Root physiology and morphology of soybean in relation to stress tolerance

The significance of root system architecture (RSA) to the productivity and adaptation of crops such as soybean (Glycine max (L.) Merr.) is well recognized. RSA is an essential trait in the selection of genotypes with improved resource acquisition and adaptation to environmental stresses. High-throughput phenotyping, imaging of root growth and structure, genomic sequencing and association analysis techniques are useful tools in soybean breeding programs that aim to improve plant performance and productivity. This chapter discusses genetic variability and plasticity in soybean root system morphology, root architecture and root anatomic traits that are relevant to increased soil resource use efficiency and better adaptation to specific soil environments. We consider the importance of soybean/rhizobia and rhizosphere interactions and highlight current challenges and future directions in improving soybean root physiology and morphology for better adaptation to abiotic stresses.