Abstract
Starch gel electrophoresis was utilized to test previous conclusions regarding the origins of the stabilized diploid hybrid species, Carex salina and C. recta, on the Lower St. Lawrence River and Gaspe Peninsula, Quebec. The enzymes PGI, 6PGD, and SkDH were examined for these hybrids and their four potential parental species, Carex aquatilis, C. nigra, C. paleacea, and C. subspa- thacea, utilizing plants collected from 42 natural populations and seedling progeny samples. The number of alleles per locus ranged from four to five, and marker alleles were observed for each of the putative parental species. Both Carex paleacea and C. subspathacea consist of a single genotype throughout the area sampled, while C. aquatilis and C. nigra are genetically more variable. Results confirm that Carex salina, which consists of a single genotype in natural populations, originated as a hybrid of C. paleacea and C. subspathacea. Carex recta is a complex of genotypes, which appears to be derived from hybridization and backcrossing between C. aquatilis and C. paleacea. However, no introgression among parental species was detected. Reproductive isolation among species of Car- ex within a section or, in some cases, among related sections, appears to be due to ecological or phenological divergence rather than to genic or chromosomal differences (Whitkus 1988). Synthetic hybrids have been readily produced between closely related species in sects. Phac- ocystis Dumort. (Faulkner 1973; Standley 1985), Ovales Kunth (Whitkus 1988), and Extensae Fries (Schmid 1982). Putative naturally occurring hy- brids have frequently been described based on intermediate morphology. Recent studies have provided evidence that spontaneous hybrids have reduced seed set, reduced pollen fertility, and are intermediate between their putative parents in foliar anatomy, achene micromor- phology, and flavonoid profiles (Jalas and Hir- vela 1964; Reznicek and Catling 1986; Toivonen 1981).
Published Version
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