Non-Destructive Seed Protein Measurement in Common Bean (Phaseolus vulgaris L.)

Food security issues for increasing human populations and current interests in plant-based sources of protein have spurred an interest in rapid, non-destructive methods to measure and select for protein contents in beans. In this study, a near-infrared (NIR) method for measuring total protein content in whole common bean seeds was developed and used to measure total protein levels in a collection of common bean genotypes with representatives from several market classes. A subsample of the larger bean collection was analyzed by combustion and mass spectrometry elemental analysis to yield lab values for total seed protein that were correlated with NIR measurements made on intact seed samples to create a calibration curve (R2 = 0.8). A calibrated NIR spectrometer was used to measure total protein contents of seed samples obtained from the complete collection grown in replicated trials in two locations. The phenotypic information was combined with genotype-by-sequencing (GBS) single-nucleotide polymorphism (SNP) data for the bean samples in a genome-wide association study (GWAS) of protein content in bean seeds. Fourteen SNPs on chromosomes 1, 2, 3, 4, 5, 8, 10 and 11 were significantly associated with protein content. These SNPs may be useful for marker-assisted selection of beans with increased total protein seed content.