Phenological Study of Irvingia gabonensis (Aubry-Lecomte ex O’ Rorke) Growing in Ihiala, Anambra State, South-East, Nigeria

Abstract

Phenology refers to periodic biological phenomena that are correlated with climatic conditions. Very little is known about the phenological pattern of most tropical fruit trees especially in the South-East, Nigeria. The aim of this study was to provide a phenological data and baseline information on the phenology of Irvingia gabonensis (Aubry-lecomte ex O’Rorke). The study was conducted with exotic species at Ihiala, South-East, Nigeria, a tropical climate. The initiation and completion of different phenophases of the tree, such as budding, leafing, flowering, fruiting and ripening were recorded at 2 weeks interval. The combination of the principal growth stages and the secondary growth stages produced 2-digit codes, were used to delineate the time-dependent phenophases. The results showed that changes in the prevailing seasons influenced the vegetative phenophases in I. gabonensis. There are splashes of rains even in the supposed dry months. Hence, bud formation, leafing and leaf fall phenophases were overlapping all through the seasons. Flowering phenophase peaked by March/April with the coming of the rains. Also fruiting and ripening peaked by June/July respectively (rainy season). Thus the study has revealed that the major seasons in the area (rainy and dry seasons) influence the various phenophases in I. gabonensis. The study has equally revealed the phenological data and base line information on the phenology of I. gabonensis which will in the future serve as correlation between phenology and climate change in the area. The study has revealed that the phenology of I. gabonensis may not be stable or resilient since it is influenced by these changing seasons, little wonder then a shift in phenology is recorded in this study.