Estimates of variation, heritabilities and gains obtained from two open-pollinated progeny test plantations of eastern white pine (Pinus strobus L.)
Date of Award
Master of Science
John C. Rennie, James B. McLaren
The objective of this study was to evaluate genetic and environmental sources of variation in height, diameter, volume, crown width, length of flush (terminal leaders), needle length, number of branches, and current and previous year needle colors in eastern white pine (Pinus strobus L.). Data from 2 8-year old plantations in Tennessee containing approximately 20,000 open-pollinated progenies from 128 half-sib families originating in 13 stands from Tennessee, North Carolina and Georgia were analyzed.
Progenies of A stands from Tennessee and Georgia grew fastest in both locations. These progenies had darker green and longer needles than progenies from other stands, indicating resistance to air pollution damage.
Variance components of the 2 locations revealed that the sources of variations were very similar. Variance components also indicate that height, diameter, volume, needle color and needle length were strongly inherited traits.
In addition to the individual location analyses, a combined location analysis was completed to obtain the interaction of location with stand and interaction of location and family within-stand. Variance components in the combined location analysis were very similar in magnitude to those of the individual location analyses. The genotype and environmental interaction variance component evaluated (interaction of location with stand and interaction of location with family withinstand) for all variables were small and did not exceed 2% of the total variation.
Narrow-sense heritability estimates based on variance components for the individual locations and the combined locations for all variables measured were very similar.
Expected gains using the 2-stage selection scheme were computed for height, diameter and volume at the 2 locations. Selection of the best 40 families regardless of stands will result in average gains of 13, 17 and 29% for height, diameter and volume, respectively. Selection of the best tree within each family row-plot increased the total average genetic gain to 22% for height, 28% for diameter and 45% for stem volume.
DesBordes, William K., "Estimates of variation, heritabilities and gains obtained from two open-pollinated progeny test plantations of eastern white pine (Pinus strobus L.). " Master's Thesis, University of Tennessee, 1979.