Differences in Root Morphologies of Contrasting Wheat (Triticum aestivum) Genotypes Are Robust of a Drought Treatment

We aimed to assess the effect of water deprivation on root traits and to establish if the wheat cultivars Spica and Maringa would be useful as parental germplasm for a genetic analysis of root traits. Plants were grown in two markedly different soils under well-watered and water-limited treatments in controlled environment growth cabinets. The drought treatment was imposed as a gradual depletion of water over 28 days as seedlings grew from a defined starting moisture content. The root traits analyzed included length, nodal root number, thickness and nodal root angle. The relative differences in traits between genotypes generally proved to be robust in terms of water treatment and soil type. Maringa had a shallower nodal root angle than Spica, which was driven by the nodal roots. By contrast, the seminal roots of Maringa were found to be similar to or even steeper than those of Spica. We conclude that the differences in root traits between Spica and Maringa were robust to the drought treatment and soil types. Phenotyping on well-watered soil is relevant for identifying traits potentially involved in conferring water use efficiency. Furthermore, Spica and Maringa are suitable parental germplasm for developing populations to determine the genetics of key root traits.