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Showing 6 results for Rice

Asad Masoumi Asl, Rreza Amiri Fahliani, Hamidreza Balouchi,
Volume 1, Issue 1 (5-2014)
Abstract

Salinity is one of the most extensive environmental stresses and is a limiting factor for the growth and development of crops, such as rice. Then, an experiment based upon completely randomized design with four low levels (0, 7.5, 15, 22.5) and four high of salinity (75, 150, 225 and 300 mM) with control as the first factor and nine cultivars of rice (dollars, Hasan Saraii, Mousa Tarom, Kamfiruz, Lenjan Askari, Gharib, Domsiah Mamassani, 304, Champa Yasouj) as the second factor with three replications was conducted in 2012 in the Yasouj University. Results showed that Hasan Saraii had salinity tolerance with the most germination percentage, germination rate and shoot length at high salinity levels (more than 75 mM), and Domsiah Mamassani with the minimum of that traits had not any salinity tolerance. But in the low salinity (less than 22.5 mM), Hasan Saraii, Lenjan and Mousa Tarom had the highest percentage of germination. The maximum germination rate was due to Mousa Tarom and the maximum shoot length observed in Gharib variety. So it seems, if we would only consider the germination percentage, Hasan Saraii is the best variety and if the maximum germination percentage and rate are considered, the variety that would be considered is Mousa Tarom. Therefore, high salinity we should not just rely on the germination but the germination rate should also be noted and in lower salinity due to different cultivars germination percentage, germination rate and dry weight of root should be paid much more attention.

Asad Masoumi Asl, Zohreh Chahabkar, Sakineh Khalili, Reza Amiri-Fahliani,
Volume 4, Issue 1 (9-2017)
Abstract

Salinity is one of the environmental stresses limiting rice cultivation. Evaluation of the tolerance and sensitivity of offsprings of segregated generations under salinity condition is one way of finding tolerant cultivars. In order to study the effects of salinity (80 mM NaCl) stress on the second generation offspring of crosses of three rice varieties (Dollars and Gharib with 304) and to compare them with their parents and their classification in terms of salinity stress, the first experiment was conducted, adopting a Completely Randomized Design with four replications (i.e., crossing parents with Yasouj and Kamfirooz varieties). In the second experiment, check cultivars and the second generation progeny were evaluated, using an augment with a completely randomized design. At the germination stage, the Dollar cultivar was sensitive to salinity stress because it had the lowest ratio of all traits except germination percentage. However, Gharib and Kamfirooz Cultivars were salt tolerant. In both crosses, second-generation offsprings showed genetic variations in terms of the traits measured. Broad-sense heritability values for Dollars×304 and Gharib×304 crosses for shoot height (5.98% and 96%), root length (8.90% and 86%) and shoot fresh weight (8.95% and 7.92%), were relatively high, indicating that we can select these traits based on their phenotypes. General irritability for the shoot and root length traits in the second generation offsprings of Dollar and 304 crosses was higher than that of the second generation progeny of 304 and Gharib crosses. Based on these results, we concluded that for the purpose of improving salt tolerance at germination stage, 304 and Dollars crosses are more useful in rice breeding programs.

Highlights:
  1. For the first time, an augment design was adopted in an experimental study to investigate the non-repeat genotypes in the generations.
  2. The tolerance and sensitivity of genotypes were evaluated, consistent with the definition of statistical intervals.
  3. The results of this research led to the introduction of superior crossings for replications at the farm level.

Mahnaz Aghdasi, Pooyan Mehrabanjoubani, Tahereh Nezamdoost, Fatemeh Tamaskani,
Volume 4, Issue 2 (3-2018)
Abstract

The present study sought to compare the effect of seed priming by hydropriming, ascorbate and calcium chloride (CaCl2) versus different concentrations of silver nanoparticles on two Iranian rice cultivars (Hashemi and Shiroodi) under drought stress. The experimental design, which was factorial, was completely randomized. The first factor was control (without priming), hydro-priming, 20 mg.L-1 calcium chloride, 20 mg.L-1 ascorbates and 20, 40 and 80 mg.L-1 of silver nanoparticles. The second factor was the drought stress, including control, -1.48 and -4.91 bars created by polyethylene glycol 6000 solutions. In plants without drought stress, the time required to reach 50% germination (T50) reduced to 34 and 54 percent under ascorbate and CaCl2 priming in the Hashemi and Shiroodi cultivars, respectively.  In the drought stress condition, ascorbate and hydropriming pretreatments decreased T50 and the time required to reach 90% germination (T90) more than silver nanoparticles, especially in the Shiroodi cultivar. On the other hand, in comparison with other pretreatments, CaCl2 had an important role in increasing the growth factors in all of the drought stress treatments. Although 40 mg.L-1 silver nanoparticles increased the growth factors to some extent, it seems that higher levels of silver nanoparticles cause stress in seeds and therefore decrease the seed germination and growth of seedlings. By decreasing reactive oxygen species, Ascorbate improves the germination and by increasing plasma membrane efficiency, CaCl2 enhances the seedling growth under drought stress.

Highlights:

  1. Silver nanoparticles increased the effect of stress on the seedlings of rice cultivars.
  2. Ascorbate and calcium chloride improved the germination and seedlings growth of the rice cultivars, respectively under drought stress conditions.

Hemmatollah Pirdashti, Yasser Yaghoubian, Zahra Nouri Akandi, Mehranoosh Emamian Tabarestani, Seyed Yaser Ashrafi, Faezeh Vadipour,
Volume 10, Issue 1 (9-2023)
Abstract

Extended abstract
Introduction: Seed germination and emergence are the most sensitive stages of growth and development of rice plants. In this regard, the use of growth-promoting fungi in the form of seed biological pretreatment (bio-priming) for germination and optimal growth of seedlings can be feasible. Therefore, this study aimed to investigate the effect of isolated root symbiotic fungi on the improvement of germination and growth components of two traditional and bred rice (Oryza sativa L.) cultivars.
Materials and Methods: This experiment was done as a factorial-based completely randomized design with three replicates at Sari Agricultural Sciences and Natural Resources University in the summer of 2021. Experimental treatments included 22 isolates of root symbiotic fungi (isolated and identified from previous experiments) and control (without inoculation) and two native (Hashemi) and bred (Roshan) rice cultivars. After the end of the germination period, the number of normal seedlings was counted and five normal seedlings were randomly selected to measure the length of the root, stem, and seedling as well as the fresh and dry weight of the root, stem, and seedling.
Results: Based on the results of cluster analysis the fungi were divided into four and three groups in Roshan and Hashemi cultivars, respectively. In both cultivars, group I was selected as the best group. In this group, the highest positive effect on vegetative traits varied from 5 to 59% compared to the control in fungal treatments was related to Bjerkandera adusta (ST1), Trichoderma atroviride (SF1), Monosporascus cannonballus (B3) and Trichoderma atroviride (SN1) in Roshan cultivar and Bjerkand adusta (ST1) in Hashemi cultivar. The best fungal treatments in germination traits of Roshan and Hashemi cultivars were Chaetomium globosum (SE2) and Bjerkandera adusta (ST1), respectively.
Conclusions: Overall, the results indicated the positive effect of most symbiotic fungi on the growth and germination characteristics of rice in both Roshan and Hashemi cultivars. These results show that symbiotic fungi use different mechanisms to increase growth and improve germination indicators in plants.

Highlights:
1- Growth-promoting fungi in the form of seed biological pretreatment were used (bio-priming) for optimal growth and germination and of rice seedlings.
2- The effect of native fungi isolated was investigated for the first time in two native (Hashemi) and bred (Roshan) rice cultivars.

Ahmad Munir Amini, Farshid Ghaderi-Far, Dr Benjamin Torabi, Asieh Siahmargue, Hamid Reza Sadeghipour,
Volume 10, Issue 2 (2-2024)
Abstract

Extended abstract
Introduction: With regard to the ever-growing water deficit in the world, the adoption of the direct-seeded rice cultivation system has been suggested as an alternative to the transplanting method. One of the disadvantages of the direct-seeded method is low and non-uniform germination and emergence due to low seed vigor in rice. Priming is a technique which improves the rate and uniformity of seed germination under these conditions. Thus, this study aimed to investigate the effects of priming treatments on seed germination of different rice cultivars under different temperature conditions using the thermal time model.
Materials and methods: This study was conducted in 2019 at the seed research laboratory of Gorgan University of Agricultural Sciences and Natural Resources. In this experiment, germination of primed and non-primed seeds in three rice cultivars (Nada, Anam, and Tolo) was investigated under different temperatures (15, 20, 25, 30, and 35°C). The priming treatments which consisted of control, hydropriming, and osmopriming with different chemicals (potassium chloride 2%, potassium nitrate 1%, calcium chloride 4%, glycine betaine 10 ppm, salicylic acid 10 ppm, and ascorbic acid 10 ppm) were investigated under different temperatures.
Results: The results showed that priming treatments had no significant effect on the seed germination percentage of rice cultivars at different temperatures. The thermal time model based on binomial distribution fitted well to cumulative germination percentages in all priming treatments. Among the parameters of the thermal time model, the greatest priming effect was on the reduction of the thermal coefficient, followed by the reduction of the sigma coefficient, which resulted in the increased rate and uniformity of germination. Priming treatments had no significant effect on base temperature. Also, the responses of rice cultivars to seed priming treatments varied so that in Anam and Neda, priming with calcium chloride but in Tolo, hydropriming was more effective on the model parameters, especially thermal time to 50% of germination.
Conclusion: In general, priming treatments did not affect the base temperature of germination in rice cultivars, but they significantly affected the rate and uniformity of seed germination. As the latter issue is one of the main problems in the direct-seeded rice system, suitable priming treatments for each cultivar can be adopted to increase the rate and uniformity of seed germination and emergence in this system.

Highlights:
  1. The thermal time model can be used to select the appropriate priming treatment for improving seed germination components of rice cultivars.
  2. The responses of rice cultivars to different seed priming treatments were different.
  3. Priming treatments did not improve the base temperature of seed germination in rice cultivars, but they significantly affected seed germination rate and uniformity.

Reza Imam Dost , Davar Molazem, Reza Taghizadeh,
Volume 11, Issue 2 (3-2025)
Abstract

Extended abstract
Introduction: Rice (Oryza sativa L.), as one of the world's most important cereals, serves as a staple food for more than one-third of the global population. This strategic crop plays a key role in the economies of many countries. Seed priming is a biotechnological tool and a simple, practical, effective, eco-friendly, and cost-efficient approach to enhancing a plant's tolerance to various environmental stresses and improving seed germination. This study was designed and conducted to investigate the germination and physiological responses of two rice cultivars under varying intensities and durations of electromagnetic field exposures.
Materials and Methods: In 2023, an experiment was conducted as a factorial arrangement in a completely randomized design at Islamic Azad University, Astara Branch, investigating the effects of electromagnetic field intensity (at four levels: 0, 50, 100, and 150 mT), exposure time (at three levels: 10, 50, and 100 minutes), and two rice cultivars (Tarom and Hashemi) with three replications. Rice seeds were treated inside a plastic bag under magnetic fields of varying intensities and durations. For the second phase of the experiment, plastic trays were used for seedling establishment, and healthy seedlings were then transferred to plastic pots filled with sand. After 25 days, the plants were evaluated for the desired traits.
Results: The analysis of variance results indicated that the effects of the magnetic field, time, cultivar, and their interactions were significant for most traits. The electromagnetic field at 100 mT for 50 minutes led to an increase in germination percentage compared to the control. In contrast, the treatment of 150 mT for 100 minutes caused a significant reduction in all germination-related traits. The highest values were observed under the 100 mT for 50-minute treatment, including germination percentage (98.80%), germination rate (12.533 seeds per day), radicle length (68.133 mm), plumule length (47.467 mm), seedling length (115.6 mm), radicle dry weight (0.715 mg), plumule dry weight (2.023 mg), seedling dry weight (2.738 mg), seedling length vigor index (11,422.96), seedling weight vigor index (270.6), chlorophyll-a (0.846 mg per gram fresh weight), chlorophyll-b (0.96 mg per gram fresh weight), and carotenoids (0.44 mg per gram fresh weight).
Conclusion: The electromagnetic field had a significant effect on germination-related traits and physiological characteristics, including germination percentage, germination rate, and chlorophyll content, leading to an increase in these indices. In the present study, the 100 mT treatment for 50 minutes improved seedling vigor in terms of both length and weight. Based on these findings, magnetopriming within the studied treatment range enhances germination and improves rice plant establishment by increasing chlorophyll levels.

Highlights:
  1. The effect of the magnetic field on the germination and physiological characteristics of rice seeds was investigated.
  2. Seed priming at 100 mT for 50 minutes increased chlorophyll and carotenoid content.


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