The number of honey bees (Apis mellifera L.) continues to decline due to parasitic mite pests and other factors. Honey bees and bumble bees (Bombus impatiens Cresson) were therefore compared for their effects on the seed set of watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] in a 2-year field experiment. The experiment was a 2 x 4 + 2 factorial, comparing bee type (honey bee or bumble bee) at four visitation levels (1, 6, 12, and 18 bee visits) to pistillate flowers, with two controls: a no-visit treatment and an open-pollinated treatment. Bee visitation level had a strong positive influence on seed set (P ≤ 0.0001). All flowers bagged to prevent insect visitation aborted, demonstrating the need for active pollen transfer between staminate and pistillate watermelon flowers. Flowers visited by B. impatiens consistently contained more seed than those visited by A. mellifera, when compared at equal bee visitation levels (P ≤ 0.0001). We conclude that bumble bees have great potential to serve as a supplemental pollinator for watermelon when honey bees available for rental are in limited supply.
M.S. Stanghellini, J.T. Ambrose, and J.R. Schultheis
Guanxing Hu, Chao Gao, Xiaoming Fan, Wenfang Gong, and Deyi Yuan
found to affect seed yield and even the fatty acid composition of seed oil ( Xie et al., 2017 ). Self-incompatibility usually refers to the phenomenon in which a fertile hermaphrodite seed plant cannot produce zygotes after self-pollination. Based on the
S. Alan Walters and Bradley H. Taylor
The objective of this study was to measure honey bee (Apis mellifera L.) impact on seed set, fruit set, and yield of jack-o-lantern (Cucurbita pepo L.), large-sized (C. maxima Duch.), and processing pumpkins (C. moschata Duch. ex Poir.) under field conditions. There were sufficient natural pollinators [including bumblebees (Bombus spp.), carpenter bees (Xylocopa spp.), honey bees, and squash bees (Peponapis pruinosa Say)] provided under field conditions to induce fruit set of jack-o-lantern pumpkins as fruit number obtained per hectare was not affected by the addition of a honey bee colony. However, the addition of honey bees did increase fruit number per hectare of the C. moschata and C. maxima cultivars evaluated. Honey bee pollination resulted in larger-sized fruit, increasing individual fruit size of all but small-sized pumpkins (<0.5 kg). Individual pumpkin fruit weights of the Cucurbita pepo, C. moschata, and C. maxima cultivars evaluated increased by about, 26%, 70%, and 78%, respectively, when honey bee colonies were included. Natural pollination was insufficient to stimulate maximum fruit size development and seed number and seed weight per fruit. Although pumpkin fruit set will occur with natural pollinators, the addition of honey bee colonies will ensure the presence of pollinators to maximize fruit size. Since pumpkins are generally sold on a weight basis, growers may generate greater revenues with the addition of honey bee colonies in pumpkin fields.
Gabriela Vuletin Selak, Slavko Perica, Smiljana Goreta Ban, Mira Radunic, and Milan Poljak
Olive trees are wind-pollinated and partially self-incompatible ( Androulakis and Loupassaki, 1990 ; Cuevas et al., 2001 ; Lavee and Datt, 1978 ; Lavee et al., 2002 ), which is probably the result of the gametophytic system of self
Dario J. Chavez and Paul M. Lyrene
of interspecific hybrid swarms ( Camp, 1942 ; Vander Kloet 1983 , 1988 ). Studies of self-pollination and cross-pollination in several Vaccinium species have provided varying results. In most cases, partial to complete self-incompatibility was
S. Alan Walters and Jonathan R. Schultheis
Cucurbit vegetables are predominantly out-crossers and depend on insect pollinators to transfer pollen from staminate to pistillate or hermaphroditic flowers for fruit set and development ( Robinson and Decker-Walters, 1997 ). Although there are
J.L. Olsen, S.A. Mehlenbacher, and A.N. Azarenko
Hazelnuts, (Corylus avellana L.), are wind-pollinated, monoecious, mostly dichogamous, and self-incompatible. About 90% of the cultivars studied are protandrous. Anthesis of the pistillate flower is temperature-dependent and occurs December through February, peaking in January. Stigmatic surfaces may remain receptive for up to 3 months. Four to 5 months separate pollination and fertilization of the ovule; the latter usually occurring between mid-May and the end of June in Oregon. A 10% pollinizer density has been the standard, with a recommended distance of 66 ft (20 m) or less between the main cultivar and the nearest pollinizer. Two or three different pollinizer cultivars, with different times of pollen shed, are recommended. The Oregon hazelnut industry is presently combating the fungal disease, eastern filbert blight, caused by Anisogramma anomala (Peck). Current management recommendations suggest reducing risk of infection are to reduce the most susceptible pollinizer cultivars to a density 5%, then gradually replace those left with immune or more resistant genotypes.
Samantha Jay Forbes, Guiliana Mustiga, Alberto Romero, Tobin David Northfield, Smilja Lambert, and Juan Carlos Motamayor
Ofori-Frimpong, 2013 ). No more than 10% of the flowers produced are naturally pollinated ( Groeneveld et al., 2010 ) and even fewer (0.5% to 5%) develop into mature pods under open pollination conditions, primarily because of fruit abortion ( Bos et al
Benjamin Campbell, Hayk Khachatryan, and Alicia Rihn
Recent pollinator population decline has become a global concern ( Gallai et al., 2009 ; Goulson et al., 2015 ; Klein et al., 2007 ). Pollinator insects are important because they contribute substantially to the global economy and food
Wagner A. Vendrame, Virginia S. Carvalho, José M.M. Dias, and Ian Maguire
before immersion in liquid nitrogen (LN) for 48 h. Four controls were established. Control 1 consisted of fresh pollinia collected from one flower and immediately used to pollinate another flower with no subsequent LN. Control 2 consisted of desiccated