Yield stability analysis for superior alfalfa ecotypes from cold regions in Iran- using univariate methods

In order to determine the yield stability and to study genotype  environment interaction, 17 alfalfa ecotypes from cold reions in Iran were studied using a randomized complete block design with three replications in 10 agricultural field research stations in 2005 and 2006 growing seasons. Simple and combined analyses of variances were performed. It was revealed that the year  location and ecotype  location  year interactions were significant at the 1% probability level, for both fresh forage and dry fodder yield. For determination of yield stability, different stability parameters were used. Considering dry fodder yield, Shoorkat and Ordoubad ecotypes had the minimum environmental variance and environmental coefficient of variation while ecotypes No. 8 and No. 12 had the minimum of Plaisted, Wrikes ecovalance and stability variance. Considering fresh forage yield ecotypes No. 6 and No. 9 were of higher stability-using environmental variance and environmental coefficient of variation. However, Plaisted, Wricke's ecovalance and stability variance procedures identified ecotypes No. 10 and No. 13 as the most stable ecotypes. In conclusion, ecotype No. 8 for dry fodder yield and ecotype No. 10 for fresh forage yield were identified as the most stable genotypes-using all of the stability parameters.