Abstract
Loblolly pine and shortleaf pine are known to naturally hybridize. In this study, we used 42 microsatellite markers and isocitrate dehydrogenase isozyme to create genetic profiles of 202 loblolly and shortleaf pine trees grown from seed collected in the 1950s for the Southwide Southern Pine Seed Source Study. Estimated ΦPT was low in both loblolly (0.061) and shortleaf (0.080) pines, indicating that most of the diversity is accounted for within seed sources. However, both loblolly and shortleaf pines showed significant correlations between seed sources’ genetic and geographic distances, with R 2 of 0.43 and 0.17, respectively. The hybridization rate was 4.0%, with more hybrids west of the Mississippi River (8.1%) than east of the river (2.1%). Additionally, about the same proportion of both species (4.5% of loblolly and 3.3% of shortleaf pine) were identified as hybrids. These results are consistent with prior studies on these two species but do contrast with the results from an amplified fragment length polymorphism (AFLP) analysis of the same samples. For example, the AFLP study concluded that 6.3% of the trees were hybrids, or 1.4 times higher than determined by this study. Of the 12 hybrids identified in the AFLP study, six were not identified as hybrids here, and of the eight hybrids identified here, only four were identified in the AFLP study. Although similar in overall results, we suggest that the microsatellite analysis is more convincing than the AFLP analysis because microsatellites provide more information per genetic locus than do AFLPs.
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Abbot JE (1974) Introgressive hybridization between shortleaf and loblolly pine in southeast Oklahoma. Oklahoma State University master’s thesis, 31pp
Al-Rahab’ah MA, Williams CG (2002) Population dynamics of Pinus taeda L. based on nuclear microsatellites. Forest Ecol Manag 163:263–271
Bohrerova Z, Bohrer G, Cho KD, Bolch MA, Linden KG (2009) Determining the viability response of pine pollen to atmospheric conditions during long-distance dispersal. Ecol Appl 19:656–667
Chagne D, Chaumeil P, Ramboer A, Collada C, Guevara A, Cervera MT, Vendramin GG, Garcia V, Frigerio JM, Echt C, Richardson T, Plomion C (2004) Cross-species transferability and mapping of genomic and cDNA SSRs in pines. Theor Appl Genet 109:1204–1214
Chen JW, Tauer CG, Bai G, Huang Y, Payton ME, Holley AG (2004) Bidirectional introgression between Pinus taeda and Pinus echinata: evidence from morphological and molecular data. Can J For Res 34:2508–2516
Cotton MH, Hicks RR Jr, Flake RH (1975) Morphological variability among loblolly and shortleaf pines of east Texas with reference to natural hybridization. Castanea 40:309–319
Dorman KW, Barber JC (1956) Time of flowering and seed ripening in southern pines. USDA Forest Service, Southeastern Forest Experiment Station, Station Paper 72
Doyle JJ, Doyle J (1988) Isolation of plant DNA from fresh tissue. Focus 12:13–15
Edwards MA, Hamrick JL (1995) Genetic variation in shortleaf pine, Pinus echinata Mill. (Pinaceae). Forest Gen 2:21–28
Edwards-Burke MA, Hamrick JL, Price RA (1997) Frequency and direction of hybridization in sympatric populations of Pinus taeda (Mill) and P. echinata (Pinaceae). Am J Bot 84:879–886
Falush D, Stephens M, Pritchard JK (2003) Inference of population structure: extensions to linked loci and correlated allele frequencies. Genetics 164:1567–1587
Hare RC, Switzer GL (1969) Introgression with shortleaf pine may explain rust resistance in western loblolly pine. USDA Forest Service, Research Note SO-88. Southern Forest Experiment Station, New Orleans, p 2
Hedrick PW (1999) Perspective: highly variable loci and their interpretation in evolution and conservation. Evolution 53:313–318
Hicks RR Jr (1973) Evaluation of morphological characters for use in identifying loblolly pine, shortleaf pine, and loblolly x shortleaf hybrids. Castanea 38:182–189
Huneycutt M, Askew G (1989) Electrophoretic identification of loblolly pine-shortleaf pine hybrids. Silvae Genet 38:3–4
Little EL (1971) Atlas of United States trees, volume 1. Conifers and important hardwoods. USDA Forest Service Miscellaneous publication no. 1146. Washington, D.C. 200 Maps
Mergen F, Stairs GR, Snyder EB (1965) Natural and controlled loblolly x shortleaf pine hybrids in Mississippi. Forest Sci 11:306–314
Nelson CD, Josserand S, Echt CS, Koppelman J (2007) Loblolly pine SSR markers for shortleaf pine genetics. In: Kabrick JM, Dey DC, Gwaze D (eds) Shortleaf pine restoration and ecology in the Ozarks: proceedings of a symposium; November 7–9, 2006; Springfield, MO. Gen. Tech. Rep. NRS-P-15. U.S. Department of Agriculture, Forest Service, Northern Research Station, Newtown Square, pp 95–98
Peakall R, Smouse PE (2006) GENALEX 6: genetic analysis in Excel. Population genetic software for teaching and research. Mol Ecol Notes 6:288–295
Pritchard JK, Stephens M, Donnelly P (2000) Inference of population structure using multilocus genotype data. Genetics 155:945–959
Raja RG, Tauer CG, Wittwer RF, Huang YH (1997) Isoenzyme variation and genetic structure in natural populations of shortleaf pine (Pinus echinata). Can J For Res 27:740–749
Schmidtling RC (2007) Genetic variation in the southern pines: evolution, migration, and adaptation following the Pleistocene. In: Kabrick JM, Dey DC, Gwaze D (eds) Shortleaf pine restoration and ecology in the Ozarks: proceedings of a symposium; 2006 November 7–9; Springfield, MO. Gen. Tech. Rep. NRS-P-15. U.S. Department of Agriculture, Forest Service, Northern Research Station, Newtown Square, pp 28–32
Schmidtling RC, Carroll E, LaFarge T (1999) Allozyme diversity of selected and natural loblolly pine populations. Silvae Genet 48:35–45
Schreiner EJ (1937) Improvement of forest trees. 1937 Yearbook of Agriculture. USDA, Washington, pp 1242–1279
Williams CG, LaDeau SL, Oren R, Katal GG (2006) Modeling dispersal distances: implications for transgenic Pinus taeda. Ecol Appl 16:117–124
Xu S, Tauer CG, Nelson CD (2008a) Natural hybridization within seed sources of shortleaf pine (Pinus echinata Mill.) and loblolly pine (Pinus taeda L.). Tree Genet Genomes 4:849–858
Xu S, Tauer CG, Nelson CD (2008b) Genetic diversity within and among populations of shortleaf pine (Pinus echinata Mill.) and loblolly pine (Pinus taeda L.). Tree Genetics and Genomes 4:859–868
Zobel BJ (1953) Are there natural loblolly-shortleaf pine hybrids? J Forest 51:494–495
Acknowledgments
We thank Mr. Robert Heineman and the crew of the Kiamichi Forestry Field Research Unit of Oklahoma State University for their assistance in acquiring the samples for this study. We also thank John Stewart’s wife Mary Tsien for her effort to make Fig. 1. Finally, we thank Dr. Shiqin Xu whose AFLP work laid the foundation for this study.
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Stewart, J.F., Liu, Y., Tauer, C.G. et al. Microsatellite versus AFLP analyses of pre-management introgression levels in loblolly pine (Pinus taeda L.) and shortleaf pine (P. echinata Mill.). Tree Genetics & Genomes 6, 853–862 (2010). https://doi.org/10.1007/s11295-010-0296-8
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DOI: https://doi.org/10.1007/s11295-010-0296-8