OPTIMIZING ROOT METAXYLEM PHENOTYPES TO IMPROVE DROUGHT TOLERANCE IN MAIZE

This project will evaluate the potential to improve the drought tolerance of corn by selecting plants with smaller but more numerous xylem vessels, which are the cellular structures in roots that carry water from the soil to the leaves. Corn is the most important crop in the USA and globally. Drought stress is the most important limitation for corn production in the USA and globally, and drought stress is expected to become more severe in coming decades as a result of global climate change. We have observed that corn lines with a large number of small vessels perform better under drought. In this project we will confirm and extend these results, and also identify genes that are responsible for this natural variation.Defining and understanding traits improving the drought tolerance of crops is needed to breed crop varieties with better yield, better drought tolerance, and less reliance on irrigation. Insufficient information exists regarding the value of xylem vessels in crop breeding. Should the importance of xylem vessels for drought tolerance be demonstrated, an entirely new tool will be available for targeted crop improvement. This project will provide validated breeding targets, germplasm sources, molecular markers, and candidate genes that could be used directly in maize breeding. Our close collaboration with maize geneticists will ensure that any useful results will be readily applied in the maize community. While this project focuses on maize, xylem vessels may also be useful breeding targets in wheat, rice, legumes, and other crops. This project therefore addresses novel scientific issues that are of demonstrable relevance to human welfare.