Apical shoot defoliation and its effect on floral differentiation of mango 'Tommy Atkins'.
Pérez Barraza M. H., Vázquez Valdivia V., Salazar García S.
Author Affiliation: Campo Experimental Santiago Ixcuintla, Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias, Apdo. Postal 100, 63300, Santiago Ixcuintla, Nay, Mexico.
Revista Fitotecnia Mexicana 29 : 313-319
Abstract : Macroscopic and microscopic characteristics were determined, as well as the date of floral differentiation in the meristem of terminal shoots of mango (Mangifera indica) cv. Tommy Atkins grown under rainfed conditions. Eighty terminal shoots from 20 mango trees were hand-defoliated every other week from 30 September though 31 December in a 15-year-old commercial orchard in Jalcocotán, Nayarit, Mexico. Control shoots were not defoliated. On each date, 40 apical buds were collected and their macro- and microscopic characteristics were recorded. On the first year, all shoots defoliated from 30 September to 15 October produced vegetative growth only, while on the second year, 12.5 and 17.0% of the shoots produced inflorescences. Production of inflorescences began on shoots treated on 31 October (20.8%). In both years, more than 85% of the apical buds from defoliated shoots were already differentiated on 31 December and the differentiated buds were classified on Stage 3. Macroscopically, these buds had a conical shape and obvious separation of bud scales, and microscopically, they showed an elongated primary axis, initial development of secondary axis and presence of tertiary axes in the inflorescence. The date of floral differentiation was associated with the accumulation of temperatures ?20°C.