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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Avaliação da retenção de nutrientes, aspectos sensoriais e microbiológicos de batata-doce (Ipomoea batatas (L.) Lam.) submetida a diferentes métodos de cocção / Nutrient retention of assessment, sensory aspects and sweet potato of microbiological (Ipomoea batatas (L.) Lam.) submitted to different cooking methods

Velho, Liana Cleide Flor de Lima January 2016 (has links)
VELHO, Liana Cleide Flor de Lima. Avaliação da Retenção de Nutrientes, Aspectos Sensoriais e Microbiológicos de Batata-Doce (Ipomoea Batatas (L.) Lam.) Submetida a Diferentes Métodos de Cocção. 2016. 109 f. Dissertação (Mestrado em Ciência e Tecnologia de Alimentos)-Universidade Federal do Ceará, Fortaleza, 2016. / Submitted by Aline Mendes (alinemendes.ufc@gmail.com) on 2016-08-31T19:41:12Z No. of bitstreams: 1 2016_dis_lcflvelho.pdf: 3304129 bytes, checksum: 703028e8641aa28d63fb0da59e643aa1 (MD5) / Approved for entry into archive by Jairo Viana (jairo@ufc.br) on 2016-08-31T23:10:40Z (GMT) No. of bitstreams: 1 2016_dis_lcflvelho.pdf: 3304129 bytes, checksum: 703028e8641aa28d63fb0da59e643aa1 (MD5) / Made available in DSpace on 2016-08-31T23:10:40Z (GMT). No. of bitstreams: 1 2016_dis_lcflvelho.pdf: 3304129 bytes, checksum: 703028e8641aa28d63fb0da59e643aa1 (MD5) Previous issue date: 2016 / The sweet potato (Ipomoea batatas (L.) Lam.) is a tuberous root plant that belongs to the Convolvulaceae family. It is one of the most important economic crops in many tropical and subtropical countries and it is the fourth most consumed vegetable in Brazil. Due to its nutritional composition, sweet potato is considered one of the healthiest foods on the planet. The sweet potato is high in energy, vitamins C and B complex, minerals, and also has phytochemical components that are beneficial to one´s health. In order to be consumed, the sweet potato must be subjected to heat for starch gelatinization to occur. However, the cooking methods cause chemical and physical changes that can modify their nutritional value. The objective of this study is to evaluate the retention of nutrients in sweet potatoes subjected to conventional cooking methods (boiling, steam, conventional oven and pressure cooker) and contemporary cooking methods (microwave and combination oven), and to evaluate the sensory acceptance and microbiological characteristics of each method. The chemical, physical-chemical, coloring, ascorbic acid, carotenoids, total polyphenols, and antioxidant activity determinations were conducted in triplicate through ABTS and FRAP assays, as well as sensory and microbiological analysis. The results were submitted to (ANOVA) variance analysis at 5% probability through the F-test and when the results were significant, they were submitted to the Tukey’s range test. The Pearson correlation coefficient (PCC) and principal component analysis (PCA) were also performed in order to correlate the results. A significant effect was found at (p ≤ 0.05) for all the treatments in the study in relation to all chemical and physico-chemical parameters of raw and cooked sweet potato samples. The sweet potato pH values showed a slight increase after processing, except for the combination oven method. The color of the cooked samples was less bright (L*), less green (negative a*) and less yellow (positive b*) than the raw sample. There was a reduction in ascorbic acid content in all the cooking methods, with less loss in samples submitted to cooking with the boiling method and in the combination oven method, which showed 9,77 ± 0,01 mg of ascorbic acid/100g in the fresh sample. Carotenoids were only detected in the boiling, oven, and microwave methods, however there was no significant difference between their means. The total polyphenol increased in all cooking methods, showing variation from 116.88 (steam) to 149.47 (oven) mg GA/100g FW (mg gallic acid/100 g fresh weight). The antioxidant activity through ABTS and FRAP assays increased in all cooking methods compared to the raw sample. Significantly high positive correlation was found between total phenolics and both the ABTS and FRAP methods, in that the cooked samples in the oven showed the highest elevation. The sensory analysis showed no significant difference between the (p > 0,05) methods for the mean test. In the CATA test, the “sweet potato flavor”, “cooked”, and “soft” characteristics were the most indicated by food tasters to characterize the samples of sweet potatoes cooked in different methods. The sample cooked in the steam method was the one that is closest to an ideal sample of the sweet potato, because it had “soft”, “homogeneous” and “baked smell” features that are required for an ideal product, according to the food tasters. / A batata-doce (Ipomoea batatas (L.) Lam.) é uma planta de raízes tuberosas pertencentes à família das convolvuláceas, sendo uma das culturas econômicas mais importantes de muitos países tropicais e subtropicais e a quarta hortaliça mais consumida no Brasil. Por sua composição nutricional é considerada um dos alimentos mais saudáveis do planeta, por ser rica em energia, vitaminas C e do complexo B, minerais, além de possuir componentes fitoquímicos benéficos à saúde. Para ser consumida deve sofrer ação do calor para que haja a gelatinização do amido. Contudo, os métodos de cocção provocam alterações químicas e físicas que podem modificar seu valor nutricional. O objetivo do estudo foi avaliar a retenção de nutrientes em batatas-doces submetidas a métodos de cocção convencionais (ebulição, vapor, forno convencional e panela de pressão) e contemporâneos (forno de micro-ondas e a vácuo no forno combinado), além de avaliar a aceitação sensorial e as características microbiológicas de cada método. Foram conduzidas em triplicata as determinações químicas, físico-químicas, coloração, ácido ascórbico, carotenoides, polifenóis totais e atividade antioxidante pelos ensaios ABTS e FRAP, bem como avaliação sensorial e análises microbiológicas. Os resultados foram submetidos à análise de variância (ANOVA) a 5% de probabilidade pelo teste F e quando significativos foram submetidos ao teste de médias (Tukey). Também foi realizado o teste de correlação de Pearson e análise de componentes principais (ACP) a fim de correlacionar os resultados. Constatou-se efeito significativo (p ≤ 0,05) em todos os tratamentos em estudo, sobre todos os parâmetros químicos e físico-químicos das amostras de batata-doce in natura e cozidas. Os valores de pH da batata-doce apresentaram aumento após o processamento, com exceção do método à vácuo no forno combinado. A cor das amostras cozidas foi menos brilhante (L*), verde (a* negativo) e amarela (b* positivo) que a amostra in natura. Houve redução no conteúdo de ácido ascórbico em todos os métodos de cocção, havendo menor perda nas amostras submetidas à cocção em ebulição e a vácuo no forno combinado, que apresentaram 9,77 ± 0,01 mg de ácido ascórbico/100g de amostra fresca. Apenas nas amostras submetidas às cocções por ebulição, forno e micro-ondas, os carotenoides foram detectados, porém, sem diferença significativa entre suas médias. Os polifenóis totais aumentaram em todos os métodos de cocção, mostrando variação de 116,88 (vapor) a 149,47 (forno) mg ácido gálico/100g peso fresco. A atividade antioxidante pelos ensaios ABTS e FRAP aumentou em todos os métodos de cocção comparados com a amostra in natura, sendo que as amostras cozidas em forno foram as que apresentaram maior elevação. Foi verificada correlação positiva de Pearson altamente significativa entre os compostos fenólicos totais e os métodos ABTS e FRAP. Na avaliação sensorial não houve diferença significativa entre os métodos (p > 0,05) pelo teste de médias. No teste CATA, as características “sabor de batata-doce”, “cozida” e “mole” foram as mais assinaladas pelos provadores para caracterizar as amostras de batatas-doces cozidas pelos diferentes métodos. A amostra de vapor foi a que mais se aproximou de uma amostra ideal de batata-doce, pois apresentou-se “mole”, "homogênea” e com “aroma de cozido”, características necessárias à um produto ideal, segundo os provadores.
2

Caracteriza??o morfol?gica e molecular de gen?tipos de batata-doce / Molecular and morphological characterization of genotypes of sweet potato

Andrade, Elis?ngela Knoblauch Viega de 24 October 2014 (has links)
Submitted by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2016-01-05T12:38:46Z No. of bitstreams: 2 elisangela_knoblauch_viega_andrade.pdf: 1007346 bytes, checksum: 82e99aa23997633aaed7026a8489fe65 (MD5) license_rdf: 22974 bytes, checksum: 99c771d9f0b9c46790009b9874d49253 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2016-01-05T17:44:56Z (GMT) No. of bitstreams: 2 elisangela_knoblauch_viega_andrade.pdf: 1007346 bytes, checksum: 82e99aa23997633aaed7026a8489fe65 (MD5) license_rdf: 22974 bytes, checksum: 99c771d9f0b9c46790009b9874d49253 (MD5) / Made available in DSpace on 2016-01-05T17:44:56Z (GMT). No. of bitstreams: 2 elisangela_knoblauch_viega_andrade.pdf: 1007346 bytes, checksum: 82e99aa23997633aaed7026a8489fe65 (MD5) license_rdf: 22974 bytes, checksum: 99c771d9f0b9c46790009b9874d49253 (MD5) Previous issue date: 2014 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (Capes) / Funda??o de Amparo ? Pesquisa do estado de Minas Gerais (FAPEMIG) / Objetivou-se realizar a caracteriza??o morfol?gica e molecular de gen?tipos de batata-doce do banco de germoplasma da Universidade Federal dos Vales do Jequitinhonha e Mucuri (UFVJM). Para a caracteriza??o morfol?gica, o experimento foi conduzido no Setor de Olericultura da UFVJM sendo avaliados 60 gen?tipos de batata-doce, utilizando 24 descritores morfol?gicos, tanto da parte a?rea quanto da parte radicular. As avalia??es da parte a?rea foram realizadas 60 e 90 dias ap?s o plantio, e as avalia??es da parte radicular foram realizadas ap?s a colheita aos 150 dias ap?s o plantio. Para a caracteriza??o molecular foram utilizadas amostras foliares de 60 acessos oriundos do banco de germoplasma-UFVJM. A extra??o do DNA foi realizada no Laborat?rio de Gen?tica e Biotecnologia Florestal (UFVJM), utilizando o m?todo Fenol-Clorof?rmio. Para a amplifica??o do DNA, foram utilizados onze primers microssat?lites espec?ficos para a batata-doce. A diversidade morfol?gica e molecular foi obtida por meio da gera??o de matrizes de dissimilaridade baseando-se no coeficiente de coincid?ncia simples e ?ndices de Jaccard, respectivamente. Para o estudo da diverg?ncia recorreu-se ao dendrograma ilustrativo obtido pelo m?todo UPGMA e ao agrupamento de Tocher. Para as matrizes de dissimilaridade obtida com os dados morfol?gicos e moleculares foram estimadas dist?ncias gen?ticas variando de 0,08 a 0,92 com m?dia 0,52 e 0,14 a 1, com m?dia 0,76, respectivamente. Observou-se pelos dendrogramas de dissimilaridade e pelo agrupamento de Tocher, que os acessos de batata-doce do banco de germoplasma da UFVJM apresentaram diversidade gen?tica e fenot?pica, sendo promissores em programas de melhoramento desta cultura. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Produ??o Vegetal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2014. / ABSTRACT The objective was to make the morphological and molecular characterization of sweet potato genotypes of the germplasm bank of the Federal University of the Jequitinhonha and Mucuri Vales (UFVJM). For morphological characterization, the experiment was conducted in the Horticulture Sector of UFVJM being evaluated 60 sweet potato genotypes, using 24 morphological descriptors of both the shoots as the root part. The shoot evaluations were performed 60 and 90 days after planting, and ratings of roots were done after harvest at 150 days after planting. The molecular characterization leaf samples from 60 hits coming from the germplasm bank-UFVJM were used. DNA extraction was performed in Forest Genetics and Biotechnology Laboratory (UFVJM) using the phenol-chloroform method. For amplification of DNA eleven microsatellite primers specific for the sweet potato were used. The morphological diversity and Molecular was obtained by generating dissimilarity matrices based on the simple matching coefficient of Jaccard indices, respectively. To study the divergence appealed to the illustrative dendrogram by UPGMA and Tocher grouping. For dissimilarity matrices obtained with morphological and molecular data were estimated genetic distances ranging from 0,08 to 0,92 with a mean 0,52 and 0,14 to 1, with mean 0,76, respectively. It was observed by dendrograms of dissimilarity and the Tocher group, the sweet potato accessions of germplasm bank of UFVJM showed genetic and phenotypic diversity, and promising in breeding programs of this culture.
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Produção e qualidade de batata-doce em função das doses e parcelamento da adubação potássica / Production and quality of sweet potato in function of rates and installments of potassium fertilization in top dressing

Corrêa, Carla Verônica [UNESP] 25 February 2016 (has links)
Submitted by CARLA VERÔNICA CORREA null (cvcorrea@fca.unesp.br) on 2016-03-16T20:42:04Z No. of bitstreams: 1 Correa_Carva Veronica Dissertação.pdf: 750219 bytes, checksum: f5fe3e70b6a0b3965d3925e56ecb12e5 (MD5) / Approved for entry into archive by Sandra Manzano de Almeida (smanzano@marilia.unesp.br) on 2016-03-17T12:58:02Z (GMT) No. of bitstreams: 1 correa_cv_me_bot.pdf: 750219 bytes, checksum: f5fe3e70b6a0b3965d3925e56ecb12e5 (MD5) / Made available in DSpace on 2016-03-17T12:58:02Z (GMT). No. of bitstreams: 1 correa_cv_me_bot.pdf: 750219 bytes, checksum: f5fe3e70b6a0b3965d3925e56ecb12e5 (MD5) Previous issue date: 2016-02-25 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Embora existam estudos sobre nutrição e recomendações de adubação para o cultivo de batata-doce, raramente se encontram trabalhos que abordem os efeitos do potássio e de seu parcelamento na adubação em cobertura na sua produção e qualidade das raízes. Em vista disso, objetivou-se, com a realização deste experimento, avaliar a influência do parcelamento e das doses de potássio em cobertura na produção e qualidade de raízes tuberosas de batata-doce. O experimento foi conduzido na Fazenda Experimental São Manuel, de 25/03/2014 a 30/07/2014. Foram avaliados dez tratamentos em esquema fatorial 3 x 3 + 1, sendo três doses de potássio (60, 90 e 120 kg ha-1 de K2O); três parcelamentos (sendo aplicados 100% no plantio; 50% no plantio e 50% em cobertura e 25% no plantio e 75% em cobertura) e uma testemunha (sem aplicação de potássio no plantio e em cobertura), no delineamento experimental de blocos casualizados, com quatro repetições por parcela, composta por três leiras com dez plantas cada, sendo as duas leiras laterais consideradas como bordadura, assim como a primeira e a última planta da leira central de cada parcela, e oito plantas foram consideradas úteis para coleta dos dados. Foram avaliados a massa fresca e seca da parte aérea e das raízes comerciais; número, comprimento e diâmetro das raízes comerciais, produtividade, extração de macronutrientes (raízes tuberosas, parte aérea e total) e qualidade pós-colheita (acidez titulável, sólidos solúveis, pH, açúcares redutores e amido) das raízes comerciais. Foi observado ajuste linear para as doses de potássio para todas as características da parte aérea nos parcelamento 50% (plantio) + 50% (cobertura) e 25% (plantio) + 75% (cobertura). Para as características de produção das raízes foi observada interação significativa entre doses e parcelamentos, sendo que o parcelamento 50% (plantio) + 50% (cobertura) apresentou os melhores resultados. A produtividade foi crescente até a dose de 120 kg ha-1 de K2O quando parcelado 50% (plantio) + 50% (cobertura). A ordem decrescente de extração de macronutrientes pelas raízes foi K>N>Ca>P>S>Mg. Já a ordem decrescente de extração da planta foi K>N>Ca>Mg>P>S. As doses de potássio aumentaram os teores de açúcares redutores e reduziram os teores de amido. / Although there are fertilizer recommendations for comercial cultivation of sweet potato, there are few research papers that relate the effect of potassium fertilizer in top dressing and installment it production and quality. The objective of this work was to evaluate the potassium rates and installment influence in top dressing in sweet potato quality and production. The experiment was lead at São Manuel Experimental Farm and the evaluations at Horticulture Department in São Paulo State University. It was evaluated ten treatments in factorial scheme 3x3+1, with three rates of potassium (60, 90 and 120 kg ha-1 of K2O) in top dressing and three installments (100% planting; 50% (planting) + 50% (top dressing) e 25% (planting) + 75% (top dressing) and one control (without potassium and planting at top dressing). The experimental design was randomized blocks, with four replications. Fresh and dry weight of shoot and commercial roots; number, length and diameter commercials roots, yield, extraction of nutrients per plant and quality post harvest (pH, total acidity, soluble solids, reducing sugars and starch) of commercials roots were evaluated. Linear effect was observed for rates of potassium for all vegetative characteristics in installments 50% (planting) + 50% (coverage) and 25% (planting) + 75% (top dressing). For root production characteristics was observed significant interaction between rates and installment, and the installment 50% (planting) + 50% (top dressing) showed the best results. Yield increased with increasing rates of potassium till 120 kg ha-1 de K2O when installment 50% (planting) + 50% (top dressing). The decreasing order of macronutrient extraction by roots was K> N> Ca> P> S> Mg. Already the decreasing order of the plant extraction was K> N> Ca> Mg> P> S. The potassium rates increased sugars and reduced starch content.
4

Produtividade e características físico-químicas de acessos de batata-doce procedentes de comunidades quilombolas do Vale do Ribeira / SP / Productibidad y cararcteristicas físico-químicas de acesos de Camote procedentes de comunidades quilombolas do Vale do Ribeira /SP

Solano Mendoza, Juan David [UNESP] 22 February 2017 (has links)
Submitted by JUAN DAVID SOLANO MENDONZA null (juan.solanomendoza@gmail.com) on 2017-04-19T18:30:02Z No. of bitstreams: 1 dissertaçao JUAN MENDOZA.pdf: 1111206 bytes, checksum: 0b4a862173ec55a33d92959d7331d935 (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-04-19T19:56:57Z (GMT) No. of bitstreams: 1 solanomendoza_jd_me_bot.pdf: 1111206 bytes, checksum: 0b4a862173ec55a33d92959d7331d935 (MD5) / Made available in DSpace on 2017-04-19T19:56:57Z (GMT). No. of bitstreams: 1 solanomendoza_jd_me_bot.pdf: 1111206 bytes, checksum: 0b4a862173ec55a33d92959d7331d935 (MD5) Previous issue date: 2017-02-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A batata-doce é uma das principais hortaliças cultivadas no mundo, as suas raízes tuberosas têm múltiplos usos na alimentção humana e animal e na produção industrial de farinha, amido e etanol. Os teores de compostos biativos, caracteristicas fisico-quimicas de quailidade pós-colheita e produtividade, podem diferir entre genótipos e idade da planta. O Vale do Ribeira é uma região de comunidades tradicionais que mantêm diferentes acessos de batata-doce. Este estudo foi realizado de fevereiro a outubro de 2015, o objetivo principal foi realizar a caracterização físico-química e de produtividade de três acessos de batata-doce pertencentes ao Banco de Germplasma da Universidade Estadual Paulista.Registro. As análises do experimento foram feitas nos acessos VR 13-01 (casca roxa e polpa roxa fortemente pigmntada), VR13-11 (casca rosa e polpa branca) e VR13-50 (casca creme e polpa branca). O delineamento experimental foi em blocos casualizados com seis repetições por tratamento e cada parcela tinha 5 plantas.O espaçamento de plantio entre plantas foi de 0,25 m e 0,80 m entre linhas. As avaliações das analises físico-químicas, compostos bioativos e produtividade foram feitas aos 120,150 e 180 dias após o plantio. Foram determinados a produçao total de matéria fresca da parte aérea, produçao total de matária seca da raiz, produtividade total de raizes, produtividade comercial de raízes, produção de raizes não comercias , teor de sólidos solúveis , teor de amido, comteúdo de compostos fenólicos totais, flavonoides totais, antocianinas totais e capacidade antioxidante. As características selecionadas pela PCA foram submetidas a análise de variância, complementadas pelo teste de Scott-Knott, a 5% de probabilidade. Considerou-se significativo quando p<0,05. Comparando os três acessos o VR 13­ 01 mostrou os maiores teores de sólidos solúveis (16,6 ° Brix), antocianinas totais (111,6 mg 100 g;1 e o VR13­50 apresentou o maior teor de amido (25,3%) e produtividades mais elevadas ( 43.011kg ha-1). / The sweet potato is one the most grown vegetable crops in the world, its storage roots have multiple uses as human and animal foods and in industrial production of flour, starch and ethanol. The starch and sugar content may differ genotypes and harvest season. The Vale do Ribeira region has traditional communities keep different accessions of sweet potato. This study was conducted from February to October 2015, and main objetive was the physico-chemical characterization, bioactive compounds and productivity of three accessions of sweet potato belonging to the Germplasn Bank of Universidad Estadual Paulista. Accession were VR 13-01 (purple skin and strongly purple pulp).VR13-11( lightly purple skin and white pulp) and VR13-50 ( cream skin and white pulp).The experimental design was randomized blocks with six replications per treatment and each plot had 5 plants. The planting distance between plants was 0.25 m and 0.80 m between rows. The biochemical , physico chemical characterization and production yields was made 120,150 and 180 days after planting. The total productions yield, soluble solids content, and starch content were determined and significant differences among accessions obtained by ANOVA and means separated by a Scott-Knott test. Comparing all three accessions. VR13-01 showed highhest soluble solid content (16,6° Brix), anthocyanin content (111,6 mg 100-1 and accessions VR13-50 showed the highest starch content (25,3 %) and the highest production yields (43.011 Kg ha 1).
5

Storage root production in sweetpotato (Ipomoea batatas (L.) Lam.) : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Plant Science at Massey University, New Zealand

Lewthwaite, Stephen L January 2004 (has links)
Sweetpotato (Ipomoea batatas (L.) Lam.) is a root crop well established throughout the world's tropical and sub-tropical regions. Despite sweepotato's importance, it has been under-researched relative to many other major crops. The main objective of this thesis is to contribute to a fuller understanding of the genetic and physiological factors underlying the production of sweetpotato storage roots for human consumption. The sweetpotato genome is diverse and subject to high levels of natural somatic mutation. Applying the AFLP (amplified fragment length polymorphism) technique allowed a direct comparison of inter and intra-cultivar DNA (deoxyribonucleic acid) base sequence variation. Analysis of the variation indicated that although sweetpotatoes are clonally propagated, clones show a lack of genetic fidelity to their source. Further, the level of genetic variation within the cultivar 'Owairaka Red' indicated the continuing emergence of distinct new strains. Plant field establishment represents the interaction of both propagation and growth phases of storage root production. A range of establishment techniques were investigated in a field trial under commercial conditions. Sprouts cut from seed roots and held for six days rather than immediate planting improved establishment as measured by growth, at little expense. Plug raised plants also improved establishment, while potentially reducing the degree of intra-cultivar genetic variation. Plant carbohydrate partitioning in three cultivars, 'Beauregard', 'Beniazuma' and 'Owairaka Red' was examined by field trial over the period of storage root growth. While cultivars differed in the proportions of dry matter partitioned to leaf, stem and root organs, the cultivar specific ratios of leaf to stem dry weight were relatively stable over time. Total storage root dry weight increased with time for all cultivars, but the distribution of storage root grades by size was cultivar specific. Within the storage roots % dry weight increased over time in all cultivars, but total sugar concentration only increased for 'Beauregard' and 'Beniazuma'. Finally, a storage root disorder called 'brown centre' curtails the temperate growing season so was investigated using low temperature storage and a field trial with various nutrition regimes. The disorder was found to be associated with susceptible germplasm, high soil nitrogen and harvest time.
6

<b>A multifaceted approach to weed management in organic sweetpotato systems</b>

Emmanuel Gonfatee Cooper (18405756) 18 April 2024 (has links)
<p dir="ltr">Sweetpotato (<i>Ipomoea batatas</i> L.) is a staple crop that provides nutritional benefits to humans globally, but it is subjected to yield loss when competing with weeds, especially during the early stage of establishment. Despite increased organic sweetpotato production in the United States, growers face challenges with limited weed management options and often resort to time-consuming and costly cultivation and hand-weeding. To address this challenge, experiments were developed to determine (1) the effect of sweetpotato cultivar on the critical weed-free period, (2) the effects of in-row plant spacing and cultivar selection on weed suppression and sweetpotato yield, and (3) the impact of buckwheat and silage tarps for row-middle weed control. 1) In 2022, field research was conducted at the Samuel G. Meigs Horticulture Research Farm (Meigs), Lafayette, IN, and at the Southwest Purdue Agricultural Center (SWPAC), Vincennes, IN to estimate the critical weed-free period for ‘Covington’, ‘Murasaki’, and ‘Monaco’ in the Midwest. The experiment was a split-plot design, with weed-free interval treatments as the main plot factor and cultivar as the subplot factor. Weeds were removed by hand and allowed to establish and compete with the crop beginning at 0, 14, 21, 28, 35, or 42 days after transplanting (DAP). As weed-free interval increased from 0 to 42 DAP, predicted total yield increased from 19 kg ha<sup>-1</sup> to 20,540 kg ha<sup>-1 </sup>for Covington, 3 kg ha<sup>-1</sup> to 11,407 kg ha<sup>-1</sup> for Monaco, and 125 kg ha<sup>-1 </sup>to 13,460 kg ha<sup>-1 </sup>for Murasaki at the Lafayette location. A threshold of ≤10% total yield reduction was achieved by maintaining sweetpotatoes weed-free 24 DAP for Covington, 20 DAP for Murasaki, and 33 DAP for Monaco. 2) In 2022 and 2023, studies were conducted at Meigs, Lafayette, IN and SWPAC, Vincennes, IN to evaluate in-row plant spacing and cultivars for weed control and sweetpotato yield. The experiment was a split-split plot design, with in-row spacings of 20, 30, and 40 cm as the main plot factor, weeding frequency (‘critical weed-free period’ and ‘weed free’) as the subplot factor, and sweetpotato cultivar (‘Covington’ and ‘Monaco’) as the sub-subplot factor. However, in 2022, we evaluated only in-row spacing and weeding frequency because of poor establishment of Monaco. In-row spacing had no significant effect on weed densities at 4, 5, and 6 WAP. As in-row spacing increased from 20 to 40 cm, total sweetpotato yield pooled across both locations in 2023 decreased from 30,223 to 21,209 kg ha<sup>-1</sup> for Covington and 24,370 to 20,848 kg ha<sup>-1</sup> for Monaco, however, jumbo yield increased for both cultivars. Findings from this study suggest that an in-row spacing of 20 cm may provide greater yield than the standard spacing, 30 cm, for both Monaco and Covington cultivars and could reduce weed interference through more rapid sweetpotato canopy closure. 3) The experiment was a randomized complete block design, with three row-middle treatments [tarp, buckwheat, and cultivation] and four replicates. Row-middle treatments were established immediately after transplanting ‘Covington’ slips 30 cm apart into raised bed plots consisting of a single row 6 m long and 2 m apart on-center. Buckwheat was planted three weeks after transplanting (WAP) at a rate of 108 kg ha<sup>-1</sup> in row-middle. Row-middles for the tarp treatment were covered for the entire growing season. Weed density at 6 WAP was 184 plants m<sup>-2</sup> for the buckwheat, and 162 plants m<sup>-2</sup> for the cultivation treatments. Total yield was 11,050 kg ha<sup>-1</sup> for the buckwheat, 19,790 kg ha<sup>-1</sup> for the cultivation, and 17,810 kg ha<sup>-1</sup> for the tarping treatments. Tarping effectively suppressed weeds and produced sweetpotato yields comparable to cultivation indicating potential for organic growers. Buckwheat yields were lower than those from tarping and cultivation.</p>

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