Allozyme variation within Solanum sect. Petota, ser. Etuberosa (Solanaceae)

Spooner, D.M.; Douches, D.S.; Contreras M, A.

Allozyme variation within Solanum sect. Petota, ser. Etuberosa (Solanaceae)

1992

Spooner, D.M. | Douches, D.S. | Contreras M, A.

Enzyme electrophoresis was employed to measure genetic variation within and divergence among 32 populations of three species in Solanum sect. Petota (S. brevidens, S. etuberosum, and S. fernandezianum). These species are self-compatible, diploid (2n = 2x = 24), and members of the monophyletic series Etuberosa. Solanum etuberosum is distributed in southern Chile, S. brevidens occurs in southern Chile and adjacent southern Argentina, and S. fernandezianum is endemic to Masatierra island in the Juan Fernandez Archipelago, 650 km west of continental Chile. Very low levels of observed heterozygosity (0.00-0.04) are found within populations of all three species. Interspecific mean genetic identities between S. brevidens and S. etuberosum (0.854) were similar to their intraspecific values (0.923, 0.865, respectively), with both species monomorphic for alleles at nine of the 12 loci examined. Solanum fernandezianum shows no heterozygosity and is more divergent to both S. brevidens (0.780) and S. etuberosum (0.698) than either is to each other. The divergence of S. fernandezianum to S. brevidens and S. etuberosum results from novel alleles at two of the 12 isozyme loci; in addition, it possesses only a subset of the variability found in S. brevidens and S. etuberosum at three other loci.

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