DETECÇÃO DE ENDOGAMIA EM SEMENTES DE Eucalyptus grandis Hill ex Maiden

Abstract

A commcrcial seed orchard of Eucalyptus grandis Hill cx Maiden, with 14 clones, selected for lhe highest basic density of wood in a base population from Coffs Harbour-Australia, was planted in Botucatu county, São Paulo State, in 1982. Sevral elements can cad to an endogamic depression, affecting the quality of seeds produced in the orchard. The electrophoresis of isozymes was applied to determine the level of in breeding and the quality of a commercial seed lot. The technique was developed in corn starch gel using cotyledons approxirnately 15-20 days of germination and seedlings approxirnately one month old. Fourteen progenies were analysed using 8 isozyme loci: MDH-I (I alicies); MDH-2 (2 alicies); ACP-I (4 alicies); ACP-3 (3 alocies); a-EST-I (4 alicies); a EST-2 (2 alicies); LAP-2 (5 alicies): GOT-2 (3 alicies). Biometric parameters related the mating system (coefficient of inbreeding - f; outcrossing rato - t) were estimated. based on the interpretation of the isozymes loci. The conclutions were: I) the inbreeding in the lot seeds was f = 0.071 and the avarage outcrossing rate ('t') in the studied population was 87.2%, demonstrating that Eucalyptus grandis is an intermediare plant, preferentially allogmous, 2) the lot of seeds have good qualitics for commercial utilizarion.