INFLUENCE OF BIOREGULATORS ON APPLE NECTAR CHARACTERISTICS, IN RELATION TO FIREBLIGHT INFECTION

Dynamics of floral nectar secretion, amount, refraction and composition of nectar were studied in an Erwinia-sensitive (‘Sampion’) and a tolerant (‘Freedom’) apple cultivar, following treatments with Regalis (a.i. prohexadione-Ca; p-Ca) Bion 50WG (a.i. acibenzolar-S-methyl; ASM) and Biomit Plussz (a leaf fertiliser).
The amount of nectar increased in ‘Sampion’ treated with ASM. The p-Ca treatment had an impeding effect on both the amount and the refraction of the nectar.
In the case of cultivar ‘Freedom’ the p-Ca treatment increased the refraction but decreased the amount of the nectar.
Concerning the dynamics of floral nectar production every treatment stimulated the secretion.
The more continuous secretion – keeping the surface of the nectary wet – may be favourable for the growth of Erwinia amylovora. As for nectar sugar components, ASM increased the amount of fructose, while p-Ca decreased the production of glucose in both cultivars.
The secretion of sucrose was stimulated in ‘Freedom’, but impeded in ‘Sampion’ by the ASM treatment.

X International Workshop on Fire Blight

ZS. Orosz-Kovács, P. Bukovics, A. Farkas, L.GY. Szabó, A. Horváth, H. Déri, T. Bubán

apple, bioregulators, Erwinia amylovora, Malus x domestica, nectar, secretory rhythm, sugar composition

https://doi.org/10.17660/ActaHortic.2006.704.17