Flowering phenology and flower quality of cultivars 'Arbequina', 'Koroneiki' and 'Picual' in different environments of southern Spain

Abstract

Olive cultivation has been expanding worldwide over the last decades. The expansion to new growing areas with different environmental conditions and the threat of climate change require knowledge of genetic and environmental influences on olive production, to which the phenology and quality of flowering are critical. The IFAPA olive breeding program of Córdoba, Spain, has established comparative trials located in different agro-climatic conditions of Andalucía, southern Spain for testing the response of cultivars and breeding selections to varied environments. This study reports initial results (two years) for flowering of ‘Arbequina’, ‘Koroneiki’ and ‘Picual’ in four locations: three trials in typical olive growing areas Antequera (AN) and Baena (BA), both under rainfed conditions, and Úbeda (UB) with drip irrigation, and the fourth, also with drip irrigation, in Gibraleón (GI), a location with mild winter temperatures at the limit of the Andalusian area of olive cultivation. We observed flowering phenology, bloom period, and flower quality, and assessed the relative influences of genetic and environmental factors and their interaction. Flowering phenology showed high variability among the different growing areas, with earliest full bloom (65) in GI for all cultivars (late April). GI also presented the longest blooming period (around 45 days) for all cultivars, while, ‘Koroneiki’ had the longest blooming period for all locations overall. In flower quality, we observed significant differences both for environments and cultivars. UB showed the best inflorescence quality, with the highest percentage of perfect (hermaphrodite) flowers (PF%), while BA showed the worst PF%, possibly related to both lime-filled soils and rainfed conditions. However, in spite of differences among growing areas, the cultivars consistently presented the same order of PF% in all locations, with highest PF% in ‘Arbequina’, followed by ‘Koroneiki’ and finally ‘Picual’.