Ecophysiological responses of olive trees to experimental warming in two contrasting cultivars (Arbequina, Coratina)

CECILIA ROUSSEAUX, M.; MISERERE, ANDREA; SEARLES, PETER

Baeza

Workshop; Workshop Olive cultivar adaptation and climatic change; 2017

In recent decades, there has been an increase in global temperature, which represents a challenge for olive production in the Northwest of Argentina, where temperature is already limiting. The objective of this study was to evaluate the response of photosynthesis (A) and transpiration (E), the production of biomass and the oil yield and its quality, to the increase of the average air temperature in two olive cultivars. Between December and May 2014-15 and 2015-16, two temperature levels were applied: control (T0) and 3-4 °C over the control (T +) to olive trees (cvs. ´Arbequina´ and ´Coratina´ ) that were well-watered, 2-3 years old, and placed in open top chambers. On three occasions during each season, A and E were measured and the water use efficiency (WUE) was determined. The whole tree was harvested and biomass production, its partition to the different organs, the production of oil (on a dry basis) and its quality were determined. Photosynthesis showed no significant differences between treatments in the evaluated temperature range, but an increase in transpiration was observed in the leaves subjected to T + and, as a consequence, the WUE was significantly reduced in the heated plants, in both seasons. Some changes in biomass were observed, mainly associated with changes in fruit yield. The oil production was negatively affected in T +, in both varieties, mainly due to the decrease in the weight of the fruits and a lower oil concentration of the same. The fruits that grew under T + showed a lower proportion of oleic acid and an increase in the levels of some tocopherols, being the effect of the temperature more accentuated in ´Arbequina´ than ?Coratina?. Increases in temperature in these regions would imply a greater consumption of water by the crop and would be negatively associated with the production of oil and its quality.