Traditional agroecosystems as conservatories and incubators of cultivated plant varietal diversity: the case of fig (Ficus carica L.) in Morocco.
BACKGROUND
Traditional agroecosystems are known to host both large crop species diversity and high within crop genetic diversity. In a context of global change, this diversity may be needed to feed the world. Are these agroecosystems museums (i.e. large core collections) or cradles of diversity? We investigated this question for a clonally propagated plant, fig (Ficus carica), within its native range, in Morocco, but as far away as possible from supposed centers of domestication.


RESULTS
Fig varieties were locally numerous. They were found to be mainly highly local and corresponded to clones propagated vegetatively. Nevertheless these clones were often sufficiently old to have accumulated somatic mutations for selected traits (fig skin color) and at neutral loci (microsatellite markers). Further the pattern of spatial genetic structure was similar to the pattern expected in natural population for a mutation/drift/migration model at equilibrium, with homogeneous levels of local genetic diversity throughout Moroccan traditional agroecosystems.


CONCLUSIONS
We conclude that traditional agroecosystems constitue active incubators of varietal diversity even for clonally propagated crop species, and even when varieties correspond to clones that are often old. As only female fig is cultivated, wild fig and cultivated fig probably constitute a single evolutionary unit within these traditional agroecosystems. Core collections, however useful, are museums and hence cannot serve the same functions as traditional agroecosystems.
Achtak
Hafid
H
INRA, UMR 1098, Développement et Amélioration des Plantes (DAP), Bat, 3, Campus CIRAD TA A 96/03, Av, Agropolis, 34398 Montpellier Cedex 5, France.
Ater
Mohammed
M
Oukabli
Ahmed
A
Santoni
Sylvain
S
Kjellberg
Finn
F
Khadari
Bouchaib
B
D000383:Agriculture; D003247:Conservation of Natural Resources; D018744:DNA, Plant / Q000235:genetics; D017753:Ecosystem; D019143:Evolution, Molecular; D030681:Ficus / Q000235:genetics*; D014644:Genetic Variation; D005838:Genotype; D005843:Geography; D018895:Microsatellite Repeats; D009018:Morocco; D017422:Sequence Analysis, DNA
D018744:DNA, Plant