Early-Stage Phenotyping of Root Traits Provides Insights into the Drought Tolerance Level of Soybean Cultivars
Résumé
Soybean (Glycine max(L.) Merr.) may contribute to the agro-ecological transition ofcropping systems in Europe, but its productivity is severely affected by summer drought. Newdrought-avoidance cropping strategies, such as early sowing, require cultivars with high early plantgrowth under suboptimal conditions. This study aims at phenotyping early-stage root and shoottraits of 10 cultivars commonly grown in Europe. Cultivars were grown in minirhizotrons under twosoil moisture status in controlled conditions. Root and shoot traits were evaluated at 10 days aftersowing. Field early growth of two cultivars was also analyzed under early and conventional sowingdates. A significant intraspecific variability (p< 0.05) was found for most investigated shoot androot morpho-physiological traits regardless of the soil moisture status under controlled conditions.However, no significant difference among cultivars (p> 0.05) was found in terms of root architecturaltraits that were mainly affected by water stress. Total root length was positively correlated with shootlength and shoot dry matter (p< 0.05). Under field conditions, the differences between cultivarswere expressed by the canopy cover at emergence, which determines the subsequent canopy coverdynamics. The significant early growth difference among cultivars was not related to the maturitygroup. Cultivars characterized by high root depth and length, high root density and narrow rootangle could be considered as good candidates to cope with water stress via better soil exploration.New agronomic strategies mobilizing the diversity of cultivars could thus be tested to improvesoybean water use efficiency in response to climate change.
Domaines
Sciences du Vivant [q-bio]Origine | Fichiers produits par l'(les) auteur(s) |
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