NEEDLE FLAVONOID VARIATION IN ABIES BALSAMEA AND A. LASIOCARPA FROM WESTERN CANADA

Abstract

SummaryA recent analysis of quantitative variation in cone and needle characteristics indicated that Abies balsamea and A. lasiocarpa from western Canada are not well differentiated morphologically. To further investigate the relationship of A. balsamea to A. lasiocarpa, 10 populations of firs collected from western Saskatchewan to central British Columbia were compared on the basis of their needle flavonoids. Easternmost populations of A. balsamea were distinct from the westernmost samples of A. lasiocarpa; the easternmost firs contain additional flavonoid derivatives including diglycosides, flavones, and dihydroflavonols that were not found in the westernmost samples of A. lasiocarpa. Flavonoid patterns of geographically intermediate populations formed a continuum from east to west beginning in the lower foothills of the east slope of the Rocky Mountains in Alberta and extending to the interior of British Columbia. Although no sharp boundary separating the two species could be detected based on flavonoid results, the observed clinal pattern was steepest at the Rocky Mountain crest. In addition, the populations on either side of the crest were more variable than the 5 mixed‐wood populations to the east of the mountains. This pattern of variation suggests that genetic interchange has occurred between A. balsamea and A. lasiocarpa to each side of the Rocky Mountain crest following post‐glacial migration.