Forage trials of four crops grown under high-input and low-input production cultures were performed at the Maricopa Agricultural Center. Six varieties of each crop were grown to evaluate yield potential under both production cultures. Only a preplant irrigation was applied to the low-input culture, but up to four additional irrigations were applied to the high-input culture. No fertilizer application was given to low-input, but a total of 135#N/A and 75#P₂O₅/A was applied to the full production culture. Barley, durum, and wheat cultivars developed for grain yield under a low-input production culture were tested for forage production under both high- and low-input practices. No advantage in forage production was observed by using the following varieties in a low-input production culture: Stampede oats, Westford barley, Mexicali durum, and 911 wheat produced the highest yields in each of the four crops. Yields were greater from crops grown under a high-input culture: Stampede oats, Harlan II barley, Aldura durum, and 911 wheat were highest yielding varieties in each crop.

Despite substantial consumer demand and willingness to pay premium prices for organically grown fruit, apple growers in Vermont and other New England states have been slow to adopt certified organic practices. Barriers cited in the past to increased adoption of organic apple production in the region include susceptibility of traditionally grown cultivars to apple scab, lack of effective insect pest management materials, and few available effective options for fruit thinning. Recent changes in apple cultivar plantings in the region, introduction of new insect pest management materials, and advances in crop thinning justified an evaluation of organic apple production systems containing cultivars identified as important to the future of the apple industry. In 2006, two apple orchards were established at the University of Vermont Horticulture Research and Education Center in South Burlington, VT to comprehensively evaluate the five commercially-important apple cultivars of `Ginger Gold', `Honeycrisp', `Liberty', `Macoun', and `Zestar!' over eight growing seasons in two organically-managed orchard production systems, including a newly-planted high-density orchard (Orchard 1) and in an existing, medium-density orchard which was top-grafted to the new cultivars (Orchard 2). Parameters for tree growth and survival, crop yield, disease and arthropod pest incidence on foliage and fruit, and long-term economic return, including a twenty-year projection of net present value (NPV) of each cultivar in the two systems were evaluated in this study. `Ginger Gold', despite high incidence of some diseases on foliage and fruit, performed the best in both orchard systems overall. The cultivar was among the cultivars with the highest measurements of tree growth. `Ginger Gold', along with `Honeycrisp', had the highest cumulative net crop yield per tree in Orchard 1 and the highest in Orchard 2. Notably, apple scab on `Honeycrisp' foliage and fruit and `Zestar!' fruit in both orchards was at a level that was not significantly different from `Liberty', a scab-resistant cultivar on which no scab was observed. However, `Honeycrisp' had the highest incidence of fruit rots in both orchards, but it was not significantly different than `Zestar!' in Orchard 1. Management of lepidopteran pests of fruit was a major challenge on all cultivars over the years of the study. For most of the tree growth parameters and cumulative net crop yield, `Liberty' was among the lowest group of cultivars in both orchards. Cumulative net crop yield of both `Macoun' and `Zestar!' were also among the lowest in both orchards with the top-grafted `Macoun' and `Zestar!' trees having significant tree death compared to the other cultivars in Orchard 2. Harvested fruit were graded to commercial standards and cumulative gross and net income calculated from grade distribution, crop yield, and fruit price data. In Orchard 1, `Ginger Gold' and `Liberty' had greater cumulative gross income per hectare from 2006-2013, in excess of US$40,000, compared to `Liberty'. However, after management costs were deducted, all cultivars in Orchard 1 had negative cumulative net income of $-77,892 or less. In Orchard 2, all cultivars had positive cumulative net income for 2006-2013, and `Ginger Gold' had the highest at $109,717/ha. The twenty-year projected NPV was negative for all cultivars in Orchard 1, but in Orchard 2, all cultivars had positive NPV with `Ginger Gold' having the highest among the cultivars.

O presente experimento foi conduzido na Unidade Experimental de Plantas Forrageiras (UEPF) em área do Departamento de Produção Animal da ESALQ/USP, em Piracicaba (SP), entre 01/07/98 e 31/12/98. Os tratamentos consistiram de combinações entre três cultivares de Cynodon spp. (Tifton-85, Florakirk e Coastcross) e quatro intensidades de pastejo (5, 10, 15 e 20 cm) estabelecidas por ovinos em regime de lotação contínua. O delineamento experimental foi o de blocos completos casualizados com quatro repetições e parcelas sub-divididas, onde na parcela foram alocados os cultivares e na sub-parcela as intensidades de pastejo. Foram analisadas as seguintes variáveis: índice de área foliar, interceptação luminosa, acúmulo de matéria seca e composição botânica/morfológica dos pastos. Tifton 85 mostrou os maiores valores de IAF para qualquer das intensidades de pastejo estudadas. As taxas de acúmulo de matéria seca foram semelhantes em todos os tratamentos. Tifton 85 apresentou como faixa ótima de uso condições de pasto que variaram de 5 a 15 cm. Já para Florakirk essa faixa foi até 20 cm e para Coastcross o limite superior deve ser maior que 20 cm. De maneira geral os diferentes cultivares devem possuir requerimentos variados de manejo de desfolha quando o objetivo é o uso eficiente da luz e demais fatores de crescimento associado a elevados índices de utilização da forragem produzida. / The present trial was carried out at the Pasture and Grazing Studies Unit, Animal Production Department, ESALQ/USP, Piracicaba, State of São Paulo, from July 1 until December 31, 1998. Treatments comprised the possible combinations between three Cynodon spp. cultivars (Tifton-85, Florakirk and Coastcross) and four grazing intensities (5, 10, 15 and 20 cm) imposed by sheep under a continuous stocking management. Treatments allocation to experimental units followed a completely randomised block design with four replications and a split-plot arrangement. Grass cultivars were allocated to plots and grazing intensities to sub-plots. The responses studied were leaf area index (LAI), light interception, herbage dry matter accumulation and swards' botanical composition. Tifton-85 showed the highest LAI for any of the grazing intensities used. Herbage dry matter accumulation rates were similar for all treatments. Tifton-85 presented a narrower range of sward conditions for grazing management (5 to 15 cm) when compared to Florakirk (5 to 20 cm) and Coastcross (5 to > 20 cm). Overall, different grass cultivars presented different grazing management requirements in situations where efficient use of light and high levels of herbage utilisation are targeted.

Submitted by Edisangela Bastos (edisangela@ufpa.br) on 2018-04-09T12:56:30Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese_InfluenciaFrutosFixacao.pdf: 3174034 bytes, checksum: c4c45bbce8ee2bc6f6eaa46a4854d29b (MD5) / Approved for entry into archive by Edisangela Bastos (edisangela@ufpa.br) on 2018-04-09T12:58:37Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese_InfluenciaFrutosFixacao.pdf: 3174034 bytes, checksum: c4c45bbce8ee2bc6f6eaa46a4854d29b (MD5) / Made available in DSpace on 2018-04-09T12:58:37Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Tese_InfluenciaFrutosFixacao.pdf: 3174034 bytes, checksum: c4c45bbce8ee2bc6f6eaa46a4854d29b (MD5) Previous issue date: 1987-03-25 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O principal objetivo desse trabalho foi obter informações sobre a relação entre o desenvolvimento reprodutivo e a atividade dos nódulos. Com essa finalidade, foram utilizadas plantas de soja noduladas induzidas a florescer em idades diferentes. As plantas foram cultivadas em vermiculita, adubadas com solução nutritiva deficiente de nitrogênio e mantidas em casa de vegetação. O controle da floração foi feito nos estádios de desenvolvimento V2, V5 e V8. Foram também realizados tratamento com flores removidas e plantas mantidas em estado vegetativo (DL) durante todo o seu ciclo. As medidas de avaliação da fixação de nitrogênio foram realizadas com o sistema de plantas intactas o qual permitiu usar as mesma plantas durante todo o seu desenvolvimento. Quando essas medidas exigiam a quantificação e o peso fresco dos nódulos, era utilizado o sistema de raízes destacadas. O seccionamento da parte aérea foi feito somente antes de iniciar as medidas. Os sistemas de plantas intactas e de raízes destacadas apresentaram atividades semelhantes da enzima nitrogenase, demonstrando que ambos os métodos são plenamente confiáveis; a vantagem do sistema intacto esta em poder utilizar as mesma plantas durante todo o experimento. Dos experimentos realizados nesse trabalho, dois foram conduzidos no verão, cujas plantas induzidas nos estádios V2 e V5 apresentaram curvas de atividades semelhantes, independentes da fase de desenvolvimento reprodutivo. Esse fato também confirmado pelos resultados dos tratamentos sem frutos e plantas mantidas em estado vegetativo, os quais não modificaram a forma curva. Em outro experimento conduzido no outono, as plantas com os mesmos tratamentos (V2 e V5) apresentaram picos de atividades em idades diferentes, correspondentes a fase de desenvolvimento reprodutivo, ou seja de preenchimento do grão. Dessa forma, nas condições desse experimento, foi obtida uma clara relação entre a presença dos frutos e a queda da atividade da enzima nitrogenase. O comportamento diferente das plantas nesse experimento comparado com os demais foi atribuído às condições menos favoráveis de luz e temperatura. Desses resultados ficou evidenciado que a competição entre frutos e nódulos por fatossintatos em plantas de soja, não é o principal fator responsável pela queda na atividade da nitrogenase, embora possa ser em certas condições menos favoráveis. / The main objective of this study was to obtain information on the relationship between reproductive development and nodule activity. For this purpose, we used nodulated soybeans induced to flower at different ages. The plants were grown in vermiculite with a nutrient solution deficient in nitrogen, and maintained in a greenhouse. Flower induction was carried out at the V2, V5 and V8 stages of development. Other treatments included the removal of flowers and the maintenance of plants in the vegetative state by growing them under long-day conditions. Measurements of nitrogen fixation were made with an intact plant system, which allows the use of the same plants throughout the growth cycle. When these measurements required the simultaneous quantification of nodule number and weight, a detached root system was used, where the shoot was sectioned immediately before the measurements. The intact and detached root systems gave similar activities for nitrogenase, showing that one system is just as reliable as the other. One advantage of the intact system is the possibility of using the same plants throughout the growth cycle. Of the experiments set up, two were carried out in the summer, where plants induces in the V2 and V5 stages produced activity curves with similar profiles and these for independent of the stage of reproductive development. This conclusion was confirmed by the data of the other treatments where fruits were removed and plants maintained vegetative under long days, since such treatments did not modify the nitrogenase activity curves. In another experiment, carried out in the autumn, plants induced at V2 and V5 produced peaks of activity at different ages corresponding to the reproductive phase, or specifically to the pod-fillinq stage. Therefore, under the conditions of this experiment at least, a clear relationship was obtained between the presence of fruits and the fall in nitrogenase activity. The different behaviour of the plants in this experiment compared with the others may be due to the less favorable conditions of light and temperature. The main conclusion reached was that the competition between the fruits and nodules for photosynthates in soybeans is not the main reason for the fall in nitrogenase activity, although it could be in less favorable conditions.

Submitted by Gabriela Lopes (gmachadolopesufpel@gmail.com) on 2017-11-06T14:55:34Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação Patrícia Milech Einhardt 2017.pdf: 2092991 bytes, checksum: 4e24b180491a12a086061863b12e0484 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2018-01-02T13:05:29Z (GMT) No. of bitstreams: 2 Dissertação Patrícia Milech Einhardt 2017.pdf: 2092991 bytes, checksum: 4e24b180491a12a086061863b12e0484 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-01-02T13:05:29Z (GMT). No. of bitstreams: 2 Dissertação Patrícia Milech Einhardt 2017.pdf: 2092991 bytes, checksum: 4e24b180491a12a086061863b12e0484 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-08-30 / As estimativas dos parâmetros genéticos desempenham papel fundamental nos programas de melhoramento, pois permitem a predição dos valores genéticos dos candidatos à seleção, propiciando um processo mais acurado. Os objetivos do presente estudo foram: a) avaliar a variação genética de genitores e progênies na geração F1 e estimar a herdabilidade no sentido amplo e restrito dos caracteres de massa média das frutas e teor de sólidos solúveis; b) caracterizar a forma das frutas de duas cultivares e nove seleções e seus descendentes F1; e c) avaliar a capacidade de conservação pós-colheita de frutas de sete seleções e duas cultivares de amoreira-preta e seus índices de mercadabilidade. Os genótipos estudados foram provenientes do Programa de Melhoramento da Embrapa Clima Temperado. O valor médio estimado da herdabilidade no sentido amplo, para massa da fruta (0,79) e sólidos solúveis (0,68) foi alto. Já no sentido restrito, para massa da fruta (0,05) foi baixo e para o teor de sólidos solúveis (0,47) foi médio. Isso demonstra que a eficiência de seleção é maior para teor de sólidos solúveis do que para massa das frutas. Observou-se que o formato das frutas das progênies tende a ser próximo daquele dos genitores. Na avaliação pós-colheita as seleções Black 139, 170 e 276 e as cultivares BRS Xingu e Tupy apresentaram boa conservação após sete dias de armazenamento a 4°C, com índice de mercadabilidade acima de 85%, o que é considerado aceitável para comercialização. Foi observado também que a cultivar BRS Xingu é similar a cultivar Tupy em firmeza e massa média das frutas e inferior em sólidos solúveis, porém, apresentou melhor conservação póscolheita. / Estimation of genetic parameters play a key role in the improvement on breeding programs because they allow the prediction of the genetic values of the candidates to selection, providing a more reliable process. The objectives of the present study were: a) to evaluate the genetic variation of parents and their F1 progenies and to estimate heritability in the broad and restricted sense of the average fruit mass and soluble solids content; B) characterize the fruit shape of two cultivars and nine selections and their F1 descendants; and c) to evaluate the fruit post-harvest conservation capacity of seven selections and two blackberry cultivars and their indices of marketability. The genotypes studied were from the Embrapa Clima Temperado Improvement Program. The broad sense heritability for average fruit mass (0.79) and soluble solids (0.68) was high, whereas the restricted sense heritability was low for fruit mass (0.05) and medium for soluble solids content (0.47). This demonstrates that the selection efficiency is higher for soluble solids content than for fruit mass. It was observed that the fruit format of the progenies tends to be close to that of the parents. In the post-harvest evaluation, it was possible to conclude that the Black 139, 170 and 276 selections and the BRS Xingu and Tupy cultivars had good conservation after seven days of storage at 4°C, with a marketability index above 85%, which is considered aceptable by the market. It was also observed that the cultivar BRS Xingu is similar to Tupy cultivar in firmness and average mass of fruits and inferior in soluble solids, however, it has a better post harvest conservation.

Submitted by (ana.araujo@ufrpe.br) on 2017-02-17T14:14:19Z No. of bitstreams: 1 Jose Machado Coelho Junior.pdf: 1596177 bytes, checksum: e2b2b69a4eb6a4394ff0b610d87af29b (MD5) / Made available in DSpace on 2017-02-17T14:14:19Z (GMT). No. of bitstreams: 1 Jose Machado Coelho Junior.pdf: 1596177 bytes, checksum: e2b2b69a4eb6a4394ff0b610d87af29b (MD5) Previous issue date: 2009-05-22 / For the cultivation of strawberries need a good planning of the planting, because the crop is susceptible to diseases and as part of the diet, one should minimize the large amount of pesticides that get to fight them. In search of the culture conditions edafoclimáticas it was necessary to open new frontiers in the tropical regions as Mesorregião da Mata de Pernambuco. This study aimed to analyze the characters of 11 cultivars of strawberry in the tropical conditions of Mesorregião da Mata. The cultivation was carried out in region of high temperatures was evaluated in greenhouse where the plant morphology, physico-chemical and topographical pseudofruit of the median leaves of cultivars. The experimental design was completely randomized, with five replications, each pot a plot. Cultivars Camino Real, Diamond, Sweet Charlie and windows were the only ones that showed production of strawberries. The Ventana cultivar showed high concentration of ascorbic acid. Cultivars Dover, Oso Grande and Tudla made the most important leaf plan. The cultivar Sweet Charlie made more rugged topography. / Para o cultivo do morangueiro é necessário um bom planejamento do plantio, devido a cultura ser suscetível a doenças e por fazer parte da dieta alimentar, devendo-se minimizar a grande quantidade de agrotóxicos que recebe para combatê-las. Em busca de condições edafoclimáticas à cultura fez-se necessário abrir novas fronteiras em regiões de clima tropical como a Mesorregião da Mata de Pernambuco. Este trabalho teve como objetivo analisar os caracteres de 11 cultivares de morangueiro nas condições tropicais da Mesorregião da Mata Pernambucana. O cultivo foi realizado em região de temperaturas elevadas em telado onde se avaliou caracteres morfológicos da planta, físico-químicos dos pseudofrutos e topográficos dos folíolos medianos das cultivares. O delineamento experimental utilizado foi o inteiramente casualizado com cinco repetições, sendo cada vaso uma parcela. As cultivares Camino Real, Diamante, Sweet Charlie e Ventana foram as únicas que apresentaram produção de morangos. A cultivar Ventana apresentou concentração elevada de ácido ascórbico. As cultivares Dover, Oso Grande e Tudla apresentaram o relevo foliar mais plano. A cultivar Sweet Charlie apresentou relevo mais acidentado.

A cana-de-açúcar é a cultura mais importante na formação do Brasil que conhecemos: presente desde o surgimento da Colônia Portuguesa até os dias atuais, foi protagonista da agroindústria brasileira em diversos momentos da história. Nesse ínterim papel fundamental tem a cana-de-açúcar, que é o vegetal de onde se originam os subprodutos da cana o açúcar, o etanol e, mais recentemente, a energia elétrica de biomassa. Como tantas outras culturas, a cana-de-açúcar teve uma diversificação de espécies com o fim de combater pragas, doenças, adaptação a diversos climas e solos, tempo de produção, aumento de sua eficiência, adequação às novas técnicas de cultivo, e muitas dessas alterações (a maçante maioria, sejamos sinceros) são fruto de pesquisas que fizeram surgir diversas espécies transgênicas, que reúnem características específicas com o fim de atender a necessidades dos produtores. A cana-de-açúcar, bem como todas as outras cultivares transgênicas hoje existentes no Brasil, são protegidas pela Lei de Proteção de Cultivares (LPC) Lei n. 9.456, de 25 de abril de 1997, lei esta feita com base nos termos propostos pelo Tratado da UPOV, em sua versão de 1978, união da qual o Brasil passou a fazer parte após a elaboração da referida lei. A LPC, contudo, trouxe em seu texto uma exceção à cana-de-açúcar, que não recebe o mesmo tratamento que as outras cultivares no país, mas sim um tratamento superior, que institui um super regime de proteção à cultivar da cana-de-açúcar, não se aplicando ao seu regime de proteção as exceções cabíveis a todas as outras cultivares, inclusive as exceções tratadas no texto da UPOV 1978. O presente trabalho discorre sobre o regime de propriedade intelectual da cana-de-açúcar no país, e aborda desde a introdução das primeiras espécies de cana no país, trazidas pelos colonizadores, e sua influência na lavoura, economia e cultura do Brasil, até os dias atuais, com a análise da evolução histórica tanto da cultivar em si, como de sua regulação pelo Estado brasileiro, inclusive pelos órgãos especializados criados ao longo da história para cuidar da cultura e comercialização da cana-de-açúcar. É feita ainda análise da legislação atual que rege a proteção à tecnologia da cana-de-açúcar no país, a Lei de Proteção de Cultivares, com breve histórico de sua elaboração, e suas determinações frente ao texto da UPOV 1978. Também são abordados aspectos relacionados ao impacto desse regime especial no mercado de cultivar no país, e eventuais efeitos desse regime, principalmente relacionados à concorrência e ao eventual abuso de direito. Com isso, pretende-se estabelecer quais são os parâmetros que efetivamente regem a proteção às cultivares transgênicas de cana-de-açúcar, e seus aspectos que extrapolam ou não os limites legais impostos pelo ordenamento jurídico nacional. / Sugarcane is the most important farming in the formation of Brazil as we know: it is found in the country since the emerging of the Portuguese Colony until nowadays, and played main role in the agribusiness in several moments of history. We main point out then that the plant of sugarcane itself has essential part in this farming, because from it comes the products derived of sugarcane sugar, sugarcane alcohol and, more recently, biomass electric energy. As many other cultures, sugarcane had a diversification of species along time in order to prevent plagues, plant diseases, to adapt to different climate and soil conditions, timing of production, increase of efficiency, to fit to new planting techniques, and many of these changes (the great majority, sincerely) are product of research that allowed the creation of several transgenic species, which gather specific characteristics aiming to fulfill the needs of producers. Sugarcane, as the other transgenic plants existing in Brazil, found themselves under the protection of the Cultivar Protection Law (CPL) Law n. 9.456, dated April 25, 1997, law based on the terms of UPOV 1978 Treaty, Union of which Brazil is part nowadays under such terms. CPL, nevertheless, conferred an exception to some of its terms to sugarcane, which do not get the same treatment as the other transgenic plants in the country, but has a superior regimen, which confers a super protection to sugarcane transgenic plants, to which do not apply the exceptions that affect all other transgenic plants, including the exceptions contained in UPOV 1978. This paper aims to discuss the regimen of intellectual property of sugarcane in Brazil, and examines since the introduction of first species of sugarcane in the country, brought by the Portuguese, and its influence in the farming, economy and culture in Brazil, until nowadays, examining the historical evolution of the plant itself, as well as of its regulation by the Brazilian State, including the specialized organs created through time to regulate the farming and commercialization of sugarcane. It is also made an analysis of laws and acts which regulate the protection of sugarcane technology in the country, the Cultivar Protection Law, with a brief examination of historical conditions and law making process of the CPL, and its directives considered from a UPOV 1978 point of view. Aspects related to the impact of such regulation in the market of sugarcane in Brazil are evaluated as well, including eventual effects of law dispositions, mostly related to antitrust aspects and abuse of rights. Therefore, it aims to stablish the parameters that effectively regulate the protection of transgenic sugarcane in Brazil, and the aspects that go beyond or do not the limits imposed by the Brazilian legal system.

Soaking is an important unit operation during the processing of seeds used for direct consumption. The change in seed volume over time during soaking (volume kinetics) relates to water uptake and the quality of final product, and affects the design of the entire processing operation. Since volume determination is labor-intensive and time consuming, volume kinetics is usually not well monitored throughout seed hydration. The first chapter of this thesis is a review on the importance of soaking and volume kinetics monitoring during seed processing, the factors affecting hydration in seeds, current volume measurement methods and models used to determine and describe the change in volume over time in seeds during soaking. The second chapter describes the design, construction and evaluation of a bean volumetric auto tester (B-VAT) for volume kinetics determination of seeds during soaking. Evaluation tests suggested the system can generate reliable, reproducible, and detailed volume kinetics results for seeds soaking at different conditions with limited labor requirements. In the third chapter, the volume kinetics of 6 pinto, 5 navy and 3 black bean cultivars were tested during soaking at 25 ºC and 55 ºC. Significant differences were observed among varieties and cultivars at both temperatures (p<0.01). As temperature increased, the hydration efficiency were enhanced for all cultivars, but with various degree. In the fourth chapter, we tested the hypothesis that a thin hydrophobic layer on the seed coat was responsible of the extended initial lag phase observed during the soaking of pinto beans. Hexane pre-treatment before soaking were used for all cultivars and contact angle measurement were done to determine the surface hydrophobicity of the beans. Good correlations were found between surface hydrophobicity and hydration efficiency of beans. Hexane effectively reduced the hydrophobicity of bean surface and improved the hydration efficiency of pinto beans. The fifth chapter covers the overall conclusion of this study and states recommendations of future work regarding the improvement of the developed system and further exploration of the bean hydration process.

Field pea is an important crop in western Canada. The current recommended seeding rate in field pea is 88 plants m-2. As certain pea genotypes have the ability for increased branching, it may be possible for a producer to seed at a lower plant population without reduced yield or to choose a highly branched cultivar to have reduced risk of yield loss under conditions of poor emergence. The objective of this research was to determine how differences in branching among seven representative pea cultivars affected crop yield at different seeding rates, and to determine if branching affected the competitive ability of pea cultivars. In the plant population experiment, seven pea cultivars were seeded at five target plant populations (10, 30, 90, 120, and 150 plant m-2) during 2005 and 2006 at Rosthern and Saskatoon, Saskatchewan. The competition experiment involved eight cultivars being seeded at 50 plants m-2 to measure competitiveness with weeds. Plant emergence, number of branches, light interception, harvest index and grain yield were measured. Growth, seasonal temperature and rainfall were near normal in 2005. Severe terminal drought occurred in 2006 which may have lead to decreased yields. Branching was greatest at low plant densities and decreased as plant density increased. Grain yield increased as plant density increased until it plateaued at 80 100 plants m-2. The response of yield to plant density differed to some extent among cultivars, with CDC Acer and CDC Bronco achieving more of their potential yield at lower densities, while Carrera and Courier required higher densities to reach the same proportion of potential yield. Weed biomass was lowest in plots sown to longer vined cultivars with normal leaf type. Branching habit did not affect the competitiveness of pea cultivars. Potential exists to plant highly branched cultivars to reduce risk of yield loss in situations where low plant emergence might occur.

Field pea is an important crop in western Canada. The current recommended seeding rate in field pea is 88 plants m-2. As certain pea genotypes have the ability for increased branching, it may be possible for a producer to seed at a lower plant population without reduced yield or to choose a highly branched cultivar to have reduced risk of yield loss under conditions of poor emergence. The objective of this research was to determine how differences in branching among seven representative pea cultivars affected crop yield at different seeding rates, and to determine if branching affected the competitive ability of pea cultivars. In the plant population experiment, seven pea cultivars were seeded at five target plant populations (10, 30, 90, 120, and 150 plant m-2) during 2005 and 2006 at Rosthern and Saskatoon, Saskatchewan. The competition experiment involved eight cultivars being seeded at 50 plants m-2 to measure competitiveness with weeds. Plant emergence, number of branches, light interception, harvest index and grain yield were measured. Growth, seasonal temperature and rainfall were near normal in 2005. Severe terminal drought occurred in 2006 which may have lead to decreased yields. Branching was greatest at low plant densities and decreased as plant density increased. Grain yield increased as plant density increased until it plateaued at 80 100 plants m-2. The response of yield to plant density differed to some extent among cultivars, with CDC Acer and CDC Bronco achieving more of their potential yield at lower densities, while Carrera and Courier required higher densities to reach the same proportion of potential yield. Weed biomass was lowest in plots sown to longer vined cultivars with normal leaf type. Branching habit did not affect the competitiveness of pea cultivars. Potential exists to plant highly branched cultivars to reduce risk of yield loss in situations where low plant emergence might occur.