Effect of Chlormequat Chloride and Trinexapac-Ethyl on Productivity and Selected Physiological Traits of Oats (Avena sativa L.) and Naked Oats (Avena nuda L.)

Oats (Avena sativa L.) are a popular crop in Poland, used primarily for animal feed, human food, and biomass in the energy sector. A three-year field experiment was conducted in Poland between 2020 and 2022. The experimental factors included hulled oat (Bingo) and naked oat (Maczo) varieties as well as growth regulators: chlormequat chloride (CCC) and trinexapac-ethyl (TE). The aim of this study was to investigate the effect of growth regulators on yield, yield structure components, selected physiological processes, and canopy architecture indices. This study found that the use of growth regulators resulted in an average 7.2% increase in oat grain yield. The yield of the Bingo variety increased after TE application, while that of the Maczo variety increased after CCC and TE application. Growth regulators also had a beneficial effect on increasing the weight and number of grains per panicle. Growth regulators, particularly CCC, caused the shortening of the main shoot and panicle. Both CCC and TE increased the leaf area index (LAI). Among the physiological parameters, the relative leaf chlorophyll content (CCI) was 2.6% higher after CCC treatment than after TE treatment, while the photosynthetic index (PI) was higher after TE treatment (a 2.2% increase compared to CCC). The Bingo cultivar showed a more favorable response to growth regulators than the Maczo cultivar. The weather conditions during the oat growing season significantly influenced some of the obtained results.