نشریه علوم و تحقیقات بذر ایران
سال پنجم شماره 4 (زمستان 1397)

In order to evaluate the effect of seed priming with salicylic acid on seed germination and seedling growth of Hibiscus sabdariffa under drought stress a factorial experiment was conducted in a randomized complete block design with four replications. First factor was included different levels of drought stress (0, -2, -4 and -6 bar) and the second factor was different levels of seed priming with salicylic acid at four levels (0, 0.5, 1 and 1.5 mM). Results showed that among different levels of seed priming, priming with 1 mM salicylic acid increased germination rate and coefficient of velocity of germination, compared with control by 42 and 14%, respectively. Salicylic acid concentrations of 0.5 mM enhanced, root length, shoot length and seedling dry weight compared with the control treatment, by 17, 18 and 27%, respectively. At drought conditions, priming reduced the mean germination time, significantly. Moreover drought stress decreased all measured traits except mean germination time. Overall, results showed that seed priming with salicylic acid in stress conditions improved roselle germination.

In order to evaluate the effect of the Russian knapweed (Acroptilon repens) aqueous extract as a biological herbicide on the germination of weeds of purslane (Portulacaoleracea), common yellow mallow (Abutilon theophrasti), and wheat (Triticum aestivum), a factorial experiment (with a completely randomized design and four replicates) was conducted in 2016 in the laboratory and greenhouse of the Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran. The experimental factors included plant types (purslane, common yellow mallow, and wheat) and concentrations of the Russian knapweed aqueous extract at 6 levels (0 (control), 5, 5.7, 10, 15, and 20%). The results showed that germination percentage, coleoptile length, radicle length, and total weight of the seedlings were significantly affected by different concentrations of the Russian knapweed aqueous extract, plant species, and their interactions. Russian knapweed aqueous extract had the least and the greatest inhibitory effect on the germination of common yellow mallow and purslane, respectively. It was observed that the reduction of the length of coleoptile under the effect of aqueous extract concentrations of Russian knapweed for all species was significant and with increase in concentration of aqueous extract of Russian knapweed to the fast slope decreased length of the coleoptile. In the case of the radicle length, the results showed that at concentration of 20% extract of Russian knapweed, the highest and lowest radicle length reduction was related to the common yellow mallow and wheat with amount of 99 and 21% compared to control treatments. Based on the test results, reduce of the dry weight of seedlings on 15 and 20% for concentrations of aqueous extract of Russian knapweed was observed for each of the three plants. The applied results of this research was includes the usability of Russian knapweed aqueous extract on concentrations of 15 and 20% and its impact on seed germination and growth of purslane and common yellow mallow weeds.

To investigate the effects of seed priming in Linum usitatissimum L. on germination characteristics and yield, experiments were conducted in the laboratory conditions. In laboratory a completely randomized design in factorial layout with 11 treatments (Poly Ethylene Glycol -5, -10 and -15 bar, gibberellin in 200, 400 and 600 ppm, KNO3 in 200, 400 and 600 ppm concentrations, hydro-priming and control) in ranges of temperatures (15/25, 20/25, 25/25 and 30/25 °C -day/night) with 4 replication. The results showed that priming had a significant effects on seed germination characters. PEG treats had the most negative effects on germination characters. The most of seed vigour, percentage and ratio of germination, length of radicle and length of plumule amounts were made by KNO3 (200 ppm) and gibberellin (400 ppm) under temperature range of 20/25 ° C (day/night). It seems this influence made by the beneficial effects of potassium nitrate in growth and plant maintenance and effectiveness of gibberellin in cell growth and photosynthesis.

In order to investigation effect of different irrigation regimes on seed germination characters in some of promising rapeseed lines, two separate split plot experimental based on CRD and RCBD design at laboratory and environmental condition, respectively, during 2015-16 cropping seasons were performed. At each experiment, different levels of irrigation––control, cut-off irrigation at the flowering stage, and cut-off irrigation at the pod formation stage––and 18 promising lines were considered as main and sub-plots, respectively. Results of analysis of variance obtained from laboratory showed that cultivar and irrigation regimes effects were significant on all of the measured characters. However, at environmental condition, only irrigation regimes, line, and their interaction effects were significant. Correlation coefficients among different characters indicated that, germination percentage under laboratory significantly correlated with final emergence percentage and final mean emerging, while correlation among electrical conductivity with some of characters such as germination percentage, daily germination and seedling dry weight was negative. Overall, our findings revealed that KS7 has desirable status than other lines. Hence, the use of this promising line for future experiments and assessing its grain yield and other related traits is recommended.

In order to evaluate the variations of soybean seed quality and also biochemical changes during seed deterioration at natural aging conditions, this research employed a factorial experiment based on a completely randomized design (in laboratory) and randomized complete block design (at field). The treatments included two cultivars of Williams and L17 and three storage durations of 6, 18 and 30 months. The studied characteristics included normal seedling percent, electrical conductivity, soluble sugars, total protein, malondialdehyde, first and final seedling emergence percent and cumulative seedling emergence rate. The result showed that seed quality significantly decreased by increasing the storage duration and this loss of seed quality storage resulted in the reduction of field seedling emergence. The reduction of seed quality in the third duration was significantly higher than the second storage duration. Also, the cultivar Williams had more storability as compared to L17. The number of normal seedlings decreased more significantly 5 and 17.8 percent for Williams and 12.9 and 25.8 percent for L17 subsequent to 18 and 30 months as compared to 6 months of storage. The results indicated a positive correlation between seed quality and seed’s soluble sugars and protein and also a negative correlation between leakage of cell substances and the rate of MDA in seeds. Total protein percent decreased from 36.5% (6 months of storage) to 33.5% and 31.5% (18 and 30 months of storage). Results revealed that seed deterioration rate after 30 months of storage was significantly higher as compared to its previous period. This finding shows that soybean seeds was storable for at least one crop season and the decrease in the seed quality and emergence problem will then be witnessed.

In order to evaluate the effect of priming by spermidin polyamine on increasing drought stress at germination and seedling growth stages of soybean, cv. Caspian, a factorial experiment was conducted based on completely randomized design with four replications at Sari Agricultural Sciences and Natural Resources University in 2016. The treatments were three drought stress levels (0, -2 and -4 bar) and three spermidine levels (0, 1 and 2 mM). The results showed that application of spermidine at the rate of 1 mM improved germination properties including germination maximum, germination rate, germination uniformity, times to 10, 50 and 90% germination, radicle length, seedling weight and final germination under mild drought stress (-2 bar). High dose of spermidine could not improve the tolerance to intensive stress in evaluated traits. Application of 1 mM spermidine led to increased activity of antioxidant enzymes ascorbat peroxidase, peroxidase, catalase, and amount of soluble protein in mild drought stress conditions compared to control. It was found no interaction between spermidine and drought stress for protein concentration. Generally results indicated that the pretreatment of seeds with spermidine improved tolerance to moderate drought stress through boosting germination indices and increasing activity of antioxidant enzymes in soybean seedlings.

In order to study on the effect of six medicinal plants of resistant to drought on some growth and biochemical parameters of sesame (Sesamum indicum), an experiment was conducted in a factorial arrangement based on completely randomized design with three replications in laboratory of Agricultural Faculty of Bardsir, Shahid Bahonar University of Kerman during 2016-2017. The experimental treatments were plant extract in six levels (Sugebrush (Artemisia annua), Licorice (Glycyrrhiza glabra), Camel thorn (Alhagi pseudoalhagi), Stinking assa (Ferula ssafoetida), Black saxaul (Haloxylon ammodendron), Thyme (Thymes vulgaris)) and extract concentrations at 7 levels (0, 100, 500, 1000, 5000, 10000, and 20000 ppm). The results showed that growth parameters as percentage and speed of germination, dry weight of plantlets, vigor index and biochemical parameters (CAT (Catalaze) and APX (Ascorbate peroxidase) activity) were affected by main and interaction effects of extract and concentration (P≤0.01). The GPX (Gayacol peroxsidase) activity was influenced by the main effect of extract concentration (P≤0.01). GPX activity increased with increasing of extract concentration to 5000 ppm and decreased at concentration of 10000 ppm. The percentage and speed of germination, dry weight of plantlets and CAT and APX activity were increased with increasing of Licorice extract concentration. Thyme, Sugebrush and Black saxaul extract reduced growth parameters and CAT activity and increased the APX activity. Camel thorn and Stinking assa extract increased root length and vigor index of plantlets and decreased APX activity.

Allelopathy refers to the interaction of plants with their released chemicals on each other. Allelopathic compounds play an important role in biodiversity and the ability to produce ecosystems.In order to investigate the effects of allelopathy on Rosa damascena Mill on germination of wheat (Triticum aestivum L.) seeds. The experiment was done as factorial based on completely randomized design with three replications. The distilled water treatments used as control and different concentrations (0, 1, 2, 3, 4 and 5%) of aqueous extract of dried Rosa flowers used as treatments. Rosa flowers were from Boukan and Khansar, the designwere completely randomized in three replications. The results of this experiment showed that the juice extract with the mentioned concentrations did not reduce germination as compared to the control.The aqueous extract of Boukan showed a significant decrease in plumulelength, radiclelength, plumuledry weight, radicledry weight, and soluble protein content in wheat. Also, the extract of Khansar showed the highest inhibitory effect on plumule fresh weight, radicle fresh weight and soluble sugar content on the wheat plant.The analysis of variance showed that the difference between the extracts, treatments and extract × treatment was significant (P <0.05). There was a significant correlation (P <0.05) between fresh weight, dry weightand length, as well as protein and sugar content in both plants.

The reasons for the low lentil yield in Iran can be mentioned to low quality of seedling, low capacity germination, emergence and poor seedling establishment. Thus, priming and seed planting depth are important methods of empowerment of seed. This experiment as a factorial in randomized complete block design with three replications was conducted in outdoor greenhouse of Gonbad Kavous University (Faculty of Agriculture and Natural Resources) in February 2015. The treatments were included priming with 4 levels (control, hydropriming, GA 50 ppm, GA 100 ppm) and 15 different planting depths (from zero to 14 cm). The results showed the effects of hydropriming and different planting depths were significant, meanwhile interaction effects were not observed significantly on the traits. Mean comparison showed that the highest plumule length, germination rate and percentage were obtained from GA treatment with concentration of 100 ppm. The highest dry weight plumule, leaflet, seedling and leaf area were observed in GA treatment with concentration of 50 ppm. Relationship rate and emergence percent were negative line with planting depth, thus with increasing of planting depth were caused rate and emergence percent decreased by 0.0016 seed per hours and 4.01 percentage, respectively. Moreover the regression relationship between seedling growth parameters with planting depth was quadratic function that be proved variable percentage between 81 to 87 percentage in studied characteristics. Totally the optimal sowing depth was 3-2.5 cm in lentil.

Potato is one of the most important agricultural product in Iran which due to vegetative propagation, incremental deterioration of tubers caused by diseases are evident after each generation. Therefore, development seed control and certification systems for sustainable production and maximizing yields to be noticed by many countries produce potatoes including Iran. For this purpose, seed tubers produced in three classes of pre-basic, through the establishment of healthy seedlings in fully controlled conditions in vitro and in vivo andproduction of healthy mini-tubers, basic and certified tubers through production on the farm under the full supervision of technical inspectors. Seed tubers monitored based on national standards that most of the emphasis is on the health of the tubers and in case of acquisition the required standards are certified. Monitoring of the health, identity and genetic purity of seed tubers in the country during the last decade showed that the most important limiting factor and disruption of this process is infection with PVY virus which is transmitted by non-persistent and due to the wide host range and distribution, control has been very difficult. Although, a decreasing trend of infection rates over time due to the use of healthy seeds in the country but still remains at the forefront of the important factors of the system. The present review article pays attention to introduce the control system and quality of potato seed and the PVY virus as an important problem in seed propagation farms.