Bulgarian Journal of Agricultural Science
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Ultrasound seed treatment for organic farming
Emilia Mihaylova, Marina Marcheva and Nikolai Peruhov
Abstract: Seed treatment is usually associated with the application of chemical, biological or physical agents to control pest and diseases, transmitted by the seeds. The conventional crop technology relies mostly on the chemical fungicides and insecticides that are unacceptable in organic farming. Common winter wheat is a major cereal culture all over the world. The main objective of the present study is to investigate the influence of ultrasonic treatment on the improvement of germination rate and the initial development of seedlings of common winter wheat and the destruction of pathogens transported by the seeds. Treating common wheat seeds with ultrasound is an alternative to conventional agriculture, meeting the requirements for minimal chemistry. Treatment with 42 kHz in an ultrasonic device having various duration: 3-9-21 min, at constant germination temperature of 22°C, has been tested on healthy and inoculated seeds. Greatest differences between the control and treated variants of healthy seeds were observed after sonification for 3 and 9 min. Sonication of contaminated seeds is particularly valuable as the shortest duration -3 min, gives significant improvement of their initial development – germination energy increases by 46%, germination rate by 35% and growth of seedling by 33%. Shorter irradiation for 3 and 9 min leads to enlarged leaves of the young plantlet on the 5th and 9th day from the germination. Longer treatments are unnecessary as in this case serious negative effect is shown – decrease with more than 20 % of the length of the leaves. The development of the contaminated seeds after different duration of ultrasound treatment is stronger and quicker, with no symptoms of any plant disease, but the results from analyses of coleoptile length, even statistically significant, are contradictory. Shorter exposition to ultrasound for 3 minutes enhances the coleoptile length on the 9th day. Quicker development of the leave on the 3rd day is observed at longer sonication for 9 min. Biggest accumulation of total biomass is achieved at the longest treatment of the seeds. The method of sonication with 42 kHz in water bath has been shown to be a good alternative for destroying fungi in seeds and accelerating the growth rate of young shoots which improves their competitiveness against weeds and avoids the need to use a herbicide as an alternative to organic farming.
Keywords: germination; organic farming; seed treatment; ultrasound; wheat
Date published: 2021-09-14
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