Morphological and Phenotypic Variability of Olive Varieties (Olea europaea sativa L.) in Algeria : Implications for Cultivation in Semi-Arid Regions

Abstract

The olive tree (Olea europaea L.) exhibits considerable genetic diversity, while environmental factors such as soil and microclimate contribute to phenotypic variation among varieties. This study evaluated the phenotypic and morphological characteristics of six olive varieties : Azeradj, Frontoio, Neb Djemel, Limli, Sigoise, and Chemlal cultivated under the semi-arid conditions of Bordj Bou Arréridj, Algeria. The objective was to characterize key morphological traits, including leaf, flower, and fruit characteristics, following the guidelines of the International Olive Council. The results showed that all varieties exhibited medium vegetative growth and elliptical-lanceolate leaves, with a floral formula of Z(4S) +(4P) + (2E) + 1C. Significant differences were observed among the varieties, particularly in tree width, trunk or main branch thickness, and leaf dimensions. Frontoio and Chemlal exhibited the highest numbers of flowers per branch and higher fruit-setting rates, indicating greater reproductive potential. Fruit size also varied among varieties, with Azeradj and Sigoise producing the largest fruits, whereas Chemlal produced the smallest. These differences may be associated with varietal characteristics and environmental conditions, particularly water availability. Overall, Frontoio and Chemlal showed superior reproductive characteristics under the study conditions. The findings highlight the importance of appropriate irrigation and soil management practices for improving olive productivity in semi-arid regions.