RELATIONSHIPS AMONG EUROPEAN BARLEY GERMPLASM .1. GENETIC DIVERSITY AMONG WINTER AND SPRING CULTIVARS REVEALED BY RFLPS

Restriction fragment length polymorphisms (RFLPs) have been proposed f or characterizing genetic diversity of barley (Hordeum vulgare L.) ger mplasm. Forty-eight (24 winter, 24 spring) cultivars from the European barley germplasm were assayed for RFLPs with 136 clone-enzyme combina tions (CEC) (48 DNA clones, three restriction enzymes). Objectives of this study were to (i) assess the amount of variation for RFLPs in the se materials, (ii) determine RFLP-based genetic similarity estimates b etween unrelated cultivars within and between the winter and spring ba rley germplasms, and (iii) examine the usefulness of RFLPs for classif ication of cultivars from different germplasm pools. Thirty-five DNA c lones detected polymorphism with at least one enzyme. For the 62 polym orphic CEC, 58% of all RFLP patterns were common to both winter and sp ring barley, and about 20% were specific to the cultivars of each grou p. Genetic similarity (GS) calculated from RFLP data ranged from 0.64 to 0.93 between unrelated pairs of cultivars. Mean GS (MGS) for unrela ted cultivar combinations within the group of winter (0.85) and spring (0.84) type cultivars were significantly greater than for winter x sp ring cultivar combinations (0.76). All winter and spring cultivars exc ept two had a smaller MGS to cultivars from the other group than to un related cultivars from the same group. Principal coordinate analysis o f GS estimates resulted in a separate grouping of winter and spring cu ltivars; further subgroups were also apparent for cultivars with a sim ilar pedigree background. Results from our study corroborate the usefu lness of RFLPs for the organization of elite barley germplasm.