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Sarah K. Taber and James W. Olmstead

Although cultivated SHB are typically capable of setting fruit when self-pollinated, growers commonly plant multiple cultivars to enhance cross-pollination ( Williamson et al., 2015 ). This recommendation is based on previous research describing the

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Blair J. Sampson, Stephen J. Stringer, and Donna A. Marshall

With recent declines in honeybee populations, manageable wild native bees could help augment natural rates of blueberry pollination ( Sampson et al., 1995 ). However, raising enough healthy, pest-free bees for even limited release may take years

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Qi Sun, Xingnan Zhao, Lei Wu, Jimin Zhao, Yunfei Yang, and Yanwen Zhang

In nature, many plant species simultaneously share multiple pollinators (i.e., generalized pollination). Different pollinators may show various adaptations to certain plants because of their specific floral designs, resulting in variations in

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Suzanne Stone, George Boyhan, and Cecilia McGregor

-maintained landraces are favorable sources of genetic variation because they are more adapted to agricultural production than wild relatives ( Villa et al., 2005 ). By their nature, open-pollinated (OP) cultivars maintain greater population-level genetic diversity than

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Todd C. Wehner and Rakesh Kumar

-Sunshine’ produces more pistillate flowers than regular monoecious cultivars, it might need more pollen for effective pollination and fruit set. An important aspect of the pollenizer is the ability to produce enough staminate flowers to pollinate the available

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G. Costa, R. Testolin, and G. Vizzotto

The aim of the experiment was to define the wind and the bees effect on kiwifrut pollination. Experiment was carried out for two years in an adult kiwifruit orchard, with a ratio between staminate (cv Matua) and pistillate (cv Hayward) vines of 1:7. Four different pollination treatments were tested on kiwifruit. Bees effectiveness was evaluated on both open pollination (OP-Bees) or net-isolated vines conditions (IV-Bees). The results obtained were compared with those achieved on net-isolated vines without bees in (IV-Wind) and on hand-pollinated vines (HP). Four rows (80 vines) were net-isolated and 14 uniform vines per treatment were choosen to collect productive data. In the IV-Wind treatment traps were used to capture insects present inside the nets. Wind speed was detected inside and outside the nets. Data showed that the net isolation system did not consistently modify wind speed and no insects were founds in the traps. As far as productive data best results were obtained on HP vines. Bee-pollinated vines always reached higher yield and average fruit weight than wind-pollinated vines. However no statistical differences were detected between fruit weight of OP-Bees and IV-Wind vines treatments. The results showed that in general bees represent a more efficient pollination agent than wind, even if the health of the bees and the position of the hives in the orchard have to be carefully considered to achieve best results.

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Michelle L. Jones and William R. Woodson

Following a compatible pollination in carnation (Dianthus caryophyllus L. `White Sim'), a signal that coordinates postpollination events is translocated from the style to the ovary and petals. In this paper the roles of ethylene and its direct precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), in this signaling were investigated. Following pollination, ethylene and ACC increased sequentially in styles, ovaries, and petals. Ethylene and ACC were highest initially in the stigmatic region of the style but by 24 hours after pollination were highest in the base. Activity of ACC synthase correlated well with ethylene production in styles and petals. In ovaries, ACC synthase activity decreased after pollination despite elevated ethylene production. Lack of ACC synthase activity in pollinated ovaries, coupled with high ACC content, suggests that ACC is translocated within the gynoecium. Further, detection of propylene from petals following application to the ovary provided evidence for movement of ethylene within the flower. Experiments that removed styles and petals at various times after pollination suggest there is a transmissible pollination signal in carnations that has reached the ovary by 12 hours and the petals by 14 to 16 hours.

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Bruce W. Wood

There is increasing evidence of substantial pollination related crop losses by pecan [Carya illinoensis (Wangenh.) K. Koch] orchards. These most likely occur in block-type orchards consisting of only one or two cultivars, but can also occur at locations with a great number of different genotypes nearby. Main crop cultivars should generally be within about two rows of pollinizers to ensure cross-pollination. Thus, block widths exceeding about four rows between pollinizers are especially likely to exhibit serious pollination problems. Scattered trees of off-type genotypes are potentially of major importance as backup orchard pollinizers. Tree age/size and spring temperatures influence the characteristics of flower maturity windows and are probably primary factors contributing to pollination-related fruit-set losses in many block-type orchards. Flower maturity tends to be earlier in older/larger trees while warmer springs accelerate catkin development relative to that of pistillate flowers. Because of substantial variability in relative differences associated with initiation and duration of flower maturity windows within either protandrous or protogynous flowering types (i.e., Type I or II), selection of complementary pollinizers should be based on the relatively high resolution 30-class flowering classification system rather than the traditional low resolution 2-class system. Other factors sometime causing pollination related crop losses are either abnormally wet weather or strong dry winds during the pollination period or abnormally warm or cool springs. Pollination problems can be visually detected by noting premature non insect related post pollination fruit drop or diminishing fruit set with increasing distance from pollinator trees or off-type genotypes within the orchard.

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María Teresa Ariza, Carmen Soria, Juan Jesús Medina-Mínguez, and Elsa Martínez-Ferri

allowing growers to produce fruit during the high-value off-season ( Salamé-Donoso et al., 2010 ). Some producers also use pollinator insects such as bees or bumblebees to improve pollination by increasing mobility of pollen grains and, consequently

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Doron Schneider, Raphael A. Stern, and Martin Goldway

Apple (Malus domestica) has a gametophytic self-incompatibility (GSI) system. Consequently, fertilization is achieved by cross-pollination with a compatible pollinator. Compatibility is governed by a multiallelic S locus. Cultivars are fully compatible when both of their S-loci differ and are semi compatible when one locus is identical and the other differs. In a previous study we found that the fruit set and yield of the apple cultivar `Topred' was reduced when it was pollinated by a semi compatible cultivar. To examine if this occurrence is a general feature in apples grown under suboptimal conditions, three additional cultivars, `Golden Delicious', `Granny Smith' and `Royal Gala', were studied as pollen recipients of semi and fully compatible pollinators. Based on PCR analysis of the S-RNase allele, it was determined that the pollination rate of the semi compatible was significantly lower than that of the fully compatible pollinator in all cases. This was reflected by the lower fruit set and seed set of `Golden Delicious' and `Royal Gala', but not of `Granny Smith'. In hand pollination experiments, where pollen was in excess, no difference was found between the semi and fully compatible pollinators in all three cases. These results indicate that the low yield, conferred by semi compatible pollinators, is due to insufficient cross-pollination (and not to cultivar characteristics). Thus, low yields due to semi compatibility may be avoided by appropriate honeybee management that will increase pollination. Still, under suboptimal conditions, for growth and pollination, full compatibility is preferable.