The adaptation of corn to upland and bottom land soils

Tests made during a 7-year period fail to disclose a difference in seed value of open-pollinated corn native to upland and bottom land soils within the same localities in eastern Nebraska. It is considered that the two types of conditions serving as seed sources differed chiefly with respect to soil fertility. In years of favorable rainfall the bottom lands under consideration have a potential yield capacity of approximately 75 bushels per acre compared with 40 bushels for the uplands. No material heritable differences were noted with respect to vegetative characteristics, or grain yield in relation to these conditions. This result is in agreement with that of Williams and Welton (5) who found no influence of soil fertility upon the seed value of corn. In view of Hoffer's (1) determination of "heritable difference between capacities for nutrient and non-essential elements," it may be concluded that the soil differences herein considered were of sufficient magnitude to result in a differentiation of strains of corn under the conditions of mass seed selection practiced on farms. There is no extreme shortage of phosphorous in any of these Nebraska soils under consideration. Conditions of so pronounced phosphorous deficiency have been observed in some sections of the United States that an application of phosphate fertilizer very materially hastens the maturity of corn. It would seem that such striking physiological effects might readily result in the selection of plant types for seed on the phosphorous deficient soils that are inherently earlier maturing than would be the case where phosphorous is abundant. Under representative upland and bottom land farm conditions within single climatic areas in eastern Nebraska and similarly situated with respect to soil moisture supply, there has been no evidence of associated heritable differentiation or adaptation of corn, and a free interchange of seed appears to be permissible. Although comparative data are not available, farm experience suggests that rather pronounced hereditary differences may prevail in cases where the bottom lands are subject to sub-irrigation or overflow, thereby resulting in a more favorable moisture supply.