Relationships between Laboratory Germination Tests and Field Emergence of Maize Inbreds

In the USA and Europe, maize (Zea mays L.) is often planted into soils that are or become cold and wet resulting in reduced field emergence, poor stands, and lower economic yields. This study was conducted to determine the relative merits of two germination tests, the cold and soak tests, for prediction of field emergence when soil temperatures are suboptimal for germination. The effects of initial seed moisture on field emergence were also investigated. Field emergence of 48 maize inbred lines was measured in eight locations in 1986 and 1987. The seeds of each inbred were also cold and soak tested. Seeds taken directly from conditioned storage and seeds dried to 80 g kg⁻¹ moisture were used in these studies. In 1986, the cold and soak test were equally correlated with field emergence r = 0.43** (significant at the 0.01 level of probability) and 0.40** respectively. In 1987, the cold test was more highly correlated with field emergence (r = 0.74**) than the soak test (r = 0.43**). These correlations between laboratory germination tests and field emergence were affected by both location and year. Drying seeds to 80 g kg⁻¹ moisture resulted in an overall 5% decrease in field emergence in both years. There was a significant inbred line-by-year interaction, but only one inbred was significantly affected in both years. The value of these germination tests as a tool to aid selection was also investigated and both tests were equally accurate (60% agreement) at predicting those inbreds with field emergence in the lower 30% in both years. The soak test may be considered a rapid, inexpensive, and effective selection tool for elimination of those inbreds with poor field emergence, however, the cold test was superior for prediction of the field emergence of a wide range of inbred lines in a number of environments.