Screening Populus deltoides Marsh. Selections by Allozymes to Assure Species Identity

The allelic constitution of 169 Populus deltoides Marsh, clones, selected in North America, was studied at 8 marker allozyme loci (Aco-2, Mdh-2, Pgi-2, Pgm-1, Pgm-3, 6-Pgd-2, 6-Pgd-4 and 6-Pgd-5) coding for 5 enzyme systems in root tips. The enzymes were assayed by horizontal starch gel electrophoresis. An examination of the allozyme profiles revealed that twenty-seven of these selections (16%) were misidentified as P. deltoides. Eighteen of the misidentified selections displayed isozyme genotypes and patterns typical of P. deltoides x P. higra L. hybrids (P. x canadenis Moench) and the remaining nine selections typical of P. deltoides x P. balsamifera L. (P. x jackii Sarg.). The results indicated a need for screening North American P. deltoides selections used for plantation, breeding, and biological studies to assure their accurate species identification. Allozyme markers can be of potential importance in detecting misidentified P. deltoides specimens and in ascertaining their correct species identity.