TETRASOMIC INHERITANCE AND ISOZYME VARIATION IN TURNERA-ULMIFOLIA VARS ELEGANS URB AND INTERMEDIA URB (TURNERACEAE)

Tetrasomic inheritance of three isozyme loci is demonstrated in Turnera ulmifolia vars. elegans and intermedia. The data support the occurrence of an autopolyploid origin for tetraploids of both taxonomic varieties. The extent of isozyme variation at 14 loci was determined for diploid and tetraploid populations. Tetraploid Turnera ulmifolia var. intermedia showed the lowest levels of isozyme variation, perhaps a result of founder effect, upon island colonization. In contrast, Turnera ulmifolia var. elegans showed the greatest levels of isozyme variation, suggesting that hybridization among locally differentiated diploid or tetraploid populations might have occurred. The number of independent origins of autotetraploidy in Turnera ulmifolia is unknown.