Germination Biology of Catchweed Bedstraw (Galium aparine L.) and Its Response to Some Herbicides

Catchweed bedstraw (Galium aparine L.) that is one of the many species which belong to genus Galium is among important weeds of many crops in many countries. It became more prominent especially in the last decade due to herbicide resistance cases as well as its competitive ability. Farmers from the Sakarya Province of Turkey have already complained about herbicides that has become inefficient in catchweed bedstraw control. The study on germination biology of catchweed bedstraw and its response to herbicides has been carried out under this context. There was no germination at 20℃ while 93.5% was recorded at 10℃ for the seeds of Sakarya population which was suspected herbicide resistant. Although it was started late and occurred slowly, the germination reached 71.5% at 4℃, which is more than twice of germination at 15℃ at 21st day. Both populations from Sakarya and Düzce Provinces, of which seeds of latter were collected from non-agricultural areas were undergone dose-response experiments in petri dishes for five different herbicide formulations namely; mesosulfuron+iodosulfuron, propoxycarbazone+mesosulfuron, chlorsulfuron, tribenuron+thifensulfuron and 2,4-D amine in petri dishes, which is resulted in less radicle elongation especially in lower rates of herbicides in Sakarya population as compared to Düzce population that implies loss of effectiveness of herbicides in Sakarya population. Sakarya population from wheat field was found 1.36 times more resistant at ED50 and 2.53 times at ED90 to mesosulfuron+iodosulfuron+ mefenpir as compared to Düzce population from non-agricultural areas in a pot experiment. The result was interpreted as loss in efficiency of herbicide although it shows a partial resistance. It is concluded that the problem of catchweed bedstraw could increase due to its germination features and loss of herbicide efficiencies, which requires more and detailed researches