Development of a model estimating root length density from root impacts on a soil profile in pearl millet (Pennisetum glaucum (L.) R. Br). Application to measure root system response to water stress in field conditions

PLoS One. 2019 Jul 22;14(7):e0214182. doi: 10.1371/journal.pone.0214182. eCollection 2019.

Abstract

Pearl millet is able to withstand dry and hot conditions and plays an important role for food security in arid and semi-arid areas of Africa and India. However, low soil fertility and drought constrain pearl millet yield. One target to address these constraints through agricultural practices or breeding is root system architecture. In this study, in order to easily phenotype the root system in field conditions, we developed a model to predict root length density (RLD) of pearl millet plants from root intersection densities (RID) counted on a trench profile in field conditions. We identified root orientation as an important parameter to improve the relationship between RID and RLD. Root orientation was notably found to depend on soil depth and to differ between thick roots (more anisotropic with depth) and fine roots (isotropic at all depths). We used our model to study pearl millet root system response to drought and showed that pearl millet reorients its root growth toward deeper soil layers that retain more water in these conditions. Overall, this model opens ways for the characterization of the impact of environmental factors and management practices on pearl millet root system development.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Agriculture
  • Droughts
  • Models, Biological
  • Pennisetum / anatomy & histology
  • Pennisetum / physiology*
  • Plant Roots / anatomy & histology
  • Plant Roots / physiology*
  • Soil / chemistry
  • Stress, Physiological
  • Water / metabolism*

Substances

  • Soil
  • Water

Grants and funding

This research was supported by the Sustainable Intensification Innovation Lab project (SIIL / Feed the Future) through the United States Agency for International Development (USAID, grant 929773554 to DM). A. Faye was supported by a PhD grant from the SIIL. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. JLC is affiliated to the Agerconsult company (Montpellier, France). Agerconsult provided support in the form of salaries for JLC, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific role of JLC is articulated in the ‘author contributions’ section.