Elevated temperature affects vegetative growth and fruit oil concentration in olive trees

ANDREA MISERERE; GEORGINA GARCÍA-INZA; PETER S. SEARLES; M. CECILIA ROUSSEAUX

Simposio; VIII International Olive Symposium; 2016

Temperature is one of the main factors that regulates the growth and development of crops and determines their yield. In recent decades, there has been an increase in global temperature, which represents a challenge for olive production. Olive trees in Argentina are grown over a wide range of latitude and altitude, and it has been observed in warmer areas of the country that some varieties have lower yields and greater vegetative growth than in their regions of origin in the Mediterranean Basin. Thus, the aim of this study was to evaluate the effect of elevated temperature on the vegetative growth and fruit oil concentration of two olive varieties by directly manipulating temperature. The experiment was conducted at an experimental station in the province of La Rioja in northwest Argentina. Two temperature levels (a control and a heated treatment; 3 °C above the control) were applied from fruit set until final harvest using open top chambers (OTC) with electronically controlled heating systems. The responses after one season of treatment for potted Coratina and Arbequina trees are shown here. Branches that developed in heated OTC elongated more than those that developed in the control OTC in both varieties, although the effect was more pronounced in Coratina. On the other hand, elevated temperature had a negative effect on fruit dry weight and oil concentration in both varieties. Elevated temperature reduced fruit dry weight by 0.34 and 0.22 g in Coratina and Arbequina, respectively. Additionally, fruit oil concentration (%) was 4.6 and 6.2 % less on a dry weight basis in fruit that received elevated temperatures. The results indicate that elevated temperature promotes vegetative growth and negatively affects oil concentration in olive trees under our climate conditions.