Genetic Parameters and Breeding Value Predictions for Eucalyptus Nitens Wood Fiber Production Traits
A base breeding population of 13,000 trees from about 300 Eucalyptus nitens families of open-pollinated origin in 6 provenances of native forest stands, was established in 8 tests, analyzed for genetic parameters and used for breeding value and gain prediction. Traits considered were basal area (BA), basic density (BD), and kraft pulp yield (PY) in 4- to 8-yr-old trees. Measurement of PY, whether taken as individual trees (PYI) or composites (PYC), were considered as the same trait, since the average Type B genetic correlation (rBg) between PYI and PYC was 0.94. Trees with the "early-adult form" typically from the Errinundra provenance appeared to have the poorest PY, averaging 1 to 3% points lower than all the other provenances. This provenance was excluded from detailed genetic analyses. Significant differences among the other five provenances were found for all traits. Four provenances were reasonably similar, but northern New South Wales was estimated to be lowest for BA and PY, and highest for BD. Single-site biased heritabilities (h²b) varied substantially from site to site, and averaged 0.32 ± 0.05 for BA, 0.43 ± 0.09 for BD, 0.37 ± 0.08 for PY. Heritability estimates from combined-site analyses were 0.19 for BA, 0.42 for BD, and 0.37 for PY. Genotype x environment (g x e) interaction was estimated using rBg. For BD and PY, rBg was 0.94, indicating no major g x e. Moderate g x e interactions were detected for SA, with rBg at 0.60. Genetic correlation between BA and PY, and between BD and PY were favorable, but between BA and BD was unfavorable (genetic correlation = 0.24, 0.41 and -0.24 respectively). For. Sci. 44(4):587-598.
Document Type: Journal Article
Quantitative Geneticist, CAMCORE, North Carolina State University, Box 8002, Raleigh, NC 27695--(919) 515-6429;, Fax: (919) 515-6430
Publication date: November 1, 1998
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