Genetic variation in agamosporous fern Pteris cretica L. in Japan

Abstract

The genetic variation of an agamosporous fern, Pteris cretica L., was examined by enzyme electrophoresis. Five diploid and six triploid clones were distinguished by differences at five polymorphic enzyme loci. Among the triploids, four clones were characterized by two alleles, Hkd and Pgi-2a, which were not found in either the 2x clones or the two other 3x clones.These two alleles, Hkd and Pgi-2a were also found in diploid sexual relative of P. cretica, P. kidoi. This evidence suggests that the 3x clones with these alleles originated through fertilisation of reduced eggs of P. kidoi by unreduced spermatozoids of 2x clones P. cretica and three different 2x clones of P. cretica appear to have participated in crosses with P. kidoi to produce 33 clones. Thus recurrent hybridizations contribute toward generating genetic variation among agamosporous species, P. cretica.