What staple crop developed by genetic engineering helped the mound builders to prosper?

The staple crop that developed through genetic engineering and significantly benefited the mound builders is a variety of maize (corn). Genetic modifications improved its yield, resilience, and nutritional value, allowing for more efficient cultivation. This enhancement enabled the mound builders to support larger populations and establish complex societies, as surplus food facilitated trade and social stratification. The prosperity derived from this crop played a crucial role in their cultural and architectural achievements.