scholarly journals Addition of Forchlorfenuron to Spray Pollination Media Increases Fruit Set in ‘Hosui’ Japanese Pear

2016 ◽  
Vol 26 (2) ◽  
pp. 185-190
Author(s):  
Daisuke Sakamoto ◽  
Shinnosuke Kusaba ◽  
Yuri Nakamura

The effects on fruit set of adding forchlorfenuron (CPPU) to media in which pollen grains were suspended and used for spray pollination was investigated in ‘Hosui’ japanese pear (Pyrus pyrifolia). The percentages of fruit set after spray pollination were lower than those after hand pollination; however, media with 2 or 10 mg·L−1 CPPU used for spray pollination resulted in greater percentages of fruit set than media without CPPU. The media with CPPU also resulted in higher levels of pollen germination compared with the medium without CPPU; however, the number of seeds per fruit with CPPU treatment tended to be almost the same or less than for fruit without CPPU treatment. From these results, the higher levels of fruit set by CPPU might not be due to the high germination rate of the pollen grains but due to the induction of partial parthenocarpic properties. The medium with 10 mg·L−1 CPPU gave the highest levels of fruit set, but the fruit had abnormally thickened and enlarged calyxes, and the fruit shape tended to be deformed at ≈21 days after flowering. In addition, all of the harvested fruit were calyx-perpetual fruit in which the calyx remains until harvest time. Fruit treated with 2 mg·L−1 CPPU also yielded calyx-perpetual fruit with high frequency, but the fruit had normal calyxes and the fruit shape tended to be more normal. Thus, we conducted experiments focusing on the medium containing 2 mg·L−1 CPPU. Although the results were variable from year to year, more than 70% of hand-pollinated flowers set fruit during the 3-year study; this level of fruit production is sufficient for practical use. Thus, spray pollination using a medium with 2 mg·L−1 CPPU is an acceptable method for pollinating ‘Hosui’ japanese pear.

2010 ◽  
Vol 40 (11) ◽  
pp. 2204-2214 ◽  
Author(s):  
E. R. Palupi ◽  
J. N. Owens ◽  
S. Sadjad ◽  
Sudarsono ◽  
D. D. Solihin

Teak ( Tectona grandis L.) is believed to have been introduced from India 400–500 years ago and there appear to be no old-growth natural forests. However, Indonesia has many teak plantation forests and 40%–50% of seeds for reforestation come from seed orchards and the remainder from plantations. In both, flower and fruit abortion results in low fruit set and thus seed production. We investigated flower and fruit development in a clonal seed orchard in East Java in 1999 and 2001 using cross- and open-pollinated trees. The rates of abortion using cross-pollinations showed a similar pattern but were lower than for open-pollinations. The highest rate of abortion in cross- and open-pollinations was during pollination and fertilization, ranging 11%–23% and 31%–32%/day, respectively, less during fruit initiation (5%–6% and 6%–8%/day) and the lowest was during fruit maturation (<0.5%/day). Cross-pollinations increased fruit production by 10-fold compared with open-pollinations. About 30% of flowers were pollinated with an average of five pollen grains per stigma in open-pollinations. Pollen viability varied among clones and time of day but was not affected by position of flowers in an inflorescence. We conclude that low pollination success and low pollen viability are major causes for low fruit production in teak and are related to insect pollinators.


HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 497E-498
Author(s):  
M.M. Peet ◽  
S. Sato

The effects of chronic, mild heat stress on fruit set, fruit production, release of pollen grains, photosynthesis, night respiration, and anther dehiscence were ex-amined in tomatoes (Lycopersicon esculentum Mill.) differing in high temperature sensitivity. Plants were grown under three temperature regimes: 1) 28/22 or 26/22 °C (optimal temperature) 2) 32/26 °C (high temperature), and 3) 32/26 °C day/night temperatures relieved at 28/22 °C for 10 days before anthesis, then returned to 32/26 °C (relieving treatment). `FLA 7156' was the only cultivar with fruit set at 32/26 °C. All five cultivars, however, had fruit set in the relieving treatment (RT). The longer the relief, the higher was the percentage of fruit set. Longer periods of relief also increased the number of pollen grains released and linear regression analysis showed a significant relationship between the number of pollen grains released and the percentage of fruit set. Germination of pollen grains was also lowered in high-temperature-grown plants. The number of pollen grains produced, photosynthesis, and night respiration did not limit fruit set under chronic, mild heat stress, however. This suggested that cultivar differences in ability to release pollen and to produce viable pollen under heat stress are the most important factors determining their ability to set fruit.


2021 ◽  
Vol 154 (1) ◽  
pp. 39-48
Author(s):  
Olga V. Nakonechnaya ◽  
Olga G. Koren ◽  
Vasilii S. Sidorenko ◽  
Sergey A. Shabalin ◽  
Tatyana O. Markova ◽  
...  

Background and aims – Interactions of insects with trap flowers of Aristolochia manshuriensis, a relic woody liana with fragmented natural populations from south-eastern Russia, were studied. Pollination experiments were conducted to identify the causes of the poor fruit set in this plant.Material and methods – The study was carried out at two ex situ sites within the natural range of A. manshuriensis in the suburban zone of the city of Vladivostok (Russia). The floral morphology was examined to verify how it may affect the process of pollination in this species. To test for a probability of self-pollination, randomly selected flowers at the female phase of anthesis (day 1 of limb opening) were hand-pollinated with pollen from the same plant. The daily insect visitation was studied. The pollen limitation coefficient and the number of visitors to the flowers were determined. To identify insects that lay eggs on the flowers, the insects were reared from eggs collected from fallen flowers. Both caught and reared insects were identified.Key results – The floral morphology and the colour pattern of A. manshuriensis are adapted to temporarily trap insects of a certain size. The hand-pollination experiment showed that flowers of this plant are capable of self-pollination by geitonogamy and require a pollinator for successful pollination. The positive value (2.64) for the pollen limitation coefficient indicates a higher fruit set after hand-pollination compared to the control without pollination. The number of visitors to the flowers was low (0.17 visitors per flower per day). Insects from three orders were observed on the flowers: Diptera (up to 90.9%), Coleoptera (8.3%), and Hymenoptera (0.8%). Four species of flies (Scaptomyza pallida, Drosophila transversa (Drosophilidae), Botanophila fugax, and Botanophila sp. 1 (Anthomyiidae)) are capable of transferring up to 2500–4000 pollen grains on their bodies and can be considered as pollinators of A. manshuriensis. Data of the rearing experiment indicate that flies of the families Drosophilidae (S. pallida, D. transversa), Chloropidae (Elachiptera tuberculifera, E. sibirica, and Conioscinella divitis), and Anthomyiidae (B. fugax, B. sp. 1) use A. manshuriensis flowers to lay eggs. Beetles were also collected from the flowers, but they were probably not involved in pollination, because no pollen grains were observed on them during our study.Conclusions – Pollinators of A. manshuriensis include mainly Diptera that lay eggs on the flowers. The poor fruit set (2%) in A. manshuriensis is associated with pollen limitation due to the lack of pollinators, as the number of visitors to flowers was extremely low. This may be due to the fact that the flowers of this species are highly specialized on insects of a certain size for pollination.


Lankesteriana ◽  
2011 ◽  
Vol 11 (3) ◽  
Author(s):  
Ericka Camacho-Domínguez ◽  
Irene Ávila-Díaz

Prosthechea aff. karwinskii (Mart.) Soto Arenas & Salazar (unpublished name) is an endemic Mexican epiphytic orchid with a restricted distribution. It occurs in deciduous oak forests, particularly on Quercus deserticola in the northern portion of Michoacán state. Due to their ornamental uses, this and other orchid species have been heavily collected from their natural populations. Learning about the reproductive biology of this species is important, as we may gain knowledge about the probable repercussions of overcollecting on their genetics and ecology. This will be a useful tool for the management and conservation of the species. The objectives were to 1) study the mating system of P. aff. karwinskii, 2) determine if the species requires an external pollinating agent for sexual reproduction, and 3) evaluate female reproductive success of this species. Exclusions (150) were made before anthesis. Once the flowers opened, we applied four pollination treatments: manual selfing, outcrossing, spontaneous autogamy, and open pollination. We subsequently quantified the production of fruits and viability of the seeds. Preliminary results showed that outcrossing and selfing treatments exhibited statistically higher fruit set than spontaneous autogamy and open pollination treatments, meaning that P. aff. karwinskii has the capability to reproduce via self-pollination. Prosthechea aff. karwinskii is pollinator-dependent for sexual reproduction, taking into account that the spontaneous autogamy treatment showed nil fruit production. Female reproductive success in open pollinated flowers was lower compared to fruit set of hand pollination treatments. This indicates that this species, as other species of tropical orchids, is pollination-limited. 


2021 ◽  
pp. 1-9
Author(s):  
Khwankhao Sinhaseni ◽  
Carla P. Catterall

Abstract The importance of wild insects as pollinators of tropical tree crops has rarely been tested. Across 18 small-scale lychee orchards in northern Thailand, we evaluated the roles of different wild insects as pollinators and predators of pests in fruit production. Quantitative assessments showed that bees (Family Apidae) were strongly dominant (83%) among insect flower visitors, comprising four species in tribes Apini and four in Meliponini. Experimental manipulations of inflorescences showed that fruit production in these orchards was: (1) dependent on flower visits by wild insects because enclosure of inflorescences in mesh bags decreased fruit set (to one-fifth) and (2) not greatly limited by pollinator deficiencies, because hand pollination of unbagged flowers did not enhance fruit set. Pollination success, as indicated by the proportion of unmanipulated flowers setting fruit, correlated positively across orchards with the abundance of large-bodied Apidae (>7 mm; most were Apis species) and of Apini, and negatively with abundance of small-bodied Apidae and of all Meliponini, despite the latter being the commonest flower visitors. We conclude that larger-bodied bees are most likely to travel sufficiently far to import genetically diverse pollen, in this landscape-scale mosaic where non-orchard habitats (both agriculture and treed patches) were sufficient to sustain wild pollinators.


HortScience ◽  
1990 ◽  
Vol 25 (10) ◽  
pp. 1226-1228 ◽  
Author(s):  
Brian A. Birrenkott ◽  
Elden J. Stang

Selective flower removal was used in 1987 and 1988 to evaluate intraplant competition or inhibition within flowering uprights of `Searles' cranberry (Vaccinium macrocarpon Ait.). The lowest two flowers were removed from uprights at various stages of plant development in 1987. With one or both of the two earliest, i.e., lowest, flowers developing `into fruit, 25% of the remaining flowers matured into fruit. Removal of the earliest two flowers at preblossom or late blossom resulted in ≈ 46% fruit set for the remaining flowers. Slightly fewer upper flowers set (36%) when the earliest flowers and fruit were removed at early fruit development. In 1988, the lowest two flowers were removed at preblossom and natural insect pollination was supplemented by hand pollination. Hand-pollinated (upper) flowers set 58% when the lowest two flowers were removed, compared to 17% for the unthinned control. Yield and fruit numbers were lowered slightly as a result of flower thinning in both years. A significant amount of variation in fruit production was explained by the number of flowering uprights per unit of production area in both years.


1986 ◽  
Vol 64 (6) ◽  
pp. 1216-1220 ◽  
Author(s):  
Geraldine A. Allen

Male plants of Oemleria cerasiformis have a larger flower display and a longer flowering period than females, and tend to show greater phenological variability. Male inflorescences generally begin to flower sooner than females, but reach their peak and finish flowering later. Their longer blooming period is mainly the result of less synchronous flower opening in males. In both sexes flowering tends to be completed more rapidly in later inflorescences. Fruit set in females is positively correlated with time of flowering (r = 0.313) and inflorescence size (r = 0.421). Hand-pollination of female flowers increased fruit set in most inflorescences, indicating that reproductive success in female O. cerasiformis may be pollen limited.


Agronomy ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1141
Author(s):  
Kimberly A. Stoner

Pumpkins and winter squash require insect pollination to set fruit, but only three bee species are important pollinators of these crops in the Northeastern US. To determine if natural levels of pollen deposition are sufficient for full fruit production, open pollination was measured by counting pollen grains on stigmas, and open pollination was compared to supplemental hand pollination for fruit set, fruit size, and seed number. A threshold of 2300 pollen grains per stigma was sufficient for full pollination and fruit production. This threshold was met in 79 out of 80 combinations of site and sample date over four years on farms across Connecticut with a wide range of field sizes and pest management practices. Along with stigma collection, bees per flower were counted hourly on 100 flowers along a transect. Counts of bumble bees on female flowers were more closely related to the amount of pollen deposited than counts of bees on all flowers or counts of honey bees or squash bees on female flowers. There was tremendous variation in abundance of the three bee species on female flowers across farms within a year and even among years on a single farm.


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