نشریه علوم و فناوری بذر ایران
سال نهم شماره 4 (پیاپی 20، زمستان 1399)

Naked oat (Avena sativa L.) is an important cereal in temperate regions. In order to investigate the effect of seeds coating with amylose and agar on germination and physiological indices of naked oats in alkali stress, a factorial experiment was conducted in a randomized complete block design. The factors used in this study included different methods of coating the seeds (non-coating, agar coating and amylose coating), different levels of alkaline stress with sodium carbonate and sodium bicarbonate ratio of 9 to 1 (values of 0-90 mM, respectively with pH 6- 10) and for 7 days in petri dish and 20 days in the pot, respectively. Seed germination ability, amylase activity, germination speed, growth, mineral and chlorophyll a and b content were evaluated. The results of this study showed that the coating of seeds plays an important role in increasing plant resistance in environmental stresses such as alkali tension. Amylose and agar are available and inexpensive materials used in this study to cover oat dextrose seeds and reduce the effect of alkaline stress and improve plant growth ability (viability), amylase activity, germination rate, plant growth, avoidance Chlorophyll decomposition and reduction of mineral absorption were in alkaline stress. Amyloid cover was better suited for seeding under normal conditions and alkaline stress but the coating was more suitable for preserving the ability to grow seed and increase seed in higher alkali concentrations.

In order to investigate the effect of seed bio-inoculation on some germination indices of Cumin under drought stress a two factors experiment was laid out. Experimental factors included priming in nine levels (bio-priming with 4 strains of PF1, PF2, PF75 and CHA0 of Pseudomonas fluorescent, and 4 strains T29, T36, T39 and T40 of Trichoderma harzianum and non-primed (control)) and three levels of drought stress (0, -3 and -6 bar imposed by PEG 6000). Results showed that by increasing the osmotic potential levels germination indices decreased. At all levels of stress, inoculated seeds had higher germination percentage and root length than non-inoculated seeds. In under stress level of -3 bar, highest germination percentage (86.66%) and seedling weight vigor index (11.93) was obtained from T36 strain that; this treatment was able increase germination by more than 35% than non-inoculated seed. Under -6 bar, the highest (76.68%) and lowest (55%) germination percentage was related to T29 that has no significant difference with T36 (75.83%) and T39 (75.83%) and the lowest amount was related to non-primed treatment (55%). Also at all stress level, the highest length seedling vigor index was related to CHA0 strain. The highest weight seedling vigor index was related to T36 strain (6.4, 5.49 and 4.7 respectively in 0, -3 and -6 abr) and the lowest (4.89) was related to non-inoculated (control) seeds. According to the results, T36 can be suggested as a suitable pretreatment in moderation of the negative effects of osmotic potential on germination of cumin seeds.

This research was carried out to evaluate the germination response of eleven Salvia species to application of Gibberellic acid (GA3) and pre-chilling treatments in the Iran Research Institute of Forests and Rangelands during 2012. Germination responses of the seeds were investigated under control treatment, 2-levels of Gibberellic acid (GA3) treatments with 500 mg/L (for 24 and 48 hours) and 2-levels of pre-chilling treatments at 4°C (for 2 and 4 weeks). The germination percentage and rate, as the physiological traits of the species, were studied based on a completely randomized design with four replications. Based on the results, applying the Gibberellic acid (GA3) treatment for 24 hours increased both the germination percentages and rates as compared to control; but the treatment for 48 hours was insignificantly changed the two mentioned parameters comparing to control. On the other hand, the pre-chilling treatment of seeds for 2 weeks also caused a significant increase in the above parameters as compared to the control treatment; while they were insignificantly different from the control treatment by the use of pre-chilling treatment for 4 weeks.

In order to evaluate the effect of different fungicides on storage behavior of forage maize seeds, a split plot experiment based on a completely randomized design with four replicates was conducted in seed laboratory of Gorgan University of Agricultural Sciences and Natural Resources. Treatments included fungicide (Teboconazole, Carboxin Tiram, Rovral TS, Difenoconazole and control), temperature (5˚C and 25˚C) and storage duration (12 months). Germination and cold tests were conducted to evaluate the seed quality. Also, the inhibitory effect of fungicides on the prevalence of Penicillium sp., Fusarium sp., and Alternaria sp. pathogens was investigated during storage. In this study, germination percentage of stored seeds was constant in all treatments during storage period, but the results of cold test showed that the quality of maize seeds decreased with increasing storage duration at both 5 and 25°C temperatures after some time (depending on the type of fungicide). Also, all the used fungicides (Except for Difconazole and Rovral TS at 25˚C) maintained the vigor of maize seeds during storage. The Rovral TS fungicides were more effective in inhibiting the growth and development of fungal pathogens, but according to the results of cold test, two Carboxin Tiram and Teboconazole fungicides were better in maintaining the maize seed quality during storage.

In order to study germination characteristics of wheat seeds Chamran cultivar of wheat obtained from Plant that treated with different levels of nitrogen and spraying cytokinin under heat stress conditions, this research carried out in factorial experiment in randomized complete design with four replications at seed technology laboratory of Agricultural Sciences and Natural Resources University of Khuzestan. In both conditions Normal (optimum planting date) and Terminal heat stress (late planting date), nitrogen (N) was in four levels (0, 75, 150, and 225 kg.ha-1) and cytokinin (Ck) was in three levels (0, 50 and 100 µM). The results showed Effect of planting date was effective significantly on all traits, with the exception of hypocotyl dry weight. The cytokinin (Ck) was effective significantly only on germination percentage, germination uniformity, D90, Length vigor index, SRUE and thousand grain weights. Results of interaction showed treatment of N× planting date had the most Germination rate (0.03 per day). The most mobility of seed reserves (1.6 mg per mg seed) and seed vigor (17.19) was obtained from high levels of N×CK treatment. The effect of N ×Ck× planting showed the most germination (100%) was obtained from high levels of N×Ck treatment and the less germination percentage (66%) was obtained from treatment of late planting date and 150 kg ha-1 N and without cytokinin. so cytokinin increased the resistance of wheat against terminal heat stress and increased germination percentage of seed produced.

In order to study the effects of storage temperature and humidity on seed germination properties and seedling growth of (Nigella sativa L.), a factorial experiment was conducted at the seed technology laboratory of Agricultural Sciences and Natural Resources University of Khuzestan based on the randomized block design with four replications. Experimental treatments were different levels of relative humidity during storage (33, 75 and 100%), storage temperatures (30, 35, 40 and 45 oC) and storage durations (24, 48, 72 and 96 hour) and control. Results showed that increase of storage temperature and relative humidity led to lower seed germination percentage and germination rate, reduction in the root and shoot length and seedling vigor indices, while mean germination time and electrical conductivity increased. Among experimental treatments, the severe deterioration was observed at 100% relative humidity and 45 oC with the durations of 96 hour and at the medium deterioration treatments, of Nigella seeds were resealed from primary dormancy and seed germination was increased, accordingly. Fitted linear regression models by experimental treatments vs germination indices and seedling growth showed that except mean germination time of seed germination, all the traits exhibited linear relationship with three independent variables studied in this experiment.

Datura is one of the most important medicinal plants that for production of various alkaloids. Seed dormancy and the problem of germination are the most important barrier to produce this plant. In order to solve the germination problem in this important medicinal plant, the present study was carried out as a factorial experiment with three factors based on completely randomized design with three replications. The first factor consisted of two datura ecotypes (Hamadan and Esfahan), the second factor included three levels of physical treatments of breaking dormancy (no scratching, scratch with sandpaper and wet bathing of bain marie bath for 7 days at a temperature of 60 ° C, scratch with sandpaper and dry chilling for 7 days at 4 ° C) and the third factor included five levels of chemical treatments of breaking dormancy (no application of chemical treatments, NaOH 20%, NaOH 20% and gibberellin 500 ppm, NaOH 20% and potassium nitrate 300 ppm, NaOH 20% and gibberellin 500 ppm and potassium nitrate 300 ppm). Interaction of ecotypes and seed dormancy breaking treatments was significant for most traits except for number of leaves per plant, root fresh weight, shoot length and stem fresh weight. The results showed that the chemical treatment of NaOH 20% and gibberellin 500 ppm, was the best dormancy braking treatment for the fresh harvested seeds. Therefore, using this treatment without significant damage to the seeds, to break seed dormancy about 80 percent is recommended.

Astragalus, is one of perennial and various species which is expanded in an Iranian’s ranges. In regard to the expansion of plant shoot in grassland with steep, we can use it to prevent soil erosion. Also, we use some species of Astragalus to gum tragacanth extract. This study aimed to identify methods of dormancy breaking and characters of germination in four species that was designed. Seeds of four species A. brevidens, A. podolobus, A. caragana, and A. cyclophyllus were purchased from the Seeds Institute of the name of Isfahan Pakan Bazr. Treatments used for the experiment were dry chilling for 15 and 30 days, moist chilling for 15 and 30 days, scarification with sandpaper, and gibberellic acid (GA3, four levels). The results demonstrated that treatments of scarification and moist chilling for 15 days are the most effective treatments to increase seed germination. The majority of species moist chilling for 15 days can significantly increase the germination index while minimum germination index belongs to scarification, which consequently increased the mean germination time. Between the species, the A .caragana has the most germination percentage and germination index, which shows the highest compatibility of this species to the ecological condition in an Iranian Ranges.

In order to response of yellow starthistle (Centaurea solstitialis) to environmental factors (temperature, drought and salinity), were conducted three separate experiments in 6 replicates in 2019 at Agricultural Sciences and Natural Resources University of Khuzestan. Temperature treatments included (5, 10, 15, 20, 25, 30, 35 and 40 °C), drought stress (0, -0.2, -0.4, -0.6, -0.8, -1 and -1.2 MPa) and salinity stress (0, 50, 100, 150, 200, 250, 300 and 350 mM), respectively. The results of Temperature indicated that the highest germination percentage was at 25(94%), 20(93/33%) and 30 °C (92%). The lowest germination percentage was at 35 °C (22.66) and at 40 °C germination completely was inhibited. Based on the estimation of the logistic equation three parameters (x50), germination percentage and germination rate were reduced by 50% at -0.70 and -0.46 -MPa levels of drought stress, respectively. The salinity required to reduce by 50% were in germination percentage (182.35mM and germination rate (130.57mM). the knowledge of seed biology of yellow starthistle can help to manage emergence in the future.

This research was carried out to investigate the effect of using seed treatment bz Carboxin Thiram, Imidacloprid, polymer, GA3 and Trichoderma (Wild and Mutant with 250gy gamma rays) on Germination Rate, Final Germination Percentage, Seedling length and Vigor index performed at the Seed Technology Laboratory of Sugar Beet Seed Institute(SBSI). GA3 alone or with chemical treatments and Trichoderma in seed coating increased the germination. Seeds coated with 2g Carboxin Thiram, 2g Imidacloprid , 2g polymerand 1000ppm GA3 showed the highest percentage of germination (99%).The result showed that the use of polymer increased the germination percentage, vigor index and seedling length. Furthermore, application of seed treatment did not show any adverse effects on germination traits. On the other hand, the use of wild species of Trichoderma reduced germination traits. Reduced effect of seed coating by Trichoderma moderated with mutant species, but there was a germination reduction when compared to the control treatment.