Modelling the intraspecific variation in the dynamics of fruit growth, oil and water concentration in olive (Olea europaea L.)

Abstract

Olive oil yield is the product of fruit weight and oil concentration at maturity; knowledge of the dynamics and allometric relationships of these components could help understanding the genotypic, environmental and management sources of variation in oil yield.The aims of this work were to: model the dynamics of fruit weight, oil and water concentration in olive varieties; quantify the relationship between the dynamics of fruit component in terms of rate and duration and their responses to environmental factors and explore the relationship between oil yield components using an allometric approach. Ten olive varieties were monitored during two seasons in Mendoza (32°S), Argentina. The evolution of fruit weight and concentration of oil and water (from pit hardening to maturity were fitted with bilinear functions and the parameters derived (maximum, rate, onset and duration) were associated with weather variables. Across seasons, fruit fresh weight (wt) (range from 252 to 749mg), fruit wt-filling rate (0.1–0.3mg°Cd−1) and fruit wt-filling duration (2288–2913°Cd) exhibited significant genotypic variation. The fruit wt-filling rate accounted for 91% of the variation in fruit fresh wt. Fruit fresh wt and fruit wt-filling rate varied between seasons while no significant differences were found for fruit wt-filling duration. Fruit oil concentration (45.5–57.4%) and duration (2425–2876°Cd) varied among varieties, but was largely unaffected by season. Oil-filling duration was the most important term in determining the fruit oil concentration (P=0.0013). During fruit growth, fruit water concentration remained stable at its maximum and declined linearly when fruit reached maximum fresh weight and oil concentration. Fruit oil concentration decreased with increasing maximum daily temperature (P=0.04) and solar radiation (P=0.01).