Estimating Elephant-Grass Adaptability and Stability for Energy-Biomass Production by Regression Models

In Brazil, elephant grass has been researched for energy generation, as it represents an alternative energy source by virtue of its biomass production. The present study was developed to examine the adaptability and energy-biomass production stability of 73 elephant-grass genotypes under a biannual-harvest regime, using the methodologies proposed by Eberhart and Russell and Cruz. The experiment was carried out at the northern region of Rio de Janeiro State, Brazil. Nine harvests and subsequent evaluations were performed at six-month intervals. Each harvest was considered an environment of genotype evaluation. After the plants were harvested, their dry matter yield (DMY) was estimated in t ha-1 harvest. Combined analysis of variance revealed highly significant effects of genotypes, harvests, and genotype × harvest interaction, by the F test. In five of the nine evaluated harvests, the genotypes had an average dry matter yield greater than the overall mean. The method of Eberhart and Russel was effective in identifying highly adaptable elephant-grass genotypes with high dry matter production stability throughout the nine harvests. When the method of Cruz was used, no genotypes were found comprising high yielding ability, adaptability to unfavorable environments, responsiveness to environmental improvement, and high stability altogether.