The rate of nitrogen fertilization is the most important factor for plant growth and development which can increase yield and grain quality assurance. But the high rates of applied nitrogen fertilizer combined with high precipitations favor stem elongation and increase risk of cereal lodging. Plant growth regulators (PGRs) are widely used for lodging control in winter wheat grown at high nitrogen rates. A field experiment was conducted during 2015-2016 winter wheat growing season at Agricultural Research and Development Station Turda to evaluate the effect of PGR on plant height, lodging, internodes length, grain yield and grain protein content of seven winter wheat genotypes tested at different rates of applied nitrogen fertilizer, in combination with foliar treatment with trinexapac-ethyl- based Plant Growth Regulator sprayed over the foliage. The genotypes used in this experience have not been tested with PGR until now. The experimental design consists in subdivided plots in a three factorial experimental system. Before sowing the wheat, nitrogen and phosphorus fertilizers were applied 50 kg N ha-1 and 50 kg P ha-1. Beside the fertilization applied in autumn nitrogen fertilization was applied on crop at boot stage (BBCH 40-49) at different rates: 0 kg N ha-1 (control), 50 kg N ha-1, 100 kg N ha-1, 150 kg N ha-1. The PGR foliar treatment included trinexapac-ethyl (0,4l/ha) sprayed over the foliage at second node visible stage (BBCH 32). Results showed that high rates of applied nitrogen fertilizer increased the risk of cereal lodging. The PGR application on wheat cause shorter plants (internodes) and less lodging. PGR applications significantly reduced lodging but didn’t necessarily completely eliminate it. On yield and grain protein content nitrogen fertilization had a bigger influence than the trinexapac-ethyl treatment. Winter wheat height was significantly influenced by PGR treatment. Reduction in plant height as a consequence of PGR treatment is associated with the reduced elongation of internodes. PGR treatment improved the crop resistance to lodging.

winter wheat, lodging, PGR, nitrogen fertilization, yield, grain protein content.

field crops and pastures

Presentation: oral