Abstract:

Olive is of great importance in the agricultural production of Türkiye. In 1989, the annual production of olive in the country was 500 thousand ton. The main environmental factor which limit to olive production in Türkiye being low temperature in winter and the various olive-producing sites represent a wide variety of climatic conditions, with winters ranging from very mild to very cold. According to Emberger, climatic classification, olive is present in the humid, sub-humid, semi-arid and arid bioclimatic zones and in all their variants like cold, cool, temperate, hot except extremely cold. On the other hand, there is a considerable variation from site to site in the olive-producing regions with regard to absolute minimum, maximum and average annual temperature. Because of this, we used to four temperature criterions to determine causes of geographic distribution of olive trees in Türkiye. The temperature criterions were as follows: 1. Numerous studies suggest that flowering is a direct effect of the amount of winter chilling < 7.2°C received. Because of this, we searched for days on which the minimum temperature was <7.2°C. A mean number of days was determined. 2. Hartmann and Whisler showed that exposure of olive trees to a diurnal sine wave of from 1.7-7.2°C and 12.8-23.9°C results in good inflorescence production and termed this diurnal range "effective chilling". We searched for mean number of effective chilling days per year. 3. This variable is based on Badr and Hartmann. They suggest that the 12.5°C temperature is a "compensation point" at which temperatures are cold enough to affect vernalization but also warm enough to allow for necessary concomitant cell division. But Denney and McEachern broadened the value 12.2< and<13.3°C. A mean number of days per year was determined. 4. To determine when compensation point temperatures occur during the winter, ten day periods were established for each of the months from October to May. Mean daily maximum, minimum and mean daily mean temperatures were determined. Examination of the results indicates that the considerable variability of response among olive-producing sites for chilling and effective chilling. For example, the number of days of chilling are 153 at Ceylanpınar and 29 at Anamur. On the other hand, a close relationship exists between number of days "compensation point" per year olive-producing regions. The number of days per year are average 17 days in areas for economic cultivation for olive. This value is below 13 days for areas where the olive has never grown. Examination of temperature data by 10-day periods show that 12.2-13.3°C temperatures occur during the middle 10-day period of March. The floral initiation in the olive occurs in late winter about 8 weeks before full bloom and the middle 10-day period of March is fall at a time which about 8 weeks before full bloom.

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