Evidence of functional gender polymorphisms in a population of the hermaphroditic lowbush blueberry (Vaccinium angustifolium)1This article is part of a Special Issue entitled “A tribute to Sam Vander Kloet FLS: Pure and applied research from blueberries to heathland ecology”.

Abstract

Lowbush blueberry ( Vaccinium angustifolium Aiton) is a wild, but cultivated for profit, agricultural system grown primarily in the northeastern regions of North America. It has been suggested that a functional gender specialization may be occurring in this hermaphroditic species in which some individuals (termed clones) effectively function as bearers (high ovule production but little or nonviable pollen) or as pollen donors (low ovule number with high quantities of viable pollen). The purpose of this study was to investigate if functional gender specialization was occurring in a randomly chosen population of 56 clones from the Blueberry Hill Research Farm in Jonesboro, Maine. For each clone, the mean number of ovules and the mean number of viable microspores per flower were determined. From this, functional gender was calculated. Five out of 56 clones, or approximately 10% of clones, were found to be functioning primarily as females, owing to their low levels of viable pollen. Thus, some evidence was found of a functional gender specialization occurring—the presence of a few plants that were nearly male-sterile. Since the most common evolutionary pathway to gynodioecy involves the invasion of male steriles, it is interesting to speculate that a trend towards gender dimorphism could be occurring in lowbush blueberry.