The description of the
extent and distribution of the different aspects of genetic
diversity in a species, and of the way in which it
is structured, is an essential prerequisite to determining
what to conserve, and where and how to conserve
it. To date, most conservation efforts, either in situ or
ex situ, have proceeded with little information on the
genetic diversity that was being conserved and there is
an urgent need to remedy this situation. The development
of such improved descriptions involves not only
describing the variation observed, but also identifying
the major factors likely to affect the genetic structure
of plant populations and determining the effect they
have on the amount of variation in a population and
the distribution of alleles in it. Such factors include climatic,
edaphic and biotic ones as well as those specific
to the populations (e.g. population size, selection), or
to the species (e.g. ploidy, breeding system, linkage)