RESTRICTION-FRAGMENT-LENGTH-POLYMORPHISM BASED PHYLOGENETIC ANALYSIS OF AVENA L

We report a molecular approach to the study of the phylogenetic relati onships of Avena diploid and polyploid species based on RFLP detected with three cDNA probes of nuclear genes belonging to multigenic famili es (low pI alpha-amylase, avenin, and globulin). All the probes were h ighly informative in the detection of polymorphism between oat species . Associations between species were determined from cluster (UPGMA) an alysis based on distance values calculated from RFLP data separately f or each of the two levels of ploidy. Results were in general agreement with morphology based phylogenetic analyses, confirming the large dif ferentiation among A and C genomes in the evolution of diploid species and the genetic homogeneity among A. brevis, A. strigosa, and A. nuda and the recently discovered A. atlantica. A certain divergence was ob served between two endemic species (A. canariensis and A. damascena) a nd the other diploid species with the A genome. The analysis of tetrap loid species relationships confirms the differentiation of the barbata complex (A. wiestii, A. barbata, A. abyssinica, and A. vaviloviana) f rom the maroccana-murphyi-agadiriana group, which, despite some simila rities in morphological and biochemical traits, seems to have accumula ted deep genetic differences along its evolutionary pathway.