GENETIC-RELATIONSHIPS AND DIVERSITY AMONG TIBETAN WHEAT, COMMON WHEATAND EUROPEAN SPELT WHEAT REVEALED BY RAPD MARKERS

An endemic hexaploid wheat found in Tibet, China was taxonomically cla ssified as a subspecies in common wheat, i.e. Triticum aestivum ssp. t ibetanum. Seven accessions of the Tibetan wheat, 22 cultivars of commo n wheat and 17 lines of spelt wheat were used for RAPD analysis to stu dy the genetic relationships of the Tibetan wheat with common wheat an d spelt wheat, and to assess the genetic diversity (GD) among and with in the taxa. RAPD polymorphism was found to be much higher within spel t wheat and the Tibetan wheat than within common wheat. The GD value b etween the Tibetan wheat and common wheat is lower than that between t he Tibetan wheat and spelt wheat. The result of cluster analysis showe d that the 46 genotypes were distinctly classified into two groups. Gr oup 1 included all European spelt wheat lines, while group 2 includes all Chinese common wheat and the Tibetan wheat accessions. However, th e Tibetan wheat was substantially differentiated from Chinese common w heat at a lower hierarchy. Our results support an earlier classificati on of the Tibetan wheat as a subspecies in common wheat. European spel t wheat and the Tibetan wheat showed much higher genetic diversity tha n Chinese common wheat, which could be used to diversify the genetic b asis for common wheat breeding.