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Effect of a Clonal Row Orchard Design on the Seed Yields of Loblolly Pine

When ramets of the same clone are planted in a clonal row, the frequency of self-pollination is expected to increase. With an increase in self-pollination, the filled seed yield would be expected to decrease as a result of increasing the frequency of homozygous embryonic lethal alleles. Pine species are buffered against the deleterious effects of self-fertilization by the large number of embryonic alleles in the population with each individual tree having a different set of alleles. When an individual ovule contains both self and outcross pollen, a viable seed can be produced if the self-fertilized embryo aborts but the outcross-fertilized embryo survives. Thus, in a clonal row orchard, self-pollination increases but the impact on seed yields is expected to be relatively low. Experimental data indicated no significant reduction in the percentage of filled seeds from clonal rows when compared to a random design.


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Author(s): David L. Bramlett, Floyd E. Bridgwater

Publication: Tree Improvement and Genetics - Southern Forest Tree Improvement Conference - 1987