Genetic Gain for Wood Volume in Progeny Trial of Grevillea robusta Cunn (Breeding Cycle 2) in Londrina, Paraná State

Abstract

Twenty and twenty three seed provenances of Grevillea robusta Cunn were imported from Australia, in 1993 and 1994 respectively, by Embrapa Florestas. This genetic germoplasm was utilized for starting a breeding program in the State of Paraná, São Paulo and Mato Grosso do Sul. Total surface occupied by Grevillea experiments managed by Embrapa Florestas reachs 27,13 ha, being provenance tests, embracing 11,22 ha, installed in 1994, and progenies tests, comprising 15,91 ha, planted in 1994. In the Presidente Castelo Branco District it was introduced a provenance/progenie test with 104 progenies and 20 provenances. In 2001, it was selected the best genotypes and the experiment was transformed in a Seed Orchard. In 2002, 37 genotypes were selected at the same area, whose seeds were utilized for the installing second generation of progenies test in Londrina, PR. Randomized blocks was the statistical design utilized, with linear plots of five plants, adjusted in a compass 3m x 3m, with 8 replications. Total height, DAP (diameter at (the) (high) (of) breast height) were the characteristics considered in the evaluations. Height was measured with the help of a telescopic ruler and diameter with a ruler of mensuration. Volume was calculated with height and DAP measures. Estimation of variance components, genetic parameters selection and genetic gain was made by SELEGEN/REML/ BLUP - model 1. Conclusions: 1- enetic gains were superior of 55%, remaining 266 genotypes (18% from the total amount of trees) in the Seed Orchard; 2 - Selecting the best 50 genotypes, the genetic gain would be superior from 120%. The installation of clonal orchard with the selected genotipies would lead to a major production of pollen and seeds, bacause of the better spacial distribution of the clones, what would not happen in seed production areas originated of progenies installed in a randomized blocks design.