African plum (Dacryodes edulis [g. don] h.j. lam) fruit development indexes clearly defined and phenophases correlated with temperature in the tropics

Abstract

Dacryodes edulis (G. Don) H.J. Lam is an underexploited oil-bearing fruit tree highly appreciated in the Central Africa rainforest. To improve horticultural management and provide relevant data to scientists for physiological studies, the reproductive phenology of D. edulis as well as their fruit (safou) development and ripening indexes has been defined and correlated to climatic conditions. Changes in safou were assessed in four production localities in Cameroon. Fruit-setto-ripening time was evaluated over 2 consecutive production years. Four fruits developmental and ripening stages and their durations were determined as follows: The putative cell division (1–2 weeks); putative elongation (10–14 weeks); pre-ripening (2–7 weeks); and ripening phases (3–5 weeks). Rainfall, average, and cumulative temperatures were found to be correlated with the chronology of reproductive phenophases. The average temperature during the period ranging from the floral bud emergence to the fruit set can be used to predict the thermal time. Similarly, the average ambient temperature during the period from floral bud emergence to anthesis can help to determine the temperature to be cumulated during the ripening phase. These findings are considerable contributions that could help producers to enhance the industrial management of safou sector, reduce fruit perishability, and better control their harvesting time.