Root anatomical traits for efficient water acquisition under drought in Maize (zea mays L.)
Open Access
- Author:
- Chimungu, Joseph Gregory
- Graduate Program:
- Horticulture
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- None
- Committee Members:
- Jonathan Paul Lynch, Dissertation Advisor/Co-Advisor
Kathleen Marie Brown, Committee Member
Gabriele Brigitte Monshausen, Committee Member
Howard Skinner, Committee Member - Keywords:
- Cortical cell file number
root costs
Zea mays L.
(Maize)
drought - Abstract:
- Drought stress is a primary constraint to crop production. The identification and understanding of root phenes improving crop drought tolerance is of paramount importance in world agriculture. Root phenes are critical for soil exploration and water and nutrient acquisition, and are important for crop improvement under drought conditions. Chapter 2 is based on a study where maize genotypes contrasting for root cortical cell file number were evaluated under water limited conditions across wide range of environments, and the results demonstrate that reduced cortical cell file number substantially reduced root metabolic cost for soil exploration thereby improving water acquisition, plant growth and consequently greater grain yield under drought. Chapter 3 is based on a study where maize genotypes contrasting for root cortical cell size were evaluated under water limited conditions across wide range of environments, and the results demonstrate that large cortical cell size substantially reduced root metabolic cost for soil exploration thereby improving water acquisition, plant growth and consequently greater grain yield under drought. Root cortical aerenchyma is known as a phene that reduces root metabolic cost by converting living cortical tissue to airspace and is associated with improved soil resource acquisition. In chapter 4 the utility of root cortical aerenchyma was evaluated in different agroecologies in field stations and on-farm in Malawi and the results are consistent with the hypothesis that root cortical aerenchyma improves maize drought tolerance by reducing metabolic cost of soil exploration improving water acquisition. Chapter 5 extends the analysis to examine if anatomical phenes affect root penetration ability of hard layers and biomechanical properties. Results indicate that that root anatomical phenes were better predictors of root penetrability than root diameter per se.