of the fibers of most wild species are
similar, with fiber elongation terminating at about two weeks
In contrast, growth is extended to three weeks
in the A-genome and
When considered in light
of the phylogeny
of the genus,
it becomes clear that this prolonged
elongation period represents a key evolutionary event in the origin
of long fiber, and that it happened in the common ancestor of these
two groups of diploid cottons prior to domestication and in Africa.
Analysis of fiber growth curves reveals that domestication itself
has been associated with further prolongation of elongation at
levels. This provokes the
speculation that the effects of parallel artificial selection for
long fiber in the four cultivated species resulted in a genetically
convergent or parallel transformation in the
responsible for this aspect of fiber development.
Natural and human-induced variation
Extraordinary variation among species
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