Mango trees have no distinct phenology: The case of mangoes in the tropics

Abstract

We propose a convenient, easily observable set of landmark developmental stages during vegetative and flowering flushes and fruiting events to characterize the changes through which individual growing mango shoots pass in the tropics and subtropics. Individual non-growing stems are in the Resting stage (R), when the apical bud (following a previous vegetative growth event) or lateral buds (following a previous flowering event) are dormant. A flush event is one in which the resting buds on many stems in a section of tree canopy initiate growth (asynchronous flush) or when the entire canopy initiates bud growth at once (synchronous flush). The stages describing vegetative shoot growth are: Vegetative Bud Emergence and Development stage, Elongating Green Leaf stage, Limp Red Leaf stage (LRL), Immature Green Leaf stage, and Mature Green Leaf stage. Reproductive growth stages in purely flowering, or generative, shoots are: Floral Bud Initiation, Emergence and Development stage, Early Panicle Elongation stage, Mid-size Panicle Early Anthesis stage, and Full-size Panicle Maximum Anthesis stage. Fruiting stages are: Emergent Fruit stage, Small-size Green Fruit stage, Mid-size Green Fruit stage, Near Full-size Immature Fruit stage, and the Full-size Mature Fruit stage. Mixed shoots, bearing both leaves and lateral inflorescences at each node, exhibit characteristics of both vegetative and flowering shoots. Landmark stages for Tommy Atkins and Keitt, two cultivars commercially growing in the Americas, were observed in tropical orchards near the village of La Mesa, Colombia. Tommy Atkins leaves had a more intense red coloration during the LRL than did ‘Keitt’. More pedicels were found in ‘Tommy Atkins’ than in ‘Keitt’ during panicle development. Young fruits of ‘Tommy Atkins’ developed their distinctive, dark red coloration, whereas ‘Keitt’ fruit developed less intense reddish coloration once they were mature. Aside from these minor phenotypic differences in distinctive shoot and stem developmental stages, attempts to ascribe a distinct phenological pattern of mango tree growth and development are impractical. Each stem terminal or groups of stem terminals borne on scaffolding branches act as independent structures influenced by environmental conditions, such as temperature, water relations, and nutrition coupled with their physiological age resulting in widely variable tree responses even in similar environments.