نشریه علوم و تحقیقات بذر ایران
سال سوم شماره 1 (بهار 1395)

In order to evaluation of nitrogen fertilizer application and seed inoculation by Azotobacter and Azosprillium on yield¡ rate and grain filling period of corn SC-500 cultivar¡ a factorial experiment was conducted based on randomized complete block design with three replications in farm of Agriculture and Natural Resource research center of Azarbaijan-e- Shargi province in 2011. The factors were included: nitrogen rates in four levels (0¡ 60¡ 120 and 180 kg/ha form urea) as N0¡ N1¡ N2 and N3 respectively and seed inoculation with rhizobacteria (without inoculation as control¡ seed inoculation with Azotobacter chrocococum strain 5¡ Azosprillium lipoferum strain OF). The results showed that maximum of nitrogen use efficiency (35.13 kg/kg) was obtained in application of 60 kg N/ha and minimum of it (23.37 kg/kg) was in application of 180 kg N/ha. Seed inoculation with bio fertilizersincreased nitrogen use efficiency compared to no seed inoculation. Nitrogen rates and seed inoculation with bio fertilizers had significantly effects on yield and yield components. Maximum of grain yield (9313.3 kg/ha)¡ grain weight (0.31 gr)¡ rate (0.0089 gr/day) and grain filling period (54.37 day) were obtained in seed inoculation with Azosprillium ×180 kg N ha-1. So¡ in order to increasing of grain yield¡ rate and grain filling period can be suggested that be applied 180 kg N ha-1 × seed inoculation with Azospirillum lipoferum.

In order to evaluate the effect of seed priming and seed size on physical and mechnical properties of onion genotypes a factorial field experiment based on a randomized complete block design with three replications was conducted in 2012 and 2013 cropping season at Agriculture and Natural Resources Research Center of East Azarbayjan, Iran. The experimental treatments included priming (at four levels: hydropriming, osmopriming (in %2 KNO3), priming with folammin amino acid (in 2%) and control (without priming), seed size (at three levels: small, medium, large) and cultivars (at two levels: RedAzarshahr and Zarguan). Following characteristics such as physical and mechnical properties include: arithmetic mean diameter, geometric mean diameter, sphericity, frontal surface area, cross-sectional of area onion, static coefficient of friction, angles of repose and terminal velocity were studied. Analysis of variance for the measurd traits indicated that all characteristics significantly were affected by treatment and seed size. Results showed that seed priming and seed size improved physical and mechnical properties characteristics. The highest arithmetic, geometric mean diameter, frontal surface area, terminal velocity, were obtained from plant that primed with folammin amino acid 56.39,53.64, 36.27 mm 4.87 m/s, respectively, and the lowest were achieved from control plants. The highest repose angle filling and emptyin were obtained from control 46.7°, 23.17° respectively, and the lowest were achieved from primed with folamin. Also the highest static friction coefficient were obtained from control on plywood (1.6) and lowest were achieved from primed with folamin (0.67) on galvanized iron surfaces.

In order to evaluate the effect of salt stress on seed germination, early growth and antioxidant enzymes activity of Chicory ecotypes (Cichorium intybus) a factorial experiment was conducted based on completely randomized design with four replications at College of Agriculture, Shiraz University in 2013. The treatments were included five salinity levels [tap water (0.62), 3, 6, 9, 12 dS m-1] of sodium chloride and chicory ecotypes (Black and White). The results showed that germination rate and germination percentage were decreased in both ecotypes with increment of salinity severity. In both ecotypes, the highest germination (100%) was observed in tap water and 3 dS m-1 and the lowest germination (37%) was obtained at 12 dS m-1. The lowest root (14.2 mm) and shoot length (12.45mm) was obtained at 12 dS m-1 respectively. The effect of salt stress on antioxidant enzyme activity was significant, so that those were enhanced with increment of salt stress; however, increasing in salinity level from 9 to 12 dS m-1 was associated with reduction in peroxidase activity in Black ecotype. The results of this study revealed that the White species was more affected by increasing in salt concentration, so it had more sensitivity salt stress. The salt tolerance also had a positive relationship with the antioxidant enzymes activities in Black ecotype, especially for catalase.

In order to study the effect of seed size on the production and dry matter accumulation and remobilization of assimilates to the grain of four bread wheat cultivars, an experiment was carried out in 2012-2013 in research farm of Rice Research Institute. A factorial experiment arrangement in randomized complete block design with three replications was used. Treatments in this study consist of four levels of seed diameter size (2.25- 2.5 mm, 2.5- 2.75 mm, 2.75- 3 mm and larger than 3 mm) and cultivars (Kohdasht, Moghan 3, Morvarid and native genotype). Results showed that cultivar had significant effect on amount of current photosynthesis, rate of yield accumulation and grain yield. Seed size had a significant effect on amount of dry matter remobilization, remobilization efficiency, contribution of remobilization, contribution of current photosynthesis, rate of grain yield accumulation, rate of biological yield accumulation, biological yield and grain yield. Seed with size greater than 3 mm had the maximum amount of dry matter remobilization (345.17 g.m-2), remobilization efficiency (32.28%) and contribution of remobilization (68.53%), while the seeds with size 2.25- 2.5 mm had the maximum contribution of current photosynthesis (55.5%). Morvarid cultivar and seed size 2.25- 2.5 mm had the lowest rate of biological yield accumulation (60.41 Kg.ha-1.day-2), biological yield (10542 Kg.ha-1), rate of grain accumulation (17.77 Kg.ha-1.day-2) and grain yield (3101.3 Kg.ha-1). The interaction of experimental treatments was significant in no one characteristic. Therefore, Native genotype and 2.75- 3 mm seed size due to better distribution of assimilates in important yield characteristics were more suitable.

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.

Vermicompost extract can reduce negetive effects of different stresses on plant, due to its porous structure, high water storage capacity, and exsistance of some substances resembling hormones and plant growth regulators. This study was performed to investigate interactions of different levels of vermicompost extract and drought stress on germination characteristics of chickpea seedlings. The experiment was conducted in completely randomized design with four replications was conducted in 2014 at the Khatam Alanbia University of Behbahan. Seeds were sown in Petri dishes at different concentrations of vermicompost extract (0, 5, 10 and 20%) and four levels of negative water potential (0, -0.3, -0.6 and -0.9 MPa) that was prepared by PEG 6000. The seeds were placed in the germinator under controlled conditions.Vermicompost extract at -0.3 MPa significantly improved some germination indices, so that 10% levels of extract had the highest germination percentage 63.66%), radicle length 4.31 cm), 20% levels had the highest plumule dry weight (50.6 mg) and 5% levels had the highest radicle dry weight (89 mg) compared to control. Under -0.6 and -0.9 MPa, vermicompost extract, did not compensate for the negative effects of drought stress on germination characteristics. In general, this study showed that the use vermicompost extract during seed germination no significant effect under Severe drought stress, but under moderate drought stress (-0.3 MPa) is effective.

In order to investigate effects of temperature and light on germination of three Artemisia species, a factorial experiment with four replications was conducted in laboratory of Science and Research Branch-Islamic Azad University in 2013. Factors were three species of Artemisia (annual, biennial and perennial), temperature at nine levels (5, 10, 15, 20, 25, 30, 35, 40 and 45°C) and light regime at three levels (dark, 14 light/10 dark and light). Results showed that maximum germination and seedling growth of perennial Artemisia was at 30 °C while it was 25 °C for two other species. Less the amount of studied characteristics such as germination percentage, radicle length, plumule length and seedling fresh in perennial Artemisia, possibly due to less investment of perennial weeds in seed production. Among investigated traits, germination percentage significantly influenced by species × light interaction. Highest percentage of germination (66.75) was seen at 25 °C and continuous light. This treatment is significantly different from other treatments. Knowledge about seed germination controlling factors will have an important role in weeds control.

In the current work, the effect of magneto-priming has been studied on seed germination of hyssop (Hyssopus officinalis L.) - a medicinal plant from Lamiaceae - in normal condition and osmotic stress. Dehydration is a consequence of osmotic stress. The primed seeds with magnetic field (45, 90, 200, 250 mT) upon different times (5, 10, 20 and 30 min) were allowed to germinate and grow in Petri-dishes for 10 days under normal condition or osmotic stress due to mannitol (100, 200, 300 mM). At these experiments, rate and percentage of germination, length and dry weight of shootlet and rootlet of seedlings and seed vigor index were evaluated. Magnetic field (MF) (200mT/5min) significantly increased percent germination (%) and seed vigor index (%) at normal condition. Moreover, MF significantly increased seedling dry weight (25%) and rootlet length (36%). Under osmotic stress, MF significantly augmented seed germination percentage by 14%. It would be concluded that at normal condition, seed priming of H. officinalis with optimal MF could increase percent germination and promote rootlet growth which subsequently causes to improved growth through stronger establishment of seedlings and higher water absorbance from medium. Furthermore, MF would be effective for early growth of H. officinalis via enhancing seed germination under osmotic stress and/or water stress.

Ziziphus spina-christi (L.) Desf. Is an arboreal species which grows in hot natuarl habitats of Southern Iran. Regarding the genetic diversity of the species in the country, collection and long-term preservation of seed germplasm in order to prevent genetic erosion and risk, have a great priority. To evaluate the possibility of long-term preservation of the Ziziphus spina-christi seeds under cryogenic conditions, three pre-cryopreservation methods including PVS2, Desiccation, and 30%Glycerol were applied before incubation of the seeds under cryopreservation conditions (-196°C) or lipuid nitrogen (LN). The treated seeds were incubated in LN for periods of 1 week, 1 month and 1 year. Subsequently, the cryopreserved seeds were removed from cryogenic condition and evaluated under laboratory and greenhouse conditions. The results showed that seeds of Ziziphus spina-christi are able to tolerate cryogenic conditions. Effects of the cryopreservation pre-treatments including 30%Glycerol, Desiccation and PVS2 were significantly different on seed attributes and, Desiccation showed the best effects on survival rates and other attributes of the cryopreserved seeds. The interaction effects between cryogenic storage periods and pretreatments were significant for some of the attributes. However some of the attributes did not show different means in different incubation periods. In greenhouse conditions, the cryopreserved seeds were germinated and established well and, Desiccation method showed better results compare to those of the 30%Glycerol and PVS2.