Investigating the influence of growth inhibitors on the growth and yield of oat (Avena sativa)

Food security is a major challenge faced by countries around the world due to the large increases in population numbers, climate change, and the problems it causes in agricultural production, such as droughts, floods, and hurricanes. Most oat varieties are characterized by their long stems, and this makes them effective Sink for the deposition of dry matter that can be directed to the grain in the case of the use of growth inhibitors (such as Cycocel and ethylene) that suppress the longitudinal growth of the stems and increase its diameter, as well as increase the number of effective branches, reduces the risk of lodging, thus increasing the grain yield. This experiment was conducted in the fields of the College of Agricultural Engineering Sciences, University of Baghdad, during the winter season of 2020-2021, to assess the effects of growth inhibitors Cycocel) CCC (and calcium carbide CaC₂ (which generates ethylene), used three replications of a randomized complete block design (RCBD), Eight treatments were tested, including spraying CCC at concentrations of 200, 400, and 600 mg/L and ground application of CaC₂ at 2 g/plant individually and in combination. The findings revealed that all treatments led to an increase in grain yield and a decrease in plant height compared to the control treatment. Notably, the C600 + CaC₂ treatment exhibited significant superiority over other treatments in grain yield (5.52 t/ha), total dry matter (20.14 t/ha), and Harvest Index (25.21). These results suggest that growth inhibitors can effectively modulate the source-sink relationship, thereby enhancing grain yield.