Roots traits for improved pearl millet tolerance to drought stress

International audience Pearl millet is an important crop for food security in arid and semi-arid regions of the world. It is traditionally cultivated in low input agroecosystems where its yield is limited by soil nutrients and water availability. Low yield potential is accentuated by climate change, characterized in these regions by more frequent drought events. As roots are responsible for water and nutrient capture, they represent good targets to improve pearl millet nutrient acquisition and drought adaptation. To better understand how root traits influence these processes in pearl millet, a panel of 160 newly re-sequenced inbred lines was grown under irrigated and vegetative drought stress treatment over two years in field conditions in Senegal and was phenotyped for root architectural and anatomical traits using shovelomics and laser ablation tomography, leaf ionomics and yield and yield components traits. We observed a large diversity of response to drought stress with some lines able to maintain growth while others were able to quickly recover after re-irrigation. Root traits associated with tolerance to drought stress and leaf ion content were identified. Association genetics was used to identify candidate genes controlling these traits. Further physiological and genetic dissection of these traits, their synergy, and interactions with the environment is underway and could provide new avenues to improve drought tolerance in pearl millet.