Yield stability is the main character of crops. Based on the knowledge about the interactions of "variety-environments"
as the behavior of
yield stability, the contents of yieId
Stability was made clear as the following after the time and space of different environment quality being analyzed: 1) yield stability is determined by the soil enviaret factors that we can predict and control more such as "soil-fertilizer-water",which is agronomy stability. 2) yield stability is determined by the universe environment factors that we can predict and control less such as "light-temperature-air", which is the adoption stability. The first one stresses on agronomywhile the second stresses on biology. During the statistic analysis of crop data, the coefficient variations of interactions between varieties and location, year iCVvu, iCVvw are the main statistic paramters of agronomy stability and adoption sability, respectively. The ideal yield stability vareties should have higher iCVvu and lower iCVvw under the precondition of high yield. This paper shows the analysis procedure of yield stability with the data from normal cotton test area of 1988 ~ 1989 in Hebei.