Apple (Malus domestica Borkh.) phenology in relation to topoclimate in Central Macedonia, Greece

Abstract

Plant phenological behavior is strongly dependent on climate conditions. In the current research, the apple (Malus domestica Borkh.) phenology response to topoclimate conditions, as mainly determined by air temperature, was investigated at two agricultural regions of the Region of Central Macedonia, Greece, Giannitsa Pellas and Rachi Pierias. In this regard, phenological observations were collected in order to evaluate the timing of appearance of the following phenophases: bud burst-green leaf tips (BBCH 53), flower bud visible-still closed (BBCH 55), pink bud stage-flower petals elongating-visible sepals slightly open (BBCH 57), and full flowering at least 50% (BBCH 65). Also, air temperature data were taken from agrometeorological stations which covered the study regions. Results showed that higher maximum and lower minimum air temperatures prevailed during almost the whole year at the plain of Giannitsa than those of Rachi. Earlier appearance of the examined apple phenophases was confirmed at Giannitsa, in comparison to Rachi, increasing the damage risk of vulnerable plant tissues during the bud development and flowering from the late spring frosts. It seems that the maximum and minimum air temperatures of March are decisive for the appearance o BBCH 53, 55 and 57 phenophases while those of April are considered as crucial factors for the onset of BBCH 65. The knowledge of relation between apple tree phenology and topoclimate, in terms of air temperature, may provide valuable information for farmers' decision-making regarding the rational planning of cultivation techniques.