Agriculture Reference
In-Depth Information
In order to evaluate the effi ciency of farmers' selection (or adaptive re-
sponse to selection pressure), farmers planted their versions of the spinach
varieties alongside the original versions in the last year of the project. The
results of these on-farm trials were not statistically exploitable because
farmers did not sow replicates, but this allowed the farmers to visually com-
pare the varieties that they had selected to the original versions. We can
report some observations made by the farmers without quantitative evalua-
tions. For example, at MC, selected versions of the varieties were globally
less blistered (a desired change) and at AVO, the original version of 'Mon-
arch Long Standing' was earlier to bolt even though AVO had selected only
the plants late to bolt. Unfortunately, the last year of the trial failed at FD due
to weather conditions. The on-station and on-farm trials were complemen-
tary, as the on-station trial could evaluate the changes of varieties at a global
level (all varieties coming from different farms) while the on-farm trials al-
lowed farmers to evaluate the effi ciency of their selection.
In this study, MC and AVO applied selection pressure and FD let the
variety respond to natural selection. However, the types of changes ob-
served were similar whether in response to natural or farmers' selection.
So in our case, the type of selection (natural or human) does not seem
to have an infl uence on the intensity of changes (the degree of signifi -
cance and number of traits with signifi cant differences). Changes in the
FD version of 'Eté de Rueil' are comparable to changes in the MC version
and even to the changes in other varieties. This shows the importance of
so-called “natural evolution” or importance of the environmental impacts
for cultivated plants. We can wonder if this capacity to respond to selec-
tion pressure could be linked with the allogamous reproductive strategy of
spinach. However, in an article by Dawson [10] on a similar experimenta-
tion of the Farm Seed Opportunities project on wheat, an autogamous spe-
cies, the same kind of results are shown for population varieties subjected
to natural selection on-farm. It would be of interest and importance for
breeding to compare the intensity and effi ciency of human and natural
selection in terms of the adaptive potential of the varieties. With this view,
a more thorough experimentation would be needed where all varieties are
selected by farmers in each environment, alongside the variety cultivated
with only natural selection pressure.
