Phenology and thermal requirements of the atemoya tree (Annona cherimola Mill. X Annona squamosa L.)

ABSTRACT The present study had as the main objective the documentation and characterization of the different phenological stages, as well as the definition of the thermal requirements, of the atemoya tree for two agronomic seasons. From shoot development to senescence and beginning of the rest period eight main stages were described (shoot development, leaf development, shoot/bud growth, inflorescence appearance, flowering, fruit development, fruit maturity and senescence and the beginning of the rest period). The number of days and the thermal requirements for completing each phenological stage were different between the two agronomic seasons of the atemoya. The first and second agronomic season presented a period of 217 and 206 days, with thermal requirements of 2469 and 2302 degree days, respectively.