Interspecific pollen transfer as a mechanism of competition: effect of Castilleja linariaefolia pollen on seed set of Ipomopsis aggregata

2000 ◽  
Vol 78 (5) ◽  
pp. 600-606 ◽  
Author(s):  
Christina M Caruso ◽  
Monica Alfaro
Keyword(s):  
Seed Set ◽  
Pollen Transfer ◽  
Competition Effect ◽  
Priority Effect ◽  
Negative Effects ◽  
Ipomopsis Aggregata ◽  
Interspecific Pollen Transfer ◽  
Hand Pollination ◽  
Stigma Closure ◽  
Pollen Flowers

We investigated whether the deposition of Castilleja linariaefolia (Pursh) V. Grant pollen on flowers of Ipomopsis aggregata (Benth.) in DC. reduced I. aggregata's seed set. Ipomopsis flowers were hand-pollinated with either pure conspecific pollen (the control) or with C. linariaefolia pollen applied prior to, simultaneously with, or following conspecific pollen. Flowers that were simultaneously given C. linariaefolia and I. aggregata pollen received 39% less conspecific pollen than flowers in the control, but did not set fewer seeds per fruit. Flowers that were given C. linariaefolia pollen first received 30% less conspecific pollen and set 38% fewer seeds per fruit than the control. These results suggest that there is a priority effect; deposition of C. linariaefolia pollen on I. aggregata flowers results in competition, but only when C. linariaefolia pollen is deposited first. Unlike pollen of another competitor of I. aggregata (Delphinium nelsonii Greene. Per.), C. linariaefolia pollen caused competition without inducing an increased rate of stigma closure. Only 12% of I. aggregata's stigmas closed when C. linariaefolia pollen was deposited, and seed set of I. aggregata was reduced relative to the control whether their stigmas closed or not. The low rate at which C. linariaefolia pollen induces closure of I. aggregata's stigmas could be an adaptation to reduce the negative effects of competition.Key words: Castilleja linariaefolia, competition, hand pollination, hummingbirds, Ipomopsis aggregata, pollination.

Hand-Pollination ofCardamine californicaImproves Seed Set

2006 ◽  
Vol 7 (3) ◽  
pp. 248-252 ◽  
Author(s):  
Kazuki Ariyoshi ◽  
Emily Magnaghi ◽  
Mark Frey
Keyword(s):  
Seed Set ◽  
Hand Pollination

Unilateral incompatibility and the effects of interspecific pollination for Erythronium americanum and Erythronium albidum (Liliaceae)

1993 ◽  
Vol 71 (2) ◽  
pp. 353-358 ◽  
Author(s):  
Lawrence D. Harder ◽  
Mitchell B. Cruzan ◽  
James D. Thomson
Keyword(s):  
Seed Production ◽  
Pollen Tubes ◽  
The Self ◽  
Pollen Transfer ◽  
Interspecific Incompatibility ◽  
Unilateral Incompatibility ◽  
Heterospecific Pollen ◽  
Interspecific Pollen Transfer ◽  
Erythronium Americanum ◽  
Incompatibility Reaction

To determine whether interspecific pollen transfer could reduce seed production by two sympatric lilies, Erythronium albidum and Erythronium americanum, we hand-pollinated flowers with mixtures of conspecific and heterospecific pollen. These species exhibited typical unilateral interspecific incompatibility, i.e., pollen tubes from the self-infertile species (E. americanum) grew apparently unimpeded in styles of the self-fertile species (E. albidum), whereas the reverse cross resulted in an incompatibility reaction. Because of this asymmetrical relation and faster growth by heterospecific pollen tubes in E. albidum stigmas than by conspecific tubes, pollination with abundant heterospecific pollen reduced fruit and seed production by E. albidum, but not by E. americanum, as long as the stigma also received some conspecific pollen. Unilateral incompatibility could benefit self-infertile species in reproductive interactions with closely related self-fertile species; however, this benefit remains to be demonstrated for naturally pollinated plants. Key words: Erythronium albidum, Erythronium americanum, interspecific pollen transfer, pollination, unilateral incompatibility.

A comparison of flower-visiting insects to rare Symphyotrichum sericeum and common Solidago nemoralis (Asteraceae)

Botany ◽  
2010 ◽  
Vol 88 (3) ◽  
pp. 241-249 ◽  
Author(s):  
Diana Bizecki Robson
Keyword(s):  
Seed Set ◽  
Visitation Rate ◽  
Hand Pollination ◽  
Insect Visitation ◽  
The Common ◽  
Insect Activity ◽  
Flower Visiting ◽  
Common Plant ◽  
Insect Visitors ◽  
Over Time

Flower-visiting insect activity to the rare Symphyotrichum sericeum (Vent.) G.L. Nesom and the common Solidago nemoralis Ait. var. longipetiolata (Mack. & Bush) Pal. & Steyerm. was examined to detect compositional and temporal similarities. A hand pollination experiment was conducted to determine whether pollen was limiting seed set. Of the 31 insect taxa that visited these plants, Bombus bifarius Cresson was the most common visitor to both species. More insect visitors of the Halictidae and Bombyliidae were received by S. sericeum than S. nemoralis, which received more visitors of the Syrphidae and Tachinidae. The insect visitation rate was not significantly different between the two plant species. Solidago nemoralis was visited by fewer insect taxa per day than S. sericeum, but the constancy of its visitors was higher. The insect visitor composition changed over time, with B. bifarius ignoring S. sericeum plants initially, then visiting them more frequently as the number of receptive S. nemoralis capitula declined. Hand pollination increased seed set in the earliest flowering capitula of S. sericeum, but not for those flowering during the peak. This research shows that the quantity of insect visits to the rare plant is comparable with that of the common plant but that pollination quality may be lower, particularly for early blooming capitula.

INFLUENCE OF MOISTURE STRESS, RELATIVE HUMIDITY AND OXYGEN DIFFUSION RATE ON SEED SET AND YIELD OF WHEAT

1969 ◽  
Vol 49 (1) ◽  
pp. 29-37 ◽  
Author(s):  
C. A. Campbell ◽  
D. S. McBean ◽  
D. G. Green
Keyword(s):  
Soil Moisture ◽  
Relative Humidity ◽  
Oxygen Diffusion ◽  
Seed Set ◽  
Diffusion Rate ◽  
Moisture Stress ◽  
Morphological Examination ◽  
Hand Pollination ◽  
Growth Chamber Studies ◽  
Oxygen Diffusion Rate

The influence of oxygen diffusion rate (ODR) and relative humidity (RH) on seed set and yield of wheat was investigated in two growth chamber studies. In one study, plants grown at 80% RH were compared with those grown at 60%. In the other, plants grown in pots without supplemental aeration were compared with plants grown in aerated pots.Wheat grown at low soil moisture stress (between 25 and 16%) produced significantly poorer seed set and grain yield than those grown at higher stress (between 25 and 10%). Seed set was less severely reduced in Manitou than in Chinook. Plants grown at low moisture stress and 60% RH gave better seed set than those grown at 80%. However, even at 60% RH, seed set was less than 65%.The oxygen diffusion rates in unaerated pots were 28 × 10−8, 100 × 10−8 and 200 × 10−8 g cm−2min−1 at 25%, 16% and 10% soil moisture (by weight). In aerated pots, ODR at 25% and 16% soil moisture were 82 × 10−8 and 180 × 10−8 g cm−2min−1, respectively.Seed set and grain yields of Chinook wheat grown at low moisture stress were increased from 54 to 82% and from 11.5 to 26.7 g/pot by improving the soil aeration.The anthers, especially the pollen, were the main reproductive components damaged by poor aeration. This was demonstrated by morphological examination and by hand-pollination experiments. Poor seed set was confined primarily to the top two-thirds of the head.

Breeding Systems of Disjunct Populations of Christmas Bells (Blandfordia grandiflora R.Br., Liliaceae): Variation in Self-Fertility and an Ovular Mechanism Regulating Self-Fertilisation

1993 ◽  
Vol 41 (1) ◽  
pp. 35 ◽  
Author(s):  
M Ramsey ◽  
N Prakash ◽  
S Cairns
Keyword(s):  
Seed Set ◽  
Pollen Tubes ◽  
Breeding Systems ◽  
Seed Abortion ◽  
Self Incompatibility ◽  
Coastal Plants ◽  
Hand Pollination ◽  
Disjunct Populations ◽  
Pollen Vectors ◽  
Blandfordia Grandiflora

The breeding systems of disjunct tableland and coastal populations of Christmas bells were determined using hand-pollination experiments. In both populations, 90% or more of self-pollinated plants produced seeds. Tableland plants were significantly more self-fertile than coastal plants (ratio of self seed set to cross seed set: tableland, 0.55 ± 0.03; coast, 0.08 ± 0.02). Significant variation among plants for self-fertility was found in both populations. Autofertility was 1.6% or less in both populations indicating that pollen vectors are necessary for seed set. Seed set by agamospermy in both populations was less than 0.1%. Percentage seed abortion was greater in self-pollinated plants than cross-pollinated plants in both populations. In both self- and cross-pollinated plants, seed abortion was twice as great in the coastal population than in the tableland population. No evidence was found for stigmatic or stylar self-incompatibility. Self and cross pollen adhered to and germinated equally well on stigmas in both populations (72 - 77% germination). Similarly, there were no differences between pollination treatments or populations in the percentage of ovules penetrated by pollen tubes (82 - 89% penetration). When self-pollination preceded cross-pollination by 24 h or longer seed set was significantly reduced compared to flowers that were cross-pollinated only, suggesting ovules were pre-empted by self pollen tubes. Collectively these results strongly suggest that self seed set was reduced by a mechanism operating at the ovule level, such as early-acting inbreeding depression due to recessive seed-aborting genes, although incomplete late-acting self-incompatibility cannot be ruled out. For coastal plants, this ovular mechanism largely prevents selfing, indicating plants were predominantly outcrossing although most produced some self seed. For tableland plants, substantial seed set by selfing may occur under natural conditions.

scholarly journals Use of timelapse photography to determine flower opening time and pattern in banana (Musa spp.) for efficient hand pollination

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Allan Waniale ◽  
Rony Swennen ◽  
Settumba B. Mukasa ◽  
Arthur K. Tugume ◽  
Jerome Kubiriba ◽  
...  
Keyword(s):  
Seed Set ◽  
Digital Camera ◽  
Female Flower ◽  
Time Lapse ◽  
Temporal Separation ◽  
Flower Opening ◽  
Main Challenge ◽  
Hand Pollination ◽  
Male Flowers ◽  
Female Flowers

AbstractSterility and low seed set in bananas is the main challenge to their conventional genetic improvement. The first step to seed set in a banana breeding program depends on pollination at the right time to ensure effective fertilization. This study aimed at determining bract opening time (BOT) to enhance efficient pollination and seed set in bananas. A Nikon D810 digital camera was set-up to take pictures of growing banana inflorescences at five-minute intervals and time-lapse movies were developed at a speed of 30 frames per second to allow real-time monitoring of BOT. Genotypes studied included wild banana (1), Mchare (2), Matooke (4), Matooke hybrid (1), and plantain (1). Events of bract opening initiated by bract lift for female flowers (P < 0.01) started at 16:32 h and at 18:54 h for male flowers. Start of bract rolling was at 18:51 h among female flowers (P < 0.001) and 20:48 h for male flowers. Bracts ended rolling at 02:33 h and 01:16 h for female and flowers respectively (P < 0.05). Total time of bract opening (from lift to end of rolling) for female flowers was significantly longer than that of male flowers (P < 0.001). On average, the number of bracts subtending female flowers opening increased from one on the first day, to between one and four on the fourth day. The number regressed to one bract on day eight before start of opening of bracts subtending male flowers. There was a longer opening interval between bracts subtending female and male flowers constituting spatial and temporal separation. Bract rolling increased from partial to complete rolling from proximal to the distal end of the inflorescence among female flower. On the other hand, bracts subtending male flowers completely rolled. Differences in BOT of genotypes with the same reference time of assessment may be partly responsible for variable fertility. Hand pollination time between 07:00 and 10:00 h is slightly late thus an early feasible time should be tried.

scholarly journals Severely pollen-limited fruit set in a pear (Pyrus communis) orchard revealed by yield assessments and DNA-based paternity assignment of seedlings

2007 ◽  
Vol 13 (3) ◽  
Author(s):  
H. Mattison ◽  
J. Sehic ◽  
H. Nybom
Keyword(s):  
Fruit Set ◽  
Seed Set ◽  
Rapd Analysis ◽  
Total Yield ◽  
Fruit Tree ◽  
Pollen Transfer ◽  
Pear Cultivar ◽  
Pollination Success ◽  
Viable Seeds ◽  
High Yields

In commercial fruit tree orchards, consistently high yields are necessary for a durable economy. The Swedish pear cultivar 'Carola' has been noted for low setting in some orchards, possibly due to insufficient pollination. In this study, fruit set was evaluated in a research orchard where `Carola' had been planted together with four potential pollinators. Total yield and number of fruits was noted during three and four years, respectively. In 2003, seeds were germinated from the harvested `Carola' fruits, and the paternity of three seedlings from 50 trees was determined with RAPD analysis. 'Clapp's Favourite' had sired 39.6% of the seedlings, closely followed by `Seigneur d'Esperen' (30.7%) and 'Clara Frijs' (26.7%) whereas 'Skanskt sockerparon' only sired 1.1% of the seedlings. The remaining 2.3% appeared to have been derived by selfing. Pollen-limited seed set was indicated at surprisingly short distances; accumulated number of fruits on the `Carola' trees was significantly higher when separated by only 2 m from one of the two most efficient pollinators, 'Clapp's Favourite' or 'Seigneur d'Esperen‘, compared to trees 4—l0 in away in the same row. Number of viable seeds per fruit was also higher in fruits from trees immediately adjacent to the pollinators, suggesting an effect of improved pollination success. The importance of very short inter-cultivar distances for efficient pollen transfer became even more clear when comparisons involved the true pollination distances as determined by RAPD; the accumulated yields decreased linearly from 55 kg at a 2 in distance to only 17 kg at 13 m.

scholarly journals Seed Set Patterns in East African Cooking Bananas are Asymmetric in Bunches and Fruits

2020 ◽  
Author(s):  
Allan Waniale ◽  
Settumba B. Mukasa ◽  
Arthur K. Tugume ◽  
Robooni Tumuhimbise ◽  
Jerome Kubiriba ◽  
...  
Keyword(s):  
Success Rate ◽  
Seed Set ◽  
Gradual Increase ◽  
East African ◽  
Pollination Success ◽  
Random Occurrence ◽  
Hand Pollination ◽  
Wild Banana ◽  
Breeding Efficiency ◽  
Targeted Approach

Abstract Background: Low female fertility in bananas is the biggest hurdle for banana breeding. The aim of this study was to determine seed set patterns in East African cooking bananas EACBs to inform future decisions on a more targeted approach of increasing seed set and subsequently banana breeding efficiency. Matooke (AAA) and Mchare (AA) bananas are genetically distinct but belong to the same genetic complex, they referred to as EACBs. Seed set patterns in ‘Enzirabahima’ (AAA), ‘Mshale’ (AA) and ‘Nshonowa’ (AA) all with residual fertility were examined after hand pollination with a highly male fertile wild banana ‘Calcutta 4’ (AA). Results: Seed set in ‘Enzirabahima’ is predominant in distal hands. Mchare cultivars have a slightly more even distribution of seeds in their hands compared to ‘Enzirabahima.’ There is a gradual increase in seed set from proximal to distal hands with a slight drop in the last hand. This pattern is more definite in ‘Enzirabahima’ and ‘Mshale’ while ‘Nshonowa’ has a somewhat inconsistent pattern. There is also a drop in seed set per 100 fruits per hand from small to larger bunches. However, larger bunches have a higher pollination success compared to smaller bunches. They therefor set more seed on 100 fruits per hand and per bunch basis if bunches without seed are accounted for. Pollination success rate increases from smaller to larger bunches of EACBs. Seed set is biased toward the distal third part of fruits of examined EACBs as well tetraploid Matooke hybrid ‘401K-1’ (AAAA) and improved diploid ‘Zebrina’ GF (AA) that were used for comparison. In comparison, in the highly female fertile ‘Calcutta 4,’ seed set is along the entire length of the fruit.Conclusion: Seed set bias in the distal hands and distal end of fruits suggests a systematic mechanism rather than a random occurrence. It is expected that this information will provide a foundation for increased crossbreeding efficiency in bananas.

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