2. An attempt has been made to determine the effect of hydropriming on increasing the tolerance of pinto bean seeds to storage and salinity stress condition.
3. The effect of pinto bean storage on biochemical changes and enzyme activity has been studied in salinity stress condition.

In order to study the effects of different levels of salinity on germination components of wheat cultivars, a factorial experiment was conducted based on a completely randomized design with three replications. Experimental factors were wheat cultivars at eight levels (Saysons, Gaspard, Finkan, MV-17, Chamran, Sardari, Atila-4 and Azar-2) and six levels of salinity (0, 25, 50, 100, 150 and 200 mM NaCl). The results indicated that salinity had significant effects on all of the traits studied (i.e., radicle length and dry weight, plumule length and dry weight, remaining seed weight after germination, seedling weight, the longest radicle and plumule, number of radicle per seed, ratio of radicle weight to plumule weight and rate, and uniformity and percentage of germination). All of these traits declined with an increase in the salinity (except the ratio of radicle weight to plumule weight, remaining seed weight after germination and seedling weight). The highest ratio of radicle weight to plumule weight, remaining seed weight after germination and seedling weight were recorded in the salinity of 200 mM NaCl. The cultivars showed significant effects on all of the traits studied (except remaining seed weight after germination and seedling weight). Chamran cultivar showed the highest number of radicle per seed, the ratio of radicle weight to plumule weight, rate and percentage of germination. The highest radicle length and the longest radicle were obtained from the Sardari cultivar while in Azar-2 cultivar it was vice versa in plumule. Atila-4 cultivar showed the highest radicle and plumule weight. It seems that compared with other cultivars, out of the cultivars studied, Chamran, Azar-2, Sardari and Atila-4 were more resistant to salinity stress.

 
 Highlights:

1. Introduction of wheat cultivars with more tolerance to salinity conditions at germination stage.
2. Study of eight different wheat cultivars in terms of germination indices under salinity stress conditions.

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.

1. Cold stratification and hydrochloric acid treatments increase the efficiency of sugar beet seeds under drought stress conditions.
2. Cold stratification and Hydrochloric acid treatment have a synergistic effect on sugar beet seeds.

1. In this study, the allelopathic effect of two important soybean weeds on germination and seedling growth of this crop were compared, which had been under-researched.
2. Seed germination reaction and seedling growth were evaluated for the extract of aerial parts in two seed culture conditions of petri dish and potted seedlings.

1. Chitosan nano particle and potassium nitrate increase quinoa germination.
2. Chitosan nano particle and potassium nitrate increase the content of chlorophyll a and b.