Variabilität der Ertragsstruktur von Sommerweizenähren unter dem Einfluß von Stickstoff – Düngung,Thermoperiode und Wachstumsregulatoren

Variability of the yield structure of spring wheat ears caused by nitrogen – supply, thermoperiod and growth regulators In two years pot experiments with spring wheat, the effect of different exogenous growth factors (N - supply, growth regulators, thermoperiod) on ear development in monoculm plants was studied. All three growth factors brought about a comparible change in the internal dominance structure of the ear. Medial-dominance within the ear was diminished by both increased N supply and growth regulators whereas it was augmented by raised temperature during organogenesis of the ear. The application of growth regulators reduced the number of spikelets per ear, but did not necessarily lead to reduced fertility of the total ear. The influence of the growth regulators with anti-gibberellic effect on dominance structures in the plant is explained by an increase in respiration which improves attraction of assimilates into the ear.