Genetic test results from a tree improvement program to develop clones of loblolly pine for reforestation

Eleven years ago, International Forest Seed Company began a tree improvement program to develop a population of loblolly pine (Pinus taeda L.) to resist infection by fusiform rust [Cronartium quercum (Berk.) Miyabe ex Shirai F. sp. fusiformel and to improve volume production as well. One hundred and twenty-seven parent trees were selected from a pool of tested first-generation selections, then mated at random using small disconnected factorials. Seedlings emerging from rust screening with no rust galls were planted into cutting orchards, from which cuttings were taken, rooted, and planted into clonal field trials. Analysis of fifthyear data between seedlings and rooted cuttings of the same checklots reveals that there are no propagation effects. Further, rooted cuttings of the select clones performed significantly better than the commercial checks in terms of morphological traits and improved resistance to fusiform rust. Genetic analysis reveals a strong clonal effect and a possible G x E interaction for the morphological traits evaluated. Sensitivity analysis on the error variance of the clone mean suggests a reallocation of resources in designing future clonal studies. Keywords: Pinus taeda L., fusiform rust, rooted cuttings, clonal propagation

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Author(s): J. B. McRae, Henry E. Stelzer, G. Sam Foster, T. Caldwell

Publication: Tree Improvement and Genetics - Southern Forest Tree Improvement Conference - 1993

Section: Closing Session