Leaf fall in the evergreen mango (Mangifera indica L.) is affected by physiological age and light environment. Details of these effects need to be determined. Previous studies have not described the dynamics of annual leaf fall of these trees. Our work aimed to decipher the effects of architectural and environmental factors on leaf fall at the scale of the growth unit (GU) during a year. Our experiment began by describing the initial states of 240 GUs, sampled from five mature ‘Cogshall’ mango trees at three depths, expressed as 1, 2, or 4 GU from the terminal GU along the branch. Leaves on a GU were considered to have the same age. The depth level of a GU was used as a proxy for age because of the rhythmic growth of the mango tree. The initial state of each GU was characterized in January 2021, by the number of nodes (i.e., initial number of leaves), remaining leaves, position (apical or lateral), and length. Hemispherical photographs were used to estimate the light environment. The number of leaves per GU was then counted monthly for one year. Leaf fall was irregular over the year, occurring during the wet season of Réunion Island. Leaf fall was separated into two processes: occurrence and intensity. Leaf age (approximated by GU depth) was strongly associated with the occurrence of leaf fall. The main peak of leaf fall occurred between November and December and coincided with the vegetative flush. Light had a minor effect on leaf fall, observed only in December 2021. At this time, young GUs placed in a shaded environment exhibited three times the leaf fall intensity of older GUs. Our work illustrated the seasonal pattern of leaf fall in the evergreen mango tree. The effects of physiological age and light environment will soon be implemented in a functional-structural plant model called Virtual-Mango. Determining the foliage distribution is of high importance to predict fruit production in mango.
Emma Carrié won the ISHS Young Minds Award for the best oral presentation at the International Symposium on Innovative Perennial Crops Management at IHC2022 in France in August 2022.
Emma Carrié, CIRAD – Persyst, UPR HortSys, Station de Bassin-Plat, BP 180, 97455 Saint-Pierre cedex, Ile de la Réunion, France, e-mail: emma.carrie@cirad.fr
The article is available in Chronica Horticulturae