Revista Chilena de Historia Natural 83 (4): 605-616, 2010
RESEARCH ARTICLE
Genetic and morphological variation and population structure in Alstroemeria hookeri
subsp. hookeri (Alstroemeriaceae), endemic to Chile
The genus Alstroemeria consists of 82, exclusively South American taxa that
are distributed mainly in Chile and Brazil. The great economic relevance, that has acquired the Chilean Alstroemeria
species, as ornamentals, has aroused great interest in the morphological variability of their flowers and genetic variability in
those species with potential economic value. One of these species is Alstroemeria hookeri which has four subspecies, of
which A. hookeri subsp. hookeri, is endemic to the Maule and Biobío Regions. Its geographic
distribution consists of two ranges, separated by the Coastal Mountain. Thus, there are populations growing in the coastal range,
between 5-20 m high, in the provinces of Arauco, Concepcion, Ñuble, and Cauquenes, and populations of the Central Valley, growing
between 100-150 m in the Biobío and Ñuble provinces. Preliminary evidence indicated phenotypic differences between coastal and
Central Valley populations, principally in colour and shape of the tepals. For this reason, a comparative morphological study was
carried out in the complete geographic distribution of this subspecies and a population genetics study was conducted also, especially
to determine the levels of population structure. Thirty three floral characters were analyzed through ordination methods. The
morphological study shows a slight tendency to separate the populations into two groups, which coincide with the extremes of
morphological variation and both geographic ranges, with characters that contribute to this separation. The genetic variability indices
were estimated using 17 allozymic loci. We estimated population structure and also carried out an AMOVA analysis. Nei’s genetic
distances among all population pairs were estimated to obtain a dendrogram showing the genetic similarity relationships. The results
indicate high levels of genetic structure and low values of within population genetic diversity were found. The results of AMOVA indicate
that the variability occurs mainly among populations. However, these results varied when populations from both geographic ranges
were separately analyzed. The genetic similarities are not congruent with the morphological divergence between both geographic
ranges, indicating that some populations from Central Valley are more related genetically to some from coastal populations than
populations from their own geographic range.
Key words:
Alstroemeria
hookeri, genetic divergence, morphological variability, population genetics
