1897, Hon. Stuart Brown, “Indian Corn—Its Cultivation and Uses”, read before the Sangamon County Farmers Institute, in Charles F. Mills (ed.), Annual Report, Illinois Farmer’s Institute, with Reports of County Farmers’ Institutes, for the Year 1897, Phillips Bros., page 115, Cross fertilization has generally given greater yields. It is done by planting with one variety in one planter box and another variety in the other.
Source: wiktionary