BREEDING SYSTEM OF THE FERN DRYOPTERIS EXPANSA: EVIDENCE FOR MIXED MATING

Autor: Douglas E. Soltis, Pamela S. Soltis
Rok vydání: 1987
Předmět:
Zdroj: American Journal of Botany. 74:504-509
ISSN: 1537-2197
0002-9122
DOI: 10.1002/j.1537-2197.1987.tb08670.x
Popis: The levels and distribution of genetic variation within and among populations of the homosporous fern Dryopteris expansa were assessed using enzyme electrophoresis. Twelve loci representing six enzymes were examined in 502 sporophytes from nine populations. Values of P, H, and mean number of alleles per locus are much lower in D. expansa compared to values for other fern species. Values of F varied from -0.014 to 0.745 with an average F of 0.335. There was also considerable population to population variation in F. In three populations the observed heterozygosity closely approximated that expected at Hardy-Weinberg equilibrium, whereas in the remaining populations observed heterozygosity was significantly lower than the expected heterozygosity. In D. expansa the major component of FIT is F,,; the relatively high FST value suggests a high degree of interpopulational differentiation. Electrophoretic data suggest that this species possesses a mixed mating system. This study, in conjunction with other investigations, indicates that just as in angiosperms, a variety of breeding systems operates in homosporous ferns, ranging from extreme inbreeding, through mixed mating to outcrossing. NUMEROUS INVESTIGATIONS have stressed the importance of breeding system in determining gene flow, the genetic structure of populations
Databáze: OpenAIRE
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