O Rio Grande do Sul se destaca como a segunda maior região em produção de leite no Brasil, sendo que a alimentação bovina é quase que exclusivamente a pasto de modo isolado e consociado com aveia e azevém no período de estação fria. As informações de campo e pesquisa qualificam a aveia branca (Avena sativa L.) e preta (Avena strigosa Schreb) como forrageira de excelente qualidade nutricional. Apresenta alta produção de biomassa, digestibilidade e teores de proteína fundamental na produção de carne e leite. A região noroeste do estado tem forte presença da agricultura colonial, estruturando a produção leiteira como alternativa à atividade de produção de grãos, condição-chave que viabiliza a atividade da agricultura familiar. Em geral, houve um aumento do número de animais e do rendimento leiteiro por animal, evolução não uniforme e que tem gerado muitos modos e formas de produção. Tais modificações ressaltam a necessidade de proposições técnicas que viabilizem a atividade em longo prazo e de maneira sustentável dos sistemas forrageiros, indicando a necessidade de um aprofundamento científico em ligar a condição experimental com a realidade de produção regional. Portanto, para a máxima oferta de biomassa aos animais, a forragem deve apresentar adequada produção e estabilidade de oferta ao longo de seu ciclo, e maior número de entradas na área de pastejo. Inclusive, boa capacidade de rebrote independente das condições de clima e solo. Desta forma, o conhecimento do potencial genético na produção de forragem da cultivares recomendadas de uma região é fator decisivo sobre a capacidade de tolerância aos fatores de clima e solo e da capacidade de maior oferta de forragem. Afora isto, o envolvimento conjunto dos aspectos genéticos e de ambiente pelos fatores climáticos é decisivo sobre a produção vegetal. Tal condição reporta da necessidade de novos modelos matemáticos que promovam simultaneamente a possibilidade de simulação da produção e definição de cultivares potenciais sobre os aspectos da planta e do clima. Desta forma, o objetivo do trabalho é a modelagem matemática de produção em aveia forrageira a partir dos caracteres decisivos sobre a produção e oferta de forragem e sua ligação com os elementos climáticos que atuam decisivamente sobre a produtividade vegetal. Afora isto, simular a produção de biomassa a partir de alteração de modelo matemático validado para outras espécies no ajuste para a aveia forrageira levando em consideração condições da realidade regional. Estudos Agrários da UNIJUÍ. Os estudos foram realizados nos anos agrícolas de 2011 O experimento foi conduzido em condições de campo no Instituto Regional de Desenvolvimento Rural/IRDeR, localizado em Augusto Pestana, RS, pertencente ao Departamento de, 2012 e 2013 em delineamento experimental de blocos ao acaso com quatro repetições. O estudo envolveu a análise sobre sete genótipos recomendados para cultivo ao longo da oferta atrelada as informações climáticas obtidas ao longo do período. As equações lineares evidenciam taxa de produção de biomassa diferenciada entre os genótipos e anos de cultivo testados. Para a interpretação da produção de Matéria Seca Total e de Folha, verificou- 6 se que as equações lineares são eficientes, podendo determinar a produção de biomassa de qualquer período do ciclo de forragem. Os modelos de regressão linear múltipla qualificam a estimativa da produção de biomassa, podendo interligar os efeitos climáticos com o desempenho de produção, independente do genótipo. O modelo já utilizado nas culturas de capim elefante, Tanzânia e Brachiaria ruzizienses, quando modificado para a cultura de aveia se mostrou adequado para a simulação da produtividade de Matéria Seca Total quando realizada alterações buscando simular a realidade local. / 98 f.

Submitted by Gabriela Lopes (gmachadolopesufpel@gmail.com) on 2017-05-08T11:40:37Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação_CezarAugustoVerdi.pdf: 1224238 bytes, checksum: 1c1a3c5dacea433a84a0663547ee817f (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-05-10T15:55:41Z (GMT) No. of bitstreams: 2 Dissertação_CezarAugustoVerdi.pdf: 1224238 bytes, checksum: 1c1a3c5dacea433a84a0663547ee817f (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-05-10T15:55:41Z (GMT). No. of bitstreams: 2 Dissertação_CezarAugustoVerdi.pdf: 1224238 bytes, checksum: 1c1a3c5dacea433a84a0663547ee817f (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-04-04 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Aveia branca é uma cultura de particular importância para a os sistemas de cultivos brasileiros, com maior importância econômica na Região Sul. Entre os múltiplos propósitos, destaca-se na produção de grãos de excelente qualidade para a alimentação humana. Constantes trabalhos de melhoramento genético e pesquisas fitotécnicas, tem possibilitado o crescimento da importância desse cereal. Os maiores desafios para o melhoramento são o desenvolvimento de cultivares com ampla adaptação, que respondam eficientemente em diferentes ambientes. A seleção de genótipos promissores encontra dificuldades pela origem dita complexa da maioria dos caracteres de interesse agronômico e sua interação com o ambiente de seleção. Com isso, algumas estratégias diferenciadas devem ser analisadas visando melhorar o ganho na seleção de genótipos superiores para diversos caracteres, bem como, a seleção de genótipos com adaptação aos mais variados ambientes. Este estudo propõe analisar estratégias de seleção aplicadas em geração inicial e a influência promovida por diferentes ambientes de seleção, na obtenção de genótipos com destaque no rendimento de grãos e qualidade industrial. Foram utilizadas seis combinações que sofreram seleção inicial (F2) quanto ao rendimento de grãos por planta, índice de grãos maior que dois milímetros e massa da panícula. Formou-se 24 bulks, os quais foram conduzidos durante três anos em Capão do Leão – RS e Augusto Pestana – RS. Posteriormente na geração F7 todos os bulks foram conduzidos em Capão do Leão – RS, totalizando assim 48 bulks, além dos genitores e testemunhas comerciais. O delineamento experimental foi de blocos casualizados com três repetições. As seleções via massa da panícula principal e rendimento de grãos por planta são eficientes, mas devem combinar o índice de grãos, para elevar a qualidade industrial. Genótipos complementares são mais eficientes na obtenção de recombinantes superiores independentemente do ambiente de seleção. Os caracteres massa da panícula e massa do hectolitro são promissores para a seleção inicial, porém, devem ser aliados ao índice de grãos, índice de descasque e número de grãos por panícula para melhorar a aptidão industrial. / Oat is a culture of particular importance to the Brazilian farming systems, with greater economic importance in the southern region. Among the multiple purposes, stands out in the production of excellent quality grain for human consumption. Constants works of breeding and phytotechnical research has enabled the growth of the importance of this cereal. The greatest challenges are to improve the development of cultivars with wide adaptation, which efficiently respond in different environments. The selection of promising genotypes is difficult by the complex said source of most agronomically important traits and their interaction with the selection environment. With this, some different strategies should be analyzed to improve the gain in the selection of superior genotypes for various characters, as well as the selection of genotypes with adaptation to the most varied environments. This study proposes to analyze selection strategies applied in early generation and the influence promoted by different selection environments in obtaining genotypes with emphasis on grain yield and industrial quality. Six combinations were used that have undergone initial selection (F2) and grain yield per plant, grain index greater than two millimeters and panicle weight. Formed 24 bulks, which were conducted for three years in Capão do Leão - RS and Augusto Pestana - RS. Later in the generation F7 all bulks were conducted in Capão do Leão - RS, totaling 48 bulks, in addition to parents and commercial checks. The experimental design was a randomized block design with three replications. The selections via panicle weight and grain yield per plant are efficient, but must match the grain index, to raise industrial quality. Complementary genotypes are more effective in achieving superior recombinant regardless of selection environment. The mass character of panicle and mass of hectoliter are promising for the initial selection, however, must be coupled with the grain index, peel index and number of grains per panicle to improve industrial capability.

Made available in DSpace on 2017-07-25T19:30:57Z (GMT). No. of bitstreams: 1 FLAVIA BIASSIO RIFERTE.pdf: 1208016 bytes, checksum: a3a41200773a41b4df4e551bc10e6c96 (MD5) Previous issue date: 2016-02-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The success of agroforestry system (AFS) is the result of appropriate combinations of crops, forage and tree component and soil fertility. Changes in the microclimate in AFS, can affect the potassium use efficiency by crops. The high absorption of potassium (K) by the plants of white oat, corn and eucalyptus make potassium fertilization an essential practice in AFS. The objectives of this study were to quantify (i) the dry matter yield (DM) and nutrient accumulation in shoots of white oat (season 2014); (ii) the DM and grain yield, and the nutritional status of maize (season 2014/15); (iii) potassium use efficiency by crops in succession (white oat - maize); and (iv) assess the main soil fertility attributes after the white oat crop (season 2014) and maize (season 2014/2015) in AFS fertilized with K. The experiment was installed in Model Farm of Agronomic Institute of Paraná (IAPAR), in the city of Ponta Grossa (PR) in an Oxisoil úmbrico. The experimental design was a randomized complete block with split plots and three replications. The plots consist of four transects - growing distances from trees (transects: 1 - 0- 4 m away; 2 - 4-8 m away; 3 - 8-12 m distance and 4 - 12-16 m away). In the subplots were studied four annual K2O levels (0, 100, 200 and 300 kg ha-1 year-1), as potassium chloride (600 g kg-1 K2O), applied to the surface, and half of each levels applied at sowing of each crop (white oat - winter and maize - summer). The DM yields and nutrients accumulation in the shoots of white oat were determined on management with herbicide. In maize, was evaluated the nutritional status and measured DM and grain yields. Also, values of pH, contents of calcium (Ca), magnesium (Mg) and K exchangeable, base saturation (V) and the percentage of K in the effective CECe were determined in the layers of 0-5, 5-10, 10-15, 15-20, 20-40 and 40-60 cm. The DM yield and the accumulation of nutrients in the shoots of white oat decreased due to the shade provided by the eucalyptus. To this culture in AFS, the levels of K2O increased the yield of DM and the accumulation of sulfur (S) in the shoot. In situation of shading of 64.5%, recycling of nutrients by white oat provided for the subsequent corn crop, better nutrition and, on average, higher DM and grain yields. In this situation, the addition of K2O (up to 230 kg ha- 1 year-1) would provide higher yield of corn grain. This decrease in K level directly implies greater potassium use efficiency, lower production cost and could make possible the cultivation of corn in AFS in the Campos Gerais region. The application of potassium fertilizer high water solubility, in the surface of the soil, reduced, in some situations, Ca and Mg content in the surface layer, it favored the mobility of K and increased its content of this nutrient throughout the soil profile and thus their participation in CECe. The tree component reduced nutrient concentrations in transecta 1 (most influential eucalyptus region), resulting in lower pH values and V in subsurface soil layers (below 20 cm deep). / O sucesso do sistema agroflorestal (SAF) é resultante das combinações adequadas de culturas agrícolas, forrageiras e componente arbóreo e da fertilidade do solo. Modificações no microclima, em SAF, podem afetar a eficiência de uso de potássio (K) pelas culturas agrícolas. A elevada absorção de K pelas plantas de aveia branca, milho e eucalipto tornam a fertilização potássica uma prática essencial. Os objetivos deste trabalho foram quantificar (i) o rendimento de matéria seca (MS) e acúmulo de nutrientes na parte aérea da aveia branca (safra 2014); (ii) o rendimento de MS e de grãos, e o estado nutricional do milho (safra 2014/15); (iii) a eficiência de uso de K pelas culturas em sucessão (aveia branca – milho) e (iv) avaliar os principais atributos de fertilidade do solo, após o cultivo de aveia branca (safra 2014) e milho (safra 2014/2015), em SAF fertilizado com K. O experimento foi instalado na Fazenda Modelo do Instituto Agronômico do Paraná, em Ponta Grossa (PR) em um Latossolo Vermelho Distrófico úmbrico. O delineamento experimental empregado foi de blocos casualizados, em esquema de parcelas subdivididas com três repetições. As parcelas consistiram em quatro transectas –distâncias de cultivo em relação às árvores (transectas: 1 – 0-4 m de distância; 2 – 4-8 m de distância; 3 – 8-12 m de distância; e 4 – 12-16 m de distância). Nas subparcelas foram estudadas quatro doses anuais de K2O (0, 100, 200 e 300 kg ha-1 ano-1), na forma de cloreto de potássio, aplicadas em superfície, em área total, sendo a metade de cada dose aplicada por ocasião da semeadura de cada cultura (aveia branca – inverno e milho – verão). Foram determinados os rendimentos de MS e acúmulos de macronutrientes na parte aérea da aveia branca por ocasião do manejo com herbicida. Com relação ao milho, foi avaliado o estado nutricional e mensurado os rendimentos de MS e grãos. Ainda, determinou-se os valores de pH; os teores de cálcio (Ca), magnésio (Mg) e K trocáveis; saturação por bases (V) e o percentual de K na CTC efetiva do solo, nas camadas de 0-5, 5-10, 10-15, 15-20, 20-40 e 40-60 cm. O rendimento de MS e o acúmulo de macronutrientes na parte aérea da aveia branca foi diminuído devido ao sombreamento proporcionado pelo eucalipto. Para essa cultura em SAF, as doses de K2O aumentam o rendimento de MS e também, o acúmulo de enxofre (S) na parte aérea. Em situação de sombreamento com intensidade de 64,5%, a reciclagem de nutrientes pela aveia branca proporcionou, para a cultura de milho, melhor nutrição e, na média, maiores rendimentos de MS e de grãos. Nessa situação, a adição de K2O (até 230 kg ha-1 ano-1) proporcionaria maior rendimento de grãos de milho. A diminuição na dose de K implica diretamente em maior eficiência de uso do potássio, menor custo de produção e possibilita viabilizar o cultivo de milho em SAF na região dos Campos Gerais. A aplicação de fertilizante potássico de alta solubilidade em água, na superfície do solo, diminuiu, em algumas situações, os teores de Ca e Mg na camada superficial, favoreceu a mobilidade do K e aumentou seu o teor deste nutriente ao longo do perfil do solo e, consequentemente sua participação na CTCe. O componente arbóreo diminuiu as concentrações de nutrientes na transecta 1 (região de maior influência do eucalipto), resultando em menores valores de pH e V nas camadas subsuperficiais do solo (abaixo de 20 cm de profundidade).

Made available in DSpace on 2017-07-25T19:30:59Z (GMT). No. of bitstreams: 1 Thays Schneider.pdf: 1808530 bytes, checksum: 30d501a211bd2062abba571e9202b79e (MD5) Previous issue date: 2016-05-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Integrated Crop-Livestock System (ICLS) is in a form of integrated production, which achieve a higher environmental, economic and social sustainability. Because of the efficient nutrient cycling and biodiversity of crops, the system combines food production with environmental conservation. The lack of research in the context of the potassium (K) dynamic in subtropical soils under ICLS and how the shading provided by the arboreal component alters the production, determined the focus of this research. The main objective of this project consists in evaluating the effects of shade (provided by eucalyptus) on the attributes of plants and soil fertility under conditions of K rates (0, 100, 200 and 300 kg ha-1 yr-1 K2O) applied on the soil surface in the entire area. Two experiments are being conducted simultaneously in an Typic Hapludox on a model farm of the Agronomic Institute of Paraná (IAPAR), Ponta Grossa (PR). The experiment employs an experimental design in randomized complete block with split plots and three replications. The plots (4 x 24 m) consists of annual plants (corn, oat and soybean) and the distances considered in relation to eucalyptus (shading effect) were: 0-4, 4-8, 8-12 and 12-16 m. The subplots (4 x 6 m) receive doses (0, 100, 200 and 300 kg ha-1 yr-1 of K2O) K (as potassium chloride), at the soil surface at the time of seeding culture of autumn-winter (oat) and at seeding of the summer crop (corn and soybeans). The second experiment was also a randomized complete block design with split plot and three replications. The plots were characterized by rows of eucalyptus and subplots doses of K (similar to the first experiment). In the maize crop (2012/13 and 2014/15) and soybean (2013/14) were evaluated nutritional status (for macronutrients) and grain maize yield (GYM and GYS). During oat growing (2013 and 2014) were evaluated the dry matter yield (DMY), height and macronutrient accumulation. The evaluation of nutritional status of eucalyptus was conducted in the summer (2013/14), and the nutrients in the leaf litter under the canopy. Soil samples of layers 0-5, 5-10, 10-15, 15-20, 20-40 and 40-60 cm were performed in both experiments at 6, 12 and 30 months after the start of the experiment (Sep / 2012). After that, was determined pH concentration, H + Al, C, Ca, Mg, K, Al, CEC and effective CEC (ECEC), base saturation (%) and aluminum (m%) and the percentage of K, Ca and Mg in the effective CEC. In general, higher concentrations of cations was observed in less shaded transects, which favored the largest DMY for oats/2014 (2218.83 kg ha-1) and GYM (10,470.1 kg ha-1 in 2012/13 and 8742, 5 kg ha-1 in 2014/15) and GYS (1989.0 kg ha-1). Moreover, high concentrations of Ca and Mg were detected in the whole profile favoring saturation in these ECEC in second experiment. Leaching was not observed in profile in the second experiment. The concentration of N, P and K in shoots of eucalypt was within the proper range, but the opposite was observed for Ca, Mg and S. The reduction of the concentration of N, P, K, Mg and S in the litter, may indicate a biochemical decomposition. However, the concentration of Ca in the litter, suggests the influence of biogeochemical cycling. K doses did not affect the production of eucalyptus at 8 years. / O sistema integrado de produção agropecuária (SIPA) consiste em uma das formas de produção integrada, o qual busca maior sustentabilidade ambiental, econômica e social. Em razão da eficiente ciclagem de nutrientes e biodiversidade de culturas, o sistema alia a produção de alimentos com a conservação do meio ambiente. A ausência de pesquisa no âmbito da dinâmica do potássio (K) em solos subtropicais sob SIPA e como a restrição de radiação proporcionado pelo componente arbóreo altera a produção, determinou o foco desta pesquisa. O objetivo deste trabalho foi avaliar os efeitos da restrição de radiação (proporcionado pelo eucalipto) sobre os atributos de plantas e de fertilidade do solo, em condições de doses de K (0, 100, 200 e 300 kg ha-1 ano-1 de K2O) aplicadas na superfície do solo, em área total. Dois experimentos paralelos foram implantados (em setembro/2012) em um Latossolo Vermelho na Fazenda Modelo, município de Ponta Grossa (PR). O primeiro experimento empregou delineamento experimental em blocos completos casualizados com parcelas subdivididas e três repetições. As parcelas (4 x 24 m) consistem das plantas anuais (milho, aveia branca e soja) e as distâncias consideradas em relação ao eucalipto (efeito da restrição de radiação) foram: 0-4, 4-8, 8-12 e 12-16 m. As subparcelas (4 x 6 m) recebem as doses (0, 100, 200 e 300 kg ha-1 ano-1 de K2O) de K (na forma de cloreto de potássio), na superfície do solo, por ocasião da semeadura da cultura de inverno (aveia branca, para produção de forragem) e na semeadura da cultura de verão (milho e soja, para produção de grãos). O segundo experimento também foi em blocos completos casualizados com parcela subdividida e três repetições. As parcelas foram caracterizadas por renques de eucalipto e as subparcelas as doses de K (similarmente ao primeiro experimento). Nas culturas de milho (2012/13 e 2014/15) e soja (2013/14) foram avaliados o estado nutricional (para os macronutrientes) e o rendimento de grãos (RGM e RGS). Durante o cultivo da aveia branca (2013 e 2014), foram avaliados o rendimento de massa seca (RMS), altura e acúmulo de macronutrientes. A avaliação do estado nutricional do eucalipto foi realizada no verão (2013/14), bem como os nutrientes na serapilheira sob a copa. Coletas de solo das camadas 0-5, 5-10, 10-15, 15-20, 20-40 e 40-60 cm foram realizadas em ambos os experimentos aos 6, 12 e 30 meses após o início do experimento (Set/2012), visando determinar as concentrações de pH, H+Al, C, Ca, Mg, K, Al, CTC potencial (CTC) e efetiva (CTCe), saturação de bases (V%) e de alumínio (m%) e a porcentagem de K, Ca e Mg na CTC efetiva. Maior influência da restrição de radiação em relação às doses de K foi observado para o experimento 1. Redução do K trocável foi observado aos 30 meses, o que reduziu a 1% a saturação de K na CTCe. Em geral, maiores concentrações de cátions foram observadas em transectos menos sombreados, o que favoreceu o maior RMS para aveia/2014 (2218,83 kg ha-1) e RGM (10470,1 kg ha-1 em 2012/13 e 8742,5 kg ha-1em 2014/15) e RGS (1989,0 kg ha-1). Por outro lado, concentrações altas de Ca e Mg foram verificadas em todo perfil, favorecendo a saturação destes na CTCe no segundo experimento. Lixiviação não foi observada no perfil no segundo experimento. As concentrações de N, P e K na parte aérea do eucalipto esteve dentro da faixa adequada, contudo concentrações baixas foram observados para Ca, Mg e S. A redução da concentração de N, P, K, Mg e S na serapilheira, pode indicar decomposição bioquímica. Todavia, aumento da concentração de Ca na serapilheira sugere a influência da ciclagem biogeoquímica. Doses de K não afetaram a produção do eucalipto aos 8 anos.

The incorporation of cereal straw/stubble often immobilises nitrogen (N). This can help conserve N in soil in organic forms, thus reducing loss through leaching over dormant winter periods. However, N-depressions that arise during decomposition can reduce crop yield. The inclusion of a legume green manure can supply fixed-N, thus alleviating the low N availability to crops. In this study, the effect of lupin (Lupinus angustifolius L.) green manure incorporation on barley (Hordeum vulgare L.) straw/stubble decomposition, and N availability was investigated. A field experiment was used to determine the effects of the green manure on decomposition. Decomposition of straw/stubble was monitored using the litterbag technique. Following green manure incorporation, soil cores were incubated in a glasshouse to determine mineral-N availability. Though not significant, the inclusion of lupin green manure seemed to increase the decomposition of straw/stubble during the growth period, then slowing it after its incorporation at 110 d. This was described by a logarithmic pattern of loss of - 4.97 g AFDW residue day⁻¹, with 60% remaining after 140 d. Treatments without lupin had a linear decomposition of - 0.12 g AFDW residue day⁻¹, with 49% remaining after 140 d. The loss of cellulose confirmed the differences in decomposition with the inclusion of lupin resulting in 2.79% less cellulose remaining in straw/stubble after 140 d compared to its exclusion. Lupin significantly increased pot oat N uptake and DM yield by 55 % and 46 %, respectively, compared to its exclusion. However, this effect was not observed in field sown wheat yields and the soil mineral-N measurements made. This study showed that the potential of lupin to increase straw/stubble decomposition by improving the retention and availability of N, leading to long-term yield benefits, needed further investigation.

A series of experiments was carried out on cultivated oat (Avena sativa L. cv Amuri) to examine the efficacies of fluazifop-butyl and glyphosate against water stressed plants, plants grown in low and high nitrogen and plants treated with gibberellic acid (GA₃). Avena sativa L. was used as a test plant and on completion of the experiments, further studies were carried out on the weed species wild oat (Avena fatua L.). In the laboratory, plants maintained at wilting point for five days before and nine days after spraying and treated with fluazifop-butyl (0.5 kg a.i./ha) appeared healthy 32 days after herbicide application, while plants supplied with water throughout the experiment were completely chlorotic/necrotic and had main stem detachment from within the leaf sheaths. In the field, plants maintained unirrigated until 14 days after spraying with fluazifop-butyl (0.25 kg a.i./ha) or glyphosate (0.18 kg a.i./ha) showed greater tolerance to the herbicides than plants irrigated regularly. Values for seed head yield for water stressed and irrigated plants, 45 days after applying fluazifop-butyl, were 66 g and zero g dryweight/m² respectively. Comparable values for glyphosate treated plants were 65 g and 25 g dryweight/m². Radiolabel studies indicated that in comparision with well watered plants, water stressed plants absorbed 20% less applied ¹⁴C-glyphosate. In addition, the proportion of absorbed ¹⁴C-glyphosate translocated from the treated leaf was 15% less under water stress conditions. Uptake of ¹⁴C-fluazifop-butyl was similar under well watered and water stress conditions and was 30-40% of that applied. The proportion of absorbed ¹⁴C-activity which was transported was very low, but was greater under well watered conditions (7.6%) than under water stress conditions (4.4%). Under well watered conditions in the laboratory and field, fluazifop-butyl (0.25 kg a.i./ha) and glyphosate (0.18 kg a.i./ha) were less toxic at low nitrogen than high nitrogen. For example, 34 days after spraying with fluazifop-butyl under laboratory conditions total plant dry weight was 1.51 g and 0.56 g at 1.0 mol/m³ and 10 mol/m³ applied nitrate respectively. As with soil water content, soil nitrogen content had no effect on uptake of fluazifop-butyl. However, the proportion of absorbed fluazifop-butyl which was translocated out of the treated lamina was greater under high nitrogen conditions (26.1 %) than under low nitrogen conditions (9.3%). Under laboratory conditions, addition of 200 µg GA₃to the leaf sheaths two days prior to spraying with fluazifop-butyl or glyphosate increased the efficacy of both herbicides at low nitrogen. Similarly, under field conditions application of GA₃ (0.21 kg/ha) two days prior to spraying with glyphosate increased the performance of the herbicide against Avena sativa L. growing in a nitrogen depleted soil. At harvest, seed head yield for GA₃ treated and non-treated plants was zero and 7.4 g dry weight/m² respectively. Experiments with Avena latua L. showed that this species was tolerant of fluazifop-butyl and glyphosate when grown in low water or low nitrogen conditions. Under water stress conditions, pre-treatment with GA₃ increased the phytotoxicity of fluazifop-butyl to Avena latua L. Similarily, GA₃ enhanced the phytotoxicity of glyphosate to Avena latua L. grown under low nitrogen conditions. Reduced performance of fluazifop-butyl under stress conditions involves a reduction in translocation of herbicide to meristems, but other factors are likely to be involved. It was concluded that for glyphosate, reductions in uptake and translocation of the herbicide are important factors causing reduced performance of this herbicide under stress conditions. Possible reasons for GA₃ enhancement of fluazifop-butyl and glyphosate activity under stress conditions are discussed and the potential of growth regulators as adjuvants is considered.

The ability to identify germplasm and select traits accurately is fundamental to successful plant breeding. Pedigrees and molecular markers facilitate these processes; however misleading experimental results can occur when incorrect relationships and/or cultivar names are recorded. Molecular markers can identify these inconsistencies, and with advances in genotyping technology these diagnostics can be done faster and more objectively. This study aimed to develop molecular marker assays and graphical genotyping methodologies for cultivar identification, seed purity assessment and trait selection in oat (Avena sativa L.). KBioscience’s Allele-Specific PCR (KASP™) and genotyping-by-sequencing (GBS) technologies were applied to a set of current Canadian oat cultivars to evaluate their utility for identifying cultivars and detecting intra-cultivar variation. Both KASP™ and GBS detected different extents of heterogeneity among a set of 160 seeds that originated from four seed sources of four cultivars. In both cases, the detected variation did not appear to be limited to a specific cultivar or seed source, reinforcing that all cultivars are heterogeneous. Graphical genotyping localized heterogeneity to specific chromosome regions, thereby distinguishing physical contamination from true genetic heterogeneity and heterozygosity. Pre-existing genotype data for 700 oat cultivars and breeding lines were also used to construct graphical genotypes for pedigree validation and discovery of potential sources for favourable quantitative trait loci (QTL) alleles. This methodology used historical QTLs and anchoring markers to identify 25 putative “high oil” allele carriers. The results from this study will provide diagnostic tools for cultivar identification and pedigree validation, in addition to meaningful information about existing heterogeneity and possible QTL locations in current cultivars.

The ability to identify germplasm and select traits accurately is fundamental to successful plant breeding. Pedigrees and molecular markers facilitate these processes; however misleading experimental results can occur when incorrect relationships and/or cultivar names are recorded. Molecular markers can identify these inconsistencies, and with advances in genotyping technology these diagnostics can be done faster and more objectively. This study aimed to develop molecular marker assays and graphical genotyping methodologies for cultivar identification, seed purity assessment and trait selection in oat (Avena sativa L.). KBioscience’s Allele-Specific PCR (KASP™) and genotyping-by-sequencing (GBS) technologies were applied to a set of current Canadian oat cultivars to evaluate their utility for identifying cultivars and detecting intra-cultivar variation. Both KASP™ and GBS detected different extents of heterogeneity among a set of 160 seeds that originated from four seed sources of four cultivars. In both cases, the detected variation did not appear to be limited to a specific cultivar or seed source, reinforcing that all cultivars are heterogeneous. Graphical genotyping localized heterogeneity to specific chromosome regions, thereby distinguishing physical contamination from true genetic heterogeneity and heterozygosity. Pre-existing genotype data for 700 oat cultivars and breeding lines were also used to construct graphical genotypes for pedigree validation and discovery of potential sources for favourable quantitative trait loci (QTL) alleles. This methodology used historical QTLs and anchoring markers to identify 25 putative “high oil” allele carriers. The results from this study will provide diagnostic tools for cultivar identification and pedigree validation, in addition to meaningful information about existing heterogeneity and possible QTL locations in current cultivars.

The overall aim of this research was to improve the understanding of the ecology and diversity of Trichoderma species within the soil and rhizosphere of onion (Allium cepa L.) and potato (Solanum tuberosum L.) under intensive management in New Zealand. The indigenous Trichoderma population was measured in a field trial at Pukekohe over a three year period under six different crop rotation treatments. The treatments included two continuous onion and potato rotations (intensive), two onion/potato mixed rotation (conventional), and two green manure rotations (sustainable). Results showed that Trichoderma populations were stable in both the rhizosphere and bulk soil (1.5 x 10² to 8.5 x 10³ CFU g⁻¹ ODS). The planting and incorporation of an oat (Avena sativa L.) green manure in the sustainable rotations positively increased Trichoderma colony forming unit (CFU) numbers in the rhizosphere soil from 3.4 x 10² to 2.5 x 10³ g⁻¹ ODS. A Trichoderma species identification method was developed based on colony morphology. Representative isolates were verified using restriction fragment length polymorphism (RFLP) and DNA sequencing. The method allowed for rapid and reliable identification of isolated Trichoderma species. Five species were identified in the Pukekohe soil: T. asperellum, T. atroviride, T. hamatum, T. harzianum and T. koningii. Results showed identical species diversity between the rhizosphere, rhizoplane and bulk soil. The species did not strongly compete between each other for the rhizosphere ecological niche and differences in species proportions seemed to be caused by environmental factors rather than the rotation treatments. The incorporation of oat green manure in pots did not significantly promote the indigenous Trichoderma population size and diversity in the rhizosphere of onion plants up to 4 months old. The identified species were the same as in the field trial. The incorporation of onion scale residues was shown to result in low Trichoderma and high Penicillium CFU numbers and a reduction in plant size. Additionally, the presence of high levels (6.0 x 10⁵ CFU g⁻¹ ODS) of Penicillium CFU was negatively correlated with the presence of Trichoderma CFU. The effect of oat incorporation on Trichoderma saprophytic growth was also investigated in a soil sandwich assay and revealed no significant differences. A series of experiments indicated that onion extract obtained from dry onion scale residues had no antifungal activity against either Trichoderma or Penicillium and instead tended to promote their hyphal growth and sporulation. It also showed that competition between Penicillium and Trichoderma isolates was limited despite the ability of Penicillium to produce a wide range of inhibitory substances. Four indigenous Trichoderma species (T. atroviride, T. hamatum, T. harzianum and T. koningii) were shown to be rhizosphere competent in a split tube experiment over a 6 week period. The results of this experiment revealed that, the Trichoderma species clearly displayed differences in their ability to colonise the rhizosphere of young onion seedlings. Species such as T. koningii had the greatest rhizosphere colonising ability regardless of soil depth while T. harzianum displayed the weakest ability. Results also indicated that when inoculated as a mixture the four species competed with one another to colonise the rhizosphere. Overall, this research indicated that the studied crop rotation treatments and the use of oat as a green manure did not strongly promote indigenous Trichoderma populations. Species diversity was constant throughout the research with T. hamatum and T. koningii being the most frequently isolated species.