Univariate and multivariate combined selection applied to Hevea breeding

The objective of this paper was to estimate the heritability coefficients b y the univariate method and genetic prediction by the multivariate method, as well as to compare the genetic gain obtained by individual and combined selection between and within progenies, in rubber tree (Hevea brasiliensis Willd. ex Adr. de Juss.) Muell. Arg.). Twenty two half-sib progenies were e stablished at the Experimental Station, in Votuporanga, Sao Paulo State, Br azil, following the randomized block design, with five replications and ten plants per plot. Three years after planting, number of latex vessel rings (NR), yield of dry rubber (YB), bark thickness (BT) and stalk circumference (SC) were evaluated. The results showed significant variability among prog enies for YB, BT and SC characters. The heritability coefficients and genet ic prediction to progenies level were high, with expressive values for the genetic prediction coefficients. Additional genetic gains were obtained by combined selection. Although the genetic gains had been small, this method is recommended, because it gives a better improvement and genetic gain. The most expressive values of improvement and genetic gain were estimated by m ultivariate method.