Breeding Acacia mearnsii in southern Brazil. [Workshop paper]
1994
Higa, A.R. | Resende, M.D.V. (EMBRAPA - CNP Florestas, Colombo (Brazil))
The Acacia mearnsii De Wild. breeding program, in southern Brazil, aims to increase tannin and timber yield. Volume production in commercial plantations has improved 10-15 percent using seed from a seed production area. Genetic parameters, estimated for growth and tannin content, were used to choose a selection strategy for families and trees in a progeny trial established with open-pollinated seed collected from trees selected in commercial plantations. Genetic gains of 18 percent in volume and 3.1 percent in tannin were predicted if the best 30 percent families and the best 17 percent of trees within family were to be selected. These estimates are based on selection using independent culling for diameter at breast height (dbh) and tannin. Recently introduced germplasm is being studied in a combined provenance and progeny trial planted in two sites. Batemans Bay provenance is showing best growth, followed by Bega and Bodalla. Genetic variability for dbh, height and survival in these introduced provenances was greater than that determined for existing germplasm. Genetic variation for these traits was highly significant, but the genotype x environment interaction was not. Between- and within-family selection at 25 and 20 percent respectively should increase volume by 15 percent in relation to the control (commercial seed).
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