Blueberry Floral Attributes and Their Effect on the Pollination Efficiency of an Oligolectic Bee, Osmia ribifloris Cockerell (Megachilidae: Apoidea)

Abstract

<jats:p>We evaluated relationships between floral traits of 23 genotypes of southern blueberries and indices of pollination efficiency (fruit set, fruit abortion, seed number, and berry size) for <jats:italic>Osmia ribifloris</jats:italic> Cockerell, a manageable solitary bee. Flower size in <jats:italic>Vaccinium</jats:italic> and presumably ovary size were proportional to berry size, except for the tiny blooms of one <jats:italic>V. tenellum</jats:italic> clone (NC7808), which produce large commercial-sized berries of ≈2 g. Longer-styled blueberry flowers visited by <jats:italic>O. ribifloris</jats:italic> produced the heaviest berries with the most seeds. <jats:italic>Osmia ribifloris</jats:italic> reliably pollinated ‘Climax’ and ‘Tifblue’ rabbiteye blueberries. However, the peculiarly misshapen blooms of ‘Premier’ rabbiteye blueberry receive less pollination from <jats:italic>O. ribifloris</jats:italic> and yield berries containing 25% fewer seeds. Fruit set for these misshapen ‘Premier’ flowers was equivalent to that of intact flowers indicating that this floral polymorphism would not greatly alter cultivar performance. For seven <jats:italic>Vaccinium</jats:italic> species, wild and cultivated alike, 80% to 100% of a plant’s fruit production depends on efficient cross-pollination by bees such as <jats:italic>O. ribifloris</jats:italic>.</jats:p>

Ploidy, Fertility, and Phenotypes of F1 Hybrids between Tetraploid Highbush Blueberry Cultivars and Diploid Vaccinium elliottii

“…The recessed stigma of V. elliottii has been noted previously (Lyrene, 1994;Sampson et al, 2013;Vander Kloet, 1998). This flower structure seems to be unique in V. elliottii compared with other section Cyanococcus species and might be used as a diagnostic character to separate V. elliottii from other highbush Cyanococcus species.…”

“…This flower structure seems to be unique in V. elliottii compared with other section Cyanococcus species and might be used as a diagnostic character to separate V. elliottii from other highbush Cyanococcus species. The inserted stigma and small corolla aperture could make V. elliottii dependent on sonicating bees for pollination (Sampson, et al, 2013).…”

Genotype‐specific effects of ericoid mycorrhizae on floral traits and reproduction in Vaccinium corymbosum

“…Inoculation reduced one measure of flower size, corolla opening diameter, but did not affect other aspects of floral morphology. Although the effect on corolla diameter was modest, it could affect the suite of insects that can access floral resources (Courcelles et al., ; Sampson et al., ) and thus plant reproductive success. Honey bees, which do not sonicate the flowers while foraging and are relatively poor pollinators of blueberry (Javorek et al., ; but see Benjamin and Winfree, ), might be restricted from entering flowers with more narrow openings.…”

“…Flowering phenology and floral display size are often directly linked to pollinator attraction (Bauer et al., ; Munguía‐Rosas et al., ), and floral morphology can have important consequences for successful pollination of blueberries (Sampson et al., ). To determine whether inoculation affected flower production, phenology, and morphology, in 2015–2016 we sampled plants of eight cultivars.…”

“…Following Sampson et al. (), we estimated corolla size as the volume of a cylinder: mm 3 = Corolla length × πr 2 , where r = corolla width/2.…”