Genetic Variability of Argan Tree and Preselection of the Candidate Plus Trees

Abstract

Argan tree productivity shows a wide disparity in space and time, while the degraded forest areas show low growth and unproductive shrubs. Moreover, even if reforestation, currently led by various local actors (Waters and Forests, Agency of Social Development, Cooperatives and Associations of development) experienced a technical improvement, the plants used do not meet any selection criteria. Generally, unknown origin seedlings are used in reforestation and good seedlings are not reproduced. In this context, this study investigates through a choice of pilot sites the characterization in-situ of populations and/or argan trees with two selection criteria related to fruit: facility of crushing and oil content. For this purpose, and with the support of local population, the identification of performance trees, prospection and collection of fruits were realized in various sites representing five principal provinces of argan trees area (Essaouira; Taroudante; Agadir Ida Outanane; Chtouka-Ait Baha and Tiznit). Within each provenance, measurements related to 6750 fruits and the morphometric data were subjected to the analysis of the variance, according to the general linear model, where the genotype factor (mother tree) is hierarchical to provenance factor. This study offers preliminary information for the development of a breeding population and allows us to make a first selection of trees, having a clear superiority relating to the characters related to the production of oil and the facility of crushing seeds. At the present moment there is a genetic base large enough to initiate a breeding program.