Studies about blooming and budding of nectarine and peach trees and selections have been carried out at the Universidade de Passo Fundo, Passo Fundo, to identify materials that are better adapted to Planalto Médio region of Rio Grande do Sul State, Brazil. Through experiments carried out in the growing seasons of 1997/98, 1998/99 and 1999/00, twelve cultivars and nine peach selections, two cultivars and one nectarine selection were studied, all with required aculate temperature lower than 7,2ºC, ranging from 150 and 400 hours. The fruit tree collections included three plants of each cultivar, which were grown at 6 x 3m from each other and conducted according to an open vase shape, without irrigation. In 1997, plants were at the beginning of the sixth growth cycle. The decrease of the occurrence of low temperatures from late June and in July, in all growing seasons, resulted in earlier blooming (up to 15 days). For most cultivars and selections flowering began in July and early August.
Prunus persica; peach; nectarine; cultivars; phenology
