COMPARING STABILITY INDEXES FOR RIPENING DATE AND YIELD IN BLUEBERRY

To determine if any of the available techniques for estimating stabili ty in different environments are useful in blueberry (Vaccinium ashei Reade and V. corymbosum L.), 14 clones were evaluated in nine environm ents for ripening date and yield. Type 1 and 2 stability statistics, p lots for each genotype mean versus its coefficient of variation (cv) a cross environments (genotype grouping), environmental index regression , and cluster analyses were compared, The highest yielding rabbiteye a nd southern highbush clones across locations were not deemed stable by Type 1 and Type 2 stability statistics, genotype grouping, or environ mental regression technique. No evidence of curvilinear response was f ound, The nonparametric cluster analysis with known cultivars included appears to be most useful compared to other methods of estimating sta bility used in this study.