Fruit Morphological Changes during Pit Hardening in Autochthonous Istrian Olive (Olea europaea L.) Cultivars

Endocarp lignifi cation is important fruit growth phenophase since aft er its completion fruit starts with oil accumulation. Th e information about duration of endocarp lignifi cation is important for timing of management practices, irrigation and pest control in oil cultivars, and fruit thinning in table cultivars to obtain uniform fruit weight and size. In this study, fruit length, width and weight of four Istrian autochthonous olive cultivars (‘Bu?a’, ‘Punto?a’, ‘Ro?injola’ and ‘Istarska bjelica’) were measured. Samples were taken from olive collection orchard of the Institute of Agriculture and Tourism in Pore? in equal growing conditions. Th e aim of the research was to defi ne an olive fruit growth dynamics during pit hardening. Fruit weight in all cultivars was increasing during endocarp lignifi cation (from 7th to 28th July). Th e highest percentage in the weight growth in the fi rst week had cultivars ‘Bu?a’ (48.5%) and ‘Ro?injola’ (44.6%) while in the second week maximum was reached by cultivars ‘Punto?a’ (44.2%) and ‘Istarska bjelica’ (42%). Th e highest increase in total fruit mass was detected in ‘Punto?a’ (1.30 g) and the least at ‘Ro?injola’ (0.56 g). Maximum increase in length (L) and width (W) had ‘Punto?a’ (L: 7.13 mm; W: 4.23 mm) and the least ‘Istarska bjelica’ (L: 2.48 mm; W: 2.70 mm).