Iranian Journal of Seed Research

Three separate experiments conducted to survey the response of two populations of common purslane weed collected from Karaj and Ahvaz on germination and early growth. The first experiment was based on 4 levels of flooding, including 1, 2, 4, 8 days plus non-flooding treatment as a control. Second experiment addressed the impact of various acidity levels, such as 4, 5, 6, 7, 8, 9, 10 and finally third experiment considered the influence of high temperatures of 60, 80, 100, 120, 140, 160, 180, 200, 220 centigrade on germination rate, germination percentage, radicle length and plumule length as well as fresh weight of the aforementioned population of common purslane (Karaj and Ahvaz). Analysis of variance revealed that in both weed populations, all germination indices were impressed by flooding periods, acidity levels and high temperatures. Extending the flooding periods resulted in reducing all measured parameters in both weed populations, so the growth of common people was completely inhibited less than 8 consecutive days of flooding. Germination rate and percentage improved gradually by increasing the acidity value from 4 up to 7. An adverse relation was observed between the measured parameters and temperature variations in both Karaj and Ahvaz weed population. Germination rate and percentage, radicle and plumule length, as well as the fresh weight of seedling, decreased significantly in response to increasing the oven temperature. Overall, it can be concluded that boosting our knowledge about both ecology and biology aspects of the common person can pave the way for introducing new ways in line with expanding long-term strategies, improving management systems and predicting the mode of germination and growth of this important weed.

Seed priming is a method which is a quite effective method for improving germination and seedling establishment. Two separate experiments were performed to determine the best hydro and osmopriming treatments effects on canola‘s seed germination. The experiments were performed in seed technology laboratory of Islamic Azad University, Karaj, Iran, 2014. The first experiment contained three canola varieties seeds hydropriming (Okapi, Zarfam and Talayeh) using tap water over time interval 0. 2, 6, 10, 14, 18, 20 and 24 hours. The second experiment included, tree canola cultivars in accompany with six concentrations of ZnS04 (0, 0.035, 0.1, 0.4, 1 and 4 gr.Lit^-1) over priming time interval of 0, 6, 10 14 and 18 hours. Both experiments were conducted as a factorial experiment in the context of completely randomized design (CRD) with four replications. The results revealed that the maximum germination percentage across all cultivars e.g. Okapi (99%), Zarfam (95%) and Talayeh (80%) is achieved at 10 hours hydropriming interval. Also concerning to germination rate, the best performance was observed for Talayeh cultivar at 10 hydropriming hour’s interval. The most vigor longitudinal and vigor weighted indices (1050.55 and 4.56) were observed in the Okapi cultivar in the fourth hydropriming level. The interaction between the cultivars, the concentration of ZnS04 and osmopriming time was significant for all characters except for shoot dry weight and vigor weighted Index. The three-way interaction showed that the highest shoots dry weight (0.11, 0.057 and 0.055) and also vigor weighted index observed in Okapi, Zarfam and Talayeh cultivar in 0.035 concentration of ZnS04 (gr.lit^-1) at the time was 10 hours, respectively. The results of this study showed that hydropriming and ZnS04 might improve the performance of rapeseed Cultivars seed.

Gaining insights into the germination and emergence patterns of weeds as well as the factors which have an impact on these patterns is beneficial for weeds management programs. In order to investigate the effect of temperature, waterlogging and salinity on germination and emergence of common lambsquarters, three separate experiments were conducted, adopting a completely randomized design with four replications. The results of the temperature experiment showed that the highest germination percentages, which were 87, 93 and 88%, were obtained in the temperature range of 15, 20 and 25°C, respectively. Maximum values of germination rate, radicle length, plumule length, and seedling dry weight were obtained at 20°C. In addition, optimum seed vigor index of 796.29 was observed at 20°C. The results of the Regression Model showed that germination percentage decreased with an increase in waterlogging duration and halted after 8 and 10 days of consecutive waterlogging. Mean comparisons revealed that radicle and plumule length, seedling dry weight and vigor index decreased significantly by increasing the period of waterlogging. Salinity adversely affected germination percentage, germination rate and seedling dry weight of common lambsquarters. These factors were at their highest amounts in the control and 50 mM NaCl treatments. A downward trend was observed in these factors as NaCl concentrations increased and finally the germination process stopped in concentrations ranging from 300 to 400 mM NaCl. Radicle and plumule length also decreased from 10.51 and 9.23 cm in the control treatment to 3.57 and 2.47 cm at 250 mM NaCl. Overall, the results revealed that the maximum seed vigor index of 851.84 was obtained in the control treatment and seed vigor halted when the salinity level increased to more than 250 mM NaCl. Finally, the results showed that optimum temperature for germination of common lamsquarters was 20 °C and the existence of salinity and waterlogging stress can decrease growth indices of this weed at germination and seedling stages.