Spatial autocorrelation of genotypes in populations of impatiens pallida and impatiens capensis

Abstract

The genetic control and small scale spatial distributions of three conspicuous genetic polymorphisms—presence or absence of corolla spotting, yellow or white corolla colour, and presence or absence of stem waxiness—were studied in populations of the plant species Impatiens pallida and I. capensis occurring in Quebec, Canada. The corolla spotting and colour morphs in I. pallida each appear to be determined by different pairs of unlinked loci. Dominant alleles at each locus pair are required for the expression of corolla spotting or yellow corolla colouration. Stem waxiness in I. capensis is also shown to be under genetic control. Significant ctustering of identical flower and stem phenotypes at small interplant distances was observed in most population samples, suggesting substructuring of genotypes in space. The sizes of patches where morph frequencies occurred in excess of random expectations were found to be consistent among populations and polymorphisms within the species, lending support to the interpretation that substructuring of genetic variation in these populations is due to restricted gene dispersal. The population genetical consequences of limited gene flow in these species is discussed. © The Genetical Society of Great Britain.