Isoenzyme Genetic Markers Useful for Studies of the Pinus Rigida x P. Taeda Hybrid

Genetically determined isozyme markers useful for studies of the Pinus rigida x P. taeda (pitch x loblolly pine) hybrid are described. Seedling progeny from seven two-parent pitch x loblolly pine hybrid crosses, as well as seedling progeny from single species crosses involving each of the seven parents of these hybrids (parental families) , were subjected to starch gel electrophoresis and stained for six different enzymes. Female gametophyte (1N) segregation patterns of isozymes in heterozygous parental families were used to determine the Mendelian genetics of the band patterns. Band patterns of embryos in the parental families were used to determine the expression of isozymes in diploid tissue of each species. Band patterns were strikingly similar in the two species and in hybrids were exactly those predicted from the genotypes and phenotypes expressed in the parental families. Thus, for the six enzymes studied, hybrids cannot be distinguished from individuals of nonhybrid origin on the basis of uniquely "hybrid" band types. However, individuals of hybrid origin are distinguishable when the parents of one species carry alleles leading to bands of different migration rate from those carried in the parents of the other species. Under these conditions, hybrid individuals express heterozygous phenotypes which are not possible among crosses within the species. Examples of how these markers may be used in genetic studies of this hybrid are given.

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Author(s): W. Thomas Adams, S. Coutinho

Publication: Tree Improvement and Genetics - Northeastern Forest Tree Improvement Conference - 1976