Interação genótipos por ambientes em clones de Eucalyptus spp. na transição entre os biomas Cerrado e Amazônia

Abstract

Eucalypts (Eucalyptus spp.) is currently the most planted forest genus in Brazil. The increase in Eucalyptus productivity is mainly due to the selection of superior genotypes through genetic improvement and silviculture. The genotype x environment (GxE) interaction is a significant challenge for tree improvement programs, as it makes the growth of genotypes in different environments unpredictable and the selection and deployment of superior genetic materials difficult. The objective of this work was to estimate the effects of GxE interaction, stability, adaptability, and genetic parameters of 50 clones evaluated in a network consisting of eight clonal trials established in Maranhão, Pará and Tocantins states in Brazil. The trials were planted in 2016 and 2017 in a randomized complete block design with six replicates, 80 treatments (clones) and linear plots of five plants. The analyzed variable was three years-old mean annual increment (MAI, m³.ha-1.year-1). Using mixed model methodology via REML/BLUP procedure, individual (per experiment) and joint analysis (of all experiments) were performed to estimate genotypic, environmental and GxE interaction effects. From these estimates, adaptability, stability and environmental stratification analysis were performed using the GGE biplot method. The genotypic effect contributed with 37.5% of the observed variance and the effect of the GxE interaction with 33.0%, in the joint analysis. Decomposing the interaction, it was possible to observe a predominance of complex interaction (61.4%), indicating the selection of superior genetic materials specific for each environment as a better strategy to capitalize gains with selection. Trials planted in the Amazon biome presented higher productivity. It was observed great potential for gain with selection in all environments, with genotypes G34 and G05 being superior. However, it was also possible to identify specific clones.