مشخصات پژوهش

Scotch thistle is a weed species on farmlands and pastures in parts of the west and northwest of Iran. Cypselas can remain in the soil seedbank over a prolonged period due to varying degrees of dormancy. This study examined different methods for breaking cypselas dormancy in two local populations of scotch thistle at the research laboratory, agricultural faculty of Azarbaijan Shahid Madani University in 2020. In these experiments, the effect of sulfuric acid, wet and dry pre-chilling, potassium nitrate, and gibberellic acid were evaluated on the breaking of dormancy. All the experiments were conducted as a completely randomized design with four replications and two runs. The response of two local populations of scotch thistle were similar, and no significant difference was observed. The experiment treatments significantly increased cypselas germination compared with the control. Maximum germination percent were observed by soaking in sulfuric acid 98% for 10 min (60.60%), KNO3 for 96 h (69.36%), GA3 for 48 h (88.43%), and wet pre-chilling for 72 h (34.61%). Although pre-chilling increased germination, it was suggested that germination could be more than recorded values if the duration of wet pre-chilling increased. The best cypselas germination rate, mean germination time, T50, radicle, and plumule length were observed soaking in GA3 for 48 h and KNO3 for 96 h. It seems that water-soluble inhibitors in the embryo and probably cypselas coat caused to seed dormancy in this weed species. These findings could help develop effective management strategies associated with the dormancy of cypselas for this species.