جستجوی مقالات مرتبط با کلیدواژه « seed vigour » در نشریات گروه « منابع طبیعی »

Yarrow (Achillea) is one of the most important species of medicinal plants that has many applications in the pharmaceutical, cosmetic and health industries. In order to investigate the effect of seed priming on the germination characteristics of degenerate seeds,, A factorial As the form of completely randomized design with 3 replications carried in the greenhouse of the Natural Resources Gene Bank of Research Institute Forests and Rangeland in 2022.. I, three yarrow species, Achillea.nobolis, A.millifolium and A.tenufolia, were artificially senesced by applying a temperature of 40 degrees Celsius and a relative humidity of 100% (for 0, 48 hours, 72 hours), seed priming at 3 levels, including hydropriming (soaking for 24 hours in distilled water), gibberellic acid, 250 and 500 ppm. The analysis of variance showed that there were main and interaction effects of species, seed priming and seed deterioration for all the traits of emergence Characteristics were significant at P≤ 1% . Comparison of the species showed , that of A. nobolis species higher values of all traits except for dry matter compare with two other species.The species of A. millifolium was ranked as second level. The highest emergence rate was obtained in non- deteriorated (hydro) seeds. Three species have high average mean values with gibberellic acid 250 ppm for all traits except the ratio of root/stem and percentage of dry matter. . The highest root length /Shoot were obtained with gibberellic acid 250 ppm, which indicates that the aged seeds inside Pots have more rooting improvement for their survival

Germination of seeds, one of the most critical stages of plant cycle is greatly influenced by drought stress. In this way, the effects of ascorbic acid to improve germination and antioxidant enzyme activities in sheep fescue seeds under drought stress were studied. A factorial experiment based on completely randomized design with three replications was done. None- primed seed (control group) and priming of different concentrations of ascorbic acid (0, 1 and 2 mM) under 0, -0.4, -0.8 and -1.2 MPa drought stress levels were evaluated. The results showed that seed priming with ascorbic acid in different drought levels increased some traits such as germination percentage, vigour index, plumule and radicle length, soluble carbohydrates and protein contents and antioxidant enzymes activities (catalase, superoxide dismutase and ascorbate peroxidase). While it decreased mean germination time, electrical conductivity and malondialdehyde content in comparison to nonprime seeds. So seed priming with 1 and 2 mM of ascorbic acid in -1.2 MPa level increased vigour index, soluble carbohydrates and proteins, respectively by 167.03, 22.26, 35.77, 187.91, 22.61 and 30.20% compared to nonprimed seeds. Also, it increased activity of catalase, superoxide dismutase and ascorbate peroxidase, respectively by 11.85, 22.81, 12.25, 13.83, 31.33 and 9.93% compared to non-primed seeds. Therefore, the use of 1 and 2 mM ascorbic acid concentrations to reduce the negative effects caused by drought stress is recommended.

One of the major factors for the low productivity of seeds is poor seed germination and early seedling mortality due to seed-borne fungi. Several grain-borne fungi, including species of Alternaria, Aspergillus, Fusarium and Penicillium, have been implicated as seedling pathogens of cereals. Experiments were conducted at the seed and Plant certification and Registration Research Institute. Experimental units were arranged factorial in a completely randomized design with two factors (cultivar and storage temperature). The result indicated that interaction between storage temperature × cultivar had significantly affected on seed-borne fungi after three months storage. The seed-borne fungi infestation sach as Asporgilau flavus and Penicillium decreased in all seeds that stored at 20-30C° (alternative temperature), also the Fusarium species infestation was reduced in Usef, Nosrat, and Productive Cultivars seed under storage at 20-30C°, whereas Alternaria alternate infestation was increased in all seeds that stored at 20-30 C° . Meanwhile, normal seedling percentage and seedling vigor were significantly improved by storage seeds at 20-30 C° that it was more pronounced in Sahra and Productive cultivars. Final germination percentage and normal seedling percentage increased, when seed-borne fungi infestation such as Aspergillus flavus,Penicillium sppand Fusarium spp decreased in seed samples. Generally, according to cultivars that examined in this experiment, seed stored at 20-30 C°(alternative temperature) could have maintained their vigour high, it is new founding that could help to control seed-borne fungi (Asporgilau flavus, Penicilliumsppand Fusarium spp) in storage condition also prevent of seed deterioration.

In order to investigate the effect of organic fertilizers on yield and seed quality criteria of Calendula officinalisL., seeds of a field experiment under application of two levels of cattle manure (without and with 20 t ha-1) and four levels of bacterial inoculant (containing N-fixing bacteria, P solubilizerbacteria, mixture of bacteria and control) were evaluated for seed quality criteria in a factorial experiment based on completely randomized design with four replications in Medicinal Plant Laboratory of Department of Horticultural Sciences and Landscape, University of Tehran in 2010 and 2011. Then, 1000 seed weight, seed yield and dimension and seed germination quality criteria such as seed germination percentage, rate and uniformity, time to 95% germination, seedling weight and length and seed vigour index were investigated. Results indicated that interaction effect of manure and bacterial inoculant caused significantly the highest 1000 seed weight and seed yield in both years. Nearly, all criteria related to seed dimension affected by cow manure and also bacterial inoculants in both years. Also, application of cow manure significantly affected seed germination percentage, seedling length and seed vigour index (both years) and inoculation of seed by plant growth promotion bacteria showed significant effects on seed germination percentage, seedling length and seed vigour index (both years) and seed germination uniformity, time to 95% germination and seedling weight (first year). In general, using cattle manure and also plant growth promotion bacteria resulted in the highest amount of all measured criteria compared to non application of manure and bacterial inoculants.

This research was conducted to evaluate the effect of drought stress andnutritioning with natural products on seed vigour under drought stress condition. Farm treatments were drought stress in four levels including normal irrigation (control), irrigation cessation at flowering, podding and flowering to physiological maturity stages and spraying with natural products in three level including spraying with distilled water (control), spraying with humic acid and spraying with seaweed extract and three varieties Hashem, ILC 482and local Miami (Local landrace) were used. Drought stress at germination stage induced by 0.8 MPa polyethylene glycol solution. The results showed that stressed seeds were larger than normal seeds and had higher germination percentage and mean germination time. Spraying could not alleviate the negative effect of drought stress. Totally drought stress on maternal plant was effective on stress tolerance and Miami (local landrace) was better than the other varieties. Results demonstrated that it is possible to enhance germination in stressed condition with making change in maternal environment.

Increased salt tolerance is essential need for sustainable barley production in areas with risk of salinisation. This requires new genetic sources of salt tolerance, and more efficient techniques for identifying salt-tolerant germplasms. This study, conduct to access salt tolerance in primary growth stage of eight barley cultivars and find the most beneficial salt tolerance traits in this stage. The cultivars were studied at Non-Stress (Normal) and salinity stress (24 dS/m) condition with four replication. Results of ANOVA showed significant differences among cultivars and condition for most traits, which demonstrates high diversity among combinations that enabled us to screen salinity tolerant cultivar. Estimation of coefficient of genotypic variation (GCV) showed less than estimate of coefficient phenotypic variation (PCV) under salinity stress condition for most traits. Also germination prcentage under salinity stress condition had high GCV and h2and suggested that there is high importance of additive gene action for seed vigority. So using these traits as selection index can be effective. Cluster analysis with Wardandrsquo;s method for both condition classified hybrids into three different groups. According to the results of this research, genotypes Salt Toleranc,EB-81-15,NomarandNimrozidentified as tolerant lines cultivars to salinity at germination stage and early seedling growth.

To determine relationship between mean germination time (MGT) and seed vigour in maize Hybrids and liness an experiment was conducted in the Faculty of Agriculture, University of Ferdowsi in year 2008. Germination test was carried out utilizing six maize Hybrids and liness (DC370, SC704, KSC400, OSSK713, SC700, B73) in a randomized completely design with four replicates of 25 seeds per replication at 24anddeg;C. Results indicated germination of Hybrids and liness ranged from 86 to 96 percentages. DC370 Hybrids and lines had significantly the lowest normal seedlings (60%) and the lowest seedlings length (16.7 cm) while OSSK713 had the highest seedlings length (20.7 cm). MGT of B73 Hybrids and lines was the highest (3.9 days) and its coefficient variation (CV) of seedling length was significantly the greatest (6.58%) (low seed vigour). Significantly negative correlation between MGT and germination percentage (r = -0.84) was found while positive correlation between MGT with CV of seedling length was shown, that means a larger variation on seedling length in Hybrids and liness with slow germination rate (higher MGT). Therefore, it was concluded that MGT is a good indicator to assess the maize seed vigour.

Salinity stress is one of the most common constraints to crop productivity in the world. Therefore it is of prime necessity trying to find suitable resistant genotypes to this limiting factor. In order to study the effect of osmotic potential, on germination and early seedling growth of ten genotypes of safflower (Carthamus tinctorius L.) including KM4, KM5, KM8, KM12, KM20, KM13, KM36, KM44, KM47 and Kouse, five concentrations of NaCl (0, -0.3, -0.5 , -1 and -1.5 MPa) were treated. An experiment with factorial arrangement was conducted by using a completely randomized design with four replications in seed technology laboratory of College of Abuoraihan,University of Tehran. Germination percentage, germination rate, the length of shoot and root, length of seedling, seed vigour, germination index, mean germination time, germination rate index and root to shoot ratio measured 6 days after germination. Results of data analysis showed that there were significant difference between genotypes, stress levels and their interaction. According to the fitted logistic model, the NaCl concentration level required for 50% reduction of seed vigirity was -0.8 Mp. Cluster analysis with Wardandrsquo;s method, classified hybrids into three different groups. According to the results of this research, genotypes KM5, KM12, KM36, KM20 identified as tolerant genotypes to salinity and Kose was resistant cultivar at germination stage and early seedling growth.