Agriculture Reference
In-Depth Information
with traits changing in both directions or not at all, showing that for certain
traits, farmer selection is necessary to maintain or improve certain traits. A
strong selection differential was expected for some traits that are observed
easily in the fi eld, for other traits such as TKW the presence of a strong
selection differential was more surprising. The results for some traits are
more complex to interpret, and it is not always clear if the lack of a se-
lection differential or response was due to a lack of genetic diversity for
those traits or because the traits used for varietal characterization may not
be the most appropriate to measure the effects of on-farm selection when
this selection is much more holistic in nature. Molecular genetic studies
are in progress on the base populations to determine the levels of genetic
variation and the on-farm evolution of both neutral variation and variation
linked to hypothesized adaptive traits such as earliness.
Signifi cant responses were found after only one cycle of selection in
farmer varieties, but this is dependent on the variety and suffi cient genetic
diversity needs to be present for selection to have an effect. Since farmer
selection is based much more on a global evaluation of the plants and
populations, and since this often produces desirable agronomic changes in
the fi eld based on the experience of farmers in the RSP over several years,
quantitative measures and analysis may be most useful when focused on a
small number of traits that are more diffi cult to evaluate by farmers, such
as protein content, or that respond unsatisfactorily to their selection, such
as LLSD. Quantitative measures may also be used after selection to moni-
tor these changes from one generation to the next, especially for traits that
have negative correlations, or to document and characterize these popula-
tions as they evolve.
While the EU directive on conservation varieties is an improvement over
existing standards which prohibit the exchange of any variety not registered
in the offi cial catalogue, it is fairly restrictive in the types of varieties that
can be registered in the special catalogue for conservation varieties. It still
includes the distinct, uniform and stable criteria for registration, with slight-
ly relaxed criteria of evaluation. In addition, they are limited to a restricted
zone of origin and percentage of the area cultivated to that species and to
limited quantities for commercial use [37]. The new directive therefore does
not include the range of farmer varieties currently of interest in organic sys-
tems, and may not be adequate for some types of on-farm conservation and
