RAPD characterization of Brazilian barley (Hordeum vulgare ssp. vulgare) varieties

Thirteen varieties of Brazilian barley selected for malting qualities were analysed by RAPD (Random Amplified Polymorphic DNA). Amplification with 18 random primers generated 221 reproducible bands, of which 206 bands were polymorphic (93%):of this number, 137 fragments (62%) detected diversity among varieties and 56 bands (25.34%) allowed the distinction of varieties or groups of them. Variation was detected in all Brazilian varieties studied. Within-variety similarities estimated by Jaccard Similarity Coefficient ranged from 0.28 to 0.94, with averages ranging from 0.57 to 0.83, and an overall average of 0.72. Nevertheless, in the cluster analysis representatives of the same variety always fell into the same group and only later joined the other varieties. The average intervarietal similarities estimated by Jaccard Similarity Coefficient ranged from 0.45 to 0.62, with an overall average of 0.52. Many bands or combinations of bands which were responsible for the differentiation of all varieties were detected. Nevertheless, the majority of these bands cannot be considered as diagnostic markers because a great number of them did not occur in many representatives of the variety or had low intensity or even because they were not easily identified in the total pattern of bands.