Biosystematics of the genus Populus. III. Naturally occurring Manitoba hybrids of introduced P. × petrowskyana with native P. deltoides var. occidentalis and P. balsamifera

Abstract

Collections of hybrid poplars made in the Roseisle area of Manitoba appear to have resulted from hybridization of introduced P. × petrowskyana Schneid. with native P. deltoides Marsh. var. occidentalis Rydb. and P. balsamifera L. This interpretation was supported by morphology of an open-pollinated seedling population of P. × petrowskyana and by chromatographic analyses. Gas chromatographic results were effective in distinguishing the three parent species; however, the hybrid nature of P. × petrowskyana made chromatographic documentation of hybridization very difficult. High fertility, indicated by abundant production of sound seed, was noted for several mature P. × petrowskyana × P. deltoides var. occidentalis female trees. No barriers were found that would prevent a three species complex of all three hybridizing species.

Marker allozyme genes and alleles for differentiation of Populus deltoides, P. nigra, P. maximowiczii, and their interspecific hybrids

“…between several species has given rise to a number of interTraditionally, identification of poplars has been primarily specific hybrids (Ronald et al 19730, 19736;Zsuffa 1975; based on morphological and phenological keys (Brayshaw Eckenwalder 1977a, 19776, 1984a, 19846). 1965Eckenwalder 1977a, 19776, 19846;Ronald et al 1973a, Identification of Populus species and hybrids is imperative, 19736; Ronald and Steele 1974) and recently, on chromatoin genetics and breeding studies. P o~u l u s "The buffer systems used are described in Rajora (1989a) and Rajora duction of secondary metabolites are apparently controlled by multiple genes, have complex inheritance patterns, and are mediated by the environment.…”

Natural hybridization between cultivated poplars and their wild relatives: evidence and consequences for native poplar populations

“…This is probably the case with P. balsamifera L., P. deltoides, and P. × jackii Sarg. (natural hybrid of P. balsamifera and P. deltoides), in part of their broad range of sympatry [78]. In North America near the Weber River in Utah, P. fremontii hybridise with P. angustifolia where their distinctive habitats come into proximity.…”

“…P. × generosa) [25,94,110] and P. × petrowskyana ( a hybrid of P. laurifolia Ledeb. × P. deltoides) [78]. P. alba L., the European white poplar, was introduced from Europe to North America in the early 18th century, and hybridises naturally with the native American aspens, Populus grandidentata Michaux and P. tremuloides Michaux.…”

“…A female clone of P. × petrowskyana (often referred to as "Russian" poplar) was introduced and widely distributed in western Canada about 100 years ago [78]. This clone hybridises occasionally with the native species P. balsamifera and more frequently with P. deltoides cv.…”

“…This clone hybridises occasionally with the native species P. balsamifera and more frequently with P. deltoides cv. occidentalis and P. × jackii [78]. Eckenwalder [27] reports on a single locality in California at which native P. fremontii has apparently hybridised successfully with a female introduced P. nigra.…”