Beziehungen zwischen Stengel- und Knollenzahl bei Kartoffeln in Abhängigkeit von Wachstumsregulatoren

Zusammenfassung In dreij?hrigen Feldversuchen führte eine Behandlung der Pflanzknollen mit vier Wachstumsregulatoren zu einer signifikanten Erh?hung der Stengel- und Knollenzahl pro Pflanze sowie einer Verminderung der Knollenzahl pro Stengel. Die durch die Behandlung erzielte signifikante Erh?hung des Pflanzgutertrages war jahres- und sortenabh?ngig. Eine hohe Effektivit?t der Behandlung ist nur zu erwarten, wenn die Erh?hung der Stengelzahl nicht zu einer sorten- oder jahresbedingten starken Verminderung der Knollenzahl pro Stengel führt.

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Summary Growth regulators (K350, GA₃, Azoluron and thiourea) were applied in a three-year field experiment to tubers of four large-tubered cultivars of different maturities (‘Arkula’, ‘Auralia’, ‘Dorisa’ and ‘Libana’). They produced significant increases in the numbers of stems and tubers per plant and a decrease in the number of tubers per stem. Only the most effective preparations increased the yield of seed and decreased overall yield, averaged over cultivar and year. Positive correlations between numbers of stems and tubers per plant contrasted with the negative correlation between the number of stems and number of tubers per stem (Fig. 1). The preparations ranked in effectiveness as follows: K350>GA₃>thiourea>Azoluron, and this was reflected in the number of stems and tubers per plant (Table 2). Increases in number of stems resulting from treatment with the regulators effectively increased the yield of seed, but only if the increases were not accompanied by strong year or cultivar related reductions in the number of tubers per stem caused by inter-stem competition (Tables 3 and 4).