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Home → Publications → Tree Improvement and Genetics → Southern Forest Tree Improvement Conference → 24th Southern Forest Tree Improvement Conference (1997) → Genetic Gains of Second Generation Selections from the NCSU-Industry Cooperative Tree Improvement Program

Genetic Gains of Second Generation Selections from the NCSU-Industry Cooperative Tree Improvement Program

Data from 93 open-pollinated progeny tests of second-generation selections were analyzed to obtain genetic parameter estimates and breeding value predictions for height, volume and rust resistance. The 623 selections were grouped into four major geographic regions: 1) Virginia and northern North Carolina with 124 parents, 2) Atlantic Coastal Plains of North Carolina, South Carolina and Georgia with 131 parents, 3) Piedmont regions of North Carolina, South Carolina and Georgia with 285 parents, and 4) Lower Gulf region with 83 parents. The best linear unbiased prediction was used to estimate breeding values for 8-year height, volume and rust infection at a 50% infection level (R-50). The estimated gains for height from 2nd-generation seed orchards in the four regions ranged from 13% to 21% over unimproved checklots. Roguing these seed orchards intensively to the best 10-15 parents could boost the gains to as much as 20-24% in height growth and an even greater improvement in volume production at harvest. A substantial number of 2nd-generation selections have not only demonstrated outstanding growth but also had less rust infection, R-50 values of 20% to 25% below the unimproved checklots. The best family from each population was generally 10-20% above the 1 st-generation seed orchard mix in height growth, indicating additional gain above the 1st generation selections. Although genetic gain for stem straightness is difficult to quantify, most of the 2nd-generation families had a higher percentage of trees with above average straightness than the checklots. Keywords: breeding value, genetic gain, open-pollinated family, second-generation, seed orchard, rust infection.


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Author(s): Bailian Li, Steven E. McKeand, A. V. Hatcher, Robert J. Weir

Publication: Tree Improvement and Genetics - Southern Forest Tree Improvement Conference - 1997

Section: Contributed Presentations: Full Papers