Vegetative and reproductive bud burst in adult mango trees: effects of light and growth unit architectural traits

• Mango tree crown receives more light prior to regrowth flush than before flowering. • Architecture and light affect differently vegetative and reproductive bud burst. • The effects of architectural traits and light are additive or in interaction. • Light quantity and quality affect differentially bud burst occurrence and dynamics. Tree growth and reproduction results from the balance between internal and environmental factors. Knowledge is lacking on this balance in evergreen fruit trees characterised by a permanent contrasted light environment within the crown. This study hypothesised that architectural traits and light environment of terminal growth units (GUs) affected their vegetative and reproductive bud burst in the mango tree. Bud burst was monitored on terminal GUs of four adult mango trees, cv. ‘Cogshall’, during vegetative growth and flowering. Some GUs architectural traits (diameter, apical vs lateral position, outer vs inner location within the crown) and their light environment (quantity: relative transmitted PPFD, TrPPFD , and quality: red to far-red ratio, ζ) were measured at sampling. Factors affecting the occurrence, intensity and dynamics of bud burst were evidenced using generalised linear mixed models. The occurrence of vegetative and reproductive bud burst increased with ζ. For vegetative buds, it also increased with GU diameter at medium to high ζ values. The occurrence of reproductive bud burst was higher in the outer than the inner part of the crown, and on the apical than the lateral GUs. Two vegetative and reproductive flushes occurred. The dates of vegetative and reproductive bud burst were globally delayed by low ζ and high TrPPFD . For GUs that burst during the main reproductive flush, bud burst occurred earlier in the outer than the inner part of the crown. The interplay between the signals leading to the observed spatial and temporal patterns of bud burst is discussed.