Influence of temperature on the growth and development of olive (Olea europaea L.) trees

Temperature is one of the most important factors controlling plant growth and development. Knowledge of the effects of temperature on plants is vital if crop management strategies are to be optimised and the best varieties chosen for local conditions. As the effects of global warming are now becoming patent, it is even more critical that we should understand how temperature affects crop growth. In this study, degree-day (DD) accumulation was used to establish the influence of temperature on flowering, vegetative growth, and fruit growth in olive. The results show that the timing of olive flowering in the study region can be predicted from mean April and May temperatures, although this can be improved by taking into account the maximum March, and even February, temperatures. With respect to heat accumulation and flowering, the lower threshold temperature (LTT) was 4.7 degrees C, with 890 degrees Cd necessary. The LTT for trunk. growth was 7 degrees C, while that for shoot and crown volume growth was 13 degrees - 14 degrees C. The LTT for fruit growth was 15 degrees C with respect to fresh weight, and 24 degrees- 26 degrees C with respect to cross-sectional diameter. The increase in the longitudinal diameter of fruit was more rapid than the increase in the cross-sectional diameter, which was more dependent on temperature. Increasing temperatures in the study area would cause olive trees to flower earlier and their growth period to be lengthened.