The investigation of Allelopathic potential of 70 wheat (Triticum aestivum) cultivars on germination and seedling growth of volunteer canola (Brassica napus)

Allelopathic effects of plant can be one of the best ways to reduce the applying of herbicides which are high costly to register and have environmental effects. Therefore, the aim of this study was to investigate the allelopathic effects of wheat cultivars and to identify the ability of them to control weeds. a field and laboratory experiment was conducted in Research Farm and Seed Technology laboratory of Aburaihan Campus, University of Tehran, during 2015-16. Seeds of 70 wheat cultivars were sown at 600 square meters of Research Farm and samples were taken for bioassay at the tillering stage. To separate the impact of allelopathic extract and osmotic potential of the extracts, different solutions were made with the same osmotic potential for each extract. Then, experiments simultaneously were conducted to investigate the effects of extract and osmotic potential on germination of canola. The results of separations of allelopathic and osmotic potential effects of extractions showed that the inhibition of canola germination is related to allelopathic effects and not osmotic potential of extraction (PEG). Results indicated that allelopathic effects of wheat cultivars had slightly increased during the releasing period of cultivars from 1940 until now, but this increase was not significant. This shows that breeders had not attention to allelopathy of wheat cultivars during breeding programs. Results indicated that there were some cultivars with high allelopathy and it is possible to include them in breeding programs to produce cultivars with high potential of weeds control.