In the Kentucky Soybean Performance Test program, varieties of maturity groups (MG) 3, 4 and 5 are tested to provide information on their relative yields. The difference in maturity between the earliest and the latest maturing variety in the test in any year is approximately 30 days. In general, although some regional differences appear, the long-term state-wide and within region yield of the different maturity groups (average yield of a 11 varieties in a maturity group) is equal (Table 1). As I've inspected results from the Kentucky Soybean Performance Tests for the last decade, it appeared that some of the variation in yield among varieties at a particular location in a particular year was due solely to the maturity of the variety. Furthermore, large deviations in maturity group yield occurred during consecutive years even within the same testing region. These points are illustrated in Table 1 by specific years from the Lexington, Wickliffe, and Nebo tests. The purpose of this note is to illustrate and discuss reducing soybean yield volatility by growing varieties from different maturity groups.

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