An overview of olive cultivation in Turkey: Botanical features, eco-physiology and phytochemical aspects

Abstract

Global climate change, especially global warming, is affecting olive production efficiency as well as its product quality. The size and water content of fruit varies depending on the olive fruit yield along with the region, climate, and geographical position as well as agricultural applications. Anthropogenic activities also affect its ecology to a great extent. The plant prefers areas with mild winters and short rainy seasons but is facing long and dry summers, sunny habitats, well drained dry, poor, loamy, clayey-loamy, slightly calcareous, pebbly and nutrient-rich soils, with a pH around 6-8. It is resistant to drought but suffers much from harsh winters and air pollutants, which affect its production. Although the olive plant tolerates temperatures between -7 degrees C to 40 degrees C, the optimum temperature demanded for growth, development, and fruit yield is 15-25 degrees C. The annual precipitation demand lies between 700-850 mm. An important part of the composition of its fruit consists of water and oil or the "liquid gold". Main ingredients are additionally fat-soluble vitamins, minerals, organic sugars, and phenolics. Phenolic substances are responsible for many beneficial health effects as well as the taste and aroma of olive fruit. Oleuropein stands out due to its inhibition of oxidation of low density lipoproteins and its hypoglycemic and cholesterolemic effects. It is also a component that protects the olive tree against various parasites and diseases, one of the reasons why olive is recorded as the "immortal tree". Olive trees are cultivated in different regions of Turkey. A series of changes occur in morphological, physiological, and biochemical features to overcome different types of stress. In this review, information about the botanical aspects, eco-physiology, and pharmaceutical features of the oil, fruit, and leaves has been evaluated.