Improving water acquisition in maize with root traits that reduce the metabolic cost of soil exploration. This project received funding from NSF BREAD (Basic Research to Enhance Agricultural Development) in 2011, 2012 and 2013.


  • Dr. Jonathan Lynch (The Pennsylvania State University)


  • Dr. Kathleen Brown (The Pennsylvania State University)
  • Dr. Shawn Kaeppler (University of Wisconsin-Madison)
  • Dr. George Kanyama-Phiri (Bunda College of Agriculture, Malawi)

Senior Personnel

  • Dr. Moses Maliro (Bunda College of Agriculture, Malawi)


Drought is a primary constraint to maize (Zea mays) production in developing countries. Development of maize varieties that are better able to acquire water from drying soil would be an important contribution to food security in these regions. This project will employ recent discoveries in root biology to develop maize varieties with enhanced acquisition of soil resources by exploiting genetic variation for root traits that reduce the metabolic cost of soil exploration. Recent discoveries have shown that maize genotypes with two specific root traits - large root cortical aerenchyma (RCA), which form as a result of the programmed death of root cortical cells in maize, and small cortical cell area (CCA) - have less root respiration, greater root elongation, deeper roots, and greater acquisition of water from drying soil. A field study showed that natural variation for RCA among closely related genotypes resulted in 800% variation in yield under water stress. This project will utilize a method to evaluate these traits in maize germplasm, tools to identify the genetic control of these traits, and research sites in the USA and Africa to evaluate their relationship with stress tolerance. This project will deploy these traits for the development of maize genotypes with greater tolerance to drought. This research will include: confirmation of the physiological utility of RCA and related traits for drought tolerance in controlled settings in the USA; analysis of natural genetic variation for RCA and related traits; evaluation of the agroecological utility of RCA and related traits in southern Africa in field stations and on-farm trials, considering other stress factors present in these agroecosystems.

Broader Impacts

This research will generate fundamental new knowledge of root traits that regulate soil resource acquisition. The utility of these traits for drought tolerance has never been investigated. This project would also identify novel traits, germplasm sources, and genetic markers for crop breeding. In addition to drought, RCA may be useful in the acquisition of limiting soil nutrients such as phosphorus and nitrogen. The proposed research will translate fundamental physiological and genetic information into products and approaches that will help to feed hungry people in Africa. Training activities are focused on the interaction between African and US scientists. Post-doctoral researchers funded at Penn State will participate in research conducted in Africa thereby gaining an appreciation of the practical challenges of translating basic knowledge into products for this region. Infrastructure in Africa will be strengthened by training African students at US institutions. This interaction will also be taken back to the classroom. A case study related to this research will be utilized in Lynch's undergraduate course in Plant Nutrition and in Kaeppler's undergraduate Plant Breeding and Biotechnology course (each has ~30 students per year).

This project addresses novel scientific issues that are of demonstrable relevance to human welfare. Public access to products of this research will be through the USDA germplasm bank, existing genetic databases such as MaizeGDB ( and GenBank, and web outreach in English, French, Portuguese, and Spanish (