Determination of Optimum Harvesting Date in Relation to Fruit and Oil Quality of Some Olive Cultivars

Document Type : Original Article


 THIS investigation was carried out through 2013 and 2014 seasons on five olive cultivars (Manzanillo, Picual, Coratina, Koroneiki and Arbequina) picked in four dates (each fifteen days) from trees were 12 years old grown in sandy soil, planted at 5x5 meter apart under drip irrigation system in a private orchard located at Cairo/Alexandria desert road. This study has been to determine the optimal harvest time for olive cultivars in which to achieve highest quality of fruits and maximum quantity and quality of oil. The investigating has identified the flowering duration, the changes in physical characteristics of fruits and chemical properties of oil during the different harvesting dates related with the maturity index to calculate the days from full bloom till the optimum harvesting date according to the category of maturity index of each cultivar.
The results observed an increment in length, width, weight of fruit and seed weight from the first to the fourth dates, while no significant difference in seed length, width and flesh/ pit ratio during the two studied seasons. Fruit oil contents were increased and total polyphenols of extracted oil were decreased from the first to fourth harvesting date in all the studying cultivars during the two studied seasons.
As a result, the optimal harvesting date was determined in Manzanillo cultivar after (166 and 170) days, Picual cultivar after (184 and 192) days, Coratina cultivar after (193 and 199) days, Koroneiki cultivar after (216 and 224) days and Arbequina cultivar after (213 and 217) in the two studied seasons respectively, calculated from full bloom.