Interaction of Magnetic Field and Dormancy Breaking Treatments on Germination and Seedling Growth of Some weed Species

Seed dormancy is the most important factor that prevents weed seed germination. Lack of simultaneous germination of weed seeds causes a number of problems in their control due to seed dormancy in the fields; therefore, weed seed dormancy is considered to be an undesirable trait for farmers. The aim of this study was to investigate the effect of magnetic field on seed dormancy elimination in some weed species.

In order to study the effect of Magnetic field on germination and seedling growth of redroot pigweed (Amaranthus retroflexus), spring wild oat (Avena fatua) and common purslane (Portulaca oleraceae), a factorial experiment based on completely randomized design was conducted at the Ecology laboratory of Science Research Branch, Islamic Azad University in 2019. Factors consisted of dormancy breaking treatment at 8 levels (gibberellic acid 1000 mg/l for 20 minutes, gibberellic acid 2000 mg/l for 20 minutes, sulfuric acid for 5 minutes, sulfuric acid for 10 minutes, sulfuric acid for 20 minutes, nitrate potassium at 0.01 g/L, nitrate potassium at 0.05 g/L and control) and magnetic field at 4 levels (0, 25, 50 and 100 mT).

Results showed that responses of three weed species to magnetic field were different. Magnetic field increased percentage of germination, fresh weight of plumule and length of plumule of redroot pigweed, so magnetic field at 100 mT was the best treatment for dormancy breaking. The highest germination percentage of wild oat was obtained in 0.01 mM potassium nitrate at 50 mT. The length plumule of wild oat increased significantly at 2000 mg/l gibberellic acid with increasing magnetic field level from zero to 25 mM. Nitrate potassium at 0.05 g/L was the best treatment for breaking the dormancy of common purslane. Magnetic field at 100 mT could increase percentage of germination of this weed.

In general, the results of this study showed that sulfuric acid treatment was not a suitable option for the removal of dormancy in the three weed species because of the elimination of seed embryos. Magnetic field treatment significantly increased the studied traits in all three species of redroot pigweed, spring wild oat and purslane. The interaction between dormancy breaking treatment and magnetic field was significant in many of the studied traits and the effect of dormancy breaking treatment was intensified by magnetic field. Therefore, the use of magnetic field treatment is recommended to increase the germination of these three species. 

1- There is a positive and significant interaction between seed dormancy elimination treatments and magnetic field.2- Sulfuric acid treatment is not a suitable option for breaking the dormancy of redroot pigweed, spring wild oat and purslane.