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

Restriction fragment length polymorphisms (RFLPs) have been proposed for characterizing genetic diversity of barley (Hordeum vulgare L.) germplasm. Forty-eight (24 winter, 24 spring) cultivars from the European barley germplasm were assayed for RFLPs with 136 clone-enzyme combinations (CEC) (48 DNA clones, three restriction enzymes). Objectives of this study were to (i) assess the amount of variation for RFLPs in these materials, (ii) determine RFLP-based genetic similarity estimates between unrelated cultivars within and between the winter and spring barley germplasms, and (iii) examine the usefulness of RFLPs for classification of cultivars from different germplasm pools. Thirty-five DNA clones detected polymorphism with at least one enzyme. For the 62 polymorphic CEC, 58% of all RFLP patterns were common to both winter and spring barley, and about 20% were specific to the cultivars of each group. Genetic similarity (GS) calculated from RFLP data ranged from 0.64 to 0.93 between unrelated pairs of cultivars. Mean GS (MGS) for unrelated cultivar combinations within the group of winter (0.85) and spring (0.84) type cultivars were significantly greater than for winter x spring cultivar combinations (0.76). All winter and spring cultivars except two had a smaller MGS to cultivars from the other group than to unrelated cultivars from the same group. Principal coordinate analysis of GS estimates resulted in a separate grouping of winter and spring cultivars; further subgroups were also apparent for cultivars with a similar pedigree background. Results from our study corroborate the usefulness of RFLPs for the organization of elite barley germplasm.