STUDY ON GROWTH CYCLE OF OLIVES (OLEA EUROPEA L.) GROWN IN VARIOUS ENVIRONMENTAL CONDITIONS OF THAILAND

This investigation is to determine the growth cycles of olives grown in tropical climate of Thailand whether or not they are similar to those of their original regions in Mediterranean basin. Olive trees 4-6 years old grown in the Northeast (Phu Phan, Phu Ruea Si Sa Ket), the North (Khao Kho) and Central (Phetchaburi) were used for studying growth cycles. Growth rates were determined monthly by measuring shoot tip elongation. At Phu Phan, an average growth rate of six olive cultivars, Oblitsa, Boozha, Rosoolja, Leccino Istrian Byclitsa and Pendolino tended to increase in dry season, January toward May and the trend gradually decreased from August. Whereas in Phu Ruea, there were two high peaks of an average growth rate of three olive cultuivars Arbequina # 1, Cipressino # 1, and Itrana # 2 found. These peaks occurred in dry season, February and at the end of wet season, September, with the lowest growth rate found in mid-May. Olives grown in Si Sa Ket were Arbequina, #31609, Arbequina, #31628, Arbequina, #31632 and Arbequina, #31650. An average growth rate of these cultivars tended to decrease from January toward March, and the trend leveled off from May to August, after that the trend gradually decreased. At Khao Kho, the average growth rate of five olive cultivars, 1742 N # 12, 1849 S # 19, 1850 S # 19, 1866 T # 20 and 1903 V # 22 was fluctuated with two peaks of growth rates occurring in May and October. The growth rate in this location tended to decrease in both dry season and wet season, March and August, respectively. Olives used for growth determination in Huai Sai, Phetchaburi are Boozha, Oblitsa, Istrian Byclitsa, Rosoolja, Leccino and Pendolino. The result showed an average growth rate tended to increase from February and reached the peak point in June, after that the trend decreased toward October. For overall, average growth rates of olives derived from five locations, olives grown in Huai Sai, Phetchaburi had a similar pattern to those of the growth cycle of olives grown in their original areas, whereas the growth curves in other places tended to drop during rainy season. Leaf nutrients from all five locations were comparable to those of the original areas.