Crop yields are expected to face more threatening circumstances due to ongoing climatic and environmental change. The continued sustainability of crop production will depend on genetic capacity of crops to adapt to increased biotic and abiotic barriers induced by climate change. Historically, shoot-based traits were breeding targets for overcoming yield gaps between developed and undeveloped nations. However, the rate of genetic gain has stabilized with conventional breeding targets for indirect yield improvement. As the availability of mineral fertilizers is steadily declining and the occurrence of low-fertility soils has increased, reoccurring yield disparities worldwide are propelling us to evaluate new breeding targets. There is potential for plant breeders to shift their focus to the root system architecture (RSA) as a new target for indirect selection, enabled by the phenotypic plasticity of winter wheat (Triticum sp.), one of the main staple agronomic crops. Our current limited understanding of the dynamic nature of the root system architecture is due to the difficulties associated with in situ phenotyping and characterization of anatomical traits. The objectives of this thesis were to 1) review advancements in root phenotyping methodologies and past, present, and future predictions; 2) evaluate differences in root biomass accumulation and remobilization among 22 Virginia Tech-developed elite germplasm; 3) evaluate potential genetic variability for root biomass accumulation across breeding lines. Minimal genetic variation was observed for root biomass accumulation through time. Soil coring proved not to be a very effective method for capturing genetic variability of root biomass accumulation from a soil depth of 10 cm. However, a low genetic signal was also observed for shoot biomass, even though the entire field plot for each genotype was sampled. Yet, a considerably higher genetic signal was observed for plant height. These results suggest that both root and shoot biomass are complex, polygenic traits that require significantly more attention to evaluate genetic differences. / Master of Science / Climate change induces numerous abiotic and biotic barriers to our global cropping systems. Mineral fertilizer reserves are expected to deplete within the next 80 years while our agricultural lands continue losing fertility. This translates into increased yield discrepancies among the most prominent staple agronomic crops. Historically, crop improvement has been performed through indirect selection upon shoot-based traits for yield improvement. However, the capacity of genetic gain from these conventional selection criteria is projected to stabilize. Therefore, it would be beneficial for future global crop production if the initiative was taken to identify a new breeding target that can ensure climate resiliency in staple crops, such as winter wheat (Triticum). Root system architecture (RSA) is defined as the spatial distribution of embryonic and post-embryonic roots throughout a growth medium. This has the potential to become a new breeding target. However, there are numerous difficulties to overcome when evaluating roots in situ. In addition, there is no standardized root phenotyping method that can be implemented nationwide due to the variability in phenotypic response in various growing environments. The objectives of this thesis are to 1) reveal the advancements in root phenotyping and its legitimacy for standardization, 2) explore the genetic architecture of root system architecture, and 3) evaluate the genetic variability of root biomass accumulation for climate resiliency. Minimal genetic variation was observed for root biomass accumulation through time. Soil coring proved not to be a very effective method for capturing genetic variability of root biomass accumulation from a soil depth of 10 cm. However, a low genetic signal was also observed for shoot biomass, even though the entire field plot for each genotype was sampled. Yet, a considerably higher genetic signal was observed for plant height. These results suggest that both root and shoot biomass are complex, polygenic traits that require significantly more attention to evaluate genetic differences.