Genome-Wide Association Study of Root Traits of Field Grown Soybean [Glycine max (L.) Merr.] Plants.

Water and nutrient acquisition are critical functions of plant root systems. Although soybean is one of the most important agronomic crops, much remains to be understood about growth, development, and function of its root system. Root traits are often complex and controlled by many genes. The objective of this study was to identify loci associated with root architectural traits of field grown soybean.  To this end, a collection of 291 soybean genotypes were grown in three environments, root systems excavated and top-soil root architectural traits assessed.   Genome-wide association studies were undertaken using ~31,000 single nucleotide polymorphism (SNPs), to identify SNPs associated with various root architectural traits. These analyses revealed a tractable number of SNP markers significantly associated with the evaluated root characteristics. Follow-up studies will be needed to confirm these markers and examine the importance of the different root characteristics for soybean productivity under a range of soil and environmental conditions.