Abstract We evaluated the genetic diversity, coancestry and heritability of an E. benthamii trial. The 115 individuals were genotyped (13 SSR) and had their height and diameter at breast height (dbh) measured. Heritability was estimated using the RR-BLUP and the pairwise kinship coefficient method. An average of nine alleles per locus was observed. The expected heterozygosity (0.655) was similar to the observed heterozygosity, with the estimated inbreeding (0.02) being low. The group coancestry (0.051) demonstrates that the trees are related to some degree. The trees were clustered in five groups using the Evanno’s method. The average kinship within each group ranges from 0.042 to 0.082. The heritability estimated by RR-BLUP was low. The heritability estimated using the kinship coefficients is moderate, reaching estimated genetic gains of 14% for dbh. After knowing how genetic groups are distributed within the population, strategies for collecting, conserving, and using these germplasm resources can be performed.

Abstract The aim of this study was to evaluate Eucalyptus badjensis concerning the genetic variation for growth traits and the potential of the species in supporting a breeding programme. The field trial was a provenance/progeny test established in Campina da Alegria, Santa Catarina, Brazil (latitude 26°52′05.1″ S, longitude 51°48′47.5″ W, altitude 1,015 m) in a soil classified as Latossolic Alumino-Ferric Brown Nitosol. The experiment comprised 60 open-pollinated progenies from the provenances Glenbog and Badja State Forest, New South Wales, Australia. Ten replicates and plots with six plants in row were used. At the age of 17 years, 279 trees were assessed for diameter of the bole at breast height (DBH), total tree height (H) and volume of wood with bark (Vol). After submitting the data to statistical genetic analysis, the overall means for DBH, H and Vol were 45.17 cm, 33.30 m and 2.84 m3, and the estimates of additive coefficient of variation [ C V a(%)] were 12.59%, 5.91% and 26.51%, respectively. Heritability coefficients of additive effects ( h a 2) were also estimated and the following values were found: 0.443, 0.312 and 0.358. Thirty-nine trees from 25 different progenies were selected. The expected means of the provenances after improvement were 50.02 cm, 34.35 m and 3.47 m3 for DBH, H and Vol, respectively.

In this study, the breeding perspectives of 41 open-pollinated progenies of Eucalyptus grandis were evaluated based on their wood traits. The progenies were distributed in two experiments in a randomized complete block design, with three replicates and linear plots containing six plants each. The traits were assessed at eight years of age. Two trees from each plot were selected for this assessment based on better growth, stem form and phytosanity. Significant differences in basic density, sapwood/heartwood ratio, bowing, specific gravity, parallel compression and static bending were detected among the progenies. These traits were potentially promising for breeding programs, with heritability coefficients that varied from 0.34 to 0.61 on a progeny mean basis. There was no genetic variation in the moisture content, board end-splitting, log volume under bark, log eccentricity, bark content, crooking, and shear strength of the progenies. Intermediate to highly significant genetic correlations were detected among the physical and mechanical properties, as well as between pairs of traits such as basic density and log end-splitting, basic density and bowing, specific gravity and bowing, sapwood/heartwood ratio and bowing, log volume and bowing, and log volume and log end-splitting. These results show that the levels of growth stress in trees can be reduced by selection using indirect traits such as the sapwood/heartwood ratio and bowing.