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An estimated two to four million acres of irrigable saline and alkali soils of the United States return very little income to land owners (17,19). Increased needs for forage crops, and the relatively high salt and alkali tolerance of some improved forage species, once established, suggests a way of increasing revenue from some of these lands without costly reclamation.

The potential of Indigofera species as forage and/or cover crops for semi-arid and arid environments was investigated in several experiments conducted on the Hatfield Experimental Farm in Pretoria, South Africa. Dormancy associated with hard seededness is the main constraint for uniform germination and large-scale propagation of these species. In this study, pretreatment increased germination in most accessions with scarification being more effective than boiling water treatment in six accessions, but not in the case of I. vohemarensis 8730. In five accessions (I. cryptantha 7067, I. brevicalyx 7517, I. arrecta 7524, I. spicata 8254 and I. vohemarensis 8730), scarification improved the total germination percentage, though it simultaneously resulted in higher seed mortality of I. brevicalyx 7517, I. arrecta 7524 and I. vohemarensis 8730 than in the control. In four accessions (I. brevicalyx 7517, I. arrecta 7524, I. vohemarensis 8730 and I. trita 10297), boiling water treatment improved germination percentage without causing any significant risk of seed mortality in the latter three species. In a field study, 41 Indigofera accessions were characterized in terms of morphological and agronomic parameters, using multivariate techniques to describe their phenotypic variability. Eight morpho-agronomic groups with various potentials were identified along with eight determinant characteristics that can be regarded as the core attributes for future Indigofera germplasm characterisation. Further evaluation of promising accessions revealed remarkable differences, both between and within species, in terms of plant height, canopy spread diameter, forage biomass, crude protein content, in vitro organic matter digestibility and indospicine level of the forage. These suggest the possibility of directly selecting accessions with forage potential for subsequent evaluation with target animals. The response of four selected Indigofera accessions under simulated moisture deficit stress and non-stress conditions exhibited significant variation. I. amorphoides was relatively sensitive while I. vicioides was able to maintain growth under water stress conditions, while the response of the two I. arrecta accessions were intermediate. The influence of season and species on forage quality was also studied. Spring growth had a significantly higher (P< 0.05) CP content than autumn growth in all species. In vitro digestibility of dry material also tended to decrease from the spring of 2004 to the autumn of 2004. Higher levels of Ca, P, Mg, Zn and Cu concentration were revealed in the leaf meal of the first harvest than in the re-growth harvest. All of the species had Ca, Mg, Zn and Mn concentration levels that could support the requirements of ruminants. P and Cu were slightly deficient for some of the species in the autumn suggesting the need to supplement P and Cu from other sources. Compared to Leucaena forage, Indigofera forage had higher apparent organic matter and dry matter digestibility coefficients and higher crude protein and neutral detergent fibre digestibility coefficients. The difference between Indigofera and Leucaena forage in terms of DM intake per unit of metabolic body weight (DMI g BW-0.75 day-1) was not significant (P> 0.05). The digestible organic matter intake (DOMI) and digestible crude protein intake (DCPI) of the sheep on Indigofera forage was similar to that of sheep fed Leucaena. In this study, lack of differences between Indigofera and Leucaena forage in terms of DOMI, DCPI and DNDFI means that Indigofera forage would likely support similar weight gains as that of Leucaena, but lower than that of M. sativa forage. / Thesis (PhD (Plant Production: Pasture Science))--University of Pretoria, 2007. / Plant Production and Soil Science / unrestricted

Submitted by Luciana Sebin (lusebin@ufscar.br) on 2016-10-05T13:14:46Z No. of bitstreams: 1 DissNBD.pdf: 2471615 bytes, checksum: a8204662dfb8062a11f60b9f5723d468 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-13T20:17:50Z (GMT) No. of bitstreams: 1 DissNBD.pdf: 2471615 bytes, checksum: a8204662dfb8062a11f60b9f5723d468 (MD5) / Approved for entry into archive by Marina Freitas (marinapf@ufscar.br) on 2016-10-13T20:18:10Z (GMT) No. of bitstreams: 1 DissNBD.pdf: 2471615 bytes, checksum: a8204662dfb8062a11f60b9f5723d468 (MD5) / Made available in DSpace on 2016-10-13T20:18:20Z (GMT). No. of bitstreams: 1 DissNBD.pdf: 2471615 bytes, checksum: a8204662dfb8062a11f60b9f5723d468 (MD5) Previous issue date: 2016-02-26 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Paspalum is the most important genus of Poaceae family in the Americas, with about 330 species and occurs throughout Brazil, Bolivia, Paraguay, Argentina and Uruguay. In Brazil, except for the Pampa Biome, the use of species of this genus as a cultivated forage is still very small. Species of the informal group Plicatula are among the most promising Paspalum genotypes for forage quality. The majority of Paspalum accessions is tetraploid and apomitic. The sexual cytotypes are rare in the Plicatula group. To add features located in different accessions, it is necessary to cross sexual species in tetraploid level with apomictic genotypes that are interesting to breeding programs and select those that have better agronomic characteristics. For the occurence of hybridization, the flowering synchronization betwemn parents is essencial. An interesting tool for this is the cryopreservation of pollen. P. notatum, popularly known as bahiagrass, is a species from Notata group and is widely used in the United States as forage. Diploid and tetraploid accessions are observed in this species and, it is easy to obtain large amounts of pollen. The purpose of this study was to evaluate the cryopreservation of pollen of P. notatum, as a model for future conservation and synchronization of flowering of other species that are interesting for breeding program. The P. notatum pollen grains were collected in the field at Embrapa Southeast Livestock. Four dehydrating agents were tested (LiCl, MgCl2, NaOH and Silica gel) with three distinct periods of exposion (30, 60 and 120 minutes). After slow thawing, pollen grains were evaluated for viability by staining with tetrazolium solution 0.25% and in vivo germination by fluorescence. The viability of fresh pollen grains was also evaluated as a control. For comparison, pollen grains were stored in freezer and refrigerator conditions for a period of 10, 60, 120 and 180 days. The data showed that the dehydration of Paspalum notatum pollen with lithium chloride during 30 minutes and silica gel during 120 minutes was adequated for the conservation in liquid nitrogen and freezer as the viability of pollen after this treatment remained equal to the control. The pollen preservation in the refrigerator without dehydration since 10 days may be an alternative for short-term storage situations. Dehydration results with dehydrated magnesium chloride for 30 and 60 minutes and dehydrated sodium hydroxide for 60 and 120 9 minutes were also statistically similar to the control. The use of the tetrazolium sollution and in vivo germination were an effective technique to evaluate the viability of pollen grains after liquid nitrogen conservation. The use of tetrazolium was also efficient for the evaluation of pollen grains after storage in freezer and refrigerator. / Paspalum é o mais importante gênero da família Poaceae nas Américas, com cerca de 330 espécies e ocorre em todo Brasil, Bolívia, Paraguai, Argentina e Uruguai. No Brasil, a exceção do Bioma Pampa, o uso deste gênero como forrageira plantada ainda é muito pequeno. As espécies pertencentes ao grupo informal Plicatula são consideradas entre as mais promissoras pela qualidade forrageira. A grande maioria dos acessos de Paspalum é tetraplóide e apomítico. São raros os citotipos de espécies do grupo Plicatula sexuais. Para agregar características localizadas em acessos distintos, é necessário cruzar espécies sexuais já em nível tetraplóide com genótipos apomíticos promissores e selecionar os que tem melhores características agronômicas. Para isso, há a necessidade de sincronização de florescimento entre os genitores. Uma ferramenta interessante para isso é a criopreservação de pólen. A espécie P. notatum, conhecida popularmente como grama-batatais, do grupo informal Notata, é muito usada nos Estados Unidos para produção de forragem. Já foram observados acessos diplóides e tetraplóides dessa espécie, sendo fácil a obtenção de grande quantidade de pólen. A proposta desse trabalho foi estudar a criopreservação de pólen de P. notatum, como um modelo, para futuramente conservar e sincronizar o florescimento de outras espécies com características de interesse para o melhoramento. Os grãos de pólen de P. notatum foram coletados em campo na Embrapa Pecuária Sudeste. Foram testados quatro agentes de desidratação (LiCl, MgCl2, NaOH e sílica gel) e um tratamento sem desidratação, todos por três tempos distintos (30, 60 e 120 minutos). Após descongelamento lento, os grãos de pólen foram avaliados quanto à viabilidade por coloração com solução de tetrazólio 0,25% e por germinação in vivo via fluorescência. A viabilidade de grãos de pólen recém-colhidos também foi avaliada como controle. Para efeitos de comparação, foram armazenados grãos de pólen em condições de freezer e geladeira, por um período de 10, 60, 120 e 180 dias. Os dados demonstraram que a desidratação de pólen de Paspalum notatum com cloreto de lítio por 30 minutos e sílica gel por 120 minutos foi adequado no armazenamento em nitrogênio liquido e em freezer, pois a viabilidade permaneceu igual aos grãos de pólen recém-colhidos 7 (testemunha). A conservação de pólen em geladeira sem desidratação por até 10 dias pode ser uma alternativa em situações de armazenamento a curto prazo. A conservação de pólen em freezer por até 60 dias também pode ser uma alternativa, já que além dos tratamentos citados acima, resultados de desidratação com cloreto de magnésio desidratado por 30 e 60 minutos e hidróxido de sódio desidratado por 60 e 120 minutos também foram estatisticamente iguais a testemunha. O uso do corante de tetrazólio e da técnica de germinação in vivo foram eficientes para a avaliação da viabilidade de grãos de pólen após o armazenamento de nitrogênio líquido. O uso do corante de tetrazólio também foi eficiente para a avaliação dos grãos de pólen após o armazenamento em freezer e em geladeira.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In Brazil, most soils used in the livestock presents some fertility limitations. One of the alternatives to improve the soils quality is the introduction of perennial species, including grassy and associated legumes and correction of the soil that it will hold the cultures forage crop. There s a lack of Information and researches on soil quality improvement using perennial forages. Therefore, the objective of this work was to evaluate different systems of forage cultures constituted by Pennisetum americanum, Arachis pintoi and Stylosanthes guianensis associated with Cynodon dactylon and both isolated species, with and without mineral fertilizer, and evaluations of the attributes of a Ultisols. In both treatments, Cynodon dactylon received 100 kg of nitrogen during a year. The crops of forage samples were accomplished at every 28 days, making botanical separation and drying the same. After the weighting to calculate the dry matter per area (ha) the samples were crushed for analyses of fiber of neutral detergent (FDN), fiber of acid detergent (FDA), rude protein (PB), calcium (Ca), magnesium (Mg), phosphorus (P) and potassium (K). The samples collecting were taken during January, March, April and October of 2007. The best results of nutritional values were found in the legumes and in the consortium, being with inferior quality the grassy ones. The dry matter present a great variation among the cuts and the forage systems. After the winter the Stylosanthes portions were lost, due to the frosts that happened during this period. This confirms that it not has an adaptation on our conditions of winter. After a year of implantation of the experiment was collected soil to analysis: density of the soil (DS), microporosity (Mip) and macroporosity (Map) porosity and total porosity of the soil (PT) and size of aggregates. In the chemical part, were analyzed total nitrogen (NT), total organic carbon (COT) and phosphorus (P) and potassium (K). DS presented variation between the treatments and the appraised layers, since 1,40 to 1,62 Mg m-3. In Mip and PT didn't present significant differences between the treatments and layers, but Map presented significant differences. In the aggregate size there was significant differences, and the geometric medium diameter (DMG) it varied from 1,41 to 3,21 mm. In the soil chemical attributes both maintained similarities, in other words, larger concentration in the first layer (0 to 5 cm). But some treatments standing out in larger concentration in the first layer, however maintain similarities in the deep layers, unless the potassium (K), that has a distribution more constantly in the evaluated layers. / No Brasil, a maioria dos solos utilizados para pecuária apresenta algumas limitações de fertilidade. Uma das alternativas para melhorar as condições desses solos é a introdução de espécies perenes, incluindo gramíneas e leguminosas consorciadas e correção do solo que comportará as culturas forrageiras. Informações e pesquisas sobre melhorias de solos com uso de espécies forrageiras perenes são escassas. Nesse sentido, o objetivo deste trabalho foi avaliar diferentes sistemas de culturas forrageiras constituídas de milheto, amendoim forrageiro e estilosantes consorciados com tifton 85 e ambas as espécies isoladas, com e sem adubação mineral, e avaliações dos atributos de um Argissolo vermelho. Em ambas as parcelas adubadas e não adubadas, o tifton 85 recebeu 100 kg de nitrogênio ano-1. As colheitas de amostras de forragem eram realizadas a cada 28 dias, realizando-se separação botânica e secagem da mesma. Feita a pesagem para calcular matéria seca (MS) por área (ha) realizava-se a moagem das amostras para análises de fibra de detergente neutro (FDN), fibra de detergente ácido (FDA), proteína bruta (PB), cálcio (Ca), magnésio (Mg), fósforo (P) e potássio (K). Realizaram-se coletas nos meses de janeiro, março, abril e outubro de 2007. Os melhores resultados de valores de PB, FDA e FDN, foram encontrados nas leguminosas e no consórcio, ficando com qualidade inferior o tifton 85 + 100 kg ha-1 de N. Quanto à produção de MS, variou muito entre os cortes e os sistemas forrageiros. Após o inverno as parcelas de estilosantes foram perdidas, devido às geadas que ocorreram no período de inverno. Isso confirma que o mesmo não tolera frio e não se adapta a nossas condições de inverno. Após um ano de implantação do experimento realizou-se coletas para análise dos atributos do solo, sendo: densidade do solo (DS), micro (Mip) e macro (Map) porosidade e porosidade total do solo (PT) e tamanho de agregados. Na parte química, analisou-se nitrogênio total (NT), carbono orgânico total (COT) e teores de fósforo (P) e potássio (K). A DS apresentou variação entre os tratamentos e as camadas avaliadas, desde 1,40 a 1,62 Mg m-3. Na Mip e PT não apresentou diferenças significativas entre os tratamentos e camadas, mas o Map apresentou diferenças significativas. Nos tamanhos dos agregados houve diferenças significativas, sendo que o diâmetro médio geométrico (DMG) variou de 1,41 a 3,21 mm. Nos atributos químicos do solo, como NT, COT, P e K ambos mantiveram semelhanças, ou seja, maior concentração na primeira camada (0 a 5 cm). Mas alguns tratamentos se destacaram em maior concentração na primeira camada, mantendo semelhanças nas camadas mais profundas, exceto o K que teve uma distribuição mais uniforme nas camadas avaliadas.