ALLOZYME ANALYSIS OF LUZULA SECT. LUZULA (JUNCACEAE) IN IRELAND: EVIDENCE OF THE ORIGIN OF

Luzula campestris, L. pallidula and tetraploid plants of this section from Ireland were studied electrophoretically. A hypothesis of alloploid origin for the Irish tetraploids from a hybrid between L. campestris and L. pallidula, based on the morphology and karyology of the relevant taxa, has been tested. The presumed parental taxa are divergent in several loci, L. pallidula being highly homozygous and L. campestris moderately heterozygous. The Irish tetraploid combines the alleles of the putative parents, has no unique alleles, and exhibits a high frequency of heterozygotes, in Adh-2 and Gpi-1, with invariably additive patterns. The Irish tetraploid has a low genotype diversity. The allozyme data support the hypothesis of alloploid origin for the Irish tetraploid with L. campestris and L. pallidula as possible parents. Recently, T.C.G. RICH detected rather aberrant plants of the L. multiflora group in Ireland. Later on, similar morphotypes were collected at a number of sites throughout Ireland. These plants proved to be tetraploid. Morphologically, they are close to the L. multiflora group but combine some features of L. campestris and L. pallidula as well. This aberrant type has been examined morphologically and karyologically (KIRSCHNER & RICH, in prep.; JAROLIMOVA & KIRSCHNER, in press) in considerable detail. Preliminary results of these investigations allow the hypothesis that the aberrant Irish tetraploid plants might have originated through chromosome doubling of a diploid hybrid between L. campestris and L. pallidula. Isozyme electrophoresis and the analysis of allozyme variation can provide evidence to test this hypothesis. Here, results of allozyme analyses of the Irish tetraploid and the putative parental taxa are presented and discussed.