Genetic diversity in early maturity Chinese and European elite soybeans: A comparative analysis

Soybean (Glycine max [L.] Merr.) is a legume crop important for global food security due to supplying high-quality vegetable protein and oil. China is the origin and rich center of soybean genetic diversity represented by numerous landraces and other genetic resources. During the nineteenth and twentieth centuries, world-wide dissemination of plant introductions laid the foundation of modern soybean production. Due to selection for regional adaptation, present-day elite soybean cultivars do have a comparatively narrow genetic base. However, as genetic variation is the major component of future breeding progress, diversity of early maturity Chinese and European elite soybeans was comparatively analyzed using a high-throughput functional SNP array and an SSR marker set. Results revealed a clear differentiation between Chinese and European elite cultivars, and the level of genetic diversity was similar between the two populations. Both in Chinese and European cultivars, unique SSR alleles were found which indicates that selection for specific adaptation can preserve genetic variation. The European population was markedly structured by maturity groups which was less clear in the Chinese population. Structure analysis indicated that European cultivars are based on two major ancestral lines, whereas Chinese elite soybean cultivars trace back to more ancestral lines pointing to the rich natural soybean diversity of China. The results confirm that long-term selection under divergent environmental and agronomic conditions can produce specific diversity which could potentially be utilized for future enhancing both Chinese and European soybean breeding.