scholarly journals Incompatibility classes and fruit set in natural populations of arctic bramble (Rubus arcticus L.) in Finland

1988 ◽  
Vol 60 (5) ◽  
pp. 327-446 ◽  
Author(s):  
Jussi Tammisola
Keyword(s):  
Clustering Algorithm ◽  
Fruit Set ◽  
Probability Distributions ◽  
Natural Populations ◽  
Guidance System ◽  
Likelihood Principle ◽  
Probability Estimates ◽  
Maximum Stability ◽  
Computerized Guidance ◽  
Compatible Pollen

In Finnish natural populations, arctic bramble proved uniformly self-incompatible. In vigorous and richly flowering populations, the intensity of fruit set is governed by the number of incompatibility classes present. Most non-fruiting populations contain only one incompatibility class (and most likely only one clone) and therefore totally lack compatible pollen. Richly fruiting populations usually contain at least three incompatibility classes. A clone with an estimated size of 80 metres and age of 160 years was found. This supports the vegetative burst explanation for the “sudden appearance” of arctic bramble populations. For the purposes of plant breeding, a large genetic collection is required. In cultivation, a thorough mixture of at least three varieties is recommended. The study was dynamically optimized. A computerized guidance system was constructed, which analyzed the accumulating results and yielded recommendations for forthcoming crosses. For the analysis into equivalence classes of incompatibility, a stepwise clustering algorithm of the single move type, based on the maximum likelihood principle, was introduced. This partitioning was based on the number of seeds in a cross, considering it as a stochastic variable. Seed number probability distributions in intraclass and interclass pollinations were acquired utilizing non-parametric density estimation. Finally, both incompatibility class and seed probability estimates were adjusted together iteratively. A recommendation algorithm was produced, based on a partially heuristic principle of maximum lability maximum stability. With the aid of the guidance system, incompatibility classes could be resolved using about one tenth of the number of crosses required in a conventional system.

scholarly journals Male and female reproductive success in natural and anthropogenic populations of Malaxis monophyllos (L.) Sw. (Orchidaceae)

2015 ◽  
Vol 39 (1) ◽  
pp. 37-44 ◽  
Author(s):  
Edyta Jermakowicz ◽  
Beata Ostrowiecka ◽  
Izabela Tałałaj ◽  
Artur Pliszko ◽  
Agata Kostro-Ambroziak
Keyword(s):  
Reproductive Success ◽  
Fruit Set ◽  
Natural Populations ◽  
Floral Display ◽  
Natural Habitats ◽  
Female Reproductive Success ◽  
Male And Female ◽  
Demographic Processes ◽  
Preliminary Study ◽  
Effective Pollinators

Abstract In the presented study, male and female reproductive success was analyzed in relation to the population size, floral display and pollinators’ availability in natural and anthropogenic populations of the orchid Malaxis monophyllos (L.) Sw. Our results indicated significant differences between all investigated populations in parameters of floral display, including heights and number of flowers per inflorescence, as well the number of flowering individuals and their spatial structure. Additionally, populations differed both in male (pollinia removal) and female (fruit set) reproductive success, but only the fruit set clearly differentiated anthropogenic and natural populations. Despite the average flower number per plant being significantly higher in two of the anthropogenic populations, it was not related to the fruits set, which was significantly lower there. Moreover, our preliminary study concerning the potential pollinators of M. monophyllos showed a higher contribution of flies in natural habitats than in anthropogenic ones. Thus, we can suspect that the main factors influencing the level of female reproductive success in M. monophyllos populations are abundance of effective pollinators, as well as flower visitors, which may have resulted in a different level of pollen discounting in populations. Therefore, further studies concerning breeding system and pollination as important forces that shape demographic processes in M. monophyllos populations are necessary. Our results also indicate that suitable conservation methods in M. monophyllos should always include the preservation of potential pollinators, especially in these new, secondary habitats.

scholarly journals Breeding biology and distyly in Palicourea rigida H. B. & K. (Rubiaceae) in the Cerrados of Central Brazil

2010 ◽  
Vol 24 (3) ◽  
pp. 686-696 ◽  
Author(s):  
Adriana de Oliveira Machado ◽  
Ana Palmira Silva ◽  
Helder Consolaro ◽  
Mariluza A. Granja e Barros ◽  
Paulo Eugênio Oliveira
Keyword(s):  
Reproductive Success ◽  
Fruit Set ◽  
Pollen Grains ◽  
Floral Biology ◽  
Nectar Production ◽  
Central Brazil ◽  
Palicourea Rigida ◽  
Floral Visitors ◽  
Compatible Pollen ◽  
Incompatibility Reactions

Distyly is a floral polymorphism more common among the Rubiaceae than in any other angiosperm group. Palicourea rigida is a typically distylous species of the Rubiaceae widely distributed in the Brazilian Cerrados. This work aimed to study the floral biology and breeding system of P. rigida in order to verify if there wasasymmetry between floral morphs. The work was carried out at Fazenda Água Limpa, Brasília-DF, from 1993 to 1995; and at Serra Caldas Novas State Park-Goias and in Clube Caça e Pesca Itororó de Uberlândia-Minas Gerais in 2005 and 2006. Density, height and pin/thrum ratio were assessed for flowering individuals in all areas. Plants were investigated for differences in floral morphology, nectar production, reproductive success and site of self incompatibility reactions. Blooming period was long and concentrated during the rains. Flowers were clearly distylous and with reciprocal herkogamy. They produced nectar and lasted for a single day. In spite of differences in density and height, populations were mostly isoplethic. Nectar production varied in volume and concentration but the differences could not be associated with floral morphs. The species is self-incompatible but reproductive success was always high and independent of floral morphs. There were differences in the site of incompatibility barriers between floral morphs, which were similar to those observed for other Rubiaceae. The main floral visitors and pollinators were the hummingbirds Colibri serrirostris and Eupetomena macroura. High fruit-set indicates that the pollinators transported enough compatible pollen grains between floral morphs, despite their territorial behavior.

scholarly journals Viability of Pollen of Two Fruit Crop Cacti of the Genus Hylocereus Is Affected by Temperature and Duration of Storage

HortScience ◽  
2000 ◽  
Vol 35 (1) ◽  
pp. 22-24 ◽  
Author(s):  
Christiane Metz ◽  
Avinoam Nerd ◽  
Yosef Mizrahi
Keyword(s):  
Moisture Content ◽  
Fruit Set ◽  
Pollen Storage ◽  
Vacuum Desiccator ◽  
Long Term Storage ◽  
Duration Of Storage ◽  
Fresh Pollen ◽  
Hylocereus Undatus ◽  
Compatible Pollen

Hylocereus undatus (Haw.) and H. polyrhizus (Weber) are new fruit crops of the Cactaceae. In Israel, flowers of the two species, which are self-incompatible, are hand cross-pollinated. In order to ensure a current supply of compatible pollen and guarantee good yields, we have developed a procedure for long-term storage of pollen. Pollen for storage was collected in the evening or in the morning. Its moisture content ranged between 45% to 50% in the evening and between 18% to 22% in the morning. Pollen was first dehydrated in a vacuum desiccator until the moisture content was reduced to 5% to 10% and then stored at various temperatures (+4, –18, –70, –196 °C) for 3 or 9 months, after which it was used for cross-pollination. Percent fruit set and fruit fresh weight (FW) were affected by the temperature but not the duration of pollen storage; storage at +4 °C reduced fruit set, fruit FW, and seed number more than did storage at subfreezing temperatures. The FW of fruits produced by frozen pollen was similar to that produced by fresh pollen in commercial orchards. The rate of seed germination was high (≈90%) regardless of the temperature during pollen storage.

scholarly journals Mating system and female reproductive success of the endemic, epiphytic Prosthechea aff. karwinskii (Orchidaceae)

Lankesteriana ◽  
2011 ◽  
Vol 11 (3) ◽  
Author(s):  
Ericka Camacho-Domínguez ◽  
Irene Ávila-Díaz
Keyword(s):  
Reproductive Success ◽  
Mating System ◽  
Sexual Reproduction ◽  
Fruit Set ◽  
Natural Populations ◽  
Fruit Production ◽  
Open Pollination ◽  
Female Reproductive Success ◽  
Hand Pollination ◽  
Northern Portion

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. 

Fruit-set after pretreatment with foreign compared with killed compatible pollen

1984 ◽  
Vol 62 (8) ◽  
pp. 1678-1681 ◽  
Author(s):  
W. David Lane
Keyword(s):  
Sweet Cherry ◽  
Direct Evidence ◽  
Fruit Set ◽  
Growth Promotion ◽  
Mineral Analysis ◽  
Foreign Pollen ◽  
Mentor Pollen ◽  
Pollen Growth ◽  
Growth Promoting ◽  
Compatible Pollen

A mechanism based on pollen growth-promoting substances has previously been proposed to explain the effects of mentor (killed compatible) pollen when it improves fertility of crosses between nearly incompatible parents. Similarly, pioneer pollination (two pollinations a day apart) stimulates growth of the last applied pollen and increases fruit-set. In the present experiments the effects of foreign-pollen pioneer treatments on fruit-set of apple, sweet cherry, and apricot were compared with the control, killed compatible pollen. All treatments were followed 24 h later with viable compatible pollen. The foreign pollen, Balsamorrhiza sagittata, did not inhibit fruit-set. When the foreign pollen was heat killed, fruit-set was at least as high as when untreated B. sagittata was used. Two other foreign pollens, Taraxacum officinale and Juniperus communis, resulted in lower fruit-set than B. sagittata but still more than the control. This effect was consistent with a previously hypothesized relationship for mentor pollen, relating size and degree of stimulation. The two nonpollen treatments examined, dried yeast and pectinase solution, slightly inhibited fruit-set. Mineral analysis of a composite of pollen and anther tissue indicated that boron and calcium were not deficient in the control pollen, and incompatibility mechanisms and heat-labile metabolites also were unlikely to have been the cause. No direct evidence was obtained, but pollen growth promotion by a diffusible growth regulator (such as gibberellin) is suggested as plausible and an area worthy of further study.

The Pollination Biology of Dendrobium speciosum Smith: a Case of False Advertising?

1988 ◽  
Vol 36 (2) ◽  
pp. 145 ◽  
Author(s):  
AT Slater ◽  
DM Calder
Keyword(s):  
Related Species ◽  
Fruit Set ◽  
Natural Populations ◽  
Climatic Conditions ◽  
Closely Related Species ◽  
High Occurrence ◽  
Bright Yellow ◽  
Pollination Mechanisms ◽  
Sunny Weather ◽  
Olfactory Display

Potential pollinators of Dendrobium speciosum are attracted to the plant by large, cream to yellow, finely segmented, aromatic inflorescences. Plants in natural populations flower synchronously, produc- ing a massive display. Osmophores scattered over the perianth produce a strong, sweet scent in sunny weather. Nectar-seeking insects are guided to the central, reproductive area of the flower by the colour gradation of the perianth, including an area of high U.V. reflection near the centre, and a bright yellow ridge along the labellum. A tube formed by the labellum and column directs the potential pollinators. The flower, however, produces no nectar. Flowers vary in size within the six recognised varieties of D. speciosum and are pollinated when visited by bees of appropriate size. Post-pollination closure of flowers prevents further access by potential pollinators. The dendrobium beetle and larvae feed on the plant and inflorescences and play no part in pollination. The low fruit set, characteristic of this species, is considered to be a combined result of self-infertility and the absence of rewards offered by the flower. The specific climatic conditions during which pollinators visit the flowers are also important. The attraction and pollination mechanisms are similar among all observed varieties of D. speciosum as well as some closely related species, possibly explaining the high occurrence of hybrids within this group. It is concluded that D. speciosum provides a visual and olfactory display through the production of a large number of hermaphrodite non-rewarding flowers on each inflorescence, and relies on infrequent outcrosses for successful pollination.

Sign in / Sign up

Export Citation Format

Share Document