ESTIMATES OF GENETIC-PARAMETERS AND GAINS EXPECTED FROM SELECTION OF JUVENILE CHARACTERS IN RUBBER TREE PROGENIES

The objective of this paper was to estimate quantitative genetic param eters for growth and yielding characters in juvenile half-sib progenie s of rubber trees [Hevea brasiliensis (Wild ex. Adr. de Juss.) Mull. A rg.]. Seventeen genotypes were randomly selected from a 35-years-old a siatic base population established in the Experimental Center of Campi nas, SP, Brazil. Open pollinated seeds were collected and planted at t he Experimental Station of Pindorama under randomized complete blocks design. The characters studied were: yield folowing Hamaker-Moris-Man (HMM) test (PPB), girth at 50 cm from the ground (CCC), bark thickness (ECC), total number of latex vessels rings, density of latex vessels per 5 mm per ring averaged over all rings (DEN), diameter of the latex vessel rings (DIA), average distance between consecutive latex vessel rings (DMA), crown evaluation (ACP), leaf area (AFO) and leaf petiole lenght (CPE). Results indicated significant differences for yield, ba rk thickness and girth. Also the different types of heritabilities wer e greater for yield, bark thickness and girth. The genetic gain estima tes for selection among and within the progenies showed considerable g enetic advances for the studied characters, revealing the possibility of successful selection.