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 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 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 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.

The pollination ecology of the late-successional tree, Oroxylum indicum (Bignoniaceae) in Thailand

2008 ◽  
Vol 24 (05) ◽  
pp. 477-484 ◽  
Author(s):  
Tuanjit Srithongchuay ◽  
Sara Bumrungsri ◽  
Ekapong Sripao-raya
Keyword(s):  
Plant Species ◽  
Fruit Set ◽  
Pollen Grains ◽  
Pollen Load ◽  
Pollination Success ◽  
Oroxylum Indicum ◽  
Tropical Plant ◽  
Fruit Bat ◽  
Highly Sensitive ◽  
Multiple Species

Abstract:Although plant species that attract multiple species of pollinators predominate in tropical plant communities, pollination specialists appear to be at a greater advantage in tropical ecosystems in which pollinators are numerous and many plants flower synchronously. The present study determined the breeding system and legitimate pollinators ofOroxylum indicumVent. in Songkhla and Patthalung Provinces, Thailand.Oroxylum indicumexhibits steady-state flowering, with one or two flowers per inflorescence opening each night. Flowers open in the evening and drop off shortly after midnight, while its bilabiate stigma is highly sensitive, and quickly close upon being touched.Oroxylum indicumis self-incompatible. Hand-cross pollination and open pollination yielded the highest pollination success (47.7% and 31.2% respectively, n = 7 trees). About 900 pollen grains are needed for initiating fruit set. It is confirmed that a fruit bat,Eonycteris spelaea, is the legitimate pollinator. Bats are responsible for all pollen load and the pollen load from only one visit is generally sufficient to initiate fruit set. AlthoughEonycteris spelaeais effective, it is an inefficient pollinator. Compared with plant species pollinated by multiple animal species, the likelihood of pollination failure resulting from the decline in populations ofEonycteris spelaeawill be much more intense inOroxylum indicum.

scholarly journals Pollen sources in the Bojanów forest complex identified on honeybee pollen load by microscopic analysis

2017 ◽  
Vol 70 (4) ◽  
Author(s):  
Ernest Stawiarz ◽  
Beata Żuraw ◽  
Agnieszka Marut
Keyword(s):  
Trifolium Repens ◽  
Robinia Pseudoacacia ◽  
Microscopic Analysis ◽  
Pollen Grains ◽  
Early Spring ◽  
Pollen Load ◽  
Pollen Loads ◽  
Pollinating Insects ◽  
Pollen Traps ◽  
Plant Families

<p>The aim of this study was to determine sources of pollen for the honeybee in the Bojanów forest complex, Nowa Dęba Forest District (southeastern Poland). Sampling of pollen loads from bees extended from the beginning of May until the end of September 2016 and was carried out at 7-day intervals using pollen traps mounted at the entrance of beehives. A total of 73 pollen load samples were collected from the study area.</p><p>Fifty-nine taxa from 31 plant families were identified in the analyzed material. From 4 to 21 taxa (average 9.5) were recorded in one sample. The pollen of Brassicaceae (“others”), <em>Taraxacum</em> type, <em>Solidago</em> type, and <em>Rumex</em> had the highest frequency in the pollen loads examined. Apart from these four taxa, pollen grains of <em>Rubus</em> type, Poaceae (“others”), <em>Calluna</em>, <em>Fagopyrum</em>, <em>Trifolium repens</em> s. l., <em>Phacelia</em>, <em>Aster</em> type, <em>Melampyrum</em>, <em>Quercus</em>, <em>Cornus</em>, and <em>Veronica</em> were recorded in the dominant pollen group. The forest habitat taxa that provided pollen rewards to honeybees in the Bojanów forest complex were the following: <em>Rubus</em>, <em>Calluna</em>, <em>Prunus</em>, <em>Tilia</em>, <em>Frangula alnus</em>, <em>Pinus</em>, <em>Quercus</em>, <em>Cornus</em>, <em>Robinia pseudoacacia</em>, <em>Salix</em>, and <em>Vaccinium</em>. Apart from forest vegetation, the species from meadows and wastelands adjacent to this forest complex, represented by <em>Taraxacum</em>, <em>Rumex</em>, <em>Plantago</em>, Poaceae, <em>Trifolium repens</em>, and <em>Solidago</em>, proved to be an important source of pollen. The study indicates that forest communities are a valuable source of pollen for pollinating insects from early spring through to late fall.</p>

scholarly journals Production and Viability of Pollen and Pollen-Ovule Ratios in Four Rabbiteye Blueberry Cultivars

2006 ◽  
Vol 131 (2) ◽  
pp. 181-184 ◽  
Author(s):  
Patricio A. Brevis ◽  
D. Scott NeSmith ◽  
Hazel Y. Wetzstein ◽  
Dorothy B. Hausman
Keyword(s):  
Fruit Set ◽  
High Efficiency ◽  
Pollen Viability ◽  
Reproductive Failure ◽  
Pollen Production ◽  
Vaccinium Ashei ◽  
Significant Difference ◽  
Total Pollen ◽  
Pollen Release

Fruit set of rabbiteye blueberries (Vaccinium ashei Reade) can be pollen-limited under certain conditions. The objective of this study was to determine production, release, and viability of pollen, as well as pollen-ovule ratios in the rabbiteye blueberry cultivars Austin, Brightwell, Climax, and Tifblue. In vitro tetrad germination varied among genotypes, although, values were high (≥80%) in all cultivars. Pollen viability does not seem to contribute to reproductive failure in the cultivars studied. Total pollen production per flower averaged 8434 tetrads across all cultivars. On a per ovule basis, pollen production was very low relative to other xenogamous species. The low pollen-ovule ratio of rabbiteye blueberry (≈400) may be an indicator of the high efficiency of its pollen dispensing mechanism. Total pollen production varied among cultivars. Furthermore, a significant difference in pollen release was found between two cultivars with similar total pollen production per flower. The possible mechanism regulating pollen release in these cultivars is discussed.

CYTOLOGY OF POPLAR SPECIES AND NATURAL HYBRIDS

1938 ◽  
Vol 16c (11) ◽  
pp. 445-455 ◽  
Author(s):  
F. H. Peto
Keyword(s):  
Size Distribution ◽  
Genetic Factors ◽  
Chromosome Complement ◽  
Pollen Grains ◽  
Pollen Size ◽  
Cell Nuclei ◽  
Good Pollen ◽  
Natural Hybrids ◽  
Pollen Diameter ◽  
High Degree

Complete analyses of pollen-mother-cell nuclei at first metaphase, percentage good pollen, pollen diameter and pollen-size distribution were determired for the following poplar species and natural hybrids: Populus grandidentata Michx., P. tremuloides Michx., P. eugenei Simon Louis, P. alba L., P. canescens Sm., natural hybrids of P. alba × P. grandidentata and of P. alba × P. tremuloides.Both of the P. alba and two of the four P. canescens trees examined were triploids (2n = 57) while all other trees examined were diploids (2n = 38). Meiotic observations on the natural hybrids indicated a high degree of homology between the chromosomes of P. alba and the native aspens (P. grandidentata and P. tremuloides), since 17 to 19 bivalents were usually found at first metaphase. In collections from one triploid P. canescens and two diploid alba-grandidentata hybrid trees, failure of a high proportion of the chromosomes to pair was attributed to genetic factors limiting pairing, rather than to non-homology.Pollen characters such as percentage good pollen, pollen diameter, and pollen size distribution were, in most cases, not indicative of the chromosome number or pairing relations at first metaphase. Consequently, triploids could not be detected by pollen observations under the conditions of this experiment. In spite of the lack of correlation between first metaphase and pollen observations, abnormally large pollen grains were observed in collections from several of the trees, and these were considered to contain the diploid or unreduced chromosome complement. The tendency for the poplars to produce unreduced pollen grains probably accounts for the number of triploid trees discovered in Canada and Sweden.

Incompatibility, stamen movement and pollen economy in a heterostyled tropical forest tree, Cratoxylum formosum (Guttiferae)

1982 ◽  
Vol 214 (1195) ◽  
pp. 273-283 ◽  
Keyword(s):  
Critical Level ◽  
Pollen Grains ◽  
Forest Tree ◽  
Incompatible Pollen ◽  
Insect Visitation ◽  
Small Pollen ◽  
Evolutionary Step ◽  
Novel Method ◽  
Compatible Pollinations ◽  
Compatible Pollen

Cratoxylum formosum shows all the classical features of a distylic species. The two types are: long-styled plants with short stamens and small pollen grains and short-styled plants with long stamens and large pollen grains. Compatible pollinations are only between the two types; incompatible pollen tubes are inhibited in the style. A significant morphological feature distinguishes Cratoxylum from distylic plants in other families. Instead of having a small number of anthers making well separated narrow discs in the two types, Cratoxylum has many anthers (144) and they are arranged on staminal bundles that produce long cylinders of anthers that partially occupy similar height zones in the two types of flower. A novel method of separation of the two height zones is achieved by the bending of the stamens of the long-styled type when the flower opens, which converts the cylinder to a narrow disc of anthers at the same height as the ‘short’ stigma. The bending coincides with anther dehiscence and is slightly later than the first daily insect visitation. The anthers return to the upright position later in the day, when the pollination is complete. There was a 20-fold difference between the amounts of pollen deposited on the two types of stigmas. The ‘long’ stigmas received 1200 pollen grains per flower, in the ratio of 46 ‘long’ to 54 ‘short’, which is close to the ratio of two types of pollen produced in the population. This random deposition of pollen on ‘long’ stigmas is, however, more than adequate for the 36 seeds produced per flower. ‘Short’ stigmas received only 64 pollen grains per flower, in the ratio of 90 ‘long’ to 10 ‘short’, and several flowers had below the critical level of 36 compatible pollen grains for full seed production. Pollen loads of the pollinating bee, Apis javana , consisted of ‘long’ and ‘short’ pollen on the thorax in the ratio found on the ‘long’ stigma, and on the head of the bee in a ratio close to the 9:1 found on the ‘short ’ stigma. The corbicular loads reflected accurately the pollen of the tree in which the bee was caught. For Cratoxylum the accurate positioning of the anthers of the long-styled plant in relation to the visiting bees head was an important evolutionary step in the effective pollination of the short-styled form, which, at least in this species, is one critical and highly selected feature of the system.

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