Plant breeding for organic and sustainable, low-input agriculture

On-farm dynamic management of wheat populations/varieties in organic agriculture: a
way to valorize GxE interactions
Isabelle Goldringer 1 , Galic Nathalie 1 , Rousselle Yves 1 , Demeulenaere Elise 2 , Bonneuil
Christophe 3 , Payement Joël 4 , Berthellot Jean-François 4 , Chesneau Vincent 4 , Mercier Florent 4 ,
Ferté Henri 4 , Pommart Alain 4 , Zaharia Hélène 4
1 UMR de Génétique Végétale, INRA Univ. Paris Sud CNRS AgroParisTech, France; 2 ENS,
CERES, Paris, France; 3 CNRS - EHESS – MNHN, Paris, France; 4 Réseau Semences
Paysannes, Brens, France
Numerous studies of traditional agricultural systems in the South have shown that the farmers
practices for seeds management were the key for local adaptation whilst maintening the genetic
diversity, due to the co-exixtence in the populations of all evolutionary mecanisms: selection,
genetic drift, migration, mutation (Smith et al., 2001 ; Almekinder et al., 2000 ; Louette et al.,
1997 ; Bertaud et al., 2001 ; Elias et al., 2001). Hence, this can be described as a dynamic
management approach. In industrialized countries, such approaches are usually developped
through the cooperation of farmers and breeders and/or researchers, and they might be of a great
interest for organic or low input farming systems where the effects of environment and practices
combine to produce a large range of contrasted conditions. Yet, these approaches are scarce and
they still do not have found a clear position in the seed regulation framework in France.
To help on farm management or participatory approaches to find an official recognition, we are
conducting a sociological, historical, ethno-botanical study of the actors, and a parallel genetic
study of the varieties/populations in order to assess the ability of farmers networks to conserve
and develop genetic diversity through local adaptation and seeds exchanges. Here, we present a
case study of an old wheat variety (Rouge de Bordeaux, RB) grown for several generations in
different farms under different conditions and farming practices. This old variety (~1880) has
recently spread over organic farms in France due to its high “artisanale” bread making quality
and good adaptation to organic conditions. Seeds samples were collected for about 25 different
farmers RB varieties as well as for 4 RB accessions from the Inra collection. In 2006-2007, they
were assessed phenotypically in 6 farms and in a research station (Le Moulon). Leaf samples of
20-35 individuals / RB-sample were collected, DNA was extracted and they will be genotyped
with a set of “neutral” SSR markers and markers of the VRN1 loci (vernalization response).
Based on the sociological survey, a partial network of seeds exchange was drawn indicating
complex and active exchanges, especially for the variety RB. The first phenotypic data show that
the different samples are significantly differentiated with regards to their early development and
to their vernalization response. Within-sample phenotypic and genetic diversity will be studied
together with the differentiation between samples at both levels.
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