The purpose of this study was to evaluate the effect of Nano TiO2 and Nano CNT on some germination indices and growth parameters of some hulled barley cultivars. The experiment was conducted in laboratory at Shahrekord University during 2014. Experiment set as factorial based on a completely randomized design with four replications. Treatments included of titanium dioxide nanoparticles and carbon nanotube (CNT) in four concentrations (0, 10, 30 and 60 mg.l-1) were applied on seeds of hulled barley cultivars including Bahman, Makoii and Nosrat. Traits were included of the dry weight of seedling and seedling length, germination percentage, germination rate, mean germination time, the percentage of resistance of radical, seedling vigor length and weight index. The results showed carbon nanotubes treatments with 60 mg.l-1 had significant impact on germination percentage, germination rate, seedling vigor length and weight index and seedling dry weight compared to other treatments. In this experiment, the highest percentage of resistance of radicle, seedling vigor weight index and seedling dry weight of Nosrat cultivar were obtained under 60 mg.l-1 carbon nanotube treatment with 70, 122.2 and 64.9% compared to control treatment respectively. As well as, 60 mg.l-1 carbon nanotube treatment, increased the seedling vigor of Makoii cultivate 39.8% compared to control treatment. It is concluded that, the Nosrat cultivar based on seedling vigor length and weight index, seedling length, seedling dry weight and the percentage of resistance of radicle showed better morphological characteristics than Bahman and Makoii cultivars, under laboratory experiment.

Effect of free and symbiotic nitrogen fixing bacteria on seed and seedling produced seeds under deficit irrigation was conducted in laboratory and field experiments in 2006. In laboratory of karaj’s Seed and Plant Research and Certificate Institute an experiment was conducted based on factorial in form of completely randomized design with four replications and in field’s of Islamic Azad University, Varamin Branch were split factorial in form of randomized completely block design with three replications. Treatments included water stress [Irrigation after 50 (Normal irrigation), 100 (Middle stress), 150 (Severe stress) mm evaporation from pan class A], Cultivar [Manokin & Williams and SRF×T3 Line] and inoculation [Inoculation with Bradyrhizobium japonicum, Bradyrhizobium japonicum co-inoculated with Azotobacter chroococcum, No seed inoculation]. Results showed that drought stress decreased the uniformity and germination speed and seedling emergence. Bacteria increased leaf dry weight, stem dry weight, leaf area and seedling vigor index but had no effect on emergence. In irrigation levels inoculated treatments had higher seedling length, leaf, stem, seedling dry weight and seedling vigor. Severs stress seeds inoculated with Bradyrhizobium japonicum had higher root dry weight than control. Therefore in seeds which were produced under deficit irrigation conditions, bacteria increased seedlings vigor.

To study the effect of production region and seed weight on some characteristics related with germinability and seedling vigour of peanut seeds, a research was performed in three peanut fields in Astaneh Ashrafieh and agronomy laboratory of Rasht branch Islamic Azad University during 2010 to 2012. This research was carried out using the standard germination test, cold and accelerated aging. For all tests a factorial experiment with a randomized complete block design in 3 replications was used. First factor was seed production region in 3 levels (Noghredeh, Amshal and Bandar-Kiyashahr) and second factor was seed weight in 3 levels [heavy (seeds heavier than 1 g), medium (seeds between 0.8 and 0.1 g) and light (seeds lighter than 0.8 g)]. The studied characteristics were including: final germination percentage, seedling vigour, radicle dry weight, hypocotyl dry weight, plumule dry weight, cotyledons dry weight and seedling dry weight. Results indicated that effect of region on the final germination percentage, seedling vigour and radicle dry weight were significant in all tests. Peanut seed weights also had a significant effect on radicle dry weight, hypocotyl dry weight, plumule dry weight, cotyledons dry weight and seedling dry weight in all tests.  Interaction of the region and seed weight on the seedling vigour of peanut seeds was significant in all tests. In accelerated ageing test, this interaction was significant on all the studied characteristics except for cotyledons dry weight. Mean comparison of studied characteristics also indicated that the greatest amount of studied parameters was observed from heavier seeds of Amshal region. The maximum germination percentage was detected in seeds produced in Amshal region with average of 86.67%. Also, maximum seedling vigour was achieved in heavy seeds produced in Amshal region with an average 54.24 (standard germination).

In order to effect primary germination percent of seed lot and seed size and shape hybrid maize (Zea mays L.,) single cross 704 (Sc. 704) on seed vigor was carried out in seed quality analysis laboratory and research field as factorial experiment by completely randomized design and randomized complete block design respectively with four replications at Seed and Plant Certification and Registration Institute (SPCRI) in 2012. The treatments were included at three seed size and shape flat, medium and round by seed primary germination percent 88, 90 and 92%. The seed and seedling vigor were studied at the laboratory by seedling growth analysis through standard germination test and normal seedlings percent, mean daily germination, coefficient of velocity of germination, seedling length and dry weight and seedling length and weight vigor indices determined in laboratory. Also seedling field emergence percent and rate and seedling length and weight vigor indices in field measured. The results showed that seeds having various primary germination percent had significant different related to seed and seedling vigor indices. Also flat seed shape compared with round shape and medium size seeds had higher germination ability and related to seed and seedling vigor indices. In spite of this results, studied related to seedling emergence and vigor if field indices of having various primary germination percent and size and shape seeds had not significant difference but mean daily germination with seedling emergence percent and rate in field had significant positive correlation. Generally, under this experiment conditions seeds having higher primary germination percent and flat shape had seeds had more germination ability and stronger vigor.

In order to comparison of different suitable seed vigour tests in relation to seedling emergence and forage yield of four sorghum cultivars (Speed Feed،Jambo،Super Dan and Suger Graze) an experiment was conducted during 2003-2004 in laboratory of Seed and Plant Improvement Institute (SPII) of Karaj، and also a field experiment at exprimental station of Agriclture College of Azad Islamic University، Mardabad، Karaj. germination standard test، seedling vigour classification test، staining index tetrazolium test، electrical conductivity tests and accelerated aging were measured in the completely randomized design with four replications in laboratory. Under field condition، with the randomized complete block design in four replications، percentage and rate of seedling emergeance and forage yield were evaluated. The result of analysis of variance in the laboratory study showed that the differences between the cultivars under the seedling vigour classification tests and staining index tetrazolium were significant at 5% probability، but under the germination standard tests، electrical conductivity and accelerated aging tests were significant at 1% of probability. Under field condition، Suger Graze and Jambo cultivars had lower and higher percentage and rate of seedling emergeance and forage yield، respectively، and also there was significant positive correlation between seed vigour tests، percentage and rate and forage yield. Among the tests under study the seed vigour classification and accelrated aging test for the percentage of emergence seedling vigour classification for the rate of emergence and also staining index tetrazolium and accelerated aging test for forage yield had the closet correlation. As a result، these above mentioned tests had a heigh ability for forage sorghum cultivars percentage of seedling emergence in field prediction and is recommended as the tests to evaluate seedling and seed vigour.

The aim of this research was to study the effect of seed source on morphology, emergence and early vigor characteristics of Quercus brantii Lindl. acorns. The acorns were collected from 4 forest habitats (seed sources) in southern Zagros (provinces of Kohkilouyeh-Bouyer Ahmad and Fars), located in elevations of 850, 1100, 1500 and 2100 m a.s.l. and planted as randomized completely design with three replications in nursery of Shahid Rousta (Ab-baric of Fars, 1700 m.a.s.l.). Results indicated that seed source significantly affected morphologic characteristics of acorns (length, width and weight), emergence (emergence percentage, emergence rate and mean time of emergence), seedling growth parameters (shoot length, shoot dry weight, leaf dry weight and leaf area) (p<0.01). The greatest shoot length, leaf dry weight, shoot dry weight, leaf area and seedling vigor index were related to low elevation seed source (850 m.a.s.l.). Correlation of seed origin with mean time of emergence was significantly positive (p>0.01) and with other seed traits was significantly negative (p>0.01). Since emergence, emergence rate, mean time of emergence, shoot length and seedling vigor index are considered as assessment criteria for seed vigor index in early growth stages, it can be suggested that low elevation seed source has highest early vigor.

Efficient seed germination and rapid and uniform seedling emergence are important in commercial agriculture. Therefore, the use of strategies to improve germination and seedling establishment is necessary for increasing productivity. Hydropriming has been suggested as a simple pre-germination strategy to improve seed performance. In this study, the effects of different durations of hydropriming (10, 24, 48 and 72 hours) at different temperatures (10 and 25 ˚C) compared to unprimed seeds on the vigor and germination performance of five milk thistle accessions (Ahvaz, Sari, Esfahan, Dezfol and Gachsaran) were evaluated. An experiment was conducted as a factorial experiment based on a completely randomized design with three replications. Germination performance was evaluated by final germination percentage, mean daily germination, mean germination time, coefficient of velocity of germination, Timson's index, time to reach 50% the final germination percentage, germination value, coefficient of uniformity of germination, length and dry weight of seedlings and vigor index. The results show that germination capacity, germination rate and seedling vigor indexes increase significantly in hydroprimed seeds at temperature of 10˚C, whereas decrease in hydroprimed seeds at temperature of 25˚C. Our results also show that the efficacy of hydropriming on seedling emergence and vigor traits depends on the priming duration and temperature. Hydropriming at 10˚C indicated the most effective on germination indicators and seedling vigor when compared to unprimed seeds. In addition, the comparison of germination and growth indicators in different durations of hydropriming in five milk thistle accessions indicated that the best duration of hydropriming for Ahvaz and Gajsaran is 72h, for Sari and Dezfol is 48 and 72h and for Esfahan is 10 and 24h. Therefor, the effect of hydropriming on germination performance and seedling vigor depends on plant association and hydroperiming time and therefore, the selection of the best condition for hydropriming will improve the seed germinability and vigor.

Application and nutrition of the maternal plant have a great role in germination and vigor of the produced seeds. In order to study the germination characteristics of barley native seeds obtained by application of different foliar application under saline irrigation (12 dS/m electrical conductivity), a factorial experiment with completely randomized design with three replications, was carried out at Isfahan Kaboutarabad Agricultural Research Station, in 2018-19. The first factor (foliar application) was in five levels: no foliar application, Zinc sulfate, Potassium sulfate, Salicylic acid and Superoxide dismutase at the beginning of tillering at 7 days interval and on three occasions. The second factor (barley cultivars) was Gohran, Mehr and Armaghan. Attributes such as germination percentage and rate, root length, shoot length, seedling vigor index, root dry weight, shoot dry weight, seedling vigor index, germination uniformity, and allometric coefficient was measured. Under saline water and different foliar application conditions, Mehr cultivar produced more radicle length, shoot length and seedling vigor index (except zinc sulfate). Seed longevity (root length, shoot length, seedling vigor index) appeared to be effective in selecting salinity tolerant cultivars. In foliar application of potassium sulfate, germination uniformity and germination rate of Mehr (salt tolerant) cultivar were higher than Armaghan (salt sensitive). The highest allometric coefficients of seed belonged to foliar application of potassium sulfate (0.85) and zinc sulfate (0.84) in Mehr (0.81) and Armaghane (0.83) cultivars.

To study the effects of sowing dates on seed germination and on seed vigor of 12 spring rapeseed cultivars, an experiment was performed in years 2005-2006. During the first year, 12 cultivars of spring rapeseed were planted in the Research Field of Seed and Plant Improvement Institute, Karaj, Iran. During the second year, standard germination test was conducted to study the performance of the seeds grown during the first year of the experiment. A factorial experiment in randomized complete block design was employed. According to the results, the seeds grown during the two seasons were significantly different from the view point of seed weight, germination, length of radicle and plumule, seedling vigor index, number of normal and abnormal seedlings, mean daily germination as well as daily germination index. In addition, the effect of cultivar was significant on seed weight, germination, length of radicle, plumule and seedlings, seedling vigor index, number of normal and abnormal seedling, mean daily germination as well as daily germination index. The seeds of autumnal cultivation were better off from the view point of seedling vigor as well as other important characteristics of seed vigor. Among the cultivars, RG405/02 was better than the others due to its high seed weight. A reduction of seed weight during germination could be used as a valuable index to determine seed vigor.

In order to compare the seed characteristics of wheat seed lots stored in outdoor, a factorial experiment based on a completely randomized design with three replications was carried out at three wheat seed purchasing and processing centers located in Mashhad, Torbat-e-Heydaryie and Torbat-e-Jam for one year from June 2005. The First factor was three wheat varieties including Falat, Chamran, Cascojen and the second factor was duration of wheat seed storage in outdoor for 0, 15, 30 and 45 days before processing. Moisture content, hectolitre weight, seed loss percentage while processing, germination percentage before and after accelerated aging test, seedling vigor index and germination rate were evaluated. Accelerated aging test was done before determine the germination percentage, seedling vigor index and germination rate test. Compound analysis of variance for locations showed that effect of variety in moisture content and seedling vigor index was significant, and the effect of  storage duration except for hectolitre weight in all traits were also significant. Between the time of purchase until 45 days after it, seed loss percentage increased  about 1.9 percent and moisture content and germination percentage were decreased before and after accelerated aging test, also seedling vigor index and germination rate were exposed to a reduction by 5.11, 4.89, 10.26 percent and 314.41, 0.036 unit, respectively. In addition cv. Chamran was less tolerate to outdoor storage conditions compared to Cascojen and Falat.