At the end of November 2015, the following article was published in the Australian Journal of Botany. A worthwhile read, the article discusses some problems with using mean time to germination (MGT) for comparing pairs or groups of means to evaluate seed vigour since MGT is an ‘index of germination speed’. Rather, the authors suggest using t50 (time to 50% germination). For more detailed information, get your own copy by clicking on the title link below! This is definitely a useful article for seed scientists, and also contains several references to other papers discussing germination measurements.
Problems with using mean germination time to calculate rate of seed germination
Elias Soltani, Farshid Ghaderi-Far, Carol C. Baskin, Jerry M. Baskin
Australian Journal of Botany