Agriculture Reference
In-Depth Information
Standing' has evolved on this aspect in the direction wished by the farmer
(earlier bolting and fl owering on 29 May).
'Eté de Rueil' showed changes for six criteria after cultivation at FD
although no human selection was applied. It is interesting to note that the
variety evolved in the same way when selected by MC.
MC selected all the varieties chosen according to the same criteria. All
the varieties showed changes but not always in the direction he wished.
For example, although MC selected dark plants later to bolt and fl ower,
we noted that, on the whole, most of MC versions had a shorter cycle and
whiter, “more yellow” and “greener” leaves (changes that we can interpret
as “lighter green” according to the correlations observed between intensity
of green and the L, A and B color parameters, data not shown). MC also
selected plants with spear shaped leaves. Three varieties showed narrower
or longer leaves ('Supergreen', 'Viking Matador' and 'Alwaro'), which
tended towards a spear shape. From those results, it does not seem possible
to distinguish which changes were due to the environment, human selec-
tion or others factors: human selection did not always produce changes in
the direction wished by the farmer, and FD did not perform any selection
and this variety did show phenotypic changes.
We measured changes as a difference between the phenotypic expres-
sions of two versions of the same variety. However, even if we recorded
the selection criteria of the farmers, we cannot say that we only measured
the adaptive response to farmers' selection. The phenotypic expression of
the plants depends on the genotype of the plant, and also on the environ-
ment (especially for spinach, which is very sensitive to nitrogen and water
for example). Our study in the last year of the project took place in a dif-
ferent environment than the on-farm environments of selection/adaptation
of the varieties. So, for example, although our observations underline that
MC versions are earlier than the original versions, we cannot claim that
MC failed in his selection of plants late to bolt and fl ower. MC's versions
are earlier in our trial conditions, but perhaps not in its farm conditions.
We know that he cultivated the spinach under plastic tunnels, and the sec-
ond year the trial was conducted in winter instead of spring. Thus, when
the seeds produced in these conditions were cultivated in our trial condi-
tions (in spring in the fi eld), we cannot conclude that the changes observed
would have been the same at MC's farm.
