Phenological growth stages of kokum tree (Garcinia indica (Thouars) Choisy) according to the extended BBCH scale

Kokum (Garcinia indica (Thouars) Choisy) is an evergreen fruit tree, naturally distributed in the tropical rainforests of the Western Ghats in India, displaying polygamous characteristics. The economic significance of this tree is attributed to its fruit rind rich in pharmaceutical compounds such as hydroxy citric acid, garcinol and anthocyanin. The fruit rind is commonly utilised to create refreshing beverages. The demand for both kokum fruit and its derived products is on the rise within the food, pharmaceutical and cosmetic industries. To facilitate genetic enhancement, agronomic management and commercial cultivation, a comprehensive understanding of the periodic growth of kokum is essential. Presently, the Biologische Bundesanstalt, Bundessortenamt and Chemische Industrie (BBCH) phenological scale stands as the most credible and widely adopted framework. In this research endeavour, specific standard codes and descriptions were established for various growth stages of kokum. Utilising an extended BBCH scale ranging from 0 to 9, we delineated seven principal growth stages in kokum: Stage 0 for vegetative bud development, Stage 1 for leaf development, Stage 3 for shoot growth, Stage 5 for reproductive bud development, Stage 6 for flowering, Stage 7 for fruit development and Stage 8 for fruit maturity. Secondary stages were assigned based on observed growth event percentages. The duration and seasonal characteristics of each principal and secondary growth stage were meticulously recorded. This newly developed phenological scale serves as a versatile tool applicable to researchers, breeders and industrialists for enhancing agricultural production and effective scientific communication in the kokum research.