Agriculturae Conspectus Scientificus, Vol 67, No 3 (2002)

Nonparametric Analysis of Yield Stability of some Winter Wheat Varieties


Pages: 143-148


The important role in the creation of the new varieties has their stability in different environments. Due to genotype x environment interaction, their performance could be altered so much that their ranking order in different environments would be different, which makes the selection of the best varieties difficult. Therefore, it is important to identify the stable genotypes. Nonparametric measures of stability are used less often then parametric measures. However, they have certain advantages. Their use does not depend on any assumption, because they are based on ranks. In this case study, the use of nonparametric methods in analysis of genotype x environment interaction and stability estimation is investigated in winter wheat variety trials yield data set. The presence of interaction is tested using four nonparametric methods, and interaction is detected in each and every year of investigation. Thereafter, the stability of genotypes is estimated using three nonparametric measures, and their values are compared with values of parametric measures estimated in an earlier study on the same data set. Comparison showed satisfactory resemblance between nonparametric and parametric measures of stability.


nonparametric measures; yield; stability; wheat

Full Text: PDF