Phenological growth stages in mangosteen (Garcinia mangostana L.) according to the extended BBCH scale

Abstract Mangosteen ( Garcinia mangostana L.) is an important fruit grown throughout South‐East Asia and is often considered as one of the best‐flavoured fruits in the world, owing to its juicy and delicate flesh and appealing taste and flavour. In spite of high nutraceutical and ethno botanical value, phenology is an often‐overlooked aspect of mangosteen ecology. In the present study, the codes and descriptions of the phenological stages of mangosteen as given in the extended Biologische Bundesantalt, Bundessortenamt und Chemische Industrie scale (the BBCH scale) were elaborated using a three‐digit system of notation. A total of seven primary growth stages, namely bud development (Stage 1), leaf development (Stage 3), shoot development (Stage 5), reproductive development (Stage 6), flowering (Stage 7), fruit development (Stage 8) and fruit maturation (Stage 9), are described and illustrated. In addition, 36 secondary growth stages have also been defined and described. The duration of each principal and secondary growth stage was measured in days and quantified in thermal accumulation/growing degree‐days. The significance of the primary growth stages for orchard management and crop improvement, in monitoring plant growth and development (especially in the light of the impacts of climate change), and in assessing fruit yield and quality is explained. Moreover, the extended BBCH scale will be a useful tool for characterisation of germplasm as well as to standardise the phenophases observed under different environmental conditions.