Melhoramento genético da candeia: procedências, progênies e seleção precoce

Abstract

The although of irrefutable importance, forest genetic improvement programs demand high financial costs and require years to present the gains of each selective cycle. The scenario becomes more challenging when the object of improvement is a native tree species such as Eremanthus erythropappus, with few studies on the variations in its natural populations and incipient genetic tests. In this context, this work aims to advance the genetic program to improve the species, approaching the results of a provenances and progenies test in rotation age on two main aspects: the genetic and environmental variations referring to different populations and families, in the first article, and the feasibility and efficiency of early selection for growth traits, in the second article. Both works were carried out in a test implemented in Baependi-MG, with five provenances and 116 half-sib families, in a complete randomized block design, with linear plots of six plants and seven replications. Growth variables were measured up to 11 years old, where survival was quantified and volume estimated. The estimation of genetic parameters was carried out through the approach of mixed models REML/BLUP performed using the software Selegen RELM/BLUP, and the effects of the model were tested by the likelihood ratio (LRT) with p< 0.01. For each approach, the relevant genetic and environmental correlations were performed and the selection was indicated according to the methodology described in each article. In general, the first article concludes that there is enough genetic variability for selection at 11 years of age, highlighting some provenances and progenies in terms of growth and adaptation factors. The second article emphasizes the feasibility of early selection for growth variables, indicating the optimal age for selection between 4 and 4.5 years for the traits.