Pollination and Breeding System of Lowbush Blueberries, <em>Vaccinium angustifolium</em> Ait. and <em>V. myrtilloides</em> Michx. (Ericacaeae), in the Boreal Forest

Abstract

Breeding systems and pollination requirements of two wild lowbush blueberries, Vaccinium angustifolium and V. myrtilloides, in the Canadian boreal forest in the Chapleau Crown Game Preserve, Ontario, were tested. Fruit production, size and seediness were significantly higher in samples exposed to natural pollination than in those cross-or self-pollinated by hand. There were no significant differences among artificial treatments (variously hand-pollinated and bagged) except when cross-pollination (xenogamy) was done by insect pins. In V. angustifolium, the density of flowering varied with forest age (canopy closure). It was most in open areas and least in the sites with the most mature forest. Although fruit-set and seediness varied among forest habitats of different ages, there were no significant differences between sites in forests of different ages. Thus, pollination seems to be similarly effective no matter the age of the forest. In both species, fruit-set in 1992, which had severe June frosts, was markedly poorer than that in 1993 when the flowers suffered little frost damage. The combined number of complete and incomplete seeds from the fruit among the breeding and pollination systems tested were similar; however, the ratio of complete seeds to total seeds was greater from cross-pollinated than from self-pollinated flowers. Our observations indicate that there is little natural fruit-set without insect-mediated cross-pollination and that cross-pollination provides much better fruit and seed-set than does self-pollination.

Temporal variation in food habits of the American Black Bear (<em>Ursus americanus</em>) in the boreal forest of northern Ontario

“…However, our study highlights the importance of summer soft mast crops to American Black Bears in the boreal forest and shows the great variation that can occur in these crops among years. For example, 1990 was an average year in terms of vegetation emergence and development in our study area, whereas in 1991 and 1992 vegetation emerged early (Usui et al 2005). Frosts in late may 1992 destroyed most of the flowers on the earlyflowering berry species such as early Lowbush Blueberry and raspberries (chapleau station: 25 may 1992 minimum air temperature -4.5°c, 26 may 1992 mini- (three levels-1990, 1991, 1992) and period (five levels-may, June, July, August, and september-October) main treatment effects, and their interaction (year • period), on dry mass of American Black Bear (Ursus americanus) food items from scats (n = 103) examined from the chapleau crown Game Preserve, Ontario.…”

“…THe cANADiAN FieLD-NATUrALisT Vol. 127 mum air temperature -2.5°c; environment canada 2013) and had a major impact on the berry crop (Usui et al 2005). early Lowbush Blueberry fruits were fully ripened in the third week of July 1991, but no blueberry fruits were available until the second week of August in 1992, when Velvet-leaved Blueberry became available.…”

“…However, a long-term demographic study of the population of American Black Bears in the chapleau crown Game Preserve showed that cub survival was lower during years of food shortages (such as 1992) and litter production rate was lower in years immediately following food shortages (Obbard and Howe 2008). Therefore, in the boreal forest zone of Ontario, where few alternate food crops are available and there can be considerable annual variation in blueberry production (Usui et al 2005), American Black Bears may not always be able to compensate for the loss of the blueberry crop. This could occur, for example, if a failure of the blueberry crop happened to coincide with a low production year for alternate crops such as Pin cherry and mountain-ashes.…”

Effects of Linear Disturbances and Fire Severity on Velvet Leaf Blueberry Abundance, Vigor, and Berry Production in Recently Burned Jack Pine Forests

“…Vaccinium species are known to be pollinated by bees [41] with fruit production, size, and seediness of Vaccinium species being significantly higher in plants exposed to natural pollination [42]. However, Vaccinium species have also been shown to have higher flowering densities in sites with an open canopy [42] and because we did not measure flower production we cannot distinguish between these factors. In fact, it is most likely to be a combination of greater flower production due to photosynthetic resources and increases in pollinator activity.…”

Floral and reproductive biology of Vaccinium meridionale (Ericaceae) in the Eastern Andes of Colombia.

“…Para las especies de Vaccinium cultivadas y silvestres del hemisferio norte, se ha determinado que la polinización cruzada, particularmente por abejas, es importante en su reproducción. Incluso en las especies que son auto-compatibles, la polinización cruzada aumenta la producción, el tamaño de los frutos y disminuye el tiempo de maduración (Lang & Danka, 1991;Brevis, 2005;Usui, Kevan, & Obbard, 2005;MacKenzie, 2009). Sin embargo, para V. meridionale no hay suficiente información sobre su sistema reproductivo y dependencia de polinizadores.…”