DAILY DYNAMICS OF FRUIT AND LEAF TEMPERATURE IN FIVE OLIVE OIL CULTIVARS

M. AGUSTINA IGLESIAS; M. CECILIA ROUSSEAUX; PETER S. SEARLES

Sevilla

Congreso; Olive Bioteq'18: 6th International Conference on the Olive Tree and Olive Products; 2018

Consejo Superior de Investigaciones Científicas (CSIC)

Fruit growth and development are regulated by microclimatic conditions within the canopy. However, despite its potential importance, the dynamics of fruit temperature have largely been unexplored in olive orchards. The objectives of this study were to evaluate the daily dynamics of fruit and leaf temperature relative to air temperature in five olive oil cultivars with different fruit sizes. A field trial was conducted during the summer of 2018 with 5-year-old trees of cvs. Arbequina, Arbosana, Coratina, Picual and Hojiblanca under full irrigation. Thermal images of fruit and leaves were obtained with an infrared camera during the daylight hours on four days, and temperatures from thermocouples inserted into fruit were recorded hourly for several weeks. Air temperature was also measured between the trees with a thermocouple protected by a solar radiation shield. Fruit temperature of sunlit fruit was several degrees higher than air temperature in large-fruited cultivars like ?Picual? and ?Hojiblanca?, while fruit temperature was more similar to air temperature in small fruited-cultivars like ?Arbequina? or ?Arbosana?. In contrast to fruit temperature, leaf temperature was almost always lower than air temperature. Under windy conditions, which were common in the afternoon, fruit temperature was often not greater than air temperature. The results indicate that fruit of different olive cultivars experience different temperature regimes based on their size. Implications of this phenomenon should be determined for oil production, which is temperature dependent, and for global warming conditions.