Agriculture Reference
In-Depth Information
As the populations chosen for the experimentation were historically in the
offi cial catalog, they had to meet the uniformity criteria when they were ini-
tially registered. Even after they were removed from the catalog, they were
conserved ex situ with very few plants and conservative selection during the
regeneration process. However, our results question the assumption that F1
hybrids are always more uniform than population varieties; this appears not
to be the case for many traits under organic conditions.
12.4 GENERAL DISCUSSION AND PERSPECTIVES
We found phenotypic changes in population varieties of spinach after two
generations of on-farm breeding. But have the varieties changed so much
that they are no longer distinct? The results of the ascending hierarchical
classification clearly showed that one variety has evolved to such a point
that its two versions were not in the same group. This leads to certain ques-
tions about what constitutes a new variety in this context, where limit is
between one variety and another, and how can we define and measure va-
riety distinctness for population varieties. From a scientific point of view,
we would like to understand the reasons for the phenotypic changes (and
maybe evolution) of a variety, and how the adaptive and evolutionary po-
tential of varieties can be conserved. The changes observed within tested
populations after two generations would cause this type of variety to be re-
jected from catalogue registration based on the criterion of stability of the
European catalogue varieties. Seed companies or gene banks that main-
tain open pollinated populations practice conservative selection based on a
certain phenotypic description of the variety, which may eliminate genetic
diversity that was initially present.
In our case, farmers chose varieties corresponding to their own criteria,
and then selected the variety based on their objectives. The two processes
are different and complementary in terms of maintaining useful genetic
diversity in agricultural species, and our results are specifi c to on-farm
conservation and breeding where farmers are seeking varieties with more
variability, as discussed in the introduction.
The possibilities for adaptation of the varieties to specifi c environmen-
tal conditions are enhanced by their intrinsic variability. This is promising
