Geographical patterns of karyotype polymorphism in Italian populations of Ornithogalum montanum (Liliaceae)

Abstract

The geographical patterns of quinacrine banding polymorphism at 20 sites, and of numbers of accessory (B) chromosomes, were studied in nine Italian populations of Ornithogalum montanum Cyr. ex Ten. (Liliaceae). Eight banding sites appear monomorphic. The standardized gene frequency variance, Fst, is heterogeneous among the remaining 12 sites; variation is greatest for four polymorphisms whose frequency is correlated with the winter temperature of the localities studied. A strong negative association is apparent between numbers of B chromosomes and Q bands. Spatial autocorrelation shows three distinct modes of geographical variation: (i) random distributions; (ii) patterns with positive short-range autocorrelation; (iii) patterns with negative intermediate-range autocorrelation. Some microevolutionary implications of these findings are discussed. © 1989, The Genetical Society of Great Britain.