Soybean Root System Architecture Trait Study through Genotypic, Phenotypic, and Shape-Based Clusters

Kevin G. Falk, Iowa State University
Talukder Zaki Jubery, Iowa State University
Jamie A. O’Rourke, United States Department of Agriculture
Arti Singh, Iowa State University
Soumik Sarkar, Iowa State University
Baskar Ganapathysubramanian, Iowa State University
Asheesh K. Singh, Iowa State University

This article is published as Falk, Kevin G., Talukder Zaki Jubery, Jamie A. O’Rourke, Arti Singh, Soumik Sarkar, Baskar Ganapathysubramanian, and Asheesh K. Singh. "Soybean Root System Architecture Trait Study through Genotypic, Phenotypic, and Shape-Based Clusters." Plant Phenomics 2020 (2020): 1925495. DOI: 10.34133/2020/1925495.


We report a root system architecture (RSA) traits examination of a larger scale soybean accession set to study trait genetic diversity. Suffering from the limitation of scale, scope, and susceptibility to measurement variation, RSA traits are tedious to phenotype. Combining 35,448 SNPs with an imaging phenotyping platform, 292 accessions (replications=14) were studied for RSA traits to decipher the genetic diversity. Based on literature search for root shape and morphology parameters, we used an ideotype-based approach to develop informative root (iRoot) categories using root traits. The RSA traits displayed genetic variability for root shape, length, number, mass, and angle. Soybean accessions clustered into eight genotype- and phenotype-based clusters and displayed similarity. Genotype-based clusters correlated with geographical origins. SNP profiles indicated that much of US origin genotypes lack genetic diversity for RSA traits, while diverse accession could infuse useful genetic variation for these traits. Shape-based clusters were created by integrating convolution neural net and Fourier transformation methods, enabling trait cataloging for breeding and research applications. The combination of genetic and phenotypic analyses in conjunction with machine learning and mathematical models provides opportunities for targeted root trait breeding efforts to maximize the beneficial genetic diversity for future genetic gains.