Natural Variations and Geographical Distributions of Seed Carotenoids and Chlorophylls in 1 167 Chinese Soybean Accessions

Understanding the composition and contents of carotenoids in various soybean seed accessions is important for their nutritional assessment. This study investigated the variability in the concentrations of carotenoids and chlorophylls and revealed their associations with other nutritional quality traits in a genetically diverse set of Chinese soybean accessions comprised of cultivars and landraces. Genotype, planting year, accession type, seed cotyledon color, and ecoregion of origin significantly influenced the accumulation of carotenoids and chlorophylls. The mean total carotenoid content was in the range of 8.15–14.72 µg g–1 across the ecoregions. The total carotenoid content was 1.2-fold higher in the landraces than in the cultivars. Soybeans with green cotyledons had higher contents of carotenoids and chlorophylls than those with yellow cotyledons. Remarkably, lutein was the most abundant carotenoid in all the germplasms, ranging from 1.35–37.44 µg g–1. Carotenoids and chlorophylls showed significant correlations with other quality traits, which will help to set breeding strategies for enhancing soybean carotenoids without affecting the other components. Collectively, our results demonstrate that carotenoids are adequately accumulated in soybean seeds, however, they are strongly influenced by genetic factors, accession type, and germplasm origin. We identified novel germplasms with the highest total carotenoid contents across the various ecoregions of China that could serve as the genetic materials for soybean carotenoid breeding programs, and thereby as the raw materials for food sectors, pharmaceuticals, and the cosmetic industry.