Sugar and phenolics level dependent on the position of apple fruitlet in the cluster

- The abscission process and the levels of selected metabolites were monitored.
- Fruitlets from lowest positions were most likely to shed.
- Fruits from the position nearest to the king fruitlet often dropped, too.
- Central and lateral fruitlets differ to a certain degree in the contents of metabolites.
- Phenolic contents are higher in fruitlets more susceptible to abscission.

The abscission process and the modifications in the levels of selected metabolites were monitored on 'Golden Delicious' apples in a two-year study. Individual sugars were analyzed using HPLC-RI and individual phenolics by UHPLC-PDA-MS. Fruitlets from lowest positions were most likely to shed. Moreover, fruits from the position nearest to the king fruitlet often dropped. The experiment initially focused on the comparison of sugar and phenolic contents among fruitlets within individual apple clusters. Central (king) fruitlets are bigger in comparison to lateral fruitlets and differ to a certain degree in the contents of metabolites. In general, the results indicate that phenolic contents are higher in fruitlets more susceptible to abscission but the level of sugars does not differ.