Resumen

AVILAN, L et al. The Effect of pruning and the use of a growth regulator on innitial flowering in mangos. Rev. Fac. Agron. [online]. 2003, vol.20, n.4, pp.430-442. ISSN 0378-7818.

 Evaluations of the floral behaviour of four mango cultivars submited to different pruning intensities and paclobutrazol aplications were made over four production cycles and through climatic registers relationships between previous and present climatic conditions during flowering were established. The cultivars Haden, Tommy Atkins, Springfels and Edward grafted on "Criollo" stalks were planted at 6x6 m (278 trees ha^-1) to evaluate the pruning effect at a height of 2m, the Paclobutrazol (PBZ) effect when applied to the soil (2,5 g. ai per tree) and flowering promoter Potassium Nitrate (KNO₃), at 6% on the vegetative growth, flowering and yield of mango cultivars. The treatments were: Checker (T), T + PBZ, Pruning (P) and P + PBZ. P + lateral branches pruning of radius at 2 m (P+L) and P + pruning of internal primary branches (P+E). The results indicated that innitiation of flowering is associated with the increment of the number of days with night temperatures under or equal to 20^oC; also they suggest the existence of different requirement of number of days under 20^oC among cultivars, independent of the annual-production cycle. With the exception of the 1998-1999 cycle, the flowering started first in the treatment T and T + PBZ in Edward with an anticipation of 2-3 weeks in relation to the other cultivars and treatments considered. The pruning aplication delayed (P) the beginning of flowering, regardles of its intensity and the cultivar. The ocurrence in all cycles of a marked disminishing of rain, which preceded the beginning of flowering, propiciated a lower vegetative development and leaf maduration, which created a conditions that favoured the leaf maturing process.

Palabras clave : Mangifera indica; cultivars; climatic conditions; agronomic management.