the assessment of adaptability and stability of yield on cotton cultivars by using uniparametric, non-parametric methods and ammi model

uniparametric, non-parametric methods and ammi model (additive main effects and multiplicative interaction) were used to evaluate the yield stability of ten cotton cultivars at six regions of golestan and mazandaran provinces (baye kola, gharakheil, kalaleh, khan bebein, karkandeh, hashem abad) during two successive years ( 2005 & 2006). the experiment was conducted in randomized complete block design (rcbd) with 4 replications. the results of varied methods were different. the main effects of genotype, environment and genotype x environment interaction effect were statistically significant, and 81.75% of variation was explained by the first two interaction principal components (ipc1, 2). biplot of ipc1 and the mean of traits for cultivars and locations had good efficiency for detecting of genotype x environment interaction effect patterns. based on biplot diagram of genotypic and environmental components, ipc1 and ipc2 interaction with mean yield of the genotypes and environments, computation of stability criterions of ammi model (sipc1), genotypic reaction pattern analysis, and also cluster analysis results, the gukorova, sepid and tabladila cultivars had the most yield stability over environments. gukorova had the lowest ipc1. khordad, 43200 and sahel showed the most interaction effects. 43200 and khordad cultivars were identified with specific adaptation for karkandeh and similar regions. varamin, nazily, tabladila and sahel cultivars had specific adaptation for east of golestan (kalaleh, khan bebein) and mazandaran province (baye kola, gharakheil). sepid and 43200 were identified as high yielding cultivars with general and specific adaptation, respectively. inverse, sahel cultivar with lowest yield had broad stability with non-fertile regions. gukorova was the most stable cultivar with moderate yield all over golestan and mazandaran.