Morphometrical Variation of Carob tree (Ceratoniasiliqua L) in Algeria.

Abstract

Mediterranean ecosystems are subject to the influence of particular climatic conditions characterized by scarcity or irregular rainfall and long dry summer periods. These climatic restrictions generally disturb the vegetation. In order to overcome these problems. The use of pioneer tree species, adapted to climatic hazards, remains the most recommended solution. The carob tree (C.siliqua) is an agro-sylvo-pastoral species with enormous socio-economic and ecological interests. This Mediterranean tree is favourably established in semi-arid and arid areas. For the success of reforestation projects, the management and preservation of this species requires prior assessment and characterization of their variability. This approach is based on multidisciplinary studies involving the analysis of the diversity of agro-morphological, adaptive traits. In this context, the present study aims to explore, using agro-morpho-metric markers of the carob tree in central and north-western Algeria. We use the pods and leaves to identify, label or characterize the different collections or germplasm of the carob tree in the world. This study was carried out on the variability of nine morpho-metric traits related to fruits (pods) and leaves through a comparative study at the level of provenances (Larabaa, BordjBounaama, Aflou, Remchi and Ain Sefra). Carob plants from three contrasting ecotypes of Ceratoniasiliqua (Remchi ecotype from the sub-humid stage, Tissemsilt and BordjBounaama ecotype from the semi-arid stage and Ain Sefra and Aflou ecotype from the arid stage) were subjected to a thorough biometric study of the leaves and pods collected after a field survey in June-July 2013. The results showed the highest mean values for the majority of the traits studied, thus indicating the importance of the provenance factor. Based on the analyses of variance and their decomposition, and depending on the biometric traits studied, the carob resource management strategy can be chosen either for the pod factor (pod weight, pod length, number of seeds per pod and number of infested seeds per pod) or the leaf factor (petiole length and leaf area). In the case of our collections, the longest size was recorded in the Bordj Bounaama population (16.66 cm ± 2.36) and Remchi (16.10 cm ± 2.78) and the smallest in the Aflou population (9.40 cm ± 1, 27). Indeed, a positive correlation between the measured parameters (length, width, thickness and weight of the pod) was observed. Differences between ecotypes were observed for all morphological traits studied.