Comparison between different selection methods of rubber trees

Abstract

The purpose of this study was to compare estimates of genetic gain using three different selection methods (between and within, combined selection and Multi-Effect Index) for the cultivation of rubber trees (Hevea brasiliensis), analyzing the variables rubber yield and the annual girth growth, evaluated at three locations. The population and consisted of 22 open pollinate progenies from different regions of rubber cultivation in the State of São Paulo (Jaú, Pindorama and Votuporanga). The experiment was arranged in a randomized block design with 6 replications, 10 plants per plot and spacing of 2m×2m. The individual narrow-sense heritability (hˆr2) and heritability of progeny means (hˆmp2) were mean and high, respectively, for all variables at the three sites, indicating little environmental influence on the variables. The within and between selection method proved more promising in Jaú, while at the other locations, gains were higher by the Multi-Effect Index, with genetic gain of over 100%. The combined selection obtained medium gains, in some cases very close to those of the Multi-Effect Index. The multi-effect selection index can increase the genetic gains, maximizing selection and enabling a reduction in the breeding cycle of the species.