Gene flow among différent taxonomic units: evidence from nuclear and cytoplasmic markers in Cedrus plantation forests

• Published in: Theoretical and applied genetics 2003-10, Vol.107 (6), p.1132-1138
• Main Authors: FADY, B, LEFEVRE, F, REYNAUD, M, VENDRAMIN, G. G, DAGHER-KHARRAT, M. Bou, ANZIDEI, M, PASTORELLI, R, SAVOURE, A, BARITEAU, M
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Cedrus - classification; Cedrus - genetics; Cedrus - physiology; Cedrus atlantica; Cedrus brevifolia; Cedrus libani; Cell Nucleus - metabolism; Classical genetics, quantitative genetics, hybrids; Cytoplasm - metabolism; DNA, Chloroplast - genetics; Fundamental and applied biological sciences. Psychology; Generalities. Genetics. Plant material; Genetic Markers; Genetic resources, diversity; Genetic Variation; Genetics; Genetics and breeding of economic plants; Genetics of eukaryotes. Biological and molecular evolution; heteroplasmy; Life Sciences; Mediterranean Region; Plant material; Pteridophyta, spermatophyta; Simple sequence repeats; Vegetals
• ISSN: 0040-5752; 1432-2242
• DOI: 10.1007/s00122-003-1323-z

Hybridization and introgression are important natural evolutionary processes that can be successfully investigated using molecular markers and open- and controlled-pollinated progeny. In this study, we collected open-pollinated seeds from Cedrus atlantica, Cedrus libani and C. libani x C. atlantica hybrids from three French-plantation forests. We also used pollen from C. libani and Cedrus brevifolia to pollinate C. atlantica trees. The progeny were analyzed using three different types of molecular markers: RAPDs, AFLPs and cpSSRs. Chloroplast DNA was found to be paternally inherited in Cedrus from the progeny of controlled-crosses. Heteroplasmy, although possible, could not be undoubtedly detected. There was no indication of strong reproductive isolating barriers among the three Mediterranean Cedrus taxa. Gene flow between C. atlantica and C. libani accounted for 67 to 81% of viable open-pollinated seedlings in two plantation forests. We propose that Mediterranean Cedrus taxa should be considered as units of a single collective species comprising two regional groups, North Africa and the Middle East. We recommend the use of cpSSRs for monitoring gene flow between taxa in plantation forests, especially in areas where garden specimens of one species are planted in the vicinity of selected seed-stands and gene-conservation reserves of another species.