A note on the variance of the stability parameter `environmental variance

The predictability of yields from one set of environments to another set of environments is usually very poor. In this paper, a simple theoretical result on the variance of phenotypic stability is proposed. The variance of the stability parameter `environmental varianceʹ (measured by the coefficient of variation) depends on the number of included environments and on the kurtosis of the underlying data set. The variance is very large even for a larger number of environments. The variance is somewhat reduced by a negative kurtosis. The theoretical results and conclusions are demonstrated for a data set of grain yields of winter wheat [one cultivar (`Diplomatʹ), one location, 24 years]. Theoretically expected and experimentally obtained values are in moderate agreement.