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Breeding Eucalyptus globulus for lower rainfall sites in the Bío-Bío Region of Chile

Rojas, P. V., Ipinza, R. C., Gutierrez, B., Molina, M. P., Arnold, R. J.
Australian forestry 2017 v.80 no.2 pp. 105-112
Eucalyptus globulus, breeding programs, clones, crossing, drought tolerance, genetic correlation, heritability, landraces, open pollination, parents, plus trees, rain, seed orchards, tree breeding, Chile
In 2006 a research project commenced to breed drought-hardy Eucalyptus globulus for the lower rainfall Secano area (mean annual rainfall below 1000 mm y –¹) of Chile’s Bío-Bío Region. Three populations were included in this project: (a) open-pollinated families of selected clones from a seed orchard of INFOR’s tree breeding program; (b) open-pollinated families of plus-trees selected from plantations of landrace origin grown under dry conditions; and (c) control-pollinated families generated by intraspecific crosses between populations (a) and (b). This paper presents results of one control-pollinated and two open-pollinated family trials on three sites representative of drier areas of Chile’s central Bío-Bío Region in 2009–2010. Growth parameters, including heritabilities and genetic correlations, of E. globulus to ages 5 to 6 years were estimated from 24 control-pollinated families at one site, and up to 61 open-pollinated families at the other two sites. Family performance was also compared with commercial E. globulus seed sources, and with seedlots of the drought-tolerant species E. camaldulensis and E. cladocalyx . There were no significant differences between the average growth of the E. globulus seed sources at any of the three sites, but there were large, significant differences between families within seed sources for average growth. In general, the top-ranked groups of families were dominated by those having as parents plus-trees of local Secano plantation origin that had been selected for superior growth and form. Conclusions presented relate to the applicability of this strategy for improving productivity of E. globulus in drier areas of the Bío-Bío Region.