Manual Pollination Research Articles

Floral Traits and Seed Production of Sorghum A‐, B‐ and R‐lines under Chilling Field Temperatures

AbstractIn A‐lines of sorghum (Sorghum bicolor L. Moench), seed production under field conditions with manual pollination is generally lower than that in self‐pollinated B‐lines. This may be associated with floral differences. Six pairs of A/B‐lines and four R‐lines were evaluated during 2005 and 2006 at Montecillo, State of México (2240 m altitude). Rachis length, number of primary branches and fertile flowers per panicle, 100‐seed weight, seed number, seed yield and seed set per panicle were evaluated. In the A‐lines, the pistil characteristics were also measured and in the male‐fertile lines, the size of anthers and the amount and size of viable pollen were recorded. Compared with the A‐ and B‐lines, the R‐lines exhibited significantly higher (P ≤ 0.05) numbers of flowers, seed set and seed yield per panicle and they also produced more pollen grains of larger size and with greater viability during their longer flowering period (FP). Between A‐ and B‐lines, there were differences (P ≤ 0.05) in most of the yield traits, which also interacted with year. The proportion of viable pollen in B‐ and R‐lines (75 %) was not considered to be a factor that might account for their low seed production. Chilling temperatures (3.5–8.4 °C) during the FP could have affected stigma receptivity in the three different line types and thus may have reduced seed set in the male‐fertile lines.

Etude de la fertilite femelle de cinq clones cultives D'<i>hevea brasiliensis</i> muell arg. (Euphorbiacee), en C&#244 D'Ivoire

After 15 years of manual pollination in Cote d'Ivoire, female fertility of Hevea brasiliensis rubber tree clones was assessed from 3 estimators of fertility, which were the aborted seed, was studied in 5 wickham clones, using a discriminate factor analysis. The PB5/51, PB260 and PB235 clones, which were good seeders, had high initial and final fruit set average rates (11.23 to 15.17 % and 7.09 to 9.13 %), with the highest average rates of aborted seeds (31.72 to 55.91 %). These were, either lower, or higher (18.86 to 41.84 %) for the GT1 and AVROS2037 clones, which were found to be bad seeders. Overall, the study showed a better understanding of the low fertility of the Hevea brasiliensis rubber tree through the identification of good (PB5/ 51, PB 260, PB 235) and bad seeders (GT 1, AVROS 2037).

Brassica rapa L. seed development in hypergravity

AbstractPrevious experiments had shown that microgravity adversely affected seed development in Brassica rapa L. We tested the hypothesis that gravity controls seed development via modulation of gases around the developing seeds, by studying how hypergravity affects the silique microenvironment and seed development. Using an in vitro silique maturation system, we sampled internal silique gases for 16 d late in the seed maturation sequence at 4 g or 1 g. The carbon dioxide level was significantly higher inside the 4-g siliques, and the immature seeds became heavier than those maturing at 1 g. Pollination and early embryo development were also studied by growing whole plants at 2 g or 4 g for 16 d inside chambers mounted on a large-diameter centrifuge. Each day the rotor was briefly stopped to permit manual pollination of flowers, thereby producing cohorts of same-aged siliques for comparison with stationary control material. The loss of starch and soluble carbohydrates during seed development was accelerated in hypergravity, with seeds developing at 4 g more advanced by 2 d than those at 1 g. Seeds produced at 4 g contained more lipid than those at 1 g. Taken together, these results indicate that hypergravity enhances gas availability to the developing embryos. Gravity's role in seed development is of importance to the space programme because of the plan to use plants for food production and habitat regeneration in extraterrestrial settings. These results are significant because they underscore the tight co-regulation of Brassica seed development and the atmosphere maintained inside the siliques.

Eficiência de acessos de Cucurbita maxima como polinizadores de abóbora híbrida do tipo "Tetsukabuto"

A abóbora tipo “Tetsukabuto” é um híbrido interespecífico, macho estéril, resultante do cruzamento entre Cucurbita maxima e C. moschata. Uma das estratégias utilizadas para produção comercial de frutos de “Tetsukabuto” tem sido o plantio adjacente e concomitante de acessos de C. maxima ou C. moschata como polinizadores. Este trabalho teve por objetivo avaliar a eficiência de diferentes acessos de C. maxima como fontes de pólen para produção comercial de abóbora tipo “Tetsukabuto”. A cultivar de moranga "Exposição" e o acesso "Nirvana" foram utilizados como polinizadores para produção de frutos de dois híbridos do tipo varietal “Tetsukabuto” ("Jabras" e "Kyoto"). Foram avaliados os tratamentos (cruzamentos) Jabras x Exposição, Jabras x Nirvana, Tetsukabuto x Exposição, Tetsukabuto x Nirvana, em quatro repetições. Foram determinados os parâmetros massa dos frutos, diâmetro dos frutos, espessura da polpa, número e massa de sementes. O acesso "Nirvana" (cultivar em fase de validação) pode ser utilizado na produção comercial como polinizador de abóboras deste grupo varietal sem nenhum prejuízo quando comparado com a moranga "Exposição".

Interspecific hybridisation and genome size analysis in Buddleja

Interspecific hybrids Buddlejadavidii × Buddlejaweyeriana, Buddlejaweyeriana × Buddlejadavidii and Buddlejadavidii × Buddlejalindleyana were generated using in vitro embryo rescue 10–11 weeks after manual pollination. The morphological variation within the F1 populations was limited. The F1 progeny of B. davidii × B. lindleyana was almost sterile and no F2 generation was obtained. From the other hybrids, F2 generations were made by self pollinations and back crosses. Hybrid nature of all F1 and F2 seedlings was confirmed by AFLP. Chromosome counting and genome size measurement for B. weyeriana (F2 selection of (diploid) B. globosa × (tetraploid) B. davidii) revealed a higher chromosome number (76 chromosomes) and genome size than expected, indicating 2n-gametes formation occurred during meiosis of B. globosa. The F1 hybrids B. weyeriana × B. davidii (76 chromosomes) had an intermediate genome size compared with the genome size of the parent plants, proving their hybrid nature. However, the F1 and F2 hybrids of B. davidii × B. weyeriana all had 76 chromosomes but had a lower genome size than expected, suggesting the occurrence of chromosome rearrangements in the genome of the hybrids. B. lindleyana had 38 chromosomes, while the F1 hybrids of B. davidii × B. lindleyana had 76 chromosomes. Also genome size measurements revealed that the F1 seedlings B. davidii × B. lindleyana had higher genome sizes than expected. Both the results of chromosome counting and genome size measurement indicate that 2n-gametes formation took place during meiosis of B. lindleyana.

Fenologia e visitantes florais de Erythrina crista-galli L. (Leguminosae: Faboideae) em Santa Maria, Rio Grande do Sul, Brasil

Phenology and fl oral visitors of Erythrina crista-galli L. (Leguminosae: Faboideae) in Santa Maria, Rio Grande do Sul, Brazil. Erythrina crista- galli is a characteristic species of the Pampa biome also used as an ornament in urban arborization. Erythrina crista-galli fl ourishes more intensively from November to December. Anthesis starts around 7:00 am to 11:00 am, and fl owers last fi ve days. A total of 1,275 fl oral visits were registered over 57h of observations. Apidae bees (Trigona spinipes and Apis mellifera) were the most frequent visitors (88.23%), followed by Muscidae fl ies (5.50%), Formicidae ants (2.35%), Ves- pidae wasps (1.56%), and Chrysomelidae beetles (1.56%). Trochilidae hummingbirds (Chlorostilbon aureoventris) (0.79%) also visited the fl owers. Trigona spinipes was observed at throughout the daytime and behaved as a probable pollinator, along with A. mellifera and C. aureoventris. E. crista-galli is autocompatible, producing fruits and seeds after manual pollination and under natural conditions.

Comportamento fenológico no evento pós-queima e biologia reprodutiva de Spiranthera odoratissima A. St.-Hil. (Rutaceae)

Post-fi re phenological behavior and breeding biology of the Spiranthera odoratissima A. St.-Hil. (Rutaceae). The phenological behavior of species in response to cerrado stricken by fi re is little known. A phenological and reproductive biological study of Spiranthera odoratissima was carried out in an anthropized area of cerrado sensu stricto affected by fi re in Goiânia County, Goiás, Brazil. Phenolocial observations indicated that the indivi- duals bloomed in synchrony three months after the fi re. The phenological rhythms were associated with the seasonal pluviometric effects, a chara- cteristic pattern of shrublet species of the cerrado. The fl owers are white with a sweet odor and are grouped in panicle infl orescences. The blos- soming occurs during dusk and begins at around 16h. It offers pollen and nectar to its visitors. The species produces 32.8μl (± 3.4) of nectar with an average concentration of 16.4% (± 0.43) in equivalents of sucrose. The pollination system (phalenophily) was proposed based on an analysis of the fl ower’s characteristics. Observed visitors were bees (Apis to be merely resource thieves. It was observed that Trigona spinipes Fabr. can act as a secondary pollinator during the pilling of pollen. The results of manual pollination and the incompatibility index (ISI) indicate that the species is xenogamous and self-compatible.

Fenologia e Biologia Reprodutiva de Tibouchina papyrus (Pohl) Toledo (melastomataceae) no Parque Estadual da Serra dos Pireneus, Goiás

The phenological and reproductive study of Tibouchina papyrus (Pohl) Toledo (Melastomataceae) was carried out in campo rupestre vegetation, at an altitude of 1,100 m in the Parque Estadual dos Pirineus, located in municipalities of Pirenopolis and Cocalzinho, in the state of Goias. Twenty individuals of the population were selected, marked, and observed for two years regarding phenological processes such as flowering and fruiting. Their reproductive system was evaluated by manual pollination and calculations of reproductive efficacy. The fruits formed were collected and their seeds germinated in Petri dishes with wet filter paper. Treatments of manual pollination indicate this is a facultative xe nogamy species with higher fruit production by cross-pollination (45%) than by self-pollination (12%). Emasculated flowers to induce agamospermy did not produce fruits. The low production of control-fruit (30%) may be explained by low presence of pollinators. The protrusion of the radicle occurred between the 7 th and the 8 th day with 55% of germination. Flowering occurred from December to June, and fruit maturation between April and October, coinciding with seed dispersal and leaf fall during the dry season. This study provides information to understand the reproductive process of T. papyrus , an endemic and still not well studied species.

Reproductive biology of Cyrtopodium polyphyllum (Orchidaceae): a Cyrtopodiinae pollinated by deceit

The genus Cyrtopodium comprises about 42 species distributed from southern Florida to northern Argentina. Cyrtopodium polyphyllum occurs on rocks or in sandy soils, in restinga vegetation along the Brazilian coast. It flowers during the wet season and its inflorescences produce a high number of resupinate yellow flowers. Cyrtopodium polyphyllum offers no rewards to its pollinators, but mimics the yellow, reward-producing flowers of nearby growing Stigmaphyllon arenicola (oil) and Crotalaria vitellina (nectar) individuals. Several species of bee visit flowers of C. polyphyllum, but only two species of Centris (Centris tarsata and Centris labrosa) act as pollinators. Visits to flowers of C. polyphyllum were scarce and, as a consequence, low-fruit set was recorded under natural conditions. Such low-fruit production contrasts with the number of fruits each plant bears after manual pollination, suggesting deficient pollen transfer among plants. C. polyphyllum is self-compatible and has a high-fruit set in both manual self- and cross-pollinated flowers. Furthermore, fruits (2%) are formed by self-pollination assisted by rain. This facultative self-pollination mechanism is an important strategy to provide reproductive assurance to C. polyphyllum as rainfall restricts the foraging activity of its pollinating bees. Fruits derived from treatments and under natural conditions had a similar high rate of potentially viable seed. Moreover, these seeds had a low polyembryony rate, which did not exceed 5%. C. polyphyllum acts by deceit involving optical signals and exploits other yellow-flowered species within its habitat by attracting their pollinators. The low capsule production under natural conditions was expected, but its reproductive success is assured through self-pollination by rain and high seed viability.

Patterns of introduction and diversification of Vanilla planifolia (Orchidaceae) in Reunion Island (Indian Ocean)

The cultivated species Vanilla planifolia is a typical example of a crop introduced from its area of origin (America) to new regions where natural pollinators are absent. Although the Vanilla cultivars are exclusively vegetatively propagated, a high degree of phenotypic variation is observed among the cultivars in their introduction areas such as Reunion Island. To test several hypotheses explaining this variation-different introduction events, somatic mutations and sexual reproduction (through manual pollination)-we used AFLP markers to elucidate the patterns of introduction of V. planifolia. Most of the accessions cultivated in the world were derived from a single accession, possibly the Mexican cultivar Mansa. The patterns of diversification of this cultivated species were also studied and compared with other cultivated (V. tahitensis) and wild (V. pompona and V. bahiana) species. Except for one particular phenotype ('Aiguille'), which may come from sexual reproduction, cultivated accessions exhibit very low levels of genetic diversity. They have evolved by the accumulation of point mutations through vegetative multiplication. The genetic diversity revealed could not explain the phenotypic diversity, which may be related to epigenetics or polyploidy. This new understanding of the basis of genetic diversity of vanilla may assist to improve management of genetic resources.

A microsatellite study on outcrossing rates and contamination in an Eucalyptus globulus breeding arboretum

Four pairs of microsatellite molecular polymorphism primers were used to analyse microsatellite fingerprints of 188 seedlings derived from an open-pollinated progeny grafted Eucalyptus globulus breeding arboretum in Victoria, south-eastern Australia. The microsatellite loci chosen for this study were highly polymorphic with the mean number of alleles per locus of 14.25. Individual mothers varied in their outcrosssing rate estimate from 15% to 95%, the overall outcrossing level in the arboretum was 47.9% and the contamination rate was 17.6%. The high selfing level was likely to result in marked inbreeding depression in the performance of open-pollinated seed lots. Open-pollinated seeds collected from such arboreta are not advisable because of its low genetic quality, although such arboreta may be useful for the seed production through large-scale manual pollination or collecting seeds only from trees or genotypes within the arboretum that have high outcrossing rates.

Aspectos da biologia floral relacionados à produção de frutos de pinha (<em>Annona squamosa</em> L.)

The State of Bahia is the largest producer of sugar apple in Brazil, reaching a production area of 5,400 ha. In order to ensure good fruit productivity and quality, studies related to pollination are essential, and provide data that subsidize phyto-improvement programs. The objective of this work was the study of floral biology aspects linked to the production of sugar apple. The study was carried out in two commercial orchards in the Southwestern region of the State of Bahia, Brazil, comprising the following steps: observation of the morphological characteristics of the flowers; collection and storage of pollen grains under two temperature conditions; analysis of the viability and pollen germinability; and manual pollination at five different times after collecting the pollen grains. The experimental design used was entirely randomized blocks. The results provided by the regression analysis and by the variance analysis enabled the conclusion that: Anthesis occurs at 5 a.m., and that the pollen grains preserved in a refrigerator (5 to 7oC) are still viable up to 12 hours after collected, enabling the production of fruits with commercially accepted weight

Armazenamento de botões florais para produção de sementes de abóbora com polinização manual

O objetivo deste trabalho foi verificar a influência do armazenamento de botões florais masculinos por diferentes períodos, na produção e qualidade de sementes de abóbora cultivar Piramoita. O experimento foi desenvolvido no período de agosto a dezembro de 2005. O delineamento experimental utilizado foi em blocos ao acaso, com quatro repetições e cinco tratamentos: polinização manual com flor aberta no dia (zero dia de armazenamento) e polinização manual com botões armazenados em geladeira (7 ºC) por 1, 2, 3 e 4 dias. Quanto maior o período de armazenamento dos botões florais masculinos, menor a produção (número e massa) de sementes por fruto e a massa média do fruto. Também há uma perda de vigor e germinação das sementes quando se aumenta o período de armazenamento dos botões florais, reduzindo sua qualidade.

Reproductive trade-offs in a specialized plant/pollinator system involving Asplundia uncinata Harling (Cyclanthaceae) and a derelomine flower weevil (Coleoptera: Curculionidae)

The reproductive interactions of a specialized plant/pollinator system involving Asplundia uncinata Harling (Cyclanthaceae) and a derelomine flower weevil (Coleoptera: Curculionidae: Derelomini) were studied at La Selva, Costa Rica. The inflorescences of A. uncinata exhibit a suite of cantharophilous characters including a precisely synchronized anthesis, protogyny, thermogenesis, olfactory attraction of visitors via modified staminodes, and narrow interfloral entrances. The weevil pollinators use the inflorescences for feeding, mating, and oviposition. The larvae are detritivorous and develop either in the detaching staminate flowers or, at a more favorable rate, in the rotting infructescences. The rate of infructescence abortion was high and caused by low levels of pollination. Manual pollination treatments yielded significantly higher seed counts than obtained under natural conditions, and furthermore demonstrated the inflorescences' ability to reproduce via geitonogamy. In the longer term, the reproductive benefits of maintaining low levels of pollination may shift away from the weevils and towards the plants via an increase in the size of the pollinator population.

Reduced seed production, inbreeding, and pollen shortage in a small population of a threatened tree, Magnolia stellata

We investigated how genetic factors and pollen shortage affect seed production in a small population of Magnolia stellata, a threatened insect-pollinated tree. We used microsatellite and manual pollination techniques, and compared a small population to a large one. Compared to the large population, the small population showed low allelic variation and had an F IS significantly greater than 0 in adults, indicating that genetic deterioration, including genetic drift and inbreeding, may have occurred in adults. Manual self-pollination lowered seed production relative to manual cross-pollination to a different extent between populations: δ (the magnitude of inbreeding depression due to self-fertilization) was lower in the small population than in the large population. However, under natural pollination, the estimated embryo mortality rates after ovules self-fertilized were similar between the two populations because the primary selfing rate was higher in the small population. The ovule mortality rate due to pollen shortage and that due to factors independent of pollen shortage and selfing were both approximately 10% higher in the small population, suggesting that pollen transfer may have decreased and genetic deterioration effects may have increased in that population. These factors reduced seed production in the small population (female reproductive success = 0.3%) compared to the large population (2.6%). Our results suggest that seed production in the small population of M. stellata is strictly limited by elevated pollen shortage, selfing, and genetic deterioration in adults, which accelerate the risk of extinction.

Gene flow from genetically modified herbicide-resistant rapeseed to cruciferous weeds

The sexual compatibility between genetically modified (GM) glyphosate-resistam rapeseed variety Q3 (Brassica napus L. ) and 5 cruciferous weeds is studied through the observation of fluorescence microscopy and cross-fertility after manual pollination. The results indicated that Q3 (as male) was highly incompatible with Thlaspi arvense L., Capsella bursa-pastoris (L. ) Medic, Cardamine hirsuta L. and Rorippa palustris (L. ) Besser (as female). Fluorescence microscopic observation showed that growing of pollen tubes terminated on the stigma surface or at the upper 1/3 part of the style. However, B. juncea×Q3 was compatible, and the compatibility index was 1.65. Under the neighboring growth and natural pollination conditions, the rates of gene flow from Q3 to T. arvense, C. bursa-pastoris, C. hirsute and R. palustris were all 0, while it was 0.86 % for B. juncea. These results indicate that there is difference in the rate of gene flow between GM rapeseed and cruciferous wild weeds, and frequency of gene flow is highly correlated with sexual compatibility.

Biologia floral e polinização de Anemopaegma chamberlaynii Bur. & K. Schum. (Bignoniaceae).

The present work deals with the floral biology, reproductive system and phenological events of Anemopaegma chamberlaynii Bur. & K. Schum. (Bignoniaceae), in the coastal strand vegetation (restinga) of Maricá RJ., between 1997 and 2000. The flowers display daytime anthesis, are yellow, very attractive, tubulous, hermaphrodite, odoriferous and produce nectar as the floral reward. The nectar is secreted by a nectariferous disk and accumulated in a chamber. The stigmas are bifid, wet and papillous. The stigmatic lobes are receptive to pollen only on the inner surfaces and are sensitive to disturbance. If the stigma is touched but no pollen is deposited, the lobes close and soon reopen. The same occurs when self-pollen is deposited on the receptive surface. However, after manual pollination with cross-pollen the lobes close permanently, enabling to estimate levels of pollination by monitoring stigma closure. Euglossa cordata L., Epicharis dejeanii Lepeletier and E. semiflava Moure are potential pollinators. Xylocopa ordinaria Smith is the primary nectar robber. The species is self-incompatible and has a low fruit set (Fruit/Flower=4.86%). The flowering pattern is the “multiple bang”, showing five episodes per year, with the same intensity, all of them occurring in the most hot and rainy months.

An Evaluation of Pollination Mechanisms for Purple Prairie-clover, Dalea purpurea (Fabaceae: Amorpheae)

Abstract Purple prairie-clover (Dalea purpurea Ventenat) is a common perennial forb that flowers during mid-summer throughout the Great Plains and adjacent biomes. Seed of D. purpurea is used for prairie restoration. This study characterizes the reproductive biology of D. purpurea. Manual pollination field trials showed that D. purpurea has a mixed pollination system. It is primarily xenogamous (45% of flowers manually pollinated with outcross pollen yielded plump seeds), but partially self-compatible (19% of selfed flowers yielded seeds). Flowers neither visited by bees nor manually pollinated rarely yielded mature seed (0–6% of flowers). A review of extensive bee community surveys from sites with prairie wildflower communities revealed that D. purpurea attracts a rich and diverse native bee fauna. Managed agricultural pollinators (Apis mellifera, Megachile rotundata) also work its flowers for pollen and nectar, yielding >20,000 seeds per plant. These observations bode well both for pollinating D. purpur...

Variação morfológica e reprodutiva de Aechmea lindenii (E. Morren) Baker var. lindenii (Bromeliaceae)

Buscou-se determinar o efeito da intensidade luminosa sobre as características morfológicas e reprodutivas de A.lindenii, em ambientes de restinga herbácea (alta luminosidade) e sub-bosque de restinga arbórea (baixa luminosidade), em Florianópolis, SC, onde os resultados indicam que a luminosidade pode influenciar no seu fenótipo, produção de néctar, fenologia e sucesso reprodutivo. As plantas esciófitas são maiores e apresentam um período de floração em torno de 120 dias, enquanto que as heliófitas são menores e florescem ao longo de todo o ano. A espécie apresenta atributos florais à ornitofilia, estando o volume (16,7 µL ± 4) e concentração (27,25%) do néctar produzido pelas flores dentro do esperado para espécies polinizadas por beija-flores. A freqüente visitação de Amazilia fimbriata, Thalurania glaucopis e Thalurania sp. (Trochilidae) confirma esta observação, porém abelhas e borboletas também foram consideradas potenciais polinizadores, sugerindo co-evolução de síndromes florais secundárias. Baseando-se nos resultados dos testes de polinizações manuais e no desenvolvimento dos tubos polínicos, pode-se concluir que a espécie não apresenta auto-incompatibilidade, formando frutos com sementes férteis, com germinação superior a 80%, oriundas tanto de fecundação cruzada quanto da autopolinização. A população heliófita apresentou elevadas taxas de partenocarpia (52, 95%) e mostrou ser um método seguro e eficaz de se avaliar a fertilização das flores, podendo-se assim, relacionar a sua freqüência e abundância à ausência ou ineficiência dos visitantes florais. Os frutos e sementes foram dispersos por pássaros das famílias Thraupidae e Pipridae e predados por lagartas da borboleta Tecla sp. (Lycaenidae).

Influência do estádio de maturação da flor na produção de sementes de pimentão com polinização manual

O objetivo deste experimento foi avaliar a produção de sementes de pimentão com polinização manual de flores em diferentes estádios de maturação. Foram cinco tratamentos: polinização manual no dia da emasculação, um, dois e três dias depois da emasculação, sempre com flores emasculadas um dia antes da antese, além da testemunha, com polinização natural. O delineamento experimental foi em blocos ao acaso, com seis repetições de dez plantas. Foi obtida maior produção (massa e número) de sementes, por fruto e por polinização, com polinizações realizadas um dia antes e no dia da antese, que não diferiram da polinização natural.