Who developed the theory of systematic colonization used in founding South Australia?

The theory of "systematic colonization" used in the founding of South Australia was developed by Edward Gibbon Wakefield in 1829.12

Wakefield’s theory proposed a careful synchronization between the sale of land at a fixed, "sufficient price" and the introduction of capital and labor to the colony. This approach was intended to make emigration a more respectable enterprise for ordinary British citizens and to ensure the new colony remained free from the "stain of convictism" associated with other Australian settlements. His ideas, further elaborated in his 1833 work England and America, directly influenced the South Australian Act of 1834, which established the colony as a province of the mother country rather than a penal settlement.123