No description available.

There is renewed interest in cotton performance grown using various row spacings and plantings patterns in the Midsouth. Cotton seed size has been reduced compared to sixty years ago. Planting smaller seeds is concerning due to having less energy for emergence as well as complicating the ginning process. Two row spacings, two planting patterns, and two cotton varieties were evaluated over eight site years from 2019-2020. The solid planting pattern produced a higher yield on a land area basis. In addition, two varieties, each with three seed counts, were planted at three seeding rates and evaluated over six site years from 2019-2020. Greater seedcotton yields were observed from larger seed sizes and higher seeding rates. Row spacing had no impact on yield but depending on input cost, a 2x1 skip pattern could be beneficial. Also, higher seeding rates and larger seeds maximized yields.

Switchgrass (Panicum virgatum) is a native warm-season grass where weed control during establishment is a limiting factor for stand. Objectives of this research are to develop a herbicide resistant cultivar and to test a variety of seed safeners to improve first year growth. Phenotypic recurrent selection (PRS) was used to select ‘Alamo’ switchgrass seedlings that showed resistance to imazapic herbicide at 245 g a.i./ha. Initial screenings of 364, 650 seedlings resulted in 63 survivors, a selection intensity of 0.0172%. Subsequent testing of the next generation of seedlings indicated that multiple generations of selection were needed in order to transfer greater resistance to the offspring. Seed safener testing consisted of three trials. Field data taken included emergence counts, weed control ratings, and end of season harvest. Results showed fluxofenin (a.i. in Concep III) as being only safener providing protection against metolachlor (83.7% a.i.).

No description available.

The cells of 𝘊𝘶𝘤𝘶𝘳𝘣𝘪𝘵𝘢 embryos contain may protein bodies surrounded by smaller lipid vesicles. Within the protein bodies are discrete spherical bodies called globoids. Globoids are made up of phytin, and are an important store of 𝘮𝘺𝘰-inositol, phosphorus, and cations including K, Mg, Ca, Mn, Fe and Zn. During early seedling growth, the protein bodies fuse together to form aqueous vacuoles, and the globoids are degraded, their mineral nutrient stores used by the growing seedling. The changes in the element composition of globoids during early seedling growth were examined in this study and the influence of light and mineral nutrient conditions on the changes were examined. Energy dispersive X-ray analysis was used to determine the element composition of globoids from the cotyledons of 𝘊. 𝘮𝘢𝘹𝘪𝘮𝘢 and 𝘊. 𝘢𝘯𝘥𝘳𝘦𝘢𝘯𝘢 seeds and seedlings at various stages of growth. The stages selected ranged from the mature, dry seed, to an established seedling with an elongated hypocotyl and expanded cotyledons. To investigate the influence of light and mineral nutrient conditions, seedlings were grown under four different sets of growth conditions: in the dark, with deionized water; in the dark, with Hoaglands solution; in the light, with deionized water; in the light, with Hoaglands solution. During early seedling growth, the element composition of globoids changed. In both species, regardless of growth conditions, the same general trend was observed for each element: P remained relatively constant, K decreased markedly and Mg, Ca, Mn, Fe, and Zn generally increased. As the protein bodies fused and became more aqueous, it appeared that K ions came off the phytate molecule and were replaced by di-and trivalent cations with a higher affinity for phytic acid. There were species-to-species differences in globoid composition changes which could be attributed, at least in part, to differences in the Ca content of the mature, dry embryos. In 𝘊. 𝘢𝘯𝘥𝘳𝘦𝘢𝘯𝘢, which had a higher initial Ca content, there was a large increase in the Ca content of the globoids during seedling growth and no significant increase in Mn. In 𝘊. 𝘮𝘢𝘹𝘪𝘮𝘢 globoids there was only a slight increase in Ca, but there was a much larger increase in Fe, Zn and Mn than occurred in 𝘊. 𝘢𝘯𝘥𝘳𝘦𝘢𝘯𝘢. Light and dark grown seedlings exhibited distinctly different morphological features, but light conditions alone did not have a significant influence on the changes in globoid composition. In combination with mineral nutrients in the later stages of growth, the presence of light resulted in a more rapid degradation of globoids. Mineral nutrient conditions had some effect on globoid composition, affecting mostly elements which were present in large amounts. The effect of mineral nutrient conditions, and its interactions with light conditions may have been mediated through changes in the mobilization of mineral nutrients out of the cotyledons during seedling growth. There were very large (5 -7μm in diameter) globoid-like particles present in some later stage cotyledon samples of both species. There was no apparent pattern to which samples they were found in. These particles had elemental compositions which were consistent with them being composed of phytin. Such large particles had not previously been found in cucurbit tissues. / Thesis / Master of Science (MS)

Perennial ryegrass (Lolium perenne L.) is widely used as a fairway turf on golf courses throughout the transition zone. The transition zone represents the geographical areas between the temperate and subtropical climates, where neither warm season nor cool season grasses are well adapted. The late-spring establishment of seeded bermudagrass could potentially enhance summer quality of a perennial ryegrass fairway during periods of extreme summer stress. Studies were conducted over two years on both perennial ryegrass and Chewings fescue (Festuca rubra L. ssp. commutata Gaud.) areas to assess the competitive effects of each species on bermudagrass seed establishment. The use of fungicides, herbicides and a plant growth regulator, as well as cultivation treatment prior to seeding, were evaluated for their effects on bermudagrass establishment, turfgrass quality, disease incidence and summer annual grass control. Turfgrass treated with preventative fungicide applications of propiconazole and chlorothalonil maintained high density and turf quality which inhibited successful establishment of bermudagrass during either year. Bermudagrass establishment in 1996 was moderately successful in plots not treated with fungicides; however, due to disease severity, turfgrass quality was unacceptable. MSMA applications did not influence turfgrass quality or bermudagrass establishment. Crabgrass populations were too low to ascertain the efficacy of either MSMA (1996) or oxadiazon (1997) on summer annual grass control. Oxadiazon followed by activated charcoal prior to bermudagrass seeding did not adversely affect bermudagrass establishment. In 1996, trinexapac-ethyl slightly enhanced bermudagrass seed establishment, but the competitiveness of perennial ryegrass prohibited establishment success. During 1997, glyphosate was evaluated as a means of eliminating competition and increasing bermudagrass establishment. Glyphosate applied in small strips across existing stands of perennial ryegrass and Chewings fescue significantly increased bermudagrass establishment. Preplant aerification and vertical mowing increased bermudagrass establishment, but slightly reduced turfgrass quality. Overall, bermudagrass establishment into existing stands of turfgrass was successful only where glyphosate was strip-treated over plots to eliminate competition or under circumstances where disease pressure reduced competition from the existing turfgrass. / Master of Science

O tratamento de sementes pode ser uma importante técnica para o fornecimento de micronutrientes na cultura do milho (Zea mays L.), sendo capaz de promover um melhor estabelecimento da cultura no campo. Solos contendo níveis insuficientes de zinco e de cobre para as plantas são frequentes em grande parte das regiões agrícolas do Brasil e do mundo. Deste modo, o fornecimento destes elementos via sementes pode ser uma alternativa viável e eficaz para produtores de milho. Este trabalho teve como objetivo avaliar diferentes tratamentos de sementes de milho contendo Zn e Cu, considerando aspectos relacionados à qualidade fisiológica das sementes e à eficiência nutricional. Para tal, foram utilizados quatro lotes do híbrido 2B688Hx, apresentando diferenças quanto ao tamanho e vigor das sementes. Os tratamentos foram compostos por diferentes dosagens e combinações de suspensões líquidas contendo óxido de Zn e carbonato de Cu, fornecidos juntos ou separadamente. Os lotes foram avaliados pelo teor de água das sementes, germinação e teste de frio em cinco épocas: 0, 30, 60, 180 e 360 dias. Nas três primeiras épocas, também foram realizados os testes de emergência de plântulas, velocidade de emergência de plântulas e análises do crescimento de raiz por meio do software SVIS®. O desenvolvimento inicial das plantas foi avaliado pela altura, área foliar e massa seca de raiz e de parte aérea. Os dados de massa seca associados aos teores de Zn e de Cu nos tecidos permitiram calcular as eficiências de absorção, transporte e utilização dos mesmos. A qualidade fisiológica de sementes de milho tratadas com Zn e Cu, isoladamente ou associados, não é afetada ao longo de doze meses de armazenamento; por outro lado, o Cu utilizado isoladamente causa fitotoxicidade quando a avaliação é realizada tendo o papel como substrato, afetando principalmente o desenvolvimento radicular das plântulas. O tratamento de sementes com zinco e cobre se constitui em alternativa viável e eficaz para o fornecimento destes elementos para as plantas de milho. / Seed treatment is a potential tool for supplying micronutrients on maize crop (Zea mays L.), enabling a better plant stand establishment in the field. Soils presenting insufficient levels of zinc and copper to plants are common in various agricultural regions throughout Brazil and the world. Thus, the supply of such elements via seeds can be viable and effective for maize crop. This study aimed to evaluate different maize seed treatments containing Zn and Cu, related to the effects on seeds physiological quality and nutritional efficiency. Thus, four seeds lots of the corn hybrid 2B688Hx, differing in size and vigor, were used for this study. The treatments were composed of liquid suspensions containing Zn oxide and Cu carbonate, applied together or separately at different dosages. The lots were evaluated by seed moisture, germination and cold test in five periods: 0, 30, 60, 180 and 360 days. Seedling emergence, seedling emergence speed and image analysis of root growth (software SVIS®) were also performed in the first three periods. The plants development was assessed by height, leaf area and dry weight of roots and shoots. The efficiencies of absorption, transport and utilization were calculated with the data of seedlings dry weight and tissues content of Zn and Cu. The physiological quality of maize seeds is not affected by the treatments containing Zn and Cu, together or separated, during the twelve-month storage period; on the other hand, the treatments containing only Cu caused phytotoxicity on paper-based tests, affecting mainly the seedlings root development. Seed treatment with zinc and copper is a viable and effective approach for supplying these elements to maize plants.

Made available in DSpace on 2016-04-28T14:58:57Z (GMT). No. of bitstreams: 1 2005-Marta Bruno Loureiro.pdf: 2008902 bytes, checksum: 98c5d8a1e29a820780c9fe727ebed874 (MD5) Previous issue date: 2005-08-29 / Funda??o Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / Apuleia leiocarpa is a forestall specie commonly known as grapia and garapa. Its trees are widely spread over Brazilian territory occurring more specifically on rain forest formations with seasonal semidecidious characteristics. Garapa seeds are an important source of medicinal substances as well as used for ornamental and environmental recovery purposes. It has been used on both tanning and timber industry and notably its natural populations have deeply decreased its growth due to massive exploitation. In this context, this work aimed to evaluate the development of A. leiocarpa seeds during the maturation phase. Researches were conducted for two successive crop years (2002 and 2003) and also analyzed seeds performance under specific storage conditions and the physiological quality of seeds. This scientific study results might be used as database information to guide the elaboration of specie s preservation proposals. Research samples were collected at Tingu? Biological Reserve, state of Rio de Janeiro, Brazil and biological analysis and tests were performed at Seeds Analysis Laboratory of Universidade Federal Rural do Rio de Janeiro at Serop?dica city, Brazil. This work results concludes that A. leiocarpa seeds physiological maturity was achieved within 98 days after anthesis (98DAA) in 2002. In 2003 it was not able to objectively determine the seeds maturity cycle. Seeds harvests are recommended as soon as fruits aspect changes from green-yellow to brown color combined with a higher proportion of brown seeds availability. The most efficient technique to overcome seed dormancy was the use of immersion treatment into concentrated sulphuric acid during 20 minutes. It was not observed any influence of either testa color or its size on A. leiocarpa seed germination process. The use of half-permeably packaging (polyethylene bags) under a nominal temperature of 18?C and 50% relative humidity was considered the most appropriate storage condition to A. leiocarpa seeds. / Apuleia leiocarpa ? uma esp?cie florestal, conhecida como gr?pia e garapa, que apresenta ampla distribui??o geogr?fica no territ?rio brasileiro, ocorrendo na mata atl?ntica, nas forma??es caracter?sticas da Floresta Estacional Semidecidual. A esp?cie apresenta import?ncia na industria madeireira e de curtume, possui indica??es de uso medicinal, ornamental e em plantios para recupera??o ambiental. No entanto, foi extra?da de forma maci?a, e suas popula??es naturais sofreram diminui??o significativa. Diante desta situa??o, os objetivos deste trabalho foram acompanhar a matura??o das sementes de Apuleia leiocarpa em dois anos de produ??o (2002 e 2003), avaliar o comportamento das sementes durante o armazenamento e analisar os fatores intr?nsecos ?s sementes que afetam sua qualidade fisiol?gica, a fim de gerar informa??es que possam nortear a elabora??o de propostas para a conserva??o da esp?cie. As coletas foram realizadas na Reserva Biol?gica do Tingu?, RJ e os ensaios conduzidos no Laborat?rio de An?lise de Sementes da Universidade Federal Rural do Rio de Janeiro, Serop?dica, RJ. Com base nos resultados obtidos pode-se concluir que a maturidade fisiol?gica das sementes de Apuleia leiocarpa foi atingida aos 98 DAA no ano de 2002 e n?o pode ser determinada em 2003. ? recomend?vel que a coleta de sementes seja realizada a partir do momento em que ocorre a mudan?a de colora??o dos frutos de verdeamarelo para marrom, juntamente com aparecimento da maior propor??o de sementes com colora??o marrom A escarifica??o com ?cido sulf?rico concentrado por vinte minutos, foi considerado o tratamento mais indicado para a supera??o da dorm?ncia de sementes. Nem o tamanho das sementes, nem a colora??o do tegumento influenciaram a porcentagem de germina??o de sementes de Apuleia leiocarpa. . A embalagem semiperme?vel sob c?mara seca (18?C e U.R. de 50%), foi considerada a condi??o mais adequada para a conserva??o de sementes de Apuleia leiocarpa.

Soil seed banks are a reservoir of viable seeds present in the soil in plant communities. They have been studied and characterized in various ways in different habitats. However, these studies are limited to modern seed banks. This study extends seed bank studies to the Paleozoic Era. It was hypothesized that size distribution and seed density in Paleozoic seed banks exhibit similar patterns as in modern seed banks. Seed sizes and seed density of fossil seed from Wise Virginia were estimated. Modern seed bank information was obtained from published data. Data were analyzed using one-way ANOVA and Kruskal-Wallis test. The Paleozoic size distribution was predominated by larger seeds and the estimated seed density of 19 200 seeds m-3 falls within the range of modern seed banks but at a higher end of modern seed bank densities. During the Paleozoic they were sufficient to insure regeneration of these economically important forests.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniv., 2007. / Härtill 11 uppsatser.