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Abstract:
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† Background and Aims Two closely related, wild tomato-like nightshade species, Solanum lycopersicoides and
Solanum sitiens, inhabit a small area within the Atacama Desert region of Peru and Chile. Each species possesses
unique traits, including abiotic and biotic stress tolerances, and can be hybridized with cultivated tomato.
Conservation and utilization of these tomato relatives would benefit from an understanding of genetic diversity
and relationships within and between populations.
† Methods Levels of genetic diversity and population genetic structure were investigated by genotyping representative
accessions of each species with a set of simple sequence repeat (SSR) and allozyme markers.
† Key Results As expected for self-incompatible species, populations of S. lycopersicoides and S. sitiens were
relatively diverse, but contained less diversity than the wild tomato Solanum chilense, a related allogamous
species native to this region. Populations of S. lycopersicoides were slightly more diverse than populations of
S. sitiens according to SSRs, but the opposite trend was found with allozymes. A higher coefficient of inbreeding
was noted in S. sitiens. A pattern of isolation by distance was evident in both species, consistent with the highly
fragmented nature of the populations in situ. The populations of each taxon showed strong geographical structure,
with evidence for three major groups, corresponding to the northern, central and southern elements of their
respective distributions.
†Conclusions This information should be useful for optimizing regeneration strategies, for sampling of the populations
for genes of interest, and for guiding future in situ conservation efforts. |