Orientador: João Antonio da Costa Andrade / Banca: Maria Elisa Ayres Guidetti Zagatto Paterniani / Banca: Pedro César dos Santos / Resumo: O fenômeno de xênia é descrito como o efeito direto do pólen no embrião e endosperma da semente, alterando suas características genéticas e proporcionando mudanças qualitativas e quantitativas. Vários caracteres do grão de milho como cor, tamanho, peso e teor de alguma substância apresentam esse efeito. Portanto existe a possibilidade deste fenômeno ser explorado com o cultivo de dois híbridos com sementes misturadas, buscando-se um aumento no rendimento da lavoura. O objetivo deste trabalho foi identificar pares de híbridos, em duas épocas de semeadura, que apresentem efeito xênia para os caracteres tamanho de grãos, peso médio de grãos e conteúdo de óleo e proteína. O trabalho foi conduzido na Fazenda de Ensino e Pesquisa da Faculdade de Engenharia de Ilha Solteira - UNESP, localizada no município de Selvíria - MS. Foram avaliados todos os pares possíveis, incluindo os recíprocos, entre os híbridos AG 8080, DKB 333B, DAS 32, P 30F80, TORK e XB 8010, sob delineamento estatístico de blocos casualizados com quatro repetições na primeira safra e três na segunda safra (safrinha). A polinização de cada híbrido (cruzamento ou "sib") foi realizada manualmente em cada parcela, de acordo com o tratamento especificado. As análises indicaram efeito xênia de 15%, no peso médio dos grãos do híbrido XB 8010 quando polinizado pelo TORK, na primeira safra, quando em comparação com o XB 8010 polinizado com seu próprio pólen. Na Segunda safra o híbrido DKB 333B proporcionou um aumento de 20% no peso médio dos grãos do AG 8080. Para conteúdo de proteína, o efeito xênia foi significativo e negativo (-9,0%) quando o híbrido DKB 333B recebeu pólen do híbrido TORK, na primeira safra, e nos demais cruzamentos não houve influência da fonte polinizadora. Para o caráter conteúdo de óleo, a manifestação do efeito xênia ocorreu nas duas épocas... (Resumo completo, clicar acesso eletrônico abaixo). / Astract: The xenia phenomenon is described as the direct effect of the pollen in the seeds's embryo and endosperm, altering their genetic traits and providing qualitative and quantitative changes. Several grain traits as color, size, weight and contents any substance, presents this effect. Therefore there is possibility of this phenomenon to be explored with the cultivation of two hybrids with mixture of seeds, seeking for a increase in the yield. The goal of this work was identify hybrid pairs for the traits grains medium weight, grains size and the oil and protein content, that show xenia effect in two sowing season. Were appraised all the pairs possible, including the reciprocal ones, among the hybrids AG 8080, DKB 333B, DAS 32, P 30F80, TORK and XB 8010, in a complete random block design, with four replicates at normal season and three replicates at no season crop. The pollination (cross and sib) of each hybrid, were realized manually in each plot, under the specified treatment. The analyses indicated 15 % of xenia effect in the grains medium weight of the hybrid XB 8010 as pollinated by TORK, at normal season, as compared with XB 8010 pollinated by your self pollen. In no season crop the hybrid DKB 333B provided an increase of 20% in the grains medium weight of AG 8080. For the protein content, the xenia effect was significant and negative (-9,0%) when the hybrid DKB 333 received pollen of TORK, at normal season, and the of others crossing have not influence the pollen, showing a larger maternal effect. For the trait oil content the xenia effect showed up in two sowing season. At normal season the pollen of hybrid DKB 333B changed significantly the grains oil percentage of AG 8080 (15%) and TORK (14%). In no season crop, the pollen of P 30F80 and DKB 333B increase in 20% and 21% the oil contents of DAS 32 and P 30F80, respectively. Therefore it was... (Complete abstract, click electronic address below). / Mestre

Made available in DSpace on 2014-06-11T19:29:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2003-05-29Bitstream added on 2014-06-13T18:39:46Z : No. of bitstreams: 1 pereira_fcd_me_ilha.pdf: 131886 bytes, checksum: ba4c06ac24276bdd5096e975fc46ff3c (MD5) / O fenômeno de xênia é descrito como o efeito direto do pólen no embrião e endosperma da semente, alterando suas características genéticas e proporcionando mudanças qualitativas e quantitativas. Vários caracteres do grão de milho como cor, tamanho, peso e teor de alguma substância apresentam esse efeito. Portanto existe a possibilidade deste fenômeno ser explorado com o cultivo de dois híbridos com sementes misturadas, buscando-se um aumento no rendimento da lavoura. O objetivo deste trabalho foi identificar pares de híbridos, em duas épocas de semeadura, que apresentem efeito xênia para os caracteres tamanho de grãos, peso médio de grãos e conteúdo de óleo e proteína. O trabalho foi conduzido na Fazenda de Ensino e Pesquisa da Faculdade de Engenharia de Ilha Solteira - UNESP, localizada no município de Selvíria - MS. Foram avaliados todos os pares possíveis, incluindo os recíprocos, entre os híbridos AG 8080, DKB 333B, DAS 32, P 30F80, TORK e XB 8010, sob delineamento estatístico de blocos casualizados com quatro repetições na primeira safra e três na segunda safra (safrinha). A polinização de cada híbrido (cruzamento ou sib) foi realizada manualmente em cada parcela, de acordo com o tratamento especificado. As análises indicaram efeito xênia de 15%, no peso médio dos grãos do híbrido XB 8010 quando polinizado pelo TORK, na primeira safra, quando em comparação com o XB 8010 polinizado com seu próprio pólen. Na Segunda safra o híbrido DKB 333B proporcionou um aumento de 20% no peso médio dos grãos do AG 8080. Para conteúdo de proteína, o efeito xênia foi significativo e negativo (-9,0%) quando o híbrido DKB 333B recebeu pólen do híbrido TORK, na primeira safra, e nos demais cruzamentos não houve influência da fonte polinizadora. Para o caráter conteúdo de óleo, a manifestação do efeito xênia ocorreu nas duas épocas... .

Transgenic corn hybrids expressing Bt toxins are widely deployed to control pests such as Helicoverpa zea (Boddie). However, Bt resistance can reduce the efficacy of Bt corn hybrids. Volunteer corn expressing Bt toxins may impact Bt resistance management of pests. Surveys in Mississippi revealed the occurrence of fall season volunteer corn in high densities. Helicoverpa zea larvae were found feeding during both vegetative and reproductive stages. However, Bt parentage and low to moderate water and nitrogen stresses did not significantly influence H. zea larval growth and development on Bt positive volunteer plants. Additionally, pollen mediated Bt gene flow to non-Bt refuge ears from Bt hybrids significantly reduced H. zea larval growth on cross-pollinated refuge ears. The implications of these findings are that volunteer corn in most Mississippi corn production regions will have little impact on H. zea Bt resistance management, but resistance management could be compromised in more southern regions.

Made available in DSpace on 2014-08-20T13:25:38Z (GMT). No. of bitstreams: 1 dissertacao_jones_eloy.pdf: 1690635 bytes, checksum: 35ae8138d7942712200eb8662fa2812e (MD5) Previous issue date: 2013-06-25 / Pollination is presented as a determining factor in the production of fruits in various fruit species, especially those that do not reproduce by parthenocarpy. This study aimed to evaluate the influence of self-pollination and cross-pollination of jelly palm in production and fruit quality. To this end, we used 14 genotypes of jelly palm of BAG of FAEM-UFPel, RS, Brazil. The treatments were: non-bagging (T1) and bagging with TNT (T2). Evaluated: average production cycle (days), average fruit weight (g), the average mass of pulp (g), pulp yield (%), average mass of pyrenes (g), number of fruits, equatorial diameter of fruits (EDF), longitudinal diameter of fruits (LDF), equatorial diameter of pyrenes (EDP), longitudinal diameter of pyrenes (LDP), relationship LDF/EDF, relationship LDP/EDP, amount of juice (ml), average number of almonds/pyrene (NA/P), almonds brocade/pyrene (%AB/P), average mass unitarian of almonds (AMUA), without almonds pyrenes (%WAP), skin colorimetry (°Hue), soluble solids (°Brix), titratable acidity (TA) ratio (SS/TA), juice pH, ascorbic acid (mg.100ml-1 juice), average date of flowering (DF) and average date of harvest (H). Self-pollination of jelly palm caused a reduction of the overall rates in the variables average mass of fruit, fruit number, EDP, NA/P, %AB/P, TA and ascorbic acid, significantly increased the average mass of pulp, relationship LDF/EDF , relationship LDP/EDP, amount of juice (ml), AMUA, % PSA, SS, ratio and pulp yield (%). It was concluded that the bagging of clusters of jelly palm cause declines, in the production, of 49.31%. However, leads to improvement in the quality of the fruit. The fruits that have been deprived of cross-pollination resulted in increased pulp yield (2.87%). The cross-pollination is essential in genotypes G. 32, G. 35, G. 57 and G. 63, without it there is no fruit production. / A polinização apresenta-se como fator determinante na produção de frutos em várias espécies de fruteiras, em especial naquelas que não se reproduzem por partenocarpia. Esta pesquisa objetivou avaliar a influência da autopolinização e da polinização cruzada de Butia odorata (Barb. Rodr.) Noblick & Lorenzi na produção e na qualidade do butiazeiro. Para tal, foram utilizados 14 genótipos de butiazeiros do banco ativo de germoplasma (BAG) da FAEM-UFPel. Os tratamentos utilizados foram: não-ensacamento (T1) e ensacamento com TNT (T2). Avaliou-se: ciclo médio de produção (dias), massa média dos frutos (g), massa média de polpa (g), rendimento de polpa (%), massa média dos pirênios (g), número de frutos, diâmetro equatorial dos frutos (DEF), diâmetro longitudinal dos frutos (DLF), diâmetro equatorial dos pirênios (DEP), diâmetro longitudinal dos pirênios (DLP), relação DLF/DEF, relação DLP/DEP, volume de suco (em ml), número médio de amêndoas/pirênio (NA/P), amêndoas brocadas/pirênio (%AB/P), massa média unitária de amêndoas (MMUA), pirênios sem amêndoas (%PSA), colorimetria da epiderme (°Hue), sólidos solúveis (°Brix), acidez titulável (AT), ratio (SS/AT), pH do suco, teor de ácido ascórbico (em mg de AA.100ml-1 suco), data média de floração (DMF em dd/mm/aa) e data média de colheita (DMC em dd/mm/aa). A autopolinização dos butiazeiros provocou redução dos índices gerais nas variáveis massa média dos frutos, número de frutos, DEP, NA/P, %AB/P, AT e ácido ascórbico; aumentou de forma significativa a massa média de polpa, relação DLF/DEF, DLP/DEP, volume de suco, MMUA, %PSA, SS, Ratio e rendimento de polpa. Concluiu-se que o ensacamento de cachos do butiazeiro diminui a produção em 49,31%, todavia, provoca melhoria na qualidade das frutas. As frutas que foram privadas da polinização cruzada resultaram em aumento do rendimento de polpa (2,87%). A polinização cruzada é fundamental nos genótipos G. 32, G. 35, G. 57 e G. 63, sem a qual não há produção de frutas.

Thesis (MScAgric (Horticulture))--Stellenbosch University, 2008. / Sweet cherries (Prunus avium L.) have a high chilling requirement and grow best in areas receiving >1 100 Utah chill units during winter. The main production areas in South Africa, and particularly the eastern Free State, frequently receive insufficient winter chilling and late spring frosts leading to problems of poor budburst, flowering, floral abnormalities and poor fruit set. Research was conducted on the cultivar ‘Bing’ to determine the main factors causing its low fruit set. Various trials were conducted to optimize the timing of rest breaking agents, identify suitable cross pollinizers that flower synchronously with ‘Bing’, and evaluate the influence of temperature and pollen-pistil interactions on fertilization and fruit set. Pollen biology studies using 2- to 3-year-old ‘Bing’ sweet cherry trees were conducted near Clarens, eastern Free State, during the 2005 and 2006 seasons to determine the most suitable cross pollinizer/s for ‘Bing’ and to assess the influence of temperature and pollen-pistil interactions on pollen tube growth and ovule longevity. Significant differences in pollen germination (‘rates’ deleted) occurred between pollinizers, although differences were noted in pollen performance on the stigma and style (in vivo) compared to the artificial media (in vitro), indicating a lack of correlation between in vitro germination and in vivo pollen-pistil interactions. Pollen tube growth, following cross pollination, was influenced by pollinizer genotype, temperature, and the number of pollen grains deposited on the stigma. The highest pollen tube growth rates in ‘Bing’ styles were recorded for the pollinizers ‘Black Tartarian’ (2006), ‘Lapins’ and ‘Rainier’ sweet cherry cultivars at temperatures of approximately 21°C. Temperature had the most significant influence on ovule longevity with the lower orchard temperatures extending ovule viability compared to the higher laboratory temperatures, although pollen tube growth rates were also reduced, thus shortening the effective pollination period. Cross pollination was also shown to extend ovule viability. The results indicate that ‘Black Tartarian’, ‘Lapins’ and ‘Rainier’ were the most suitable pollinizers for ‘Bing’. Hand-pollination with pollen from these donors resulted in a several-fold increase in seed set over naturally-pollinated control flowers. It appears that the principle factors causing poor fruit set in ‘Bing’ sweet cherry are premature abortion of the ovule before fertilization and inadequate transfer of sufficient viable pollen under orchard conditions. Rest breaking trials were conducted on 4-year-old ‘Bing’ sweet cherry trees on ‘Gisela® 5’ rootstock near Clarens (28°28’S; 28°19’E, 1860m) and Reitz (28°0’S; 28°28’E; 1717m) in the eastern Free State, South Africa, during the 2005 and 2006 seasons respectively. In 2005 five treatments were evaluated; viz. 1% and 2% Dormex® (hydrogen cyanamide, HCN); 1% Dormex® + 3% mineral oil; and 3% Lift® (thidiazuron and mineral oil) sprayed at three dates (29 July 2005, 5 August 2005 and 12 August 2005) preceding expected the “green-tip” stage of flower development, plus an unsprayed control. In 2006 four treatments were evaluated; viz. 1% Dormex®; 1% Dormex® + 3% mineral oil; 3% Lift® applied on three dates (26 July 2006, 7 August 2006 and 12 August 2006) and an unsprayed control. No interaction was observed between time of application and type of rest breaking agent (RBA). RBAs were effective at improving budburst and yield during both seasons with the time of application of RBAs having the most significant influence on budburst and production efficiency in ‘Bing’ sweet cherry trees. RBAs were most effective at improving vegetative budburst when applied 9 to 16 days before the (‘actual’ deleted) “green-tip” stage of flower development. Floral budburst and yield were increased by 1% Dormex® + 3% mineral oil and 3% Lift®, but results varied between seasons indicating that time of RBA application should be based on chilling accumulation and bud development stage and not based on calendar date. This current research suggests that ‘Bing’ sweet cherry is poorly suited climatically to the current production areas of the eastern Free State and short-term research needs to identify methods of improving chilling and fruit set by means of evaporative cooling and fruit set-enhancing plant growth regulators. Longer term work requires the identification of new, lower chill cultivars with improved climatic adaptation to South African conditions.

Sisyrinchium micranthum Cav. is an herbaceous plant, one of the rare species of the genus which is described as annual. In Brazil, its distribution occurs throughout the states of Rio Grande do Sul (RS), Santa Catarina (SC), Paraná (PR), São Paulo (SP), and Rio de Janeiro (RJ). The species has a wide morphological variability reported in several studies, and different combinations of morphological features can be observed in the wild. Based on these combinations that characterize various plant profiles, three morphological types have been described as CI, CII and CIII. Sisyrinchium micranthum has three ploidy levels described in the literature whose basic number is x = 8, 2n = 2x = 16, 2n = 4x = 32, and 2n = 6x = 48. To contribute to the knowledge on the taxonomy, reproduction and evolution of the species, this study investigated genetic and cytogenetic characteristics of S. micranthum, as well as aspects of reproductive biology. To study the population genetic structure of S. micranthum in southern Brazil, firstly, nine microsatellite markers were isolated using an enriched genomic library, and characterized in a diploid population. Later, from the analysis of genetic variability with seven markers for 583 plants of 14 sampled sites in the states of RS, SC and PR, populations with individuals of different ploidy levels were observed. An autopolyploid origin was presumed for these polyploids. The gene and allelic diversities were rather similar for most of the accessions. The inbreeding coefficient over all loci showed that S. micranthum exhibited an average excess of heterozygotes (negative inbreeding coefficient value), but the FIS values of individual populations ranged from -0.273 to 0.454. The heterozygote excess could be expected since autopolyploids present polysomic inheritance, which contributes substantially for a high heterozygosity. In addition, the populations were highly structured. The results from the cytogenetic analyses, demonstrated that the variability of S. micranthum is also present in terms of genome organization. Regarding S. micranthum and related species S. laxum Otto ex Sims and S. rosulatum E.P. Bicknell, it was verified that the 18S-26S rDNA varies in number of loci, with a notable reduction of the same in polyploids in relation to diploids, while 5S locus showed a proportional increase in the number of signals as increased ploidy level. The data on genome size (Cx) for the three species studied showed a genome downsizing from diploids to polyploids, and also a small inter and intraspecific variation with respect to the C-value. In terms of reproductive biology, selfing and outcrossing were recorded for the species. Furthermore, crossing between different morphological categories of S. micranthum are compatible as resulted in the formation of fruits. Likewise, the data suggest that S. micranthum and S. laxum do not present complete reproductive isolation. The genetic variability of S. micranthum demonstrated in this study in terms of genetic divergence between populations and variation in rDNA loci number possibly reflect the complex relationship between polyploidy and reproductive aspects of the species. / Sisyrinchium micranthum Cav. est une espèce herbacée, l'une des rares du genre qui est décrite comme annuelle. On la trouve au Brésil dans les états du Rio Grande do Sul (RS), Santa Catarina (SC), Paraná (PR), São Paulo (SP) et Rio de Janeiro (RJ). Cette espèce montre une grande variabilité morphologique signalée dans plusieurs études, et différentes combinaisons de caractères morphologiques peuvent être observées dans la nature. Sur la base de ces combinaisons qui caractérisent les profils de plantes différentes, trois types morphologiques ont été décrits, CI, CII et CIII. Sisyrinchium micranthum a trois niveaux de ploïdie décrits dans la littérature à partir du nombre de base x = 8, 2n = 2x = 16, 2n = 4x = 32 et 2n = 6x = 48. Pour contribuer à la connaissance taxonomique, reproductive et évolutive de l’espèce, cette étude a considéré des caractéristiques génétiques et cytogénétiques de S. micranthum, ainsi que les aspects de la biologie de la reproduction. Pour étudier la structure des populations de S. micranthum dans le sud du Brésil, neuf marqueurs microsatellites ont été isolés à l'aide d'une banque génomique enrichie, et caractérisés dans une population diploïde. A partir de l'analyse de la variabilité génétique avec sept marqueurs pour 583 plantes de 14 localités d’échantillonnage de RS, SC et PR nous avons observé l'existence de populations possédant des individus à différents niveaux de ploïdie. Une origine autopolyploïde a été présumé pour ces polyploïdes. La diversité génique et allélique était à peu près similaire dans la plupart des populations. Le coefficient de consanguinité sur tous les loci a montré que les populations de S. micranthum ont présenté un excès des hétérozygotes (coefficient de consanguinité négative), mais les valeurs de FIS de populations individuelles variaient de -0,273 à 0,454. L'excès d'hétérozygotes peut être dû à un héritage polysomique des autopolyploïdes, ce qui contribue sensiblement à une hétérozygotie élevée. En outre, les populations sont très structurées. Les résultats de l'analyse cytogénétique montrent que la variabilité chez S. micranthum s’exprime aussi en termes d'organisation du génome. En ce qui concerne S. micranthum et les espèces proches S. laxum Otto ex Sims et S. rosulatum E.P. Bicknell, il a été démontré que l'ADNr 18S-26S varie en nombre de loci, avec une réduction importante chez les polyploïdes par rapport aux diploïdes, tandis que le locus 5S a montré une augmentation du nombre de signaux proportionnelle au niveau de ploïdie. Les données sur la taille du génome pour les trois espèces étudiées ont montré une tendance à la baisse du génome monoploïde (1Cx) chez les polyploïdes (« genome downsizing »), ainsi qu’une faible variation inter et intraspécifique de la valeur C. En termes de la biologie de reproduction, l'autofécondation et l’allofécondation ont été observées chez cette espèce. En outre, il a été constaté que des croisements entre différentes catégories morphologiques de S. micranthum ont été possibles puisqu’ils ont abouti à la formation des fruits. De même, les données obtenues suggèrent aussi qu’il n’existe pas une barrière reproductive complète entre S. micranthum et S. laxum. La variabilité génétique de S. micranthum mise en évidence dans cette étude en termes de divergence génétique entre les populations et variation dans le nombre de loci d’ADNr probablement reflètent une relation complexe existante entre la polyploïdie et les aspects de la reproduction de l’espèce. / Sisyrinchium micranthum Cav. é uma planta herbácea, sendo uma das raras espécies do gênero que são descritas como anuais. No Brasil, sua distribuição ocorre ao longo dos estados do Rio Grande do Sul (RS), Santa Catarina (SC), Paraná (PR), São Paulo (SP) e Rio de Janeiro (RJ). A espécie apresenta ampla variabilidade morfológica relatada em vários trabalhos, sendo que diferentes combinações de aspectos morfológicos podem ser observadas na natureza. Baseando-se nessas combinações que caracterizam diversos perfis vegetais, três tipos morfológicos foram descritos, CI, CII e CIII. Sisyrinchium micranthum tem três níveis de ploidia descritos na literatura a partir do número básico x = 8, sendo eles 2n = 2x = 16, 2n = 4x = 32 e 2n = 6x = 48. A fim de contribuir para o conhecimento taxonômico, reprodutivo e evolutivo da espécie, neste trabalho foram investigadas características genéticas e citogenéticas de S. micranthum, assim como aspectos da biologia reprodutiva. Para estudar a estrutura populacional de S. micranthum no sul do Brasil, primeiramente, nove marcadores microssatélites foram isolados usando uma biblioteca genômica enriquecida, e caracterizados em uma população diploide. Posteriormente, a partir da análise da variabilidade genética com sete marcadores para 583 plantas de 14 localidades amostradas nos estados do RS, SC e PR observou-se a existência de populações com indivíduos de diferentes níveis de ploidia, e uma possível origem autopoliploide para os poliploides. As diversidades gênica e alélica foram aproximadamente semelhantes para a maioria dos acessos. O coeficiente de endogamia sobre todos os locos mostrou que S. micranthum apresentou um excesso médio de heterozigotos (valor de coeficiente de endogamia negativo), mas os valores FIS das populações individuais variaram de -0,273 a 0,454. O excesso de heterozigotos poderia ser esperado uma vez que autopoliploides apresentam herança polissômica, o que contribui substancialmente com uma heterozigosidade elevada. Além disso, as populações mostraram-se altamente estruturadas. Os resultados provenientes das análises citogenéticas, mostram que a variabilidade de S. micranthum está presente também em termos de organização do genoma. Considerando S. micranthum e as espécies relacionadas S. laxum Otto ex Sims e S. rosulatum E.P. Bicknell, foi possível verificar que o rDNA 18S-26S varia em número de locos, com notável redução dos mesmos em poliploides em comparação com os diploides, enquanto o loco 5S mostrou aumento proporcional no número de sinais conforme o aumento no nível de ploidia. Os dados relativos ao tamanho do genoma (Cx) para as três espécies estudadas mostraram uma tendência de redução do genoma de diploides para poliploides; e também uma pequena variação inter e intraespecífica com relação ao valor C. Em termos de biologia reprodutiva, foi registrada a ocorrência de autofecundação e fecundação cruzada para a espécie. Além disso, foi verificado que cruzamentos entre as diferentes categorias morfológicas de S. micranthum são compatíveis uma vez que resultaram na formação de frutos. Da mesma forma, os dados obtidos sugerem que S. micranthum e S. laxum não representam táxons totalmente isolados reprodutivamente. A variabilidade genética de S. micranthum encontrada no presente estudo em termos de divergência genética entre populações e de variação do número de locos de rDNA, possivelmente, reflete a complexa relação existente entre a poliploidia e os aspectos reprodutivos da espécie.

The goals of this research project were to identify the various insects observed to visit inflorescences of Echinacea angustifolia DC, and to rank these visitors according to their importance as pollinators of E. angustifolia in Saskatchewan. Studying nectar and the nectary is essential to understanding the interaction of disc florets with pollinators. Nectar-sugar production by disc florets of E. angustifolia and E. purpurea (L. Moench) was quantified from anthesis to cessation with production per disc floret peaking in the afternoon of the staminate phase (191.7 µg) and at midday of the first day of the pistillate phase (156.6 µg), respectively. Morphology of the disc-like floral nectaries of both Echinacea species was studied, as well as the ultrastructure of the nectary of E. purpurea. Modified stomata on the nectary rim are the most likely exits for nectar, but creases in the epidermis may also participate. The nectary of E. purpurea is vascularized by phloem alone, which occurred adjacent to the epidermis. Companion cells possessed wall ingrowths, and these cells may unload arriving sugar destined for either an apoplastic or symplastic pathway. Lobed nuclei were a key feature of secretory parenchyma cells, as was a predominance of mitochondria, suggesting that energy-requiring eccrine secretion predominates in E. purpurea. E. angustifolia exhibited a generalist pollination system, with pollinating insects belonging to the orders Coleoptera, Diptera, Hymenoptera, and Lepidoptera. The pollination efficiency of visitors was determined by single insect visits to bagged, virgin inflorescences followed by quantifying pollen tubes at the bases of receptive styles and/or calculating the percentage of shrivelled styles. It was determined that bumble bees (Bombus spp.) were efficient pollinators, indicating that they would likely contribute much to the pollination of E. angustifolia. Grasshopper bee flies (Systoechus vulgaris Loew) were plentiful but individually were not efficient pollinators, but taken together, they provided much pollination. Golden blister beetles (Epicauta ferruginea Say) were efficient pollinators but where yellow-petalled flowers occurred, their numbers on E. angustifolia decreased. Honey bees (Apis mellifera L.) were efficient pollinators and were present in low numbers without managed introduction. Pierid (2003) butterflies were regular visitors and efficient pollinators, and likely contributed significantly to E. angustifolia pollination. When introduced, the alfalfa leafcutter bee (Megachile rotundata Fabr.) preferred not to forage on E. angustifolia and as such, these solitary bees were not suitable as managed pollinators. In large agricultural plantings of E. angustifolia, however, native insects may not be capable of providing sufficient pollination for seed production when floral competition occurs.

The goals of this research project were to identify the various insects observed to visit inflorescences of Echinacea angustifolia DC, and to rank these visitors according to their importance as pollinators of E. angustifolia in Saskatchewan. Studying nectar and the nectary is essential to understanding the interaction of disc florets with pollinators. Nectar-sugar production by disc florets of E. angustifolia and E. purpurea (L. Moench) was quantified from anthesis to cessation with production per disc floret peaking in the afternoon of the staminate phase (191.7 µg) and at midday of the first day of the pistillate phase (156.6 µg), respectively. Morphology of the disc-like floral nectaries of both Echinacea species was studied, as well as the ultrastructure of the nectary of E. purpurea. Modified stomata on the nectary rim are the most likely exits for nectar, but creases in the epidermis may also participate. The nectary of E. purpurea is vascularized by phloem alone, which occurred adjacent to the epidermis. Companion cells possessed wall ingrowths, and these cells may unload arriving sugar destined for either an apoplastic or symplastic pathway. Lobed nuclei were a key feature of secretory parenchyma cells, as was a predominance of mitochondria, suggesting that energy-requiring eccrine secretion predominates in E. purpurea. E. angustifolia exhibited a generalist pollination system, with pollinating insects belonging to the orders Coleoptera, Diptera, Hymenoptera, and Lepidoptera. The pollination efficiency of visitors was determined by single insect visits to bagged, virgin inflorescences followed by quantifying pollen tubes at the bases of receptive styles and/or calculating the percentage of shrivelled styles. It was determined that bumble bees (Bombus spp.) were efficient pollinators, indicating that they would likely contribute much to the pollination of E. angustifolia. Grasshopper bee flies (Systoechus vulgaris Loew) were plentiful but individually were not efficient pollinators, but taken together, they provided much pollination. Golden blister beetles (Epicauta ferruginea Say) were efficient pollinators but where yellow-petalled flowers occurred, their numbers on E. angustifolia decreased. Honey bees (Apis mellifera L.) were efficient pollinators and were present in low numbers without managed introduction. Pierid (2003) butterflies were regular visitors and efficient pollinators, and likely contributed significantly to E. angustifolia pollination. When introduced, the alfalfa leafcutter bee (Megachile rotundata Fabr.) preferred not to forage on E. angustifolia and as such, these solitary bees were not suitable as managed pollinators. In large agricultural plantings of E. angustifolia, however, native insects may not be capable of providing sufficient pollination for seed production when floral competition occurs.