Differences on flowering phenology under Mediterranean and Subtropical environments for two representative olive cultivars

Abstract

Olive flowering phenology is highly affected by climatic conditions. Phenological models have been developed to forecast flowering date on olive mainly based on temperature. These models have used flowering datasets collected from trees growing under Mediterranean climatic conditions. In most of the cases, in those conditions, chilling requirements are rapidly fulfilled. In other cases, artificial modifications of the climatic conditions has been practiced by using growth chambers. In the present work, we compare the flowering phenology of ‘Picual’ and ‘Arbequina’ olive cultivars in Mediterranean conditions of Andalucía, Southern Spain, with those in Tenerife, Canary Islands with Sub-Tropical climate. The climatic conditions of Tenerife respect to Andalucía promoted an earlier flowering date but, more importantly, a much longer flowering period. This is mainly produced by an asynchronous flowering bud burst that will generate negative impacts on yield and quality. Quite likely, those differences on flowering phenology between Andalucía and Tenerife climatic conditions are mainly caused by the lack of winter chilling in Tenerife locations. Based on those results, we propose that future works studying the effect of lack of winter chilling on olive should include the length of the flowering period as a parameter to be modeled. Besides, studies on natural climatic conditions with warm winters, as the one here reported, are needed to really assess the effect of winter chilling on olive.