scholarly journals A Novel Method to Quantify Transport of Self- and Cross-pollen by Bees in Blueberry Plantings

HortScience ◽  
2005 ◽  
Vol 40 (7) ◽  
pp. 2002-2006 ◽  
Author(s):  
Patricio A. Brevis ◽  
D. Scott NeSmith ◽  
Lynne Seymour ◽  
Dorothy B. Hausman
Keyword(s):  
Pollen Dispersal ◽  
Consistent Difference ◽  
Vaccinium Ashei ◽  
Frequency Distributions ◽  
Cross Pollination ◽  
Berry Size ◽  
Pollen Mixture ◽  
Novel Method ◽  
Ripening Rate ◽  
Pollen Diameter

Blueberry species (Vaccinium section Cyanococcus) benefit from cross-pollination. Outcrossing increases fruit set, berry size, and ripening rate. Although knowledge of pollen dispersal is essential for maximizing cross-pollination and achieving optimal planting designs, this process has not been quantified previously in blueberry plantings. A novel method was developed to estimate the proportion of self- and cross-pollen transported by blueberry pollinators. The proposed technique requires a consistent difference in pollen size between two cultivars to predict the composition of a pollen mixture based on frequency distributions of pollen diameter. Vaccinium ashei Reade `Brightwell' and `Climax' were chosen for this study because they produce pollen tetrads of different size. Tetrad diameter and number were analyzed with a particle counter. The technique was validated by predicting the proportion of `Brightwell' in pollen mixtures where the cultivar composition was known, and predicted and actual values were linearly correlated (r = 0.995, P < 0.0001). The technique was then applied to pollen samples extracted from the bodies of pollinators that were collected in a mixed `Brightwell' and `Climax' blueberry plot. Numbers of blueberry tetrads extracted per bumblebee (Bombus spp.) averaged 4595 and 797 in 2003 and 2004, respectively, which was considered adequate to make accurate predictions based on frequency distributions of tetrad diameter. The proportion of `Brightwell' pollen carried by bumblebees changed with the phenology of the crop following an expected pattern, indicating that the method performed well under field conditions. This technique could potentially be used to quantify the likelihood for outcrossing and establish the effect of cultivar arrangements on pollen dispersion, as well as to examine pollen collection and manipulation, and cultivar preference by bees.

scholarly journals Transport of Cross-pollen by Bumblebees in a Rabbiteye Blueberry Planting

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1127B-1127
Author(s):  
Patricio A. Brevis ◽  
D. Scott NeSmith
Keyword(s):  
Fruit Set ◽  
Pollen Grains ◽  
Pollen Load ◽  
Vaccinium Ashei ◽  
Pollen Loads ◽  
Cross Pollination ◽  
Limited Degree ◽  
Novel Method ◽  
Pollen Release ◽  
Pollen Diameter

Blueberries are bee-pollinated species that benefit from cross-pollination. Cross-pollination is particularly critical for optimum fruit set of rabbiteye blueberries (Vaccinium ashei Reade) because of their limited degree of self-fertility. In order to determine if the failure to set adequate commercial fruit loads is due to a lack of cross-pollination, research was needed to establish how much out-crossing rabbiteye blueberry pollinators actually do. A novel method was developed to identify pollen grains on the bodies of bumblebees by cultivar. The technique discriminates between two cultivars, based on differences in pollen diameter. Bumblebees were collected in a plot composed of blueberry plants of the cultivars Brightwell and Climax since these cultivars produce pollen of different size. Pollen loads of bumblebees contained low proportions of cross-pollen regardless of the cultivar they were visiting. Data suggest that inadequate levels of cross-pollination play a major role in low fruit set problems of rabbiteye blueberry. The composition of bees' pollen load changed with the phenology of the crop. The greatest likelihood for cross-pollination occurred around the time of maximum bloom overlap. Bumblebees foraging on `Brightwell' flowers carried more total blueberry pollen and a higher proportion of self-pollen than those visiting `Climax'. This may be due to differences in pollen release between flowers of these two cultivars.

scholarly journals Transport of Cross-pollen by Bumblebees in a Rabbiteye Blueberry Planting

HortScience ◽  
2005 ◽  
Vol 40 (7) ◽  
pp. 2007-2010 ◽  
Author(s):  
Patricio A. Brevis ◽  
D. Scott NeSmith
Keyword(s):  
Fruit Set ◽  
Vaccinium Ashei ◽  
Particle Counter ◽  
Frequency Distributions ◽  
Fruit Crop ◽  
Cross Pollination ◽  
Flowering Season ◽  
Small Fruit ◽  
Median Proportion ◽  
Pollen Diameter

Rabbiteye blueberry (Vaccinium ashei Reade) is a bee-pollinated small fruit crop that often exhibits poor fruit set. Mixed cultivar plantings are recommended because cross-pollination is required for optimum yields, and bees are expected to transfer pollen from one cultivar to another. The objective of this study was to assess transport of cross-pollen by bumblebees in a rabbiteye blueberry planting. Experiments were conducted in 2003 and 2004 in a plot composed of `Brightwell' and `Climax' plants arranged in alternating rows. The proportion of `Brightwell' and `Climax' pollen carried on the bodies of bumblebees was estimated based on frequency distributions of pollen diameter, measured with a particle counter. About 75% of bumblebees collected in 2003 carried <20% cross-pollen. Proportions of cross-pollen in 2004 were higher than in 2003, but still, about 85% of bumblebees collected carried <40% cross-pollen. The proportion of cross-pollen carried by bumblebees changed during the flowering season. The greatest likelihood for cross-pollination occurred during the time of maximum bloom overlap, although the median proportion of cross-pollen was not >30% on any sampling day of 2004. The results from this study emphasize the need to select more self-fertile rabbiteye blueberry cultivars and to maximize bloom overlap in blueberry plantings.

scholarly journals Evaluation of pollen dispersal and cross pollination using transgenic grapevine plants

2009 ◽  
Vol 8 (2) ◽  
pp. 87-99 ◽  
Author(s):  
Margit Harst ◽  
Beatrix-Axinja Cobanov ◽  
Ludger Hausmann ◽  
Rudolf Eibach ◽  
Reinhard Töpfer
Keyword(s):  
Pollen Dispersal ◽  
Cross Pollination ◽  
Transgenic Grapevine

scholarly journals POLLEN DISPERSION IN RABBITEYE BLUEBERRY

HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 874c-874
Author(s):  
Patricio Brevis ◽  
Scott NeSmith ◽  
Lynne Seymour
Keyword(s):  
Fruit Set ◽  
Bumble Bees ◽  
Pollen Load ◽  
Pollen Dispersion ◽  
Cross Pollination ◽  
Novel Method

Poor fruit set is one of the most important horticultural problems of the rabbiteye blueberry industry. Rabbiteye blueberries require cross-pollination and several bee species are expected to transfer pollen from one cultivar to another. A novel method was developed to measure bee-mediated pollen dispersion in rabbiteye blueberry. Pollen diameters were used to predict the proportion of cross-pollen in bumble bees' pollen load. Bumble bees visiting blueberry flowers had low proportions of cross-pollen. It is proposed that inadequate levels of cross-pollination play a major role in the failure of rabbiteye blueberries to set adequate commercial crops. The composition of bees' pollen load changed with the phenology of the crop. Data indicate that the greatest likelihood for cross-pollination occurred around the time of maximum bloom overlap of the two studied cultivars.

scholarly journals `VERNON': A NEW EARLY SEASON RABBITEYE BLUEBERRY CULTIVAR

HortScience ◽  
2005 ◽  
Vol 40 (3) ◽  
pp. 886b-886
Author(s):  
D. Scott NeSmith ◽  
Arlen D. Draper ◽  
James M. Spiers
Keyword(s):  
Seed Development ◽  
Coastal Plain ◽  
Fruit Size ◽  
Average Weight ◽  
Similar Time ◽  
Vaccinium Ashei ◽  
Early Season ◽  
University Of Georgia ◽  
Berry Size ◽  
The University

Released in 2004 by the University of Georgia and U.S. Dept. of Agriculture, `Vernon' is an early season rabbiteye blueberry (Vaccinium ashei Reade), having large fruit size, good yields and excellent plant vigor. `Vernon', tested as T-584, was selected in 1990 at the Coastal Plain Experiment Station in Tifton, Ga. from a cross of T-23 × T-260. `Vernon' fruit ripens early with the cultivar Climax in south Georgia, and few days before `Premier'; however, `Vernon' flowers 5 to 10 days after the standard cultivars. On average over a 6 year period, `Vernon' yielded 5.8 kg/plant per season, compared to 3.1 and 4.5 kg/plant for `Climax' and `Premier', respectively. Berry stem scar, color, firmness, and flavor of the new cultivar are good to excellent. Berry size of `Vernon' is considerably large, averaging 2.05 g/berry over 4 locations in 2003, compared to only an average weight of 1.56 g/berry for `Climax'. `Vernon' berries are firmer than `Premier'. Propagation of the new cultivar is easily accomplished from softwood cuttings. Chill hour requirement is estimated to be in the range of 500 to 550 hours (<7 °C). `Vernon' should be planted with other rabbiteye blueberry cultivars with a similar time of bloom to provide optimum pollination. Propagation rights are controlled by Georgia Seed Development Commission, 2420 S. Milledge Avenue, Athens, GA 30606 (for more information go to www.gsdc.com).

scholarly journals Metrical Analysis of a Putative Source for Semi-seedlessness in Rabbiteye Blueberry, Vaccinium ashei Reade.

HortScience ◽  
1996 ◽  
Vol 31 (2) ◽  
pp. 272-274 ◽  
Author(s):  
M.K. Ehlenfeldt ◽  
M.R. Hall
Keyword(s):  
Embryo Abortion ◽  
Vaccinium Ashei ◽  
Cross Pollination ◽  
Seedless Fruit ◽  
Metrical Analysis

T 286, a rabbiteye blueberry selection from a `Delite' × `Tifblue' cross, generally has been regarded as producing semi-seedless fruit. A comparison of nonpollinated flowers of T 286, `Delite', and `Tifblue' showed no differences in ovule count, and comparisons of ovules at 10, 20, and 40 days from manual cross-pollination showed no obvious evidence of embryo abortion. Manually cross-pollinated flowers contained 85, 60, and 38 seeds per fruit for `Delite', `Tifblue', and T 286, respectively. Open-pollinated fruit of T 286 had a seed count similar to that of open-pollinated `Tifblue' but possessed significantly heavier fruit. The number of seed in T 286 and `Tifblue' indicates a tendency toward parthenocarpy.

scholarly journals Response of Rabbiteye Blueberry (Vaccinium ashei Reade) to the Growth Regulators CPPU and Gibberellic Acid

HortScience ◽  
2002 ◽  
Vol 37 (4) ◽  
pp. 666-668 ◽  
Author(s):  
D. Scott NeSmith
Keyword(s):  
Gibberellic Acid ◽  
Growth Regulator ◽  
Fruit Set ◽  
Total Yield ◽  
Control Treatment ◽  
Single Application ◽  
Treatment Results ◽  
Vaccinium Ashei ◽  
Berry Size ◽  
Mature Field

Experiments were conducted during 1999 and 2000 at Griffin, Ga., with rabbiteye blueberries (Vaccinium ashei Reade) to determine how the growth regulator CPPU affected fruit set, berry size, and yield. CPPU (applied at two different timings) was used alone, and in conjunction with GA3 on mature, field-grown `Tifblue' plants. A control treatment without either growth regulator was also included. The CPPU concentration used was 10 mg·L-1 (a single application per treatment), and the GA3 concentration used was 200 mg·L-1 (two applications per treatment). Results from both years showed a positive benefit of CPPU with respect to fruit set and berry size, especially in the absence of GA3. Depending on timing, berry number per plant was increased by more than 200% in 1999 using CPPU. Berry size increases of more than 30% occurred in 2000 when CPPU alone was applied at 17 d after flowering (DAF). CPPU did not increase berry size of GA3-treated plants in either year. Total yield per plant during 2000 was 5.0, 7.1, and 8.3 kg for control, CPPU applied 7 DAF, and CPPU applied 17 DAF treatments, respectively, without GA3. While CPPU did substantially increase fruit set, berry size, and yield of `Tifblue', there was a notable delay in fruit ripening. These results suggest that CPPU may be useful for increasing yield of rabbiteye blueberries under conditions of inadequate fruit set (such as occurs in much of the Southeast), but a delay in ripening will likely result. Chemical names used: N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU); gibberellic acid (GA3).

Spatially explicit modelling of transgenic maize pollen dispersal and cross-pollination

2003 ◽  
Vol 225 (2) ◽  
pp. 241-255 ◽  
Author(s):  
Christine Loos ◽  
Ralf Seppelt ◽  
Sara Meier-Bethke ◽  
Joachim Schiemann ◽  
Otto Richter
Keyword(s):  
Pollen Dispersal ◽  
Transgenic Maize ◽  
Spatially Explicit ◽  
Maize Pollen ◽  
Cross Pollination

Pollen fertility and berry setting behaviour of the grape variety Carina

2007 ◽  
Vol 47 (7) ◽  
pp. 877 ◽  
Author(s):  
S. M. Liu ◽  
S. R. Sykes ◽  
P. R. Clingeleffer
Keyword(s):  
Fruit Quality ◽  
Male Fertility ◽  
Pollen Viability ◽  
Grape Variety ◽  
Embryo Recovery ◽  
Cross Pollination ◽  
Berry Size ◽  
Seedless Fruits ◽  
Berry Set

Carina is a significant grape variety grown in Australia to produce dried currants. Its yield and fruit quality are restricted by pollination; however, this can be improved by the judicious use of hormone-based setting sprays. Male fertility and seedless berry set in Carina were investigated by examining pollen viability, the effect of self- and cross-pollination on berry set and in ovulo embryo recovery in comparison with two pollen sterile varieties, Hunisa and Kishmishi. Carina pollen failed to germinate in vitro and gave poor berry set when used to pollinate Hunisa and Kishmishi. Percentage berry set in Carina was unaffected by pollination treatments, but cross-pollination increased berry size. Larger seed traces (>1.2 mm in length) were present in most cross-pollinated Carina berries and their size and number were correlated positively with berry size. In ovulo embryo recovery rates ranged from 19.7 to 49.0% and 6.8 to 13.6% for cross-pollinated combinations of Carina when ovules were cultured at 50 and 75 days after pollination, respectively. In contrast, embryo recovery was zero from self-pollinated ovules. The results indicated that Carina produces sterile or non-functional pollen and is capable of setting seedless fruits through either parthenocarpy and/or stenospermocarpy.

scholarly journals Doing the twist: a test of Darwin's cross-pollination hypothesis for pollinarium reconfiguration

2005 ◽  
Vol 2 (1) ◽  
pp. 65-68 ◽  
Author(s):  
Craig I Peter ◽  
Steven D Johnson
Keyword(s):  
Inbreeding Depression ◽  
Mating Success ◽  
Positive Relationship ◽  
Pollen Dispersal ◽  
Strong Support ◽  
Cross Pollination ◽  
Self Pollination ◽  
Strong Positive Relationship ◽  
Mating Opportunities

Mating success in plants depends largely on the efficiency of pollen dispersal. For hermaphrodite plants, self-pollination, either within or among flowers, can reduce mating opportunities because of pollen and ovule discounting and inbreeding depression. Self-pollination may be particularly detrimental in plants such as orchids and asclepiads that package each flower's pollen into one or more pollinia which, together with accessory structures, comprise a pollinarium. Darwin proposed that physical reconfiguration of pollinaria serves as a mechanism for reducing the likelihood of self-pollination. To be effective, the time taken for pollinarium reconfiguration would need to exceed that spent by a pollinator on a plant. We investigated pollinarium reconfiguration (including pollinarium bending, pollinium shrinking and anther cap retention) in 19 species and found a strong positive relationship between reconfiguration time and the duration of pollinator visits. Reconfiguration times were also consistently longer than pollinator visit times. These results provide strong support for Darwin's idea that this mechanism promotes cross-pollination.

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