THE GENOTYPE-ENVIRONMENT INTERACTION IN EXPERI- MENTS OF SUGARCANE VARIETY TRIALS (SACCHARUM SPP.): COMPARISON OF THREE STABILITY METHODS *

ABSTRACT The genotype-environment interaction (g x e) for yield and brix' in eight sugarcane variety trials with 20 genotypes was calculated. The trials were carried out in two localities during three harvest periods. A statistically significant interaction, g x e, in both localities was observed. All data were analyzed by 3 methods in order to determine stability and/or adaptability. The methods were: linear regression, ecovalence method and the coefficient of determination. All the methods used verified in itis' own way the discrimination of genotypes by their stability in relation to environment changes. Finally, the Kendall Coefficient of Correlation was calculated among all stability parameters used verifying positive and significant I correlation between ecovalence and linearity deviation, ecovalence and coefficient of determination, and coefficient of determination and linearity deviation