Phenological growth stages of the cashew tree (Anacardium occidentale L.) according to the extended BBCH scale

The cashew is an important nut crop cultivated in the tropical regions. It is known for its economic and nutritional value. Phenology is the study of seasonal timing of recurring events in the annual growth cycle. A generic scale such as the Biologische Bundesantalt, Bundessortenamt and Chemische Industrie (BBCH) scale defines developmentally similar growth stages of different crops and within it, more specific scales for individual species can be developed. In the current study, detailed descriptions and codes are proposed for the growth stages of cashew using a modified three-digit scale of BBCH. Seven principal growth stages viz. bud, leaf and shoot development, inflorescence emergence, flowering, fruit development, and fruit maturity were described. A total of thirty-seven secondary growth stages were identified and described within the seven principal growth stages. Due to the importance of phenological growth stages in crop management and crop improvement, the proposed phenological scale is expected to facilitate better adoption of cultural practices, efficient germplasm characterisation and help in studying the impact of climate change on cashew production.