Functional traits diversity and fitness evaluation in response to salt stress in some Medicago spp wild populations

M. S. Y. Amokrane (1, 2, 3, 4, 5, 6) , A. Kadri (1, 2, 7) , Meriem Laouar (1) , C. Ben (3, 4, 5, 6) , Bernadette Julier (8) , L. Gentzbittel (3, 4, 5, 6) , A. Abdelguerfi (2)

1 Laboratoire d’Amélioration Integrative des Productions Végétales
2 Laboratoire des Ressources Génétiques et Biotechnologies
3 LEFE - Laboratoire Ecologie Fonctionnelle et Environnement
4 CNRS - Centre National de la Recherche Scientifique
5 Toulouse INP - Institut National Polytechnique (Toulouse)
6 UT3 - Université Toulouse III - Paul Sabatier
7 Faculté des Sciences, Département d’Agronomie
8 P3F - Unité de Recherche Pluridisciplinaire Prairies et Plantes Fourragères

Land salinity is one of the major abiotic constraints that affect negatively crop production worldwide. Medicago genus, mostly composed by annual species, is of a real interest in improving soil fertility and maintaining pastures for livestock. We assessed adaptive traits for salt tolerance in 40 contrasted populations belonging to 6 Medicago species. In a common site, trial was performed in saline and non-saline soils where functional and fitness traits were recorded. Only M. ciliaris populations survived in the saline soil, highlighting the negative effect of even low salt levels at plant lift. ANOVA and PCA revealed that lifting rate, length branch at flowering time and total pod number might be involved in salt tolerance. The response to salt stress of Medicago was further studied by analyzing germination kinetics of 37 populations under five ranges of NaCl concentrations from 0 to 200 mM, during 7 days. Kaplan-Meier survivor curves and Cox PH models indicated that time to 50% germination, germinability and germination synchrony are affected by the increase of salts. The risk of non-germinated seeds depends on species, populations and NaCl concentrations. Altogether, these results show that both salt level and exposition duration affect the phenotypical traits. Local adaptation may partly explain the patterns of salt tolerance. M. ciliaris is the most tolerant species, with a relatively high level of intraspecific variability for most studied traits.

Mots clés: trait fonctionnel; population sauvage; réponse au stress; stress salin; medicago

Domaines: Sciences agricoles

M. S. Y. Amokrane, A. Kadri, Meriem Laouar, C. Ben, Bernadette Julier, et al.. Functional traits diversity and fitness evaluation in response to salt stress in some Medicago spp wild populations. 2. International Legume Society Conference (ILS2), Oct 2016, Troia, Portugal. 335 p., 2016, Legumes for a Sustainable World. ⟨hal-01594784⟩