Root Phenotyping of Winter Wheat for Phosphorus Acquisition.

Important to the Green Revolution was the development of semi-dwarf and higher yielding wheat varieties that were more resistant to lodging. Norin-10, a dwarf wheat variety from Japan, was introduced into US breeding lines during the 1950s to develop semi-dwarf lines. Development of these new lines typically occurred in fertilized conditions and focused solely on aboveground traits, such as shoot length, grain yield, and disease resistance. As a result, belowground traits related to nutrient acquisition may have been lost over time. This study assessed both root system architecture and chemical traits in a diverse panel of winter wheat lines. Cultivars were primarily selected based on decade of release and were further selected based on genotypic coancestry. A panel of ten cultivars were grown in gel and imaged using light tomography to create three-dimensional images of root systems during growth. Root system architectural traits including seminal root angle, bushiness, network area, maximum vertical depth, and root number were determined among other parameters using GiA Roots software. Statistical analysis indicates differences in root growth and root architectural traits between semi-dwarf and wild type cultivars. Cultivars were also grown in liquid culture under phosphorus limiting conditions for analysis of chemical traits including root tip organic acid concentration, exudate composition, and root quality. Root tip oxalic acid content is two-fold greater in wild type cultivars. Dwarfing has corresponded with unintentional changes to both root architecture and chemical function.