Forest hazelnuts are very valuable fruits, both for their phytochemical content and economically for cultivation. In this work, the development of some hazelnut varieties, such as Tonda Gentile Delle Longue, Butler, Tonda Romana, Tonda di Giffoni, and Barcelona, has been studied. Morphological characteristics were analysed in two periods, at 30 days and 60 days, "in vitro," by recording the number of roots and leaves as well as their length. From the analyses carried out, it was found that the genetic variation of the five varieties studied had a significant influence on all the morphological characteristics examined and the varieties Tonda di Giffoni and Barcelona show higher plasticity under in vitro conditions compared to the other varieties included in the study. In addition, total polyphenol (TPh) content and antioxidant capacity were analysed using FRAP and DPPH assays and the results reported that the Tonda di Giffoni cultivar recorded the highest TPh content (192.71±0.77 mg GAE/100 g Fw), with high antioxidant capacity (FRAP = 5.9±0.02 and DPPH = 216.31±1.38 mol TE/100 g Fw), compared to the other varieties studied.