Taxonomic revision of genus Hordeum L. (Gramineae) in Egypt

Abstract

This study was conducted to revise the taxonomic identity and clarify inter- and intra-specific relationships among the studied wild and cultivated Hordeum taxa in Egypt. The studied taxa includedHordeum marinum subsp. gussoneanum, H. marinum subsp. marinum, H. Hordeum leporinum,Hordeum glaucum, Hordeum spontaneum and Hordeum vulgare. The results revealed that unweighted pair group method with arithmetic mean (UPGMA) dendrogram showed a considerable degree of dissimilarity among the studied Hordeum taxa at 1.50 dissimilarity distance. It divided the studied taxa into four groups at 1.33. Group 1 included H. marinum subsp. gussoneanum and H. marinum subsp.marinum. Group 2 included H. leporinum. Group 3 included H. glaucum. Group 4 included H.spontaneum and H. vulgare which is related to the other groups (1, 2, and 3). Moreover, by using UPGMA dendrogram, H. leporinum and H. glaucum are located in transitional position between H. marinum and both of H. vulgare and H. spontaneum forming a transitional step between the taxa of Group 1 and 4. This work provided a taxonomic key and separated the two subspecies of H. murinuminto different species namely H. glaucum and H. leporinum. Moreover, the morphological similarities among Hordeum taxa have been proved. Key words: Taxonomy, Hordeum marinum, Hordeum leporinum, Hordeum glaucum, Hordeum spontaneum, Hordeum vulgare, unweighted pair group method with arithmetic mean (UPGMA)dendrogram, Egypt.