In 1993, an on-farm study funded. by the Kentucky Soybean Promotion Board showed that the best Maturity Group (MG) II variety tested was quite competitive with the best available MG IV variety. However, other MG II varieties did not fare as well, indicating that careful variety selection will be essential for on-farm success with this MG II cropping system. MG II varieties used in past University of Kentucky tests have been chosen based on their performance in university variety trials where they are normally grown, for example, in Iowa, Illinois, Indiana, and Ohio. Such tests include relatively large numbers of MG II varieties. For example, Iowa routinely tests up to 200 such varieties at multiple locations. Thus, it would seem that Kentucky growers ought to be able to simply use the Iowa results to choose MG II varieties to plant in Kentucky. However, some growers have expressed interest in obtaining yield performance data for MG II varieties grown under Kentucky conditions. Some suspect that our warmer temperatures, heavier insect and disease pressures, and more prevalent soybean cyst nematodes might alter the relative yield ranking of varieties moved well south of their intended growing area. However, recent cooperative work between the University of Kentucky and the University of Minnesota showed no evidence that some early maturing varieties are better suited to "move south" than other varieties. Thus, northern data ought to be suitable for use in MG II variety selection in Kentucky.
Grabau, Larry J. and Steele, Colleen C., "An Evaluation of Twelve Maturity Group II Soybean Varieties at Lexington, Kentucky" (1994). Agronomy Notes. 40.