摘要 : In the Tyrrhenian coastal area, frequent late frosts have occurred during the last ten years. The most severe event happened in 2003, causing a strong reduction in yield, above all in stone fruit species. However, several apricot ... 展开 In the Tyrrhenian coastal area, frequent late frosts have occurred during the last ten years. The most severe event happened in 2003, causing a strong reduction in yield, above all in stone fruit species. However, several apricot selections, from different breeding sources, had a considerable yield, as a consequence of high flower and/or young fruit survival. The aim of this research was to evaluate the degree of tolerance to spring frost of ten selections and their own parents. During three subsequent years, the frost sensitivity of flower buds at dormant and swelling phenological stages was determined using the Phenolic CompoundLeakage (PCL) test after an artificial frost treatment (-4 degrees C). When this temperature was applied to flower buds at the dormant stage did not cause significant injuries, as indicated by the low PCL values. At the pre-flowering stages a significant increase in PCL was observed in most genotypes. On the basis of different levels of PCL, the genotypes were classified into three groups in relation to their frost sensitivity: (i) very frost-tolerant; (ii) frost-tolerant and (iii) frost-sensitive. Within the very frost-tolerant group, the selections 7C 20/3, 11/48/7 and 11/19/2, were the best genotypes confirming a good yield performance recorded after the severe spring frost of 2003. 收起