تاثیر عمق قرارگیری بذر بر رشد گیاهچه‌های یولاف وحشی زمستانه مقاوم و حساس به علف‌کش کلودینافوپ‌پروپارژیل

This study was conducted in order to investigate the effect of planting depth on the dry weight of winter wild oat seedlings (Avena sterilis subsp. ludoviciana) resistant and susceptible to the clodinafop-propargyl, as a randomized complete block design with three replications. Wild oat seeds suspected of resistance were collected from wheat fields of Golestan Province (Inche Brun, Kalaleh, Gonbadkavus, Gorgan, and Aliabad Katul cities). Also, susceptible winter wild oat seeds were collected as a control from fields or areas with no history of chemical control with clodinafop-propargyl (within the fields). Then, to control the seeds' genetic background, the given populations were cultivated in separate pots with the same soil in the same environmental conditions, and the seeds from first generation (F1) were screened, for the initial screening of the populations suspected to resistant, clodinafop-propargyl (Topik, EC 8%) at the rate of 1 L-1 ha (80 g a.i. h-1) was applied. Planting depths included 1, 2, 3, 4, 5, 6, 7 cm, and 15 wild oat seeds from each resistant and susceptible population were planted in pots with a diameter of 10 cm at the given depths. The pots were watered in the same way. The appearance of aerial parts on the soil surface was considered as green seeds, and at the end, the dry weight of three germinated seedlings was measured. The results of compound variance analysis showed that there was a significant difference between the resistant and the susceptible populations in all regions, and therefore, the resistant populations showed less dry weight. Conversely, a significant difference was observed among the different depths of seed placement, except for Aliabad. The maximum dry weight of winter wild oat seedlings was significantly higher in susceptible populations from Inche Brun and Kalale compared to resistant populations. A depth range of 4.87 to 6.40 cm in susceptible populations and 4.61 to 5.80 cm in resistant populations resulted in a 50% reduction in seedling dry weight. The rate of decline in dry weight was not significantly different between susceptible and resistant populations, except for the Inche Brun population. The depth at which a 50% reduction in dry weight occurred was not significantly different between susceptible and resistant populations across all regions. The dry weight of all susceptible and resistant populations decreased gradually up to a depth of 3 cm, after which the rate of dry weight decline increased significantly. Overall, with an increase in seed placement depth, the growth of the resistant and the susceptible winter wild oat seedlings decreased, and this reduction was not significant only in the Aliabad population. It seems that by adjusting the plowing depth and tillage, a sustainable strategy can be provided to control winter wild oat resistant to clodinafop-propargyl.