ELECTROPHORETIC STUDY OF THE ALLOPOLYPLOIDAL ORIGIN OF TALINUM TERETIFOLIUM AND THE SPECIFIC STATUS OF T. APPALACHIANUM (PORTULACACEAE)

Electrophoretic evidence supported the hypothesis that Talinum teretifolium is an allopolyploid derivative of T. mengesii and T. parviflorum. Electrophoretic variation was examined for 384 individuals from 21 populations of four Talinum species. Plants were scored for isozymes of nine enzyme systems specified by 23 gene loci of which 4 were monomorphic and 19 polymorphic. Talinum teretifolium populations were electrophoretically uniform, and all alleles of this species were accounted for by combining alleles present in its presumed parents. Genetic identity values between T. teretifolium and each of its presumed parents (I ≥ 0.817) were higher than between any other pair of the four Talinum species examined. The electrophoretic evidence did not support an alternative hypothesis that T. calycinum is a progenitor of T. teretifolium. Electrophoretic data also showed that T. appalachianum is a disjunct population of T. parviflorum. The average genetic identity between T. appalachianum and T. parviflorum (I = 0.884) was higher than the average genetic identity for conspecific populations of both T. mengesii and T. calycinum.