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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

Growing Salvia miltiorrhiza in Mississippi

Xing, Zhiheng 10 May 2024 (has links) (PDF)
Salvia miltiorrhiza is a traditional Chinese herbal medicine widely used to prevent and treat cardiovascular and other diseases. With the increasing awareness and use of herbal medicines worldwide, there has been a rapid increase in the use of medicinal plants in the United States. Currently, the majority of medicinal plants used in the US are imported from foreign countries. However, increasing concerns over safety such as heavy metal and chemical contaminations pose significant challenges to US pharmaceutical and related industries in sourcing quality plant materials. It is critical for US industries to have access to high-quality medicinal plants, which provides an opportunity for US farmers to incorporate medicinal plants as an alternative crop. The purpose of this study is to evaluate and identify adaptive cultivars and develop best management practices for Salvia miltiorrhiza production in Mississippi. Salvia miltiorrhiza seeds from different sources were sown and grown in a greenhouse at Mississippi State University (MSU) in 2019, 2020, and 2021. Plants were transplanted into a container or field located at MSU North Farm to evaluate cultivar performance and production practices including different seed sources, fertilization (0, 2, 4, 6, or 8 g N per plant from NH4NO3), planting density (20×30, 20×45, 30×30, 30×45, 40×30, 40×45 cm), and timing of harvest (60, 120, 180 days after transplanting). The data were processed by ANOVA using the PROC GLM procedure. The three seed sources tested in this study (V1, V2, and V3) differed in germination rates, maximum root lengths, and maximum root diameters in both years (2019, 2020). V1 and V2 had higher germination rates than V3. In general, plants treated with 6 or 8 g N per plant and plants planted in 30×45 or 40×45 cm had better performance in shoot growth, root growth, and content of bioactive compounds, including tanshinone I, tanshinone IIA, cryptotanshinone, and salvianolic acid B. Shoot growth, root growth, and content of bioactive compounds increased with increasing days to harvest after transplanting.
2

Industrial hemp agronomic management for grain, fiber, and forage

Podder, Swarup 12 September 2023 (has links)
This research involved testing several aspects of industrial hemp (Cannabis sativa L.) production, including the impact of tillage on seed and fiber production, optimal harvest time for seed yield and quality, the response of seed yield to nitrogen fertility rates, and the potential of hemp as a forage crop. A three-year study was conducted in Blacksburg and Orange of Virginia State to assess the effects of tillage management and production systems (e.g., seed, dual, and fiber) on hemp establishment and productivity. Two cultivars, Joey (a dual-purpose variety) and EcoFibre (bred specifically for fiber), were planted into seedbeds prepared with conventional tillage and no-till management. The cultivar Joey, lower plant populations under seed production systems resulted in taller plants (P = 0.0002) compared to the dual-purpose production systems in 2020. Greater plant heights (P < 0.0001) with fiber production systems in 2021 and 2022 were due to differences between cultivars and their time of flowering. Conventional tillage resulted in greater (P ≤ 0.0161) plant populations than no-tillage for all production systems in each year, and this response was more pronounced with fiber management in 2020 (tillage × production systems interaction; P = 0.0007). Greater (P < 0.001) yields with fiber systems observed in 2021 and 2022 were largely driven by the more productive EcoFibre cultivar. Despite treatment differences in population density, biomass and seed yields varied less by tillage management and production systems. Lower plant population density was associated with greater biomass and seed yields per plant. However, for desired fiber quality and mechanical harvest feasibility, a higher plant population density is recommended. A second study aimed to determine the optimum harvest time for seed yield of two hemp cultivars. 'Joey', and 'Grandi,', were established in Blacksburg and Orange, Virginia in mid-May/early June of 2021 and 2022. The experiment was conducted as a randomized complete block design with a repeated measurement arrangement and four replicates. Plants were harvested four times at one-week intervals starting in mid-summer. Harvest date significantly affected seed yield, with the response differing by cultivar (cultivar × date interaction; P = 0.001) in 2022 at the Orange site. In Blacksburg, seed yields were similar for the two cultivars and greatest at the second harvest each season (July 22, 2021, and July 25, 2022), although they were substantially lower in 2022 due to drought (1750 vs. 480 kg ha-1; P < 0.0001). In Orange, in 2021, as planting occurred late, harvests were also deferred until August 17, and seed yields were greatest at this first harvest (1180 kg ha-1; P<0.0001). In 2022, yields at the Orange location were highest for Grandi at the first harvest (July 21; 1510 kg ha-1) and for Joey at the second harvest (July 28; 1280 kg ha-1) (Harvest Time by Cultivar interaction, P = 0.0010). Over the subsequent weeks of harvest, yields drastically declined (16 to 41% in 2021 and 27 to 47% in 2022 in Blacksburg; 52% to 91% in 2021 and 28% to 65% in 2022 in Orange, compared to the highest yield). Harvest timing is critical to achieving optimum seed yield, and it varies with cultivar, eco-physiographic location, and weather (e.g., rainfall). Fatty acids (FA) varied by cultivar, location, and harvest timing, but patterns of response were not consistent across FA. Gamma-linolenic (P ≤ 0.002) and oleic acids (P ≤ 0.023) were generally greater in Joey, with greater arachidic acid (P ≤ 0.013) concentrations in Grandi. Stearidonic acid concentrations declined with later harvest date in Orange location (P ≤ 0.0034). A third study aimed to measure hemp's response to different N rates and to determine the ability to predict plant N content and seed yield based on UAV-based multispectral imagery. Two hemp cultivars, 'Joey' and 'Grandi', were planted and five N rates (0, 60, 120, 180, 240 kg N ha-1) were tested in Blacksburg, Virginia in 2020, 2021, 2022. Aerial image acquisition occurred at three different growth stages in 2021 using dji M 300 drones mounted with multispectral sensors. Red/Blue index (R2=0.89), near-infrared (NIR) band (R2=0.84) and Enhanced vegetation index (EVI) (R2=0.81) were better predictors of N content in leaf samples than other vegetation indices that were evaluated. Green normalized difference vegetation index (GNDVI) was the better predictor of hemp seed yield (R2=0.58) than other evaluated vegetation indices. The seed yield of hemp was influenced (P ≤ 0.0177) by the N input in all three experimental years. In 2020, seed yield did not increase steadily with the increase of N rate; the highest seed yield, 1640 kg ha-1, was observed at 120 kg N ha-1. In 2021, maximum seed yield of 2500 kg ha-1 occurred at the maximum N rate (240 kg N ha-1). In 2022, a weak response to N rate was observed; maximum seed yield was 380 kg ha-1, again at 240 kg N ha-1. The overall growth of the hemp plants was affected by limited rainfall and weed pressures in 2022, leading to a significant reduction in seed yield. Response to N rate will vary depending on other factors such as available soil moisture during the growing season, weed pressure, and growing period. A fourth study examined the yield and nutritive value of three hemp cultivars, 'Grandi', 'Joey', and 'EcoFibre' as potential forage crops when harvested at weekly intervals in Blacksburg, VA. The greatest biomass and TDN yields across cultivars were 3.17 Mg ha-1 and 2.08 Mg ha-1 respectively, at two months after establishment in 2021. In the dry 2022 season, biomass and TDN yield were 1.9 Mg ha-1 and 1.03 Mg ha 1, respectively, two months after establishment. Hemp nutritive value measures varied by cultivar and harvest time (P < 0.05). Depending on the cultivar and harvest time, hemp plant biomass contained 13 to 32% CP, 22 to 45% NDF, 20 to 38% ADF, 4 to 9% lignin, and 52 to 80% TDN (cultivar × time interaction; P < 0.05). Hemp CP and TDN decreased gradually with maturation while ADF, NDF, and lignin increased (P<0.0001); however, this decline with maturity did not appear as severe as occurs with many other forages. These preliminary results suggest that hemp has the potential to be used as a forage crop. More research is needed to address hemp management and utilization, including field establishment and production, harvest timing for optimum tonnage and forage quality, and animal intake and performance studies. These findings provide new insights into industrial hemp production in the mid-Atlantic region of the United States. Optimal tillage practices, precise harvest timing, appropriate N fertility rates, and proper management techniques all are crucial for maximizing hemp seed and fiber production and quality. Furthermore, hemp shows promise as a forage crop with its adaptability and favorable nutritional properties. Further research is warranted to refine cultivation techniques, improve crop quality, and explore the full potential of hemp in various industries. / Doctor of Philosophy / Industrial hemp (Cannabis sativa L.) is a versatile crop with numerous applications in various industries, but much work must be done to understand crop responses to management practices and improve its potential as a crop for greater sustainability. In this study, we explored different aspects of hemp agronomic management. Hemp traditionally has been planted into tilled fields, which increases the chance for soil erosion. We examined whether hemp could be established without tillage and found that although tilled fields generally had great populations of taller plants; total biomass and seed yields were not as influenced by tillage. Our research suggests that with some tweaking, hemp can be successfully established without soil tillage. Next, we investigated the optimal time to harvest hemp for maximum seed yield. Harvesting at the right moment is crucial, as seeds ripen unevenly, resulting in varying quality and yield. By carefully timing the harvest, we can maximize seed yield and ensure high-quality seeds. Our cultivars were best harvested in a late July to early August time frame. Under favorable weather conditions, we observed seed yields ranging from 1,180 to 2,510 kilograms per hectare, depending on the hemp cultivar and location. Additionally, we studied the response of hemp seed yield to nitrogen fertilization rates. Nitrogen is an essential nutrient for plant growth, and we found that nitrogen significantly influenced seed yield, although the pattern of response varied by growing conditions. Over three years, seed yields ranged from 380 to 2,510 kilograms per hectare. Yields generally increased with nitrogen inputs but were highly affected by available moisture. Fertility studies help farmers determine the ideal nitrogen levels for their hemp crops, promoting healthy growth, maximizing yield, and minimizing environmental contamination. Within this study, we also evaluated aerial imagery technologies to monitor plant nitrogen status and we observed that remote sensing technologies are promising for building predictive nutrient management tools. Lastly, we explored the potential of hemp as a forage crop. Hemp plants have unique nutritional properties (e.g., protein, fatty acids) and can be used as feed for livestock. We investigated the best time to harvest hemp for maximum biomass and nutrient content, important factors for animal nutrition. Hemp plants grow rapidly and within two months after establishment they yielded up to 3.17 metric tons of biomass per hectare, with relatively high nutritional value. Overall, these studies provide valuable insights into hemp production, including the importance of tillage practices, optimal harvest timing, and appropriate nutrient management. By applying these findings, farmers can enhance their hemp cultivation techniques, resulting in higher yields, improved crop quality, and better environmental outcomes.
3

Dessecação química e retardamento de colheita em soja visando à produção de sementes

Barbosa, Adriano Silveira 09 March 2018 (has links)
A aplicação de dessecantes em pré-colheita da soja reduz o tempo de permanência das plantas no campo, podendo minimizar os efeitos adversos das condições climáticas na qualidade das sementes. Entretanto, estudos sobre o efeito da dessecação aliada ao retardamento de colheita, nas qualidades das sementes, são escassos em cultivos sob baixa latitude. Assim, no ano agrícola 2016/17, foi realizado um experimento em Gurupi-TO, em delineamento de blocos casualizados, com três repetições, sendo os tratamentos dispostos em esquema de parcelas subsubdivididas, sendo alocados nas parcelas duas cultivares de soja com tipos de crescimento diferentes (NA 8015 RR-indeterminado; M 8349 IPRO-determinado), nas subparcelas dois sistemas de manejo (com dessecação e testemunha) e nas subsubparcelas quatro épocas de colheita (R8, R8+7, R8+14, R8+21). O dessecante utilizado foi um herbicida com princípio ativo Paraquat, na dosagem recomendada para a soja (1,5 L.ha-1), aplicado no estádio R7.2 da cultura. Após a colheita, as sementes foram submetidas aos testes de germinação em laboratório, emergência em campo, produtividade, teores de óleo e proteína dos grãos. As médias das cultivares e dos sistemas de manejo foram comparadas pelo teste de Scott-Knott, a 5% de significância. Para as épocas de colheita, foram ajustados polinômios ortogonais. Não houve efeito da dessecação química e do retardamento de colheita na composição química dos grãos. O retardamento da colheita afetou negativamente a germinação, emergência e produtividade das sementes. A cultivar M 8349 IPRO foi mais tolerante aos testes. Os dessecantes podem ser usados visando antecipar a colheita da soja. / The application of desiccants in pre-harvesting of soybeans contributes to the reduction of seed exposure to unfavorable climatic conditions and to reduce the possibility of germination and vigor losses, as well as to allow uniformity of maturation and to anticipate harvesting of soybean from three days to one week. However, studies on its effect on physiological quality and chemical composition of soybeans with harvest delay are scarce in crops under low latitude. Thus, in the agricultural year 2016/17, an experiment was carried out in Gurupi-TO, in a randomized block design, with three replications, and the treatments were arranged in a sub-split plot scheme, being allocated in plots two cultivars of soybeans with different growth types (NA 8015 RR-undetermined; M 8349 IPRO-determined), in the subplots two management systems (with and without desiccant application) and in sub-subplots four harvesting times (R8, R8+7, R8+14, R8+21). The desiccant used was the herbicide Gramoxone (active principle Paraquat), at the recommended dosage for soybean (1.5 L.ha-1), applied at the R7.2 stage of the culture. After the harvest, the seeds were submitted to germination tests in the laboratory, field emergence, yield, oil content and grain protein. The means of cultivars and management systems were compared by the Scott-Knott test, at 5% significance. For the harvest times, orthogonal polynomials were fitted. The cultivar M 8349 IPRO was more conducive to desiccation. Harvest delay negatively affected the physiological quality of the seeds, with no effect on the chemical composition of the seeds. Chemical desiccation kept the seeds with better physiological quality for a longer period.
4

Aquisição da qualidade fisiológica de sementes de feijão-caupi (Vigna unguiculata (L) Walper) / Acquisition of the physiological quality of seeds of feijão-caupi (Vigna unguiculata (L) Walper)

Moreno, Leticia de Aguila [UNESP] 27 January 2017 (has links)
Submitted by Leticia de Aguila Moreno null (leticia-moreno@ig.com.br) on 2017-05-10T17:06:46Z No. of bitstreams: 1 Dissert. Leticia Moreno.pdf: 1497532 bytes, checksum: f856281196b266bffabba1eca36f929c (MD5) / Approved for entry into archive by Luiz Galeffi (luizgaleffi@gmail.com) on 2017-05-10T19:10:49Z (GMT) No. of bitstreams: 1 moreno_la_me_bot.pdf: 1497532 bytes, checksum: f856281196b266bffabba1eca36f929c (MD5) / Made available in DSpace on 2017-05-10T19:10:49Z (GMT). No. of bitstreams: 1 moreno_la_me_bot.pdf: 1497532 bytes, checksum: f856281196b266bffabba1eca36f929c (MD5) Previous issue date: 2017-01-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O feijão-caupi (Vigna unguiculata) é uma espécie relativamente bem estudada, contudo faltam informações sobre a aquisição da qualidade fisiológica ao longo da maturação. Determinar o período em que cada componente da qualidade fisiológica é adquirido permite um ajuste no momento ideal da colheita e consequentemente uma colheita no período em que a semente se encontra com o máximo de qualidade fisiológica. Este trabalho teve como objetivo, determinar quando sementes de Vigna unguiculata adquirem qualidade fisiológica, incluindo a aquisição de tolerância à dessecação e a longevidade. O estudo foi realizado na Universidade Estadual Paulista Júlio de Mesquita Filho (UNESP), Faculdade de Ciências Agronômicas - Laboratório de Análise de Sementes - Departamento de Produção e Melhoramento Vegetal (DPMV), Campus de Botucatu-SP. A produção de sementes foi realizada em abril de 2015, seguida de coleta e caracterização morfológica das sementes nos estádios reprodutivos 17, 20, 23, 25, 28, 31, 34, 37 e 40 dias após a antese (DAA). Para cada estádio foi determinado o teor de água, massa fresca, massa seca, germinação e vigor nas sementes frescas. Em seguida sementes foram submetidas a secagem e foi realizado o teste de germinação para se determinar a aquisição de tolerância à dessecação. As sementes secas foram então armazenadas à 35°C e 75% umidade relativa, para caracterizar a aquisição de longevidade. A qualidade fisiológica (germinação, tolerância à dessecação, vigor e longevidade) em feijão-caupi é adquirida ao longo da maturação da semente. O acúmulo de massa seca se iniciou próximo aos 17 DAA e atingiu o máximo aos 31 DAA. A germinação foi iniciada aos 28 DAA e atingiu seu máximo aos 37 DAA. A tolerância à dessecação foi iniciada a partir dos 28 DAA atingindo seu máximo aos 31 DAA. O vigor e a longevidade foram iniciados a partir dos 31 DAA apresentando seus máximos aos 37 DAA. / Cowpea (Vigna unguiculata) is a relatively well-studied specie, but lack information on the acquisition of physiological quality throughout maturation. Determine the period in which each physiologic component is obtained allows an adjustment in the optimal time of harvesting a crop and consequently the period in which seed acquire the maximum physiological quality. This study aimed to determine when Vigna unguiculata seeds acquire physiological quality, including acquisition of desiccation tolerance and longevity. The research was conducted at the Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Faculty of Agricultural Science - Laboratory of Seed Analysis - Department of Plant Breeding and Production, Botucatu-SP. Seed production was performed at the beginning of the year 2015, followed by collection and morphological characterization of the seeds in the reproductive stages 17, 20, 23, 25, 28, 31, 34, 37 and 40 days after anthesis (DAA). For each stage was determined the water content, fresh weight, dry weight, germination and vigor on fresh seeds. Then seeds were submitted to drying and carried out the germination test to determine the acquisition of desiccation tolerance and longevity. The dried seeds were then stored at 35 ° C and 75% relative humidity, to characterize the acquisition of longevity. The physiological quality (germination, desiccation tolerance, vigor and longevity) of Vigna unguiculata is acquired during seed maturation, after the maximum dry matter accumulation. The dry matter accumulation began close to 17 DAA and reached the maximum at 31 DAA. Germination was acquired at 28 DAA and reached its maximum at 37 DAA. The desiccation tolerance was acquired from 28 DAA reaching its maximum at 31 DAA. The vigor and longevity were acquired from 31 DAA showing their maximum to 37 DAA.
5

Formação de sementes de soja: aspectos físicos, fisiológicos e bioquímicos / Formation of soybean seeds: physical, physiological and biochemical aspects

Trzeciak, Mário Borges 14 March 2013 (has links)
Os objetivos dessa pesquisa foram avaliar as alterações de natureza física, fisiológica e bioquímica durante a formação das sementes de soja, produzidas nos anos 2009 e 2010, em Piracicaba, São Paulo. Foram utilizadas sementes de dois cultivares de soja, CD - 202 e CD - 224, e os tratamentos foram compostos pelos momentos de colheita, ao longo do processo de formação das sementes, e pela utilização ou não da secagem artificial. Para as avaliações foram determinados os número de dias para a emergência da plântula, para a floração, para a floração plena, para a colheita, os parâmetros físicos (produtividade, teor de água das sementes e massa de mil sementes) fisiológicos (viabilidade e vigor) e bioquímicos (teores de óleo, de proteína, de clorofila, carotenoides, de lignina e de carboidratos). O delineamento experimental utilizado foi em blocos ao acaso, em que cada bloco continha uma unidade experimental de cada cultivar, distribuída de forma casualizada, em esquema fatorial de onze (momentos de colheita) x dois (sem secagem e com secagem), com quatro repetições e as análises estatísticas foram realizadas com o software R. Foi possível concluir que na maturidade fisiológica das sementes de soja, estádio R7, independentemente do cultivar e da avaliação das sementes úmidas ou secas, a produtividade, a viabilidade e os teores de lignina são máximos; No momento de colheita das sementes de soja, estádio R9, independentemente do cultivar e da avaliação de sementes úmidas ou secas, o acúmulo de massa é máximo, há a redução do teor de água, da viabilidade e do vigor e a semente tem mais óleo e proteína; O vigor das sementes é máximo no estádio R7 para as sementes avaliadas secas e no estádio R8 para as avaliadas úmidas, independentemente do cultivar; Há a degradação completa da clorofila nos estádios R7, para as sementes do cultivar CD - 202, e R8, para as sementes do cultivar CD - 224; Há carotenoides em todos os estádios de desenvolvimento da semente de soja, porém há mais carotenoides no início do processo de formação das sementes; Há variação da quantidade de carboidratos em função da avaliação das sementes úmidas ou secas. / This experiment aimed at the evaluation of the physical, physiological and biochemical changes during formation of soy seeds, produced in 2009 and 2010, in Piracicaba, São Paulo. Seeds of two cultivars of soy were used, namely CD - 202 and CD - 224, and treatments were composed by the moment of harvest, along the process of formation of seeds, and by the use or non-use of artificial drying. For the evaluations, we determined the number of days for seedling emergency, flowering, full flowering, harvest, physical parameters (productivity, rate of water in the seeds and mass of a thousand seeds) physiological parameters (viability and vigor) and biochemical parameters (rate of oil, of protein, of chlorophyll, of lignin and carbohydrates). The experimental delineation in use was in random blocks, in which each block contained one experimental unit of each cultivar, distributed at random, in a factorial scheme of eleven (harvesting periods), x two (dried and not dried), at four repetitions, and the statistical analysis were performed with software R. It was possible to conclude that at physiological maturity of soy seeds, stage R7, independently of the cultivar and of the evaluation of dry or humid seeds, the productivity, viability and rates of lignin are at their maximum; In the moment of harvest of soy seeds, stage R9, independently of the cultivar and evaluation of humid or dry seeds, the accumulation of mass is at its maximum, there is a drop in the level of water, of the viability and vigor, and the seed contains more oil and protein; The vigor of the seeds is at its maximum at stage R7 for the seeds which were evaluated dry and at stage R8 for the ones evaluated as humid, independently of the cultivar; There is the complete deterioration of the chlorophyll at stages R7, for the seeds of cultivar CD - 202 and R8, for the seeds of cultivar CD - 224; There are carotenoids in all stages of development of soy seed, however there are more of them in the beginning of the process of formation of seeds. There is variation of quantity of carbohydrates according to the evaluation of humid or dry seeds.
6

Effect of tree girdling, harvest time and ripening temperature on "hass" avocado fruit skin colour development during ripening

Sibuyi, Hazel January 2018 (has links)
Thesis (M. Sc. (Horticulture)) -- University of Limpopo, 2018 / ‘Hass’ avocado fruit changes skin colour from green to purple and then black during ripening. However, markets importing South African avocado fruit have been complaining about the ‘Hass’ skin colour not changing to purple/black during ripening. Thus, the study aimed to investigate the effect of tree girdling, harvest time and ripening temperature on ‘Hass’ avocado fruit skin colour development during ripening. The mature ‘Hass’ avocado fruit were harvested from girdled and non-girdled trees during early (April), mid- (May) and late (June) harvest times. Upon arrival, in the laboratory fruit were cold stored at 5.5°C for 28 days. After storage, fruit were ripened at 25, 21 and 16°C for 8, 6 and 4 days, respectively. After withdrawal from clod storage fruit were evaluated for skin colour development, ripening and physiological disorders (chilling injury). Fruit from girdled trees showed high maturity (low moisture content) when compared with fruit from non-girdled trees during early and mid-harvest. With respect to skin colour development, the results indicate that skin eye colour development of fruit from girdled and non-girdled trees minimally increased from emerald green (1) to olive green (3) across all harvest times, ripening temperature and ripening duration. However, late season fruit from non-girdled trees improved to purple (4) when ripened at 21°C when compared with fruit from girdled trees. In terms of objective colour, lightness, hue angle and chroma decreased for fruit from girdled and non-girdled trees, across all harvest times, ripening temperature and ripening duration. Lightness and hue angle of fruit from girdled trees were slightly reduced when compared with fruit from non-girdled trees, throughout all harvest times, ripening temperature and duration. Early and mid-season fruit harvested from girdled trees showed rapid decrease of chroma when compared with fruit from non-girdled trees, throughout ripening temperature and x duration. In terms of softening, fruit from girdled trees showed higher firmness loss and ripening percentage within 6 (16°C) and 4 (21 and 25°C) days when compared with fruit from non-girdled trees during early and mid-harvest, whereas, late harvest fruit from girdled trees reached higher ripening percentage and firmness loss within 4 days throughout ripening temperatures. With respect to cold damage, late harvested fruit from girdled trees showed higher external chilling injury when compared with non-girdled trees, throughout ripening temperature. In general, girdling treatment improved fruit maturity, ripening rate and firmness loss. However, the incidence of variable skin colouring of ‘Hass’ avocado fruit during ripening was also prevalent in early harvested fruit from girdled tree, irrespective of ripening temperature. Keywords: girdling, harvest time, physiological disorder, ripening temperature, variable colouring
7

Effect of tree girdling, harvest time and ripening temperature on "hass" avocado fruit skin colour development during ripening

Sibuyi, Hazel January 2018 (has links)
Thesis (M.Sc. (Horticulture)) --University of Limpopo, 2018 / ‘Hass’ avocado fruit changes skin colour from green to purple and then black during ripening. However, markets importing South African avocado fruit have been complaining about the ‘Hass’ skin colour not changing to purple/black during ripening. Thus, the study aimed to investigate the effect of tree girdling, harvest time and ripening temperature on ‘Hass’ avocado fruit skin colour development during ripening. The mature ‘Hass’ avocado fruit were harvested from girdled and non-girdled trees during early (April), mid- (May) and late (June) harvest times. Upon arrival, in the laboratory fruit were cold stored at 5.5°C for 28 days. After storage, fruit were ripened at 25, 21 and 16°C for 8, 6 and 4 days, respectively. After withdrawal from clod storage fruit were evaluated for skin colour development, ripening and physiological disorders (chilling injury). Fruit from girdled trees showed high maturity (low moisture content) when compared with fruit from non-girdled trees during early and mid-harvest. With respect to skin colour development, the results indicate that skin eye colour development of fruit from girdled and non-girdled trees minimally increased from emerald green (1) to olive green (3) across all harvest times, ripening temperature and ripening duration. However, late season fruit from non-girdled trees improved to purple (4) when ripened at 21°C when compared with fruit from girdled trees. In terms of objective colour, lightness, hue angle and chroma decreased for fruit from girdled and non-girdled trees, across all harvest times, ripening temperature and ripening duration. Lightness and hue angle of fruit from girdled trees were slightly reduced when compared with fruit from non-girdled trees, throughout all harvest times, ripening temperature and duration. Early and mid-season fruit harvested from girdled trees showed rapid decrease of chroma when compared with fruit from non-girdled trees, throughout ripening temperature and x duration. In terms of softening, fruit from girdled trees showed higher firmness loss and ripening percentage within 6 (16°C) and 4 (21 and 25°C) days when compared with fruit from non-girdled trees during early and mid-harvest, whereas, late harvest fruit from girdled trees reached higher ripening percentage and firmness loss within 4 days throughout ripening temperatures. With respect to cold damage, late harvested fruit from girdled trees showed higher external chilling injury when compared with non-girdled trees, throughout ripening temperature. In general, girdling treatment improved fruit maturity, ripening rate and firmness loss. However, the incidence of variable skin colouring of ‘Hass’ avocado fruit during ripening was also prevalent in early harvested fruit from girdled tree, irrespective of ripening temperature. Keywords: girdling, harvest time, physiological disorder, ripening temperature, variable colouring
8

Formação de sementes de soja: aspectos físicos, fisiológicos e bioquímicos / Formation of soybean seeds: physical, physiological and biochemical aspects

Mário Borges Trzeciak 14 March 2013 (has links)
Os objetivos dessa pesquisa foram avaliar as alterações de natureza física, fisiológica e bioquímica durante a formação das sementes de soja, produzidas nos anos 2009 e 2010, em Piracicaba, São Paulo. Foram utilizadas sementes de dois cultivares de soja, CD - 202 e CD - 224, e os tratamentos foram compostos pelos momentos de colheita, ao longo do processo de formação das sementes, e pela utilização ou não da secagem artificial. Para as avaliações foram determinados os número de dias para a emergência da plântula, para a floração, para a floração plena, para a colheita, os parâmetros físicos (produtividade, teor de água das sementes e massa de mil sementes) fisiológicos (viabilidade e vigor) e bioquímicos (teores de óleo, de proteína, de clorofila, carotenoides, de lignina e de carboidratos). O delineamento experimental utilizado foi em blocos ao acaso, em que cada bloco continha uma unidade experimental de cada cultivar, distribuída de forma casualizada, em esquema fatorial de onze (momentos de colheita) x dois (sem secagem e com secagem), com quatro repetições e as análises estatísticas foram realizadas com o software R. Foi possível concluir que na maturidade fisiológica das sementes de soja, estádio R7, independentemente do cultivar e da avaliação das sementes úmidas ou secas, a produtividade, a viabilidade e os teores de lignina são máximos; No momento de colheita das sementes de soja, estádio R9, independentemente do cultivar e da avaliação de sementes úmidas ou secas, o acúmulo de massa é máximo, há a redução do teor de água, da viabilidade e do vigor e a semente tem mais óleo e proteína; O vigor das sementes é máximo no estádio R7 para as sementes avaliadas secas e no estádio R8 para as avaliadas úmidas, independentemente do cultivar; Há a degradação completa da clorofila nos estádios R7, para as sementes do cultivar CD - 202, e R8, para as sementes do cultivar CD - 224; Há carotenoides em todos os estádios de desenvolvimento da semente de soja, porém há mais carotenoides no início do processo de formação das sementes; Há variação da quantidade de carboidratos em função da avaliação das sementes úmidas ou secas. / This experiment aimed at the evaluation of the physical, physiological and biochemical changes during formation of soy seeds, produced in 2009 and 2010, in Piracicaba, São Paulo. Seeds of two cultivars of soy were used, namely CD - 202 and CD - 224, and treatments were composed by the moment of harvest, along the process of formation of seeds, and by the use or non-use of artificial drying. For the evaluations, we determined the number of days for seedling emergency, flowering, full flowering, harvest, physical parameters (productivity, rate of water in the seeds and mass of a thousand seeds) physiological parameters (viability and vigor) and biochemical parameters (rate of oil, of protein, of chlorophyll, of lignin and carbohydrates). The experimental delineation in use was in random blocks, in which each block contained one experimental unit of each cultivar, distributed at random, in a factorial scheme of eleven (harvesting periods), x two (dried and not dried), at four repetitions, and the statistical analysis were performed with software R. It was possible to conclude that at physiological maturity of soy seeds, stage R7, independently of the cultivar and of the evaluation of dry or humid seeds, the productivity, viability and rates of lignin are at their maximum; In the moment of harvest of soy seeds, stage R9, independently of the cultivar and evaluation of humid or dry seeds, the accumulation of mass is at its maximum, there is a drop in the level of water, of the viability and vigor, and the seed contains more oil and protein; The vigor of the seeds is at its maximum at stage R7 for the seeds which were evaluated dry and at stage R8 for the ones evaluated as humid, independently of the cultivar; There is the complete deterioration of the chlorophyll at stages R7, for the seeds of cultivar CD - 202 and R8, for the seeds of cultivar CD - 224; There are carotenoids in all stages of development of soy seed, however there are more of them in the beginning of the process of formation of seeds. There is variation of quantity of carbohydrates according to the evaluation of humid or dry seeds.
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Chemical Compositions of Edamame Beans and Valorization of Edamame Shells

Yu, Dajun 23 January 2023 (has links)
Edamame is becoming more popular in the U.S. due to its high nutritional value and potential health benefits. However, more than 70% of edamame is imported from outside of the U.S. Therefore, developing elite edamame genotypes is critically desirable to increase the domestic production of edamame in the U.S. Genotype, planting location, and harvest time play essential roles in the chemical composition of edamame, which further decide edamame's nutritional value and sensory characteristics. Therefore, the first goal of this study is to comprehensively evaluate the chemical composition of edamame genotypes grown in different locations. Ten selected edamame genotypes were grown in three locations in the U.S. - Whitethorne, Virginia (VA), Little Rock, Arkansas (AR) and Painter, VA. Sugars, alanine, protein, oil, neutral detergent fiber (NDF), starch, ash, and moisture contents, were comprehensively analyzed. The results showed that location had significant effects on all chemical components of edamame with p < 0.05. Compared to Painter and Little Rock, genotypes planted in Whitethorne had higher averaged free sucrose, fructose, glucose, raffinose, stachyose, and starch contents and total sweetness. The highest crude protein and oil contents were found on edamame planted in Painter, while Little Rock produced edamame with the highest free alanine, ash, and moisture contents. Genotype significantly affected chemical compositions except for NDF and raffinose. Therefore, planting location and edamame genotype should be considered when producing elite edamame for the U.S. market. Chemical composition changes with the development of edamame; therefore, harvest time is essential for harvesting high-quality edamame. The second objective of this study is to quantify the changes in both physical and chemical properties of edamame over bean development and apply a combined spectroscopy and machine learning (ML) technique to help determine the optimal harvest time. Physical and chemical properties were analyzed for edamame harvested at R5 (beginning seed), R6 (full seed), and R7 (beginning maturity) growth stages, and the spectral reflectance (360 – 740 nm) of edamame pods was measured using a handheld spectrophotometer. The samples harvested at different stages were labeled as 'early,' 'ready,' and 'late.' At R6, pod/bean weight and pod thickness reached the peak and then stayed stable, while sugar, alanine, starch, and glycine also peaked at R6 but declined afterward. The spectra-based ML method had high accuracy (0.95) when classifying 'early' and 'late' edamame, and the accuracy was 0.87 for classifying 'early' and 'ready' edamame. These results indicated that this spectra-based ML method could determine the optimal harvest time of edamame. Food waste and loss not only lead to economic loss but also significant greenhouse gas emissions. With edamame food/snack production increasing, edamame shells, the low-value byproduct from this processing, will potentially threaten the environment. Similar to other food processing byproducts, edamame shell is rich in dietary fiber (DF). However, the high concentration of insoluble dietary fiber (IDF) limits its application as a food additive. Therefore, extraction/modification processes are needed to convert IDF to soluble dietary fiber (SDF) and improve the properties of edamame shell-derived DF. Ball milling is one of the most efficient techniques to break down biomaterials into sub-micro-level particles. Citric acid, as a natural and safe food additive, can help break down cell walls and improve the dissolution of SDF by ionizing the hydrogen ions with carboxyl groups. Therefore, the third objective of this study is to develop a process that combines ball milling and citric acid treatments to produce SDF from edamame shells. We investigated different treatment parameters, including different citric acid concentrations, treatment temperatures and time, and the application of ball milling. To determine if the combined treatment can potentially improve the properties of the produced SDFs, we characterized the physicochemical, morphological, structural, rheological, thermal, and functional properties of SDFs produced at different conditions. The results showed that the highest SDF yield (19.5%) was found when the edamame shells were pretreated by a ball mill. In addition, the combined citric acid and ball milling treatment altered several properties of the produced SDFs, including particle size, morphology, and crystallinity. Moreover, ball milling treatment led to a higher exothermic temperature peak of SDF indicating better thermal stability. All produced SDFs significantly elevated the production of short-chain fatty acids during in vitro fermentation (compared to the control fermentation) which indicated their potential benefits of promoting gut health. Overall, we demonstrated that ball-milling-assisted citric acid processing can be an effective green technique to produce SDF from edamame shells. The SDF produced from edamame shells can be regarded as a promising and novel ingredient with great potential to be used in foods. / Doctor of Philosophy / Edamame is becoming increasingly popular among consumers in the U.S. because it is nutritious and good for health. However, more than 70% of edamame in the U.S. market is imported from other countries. Therefore, having more edamame genotypes that adapt to the growing environment in the U.S. will help increase the domestic production of edamame. Genotype and planting location are essential in deciding edamame's nutritional value and taste. Therefore, the first objective of this study is to comprehensively understand the nutritional value of different edamame genotypes grown in three planting locations. The results showed that both location and genotype affected the nutritional values of edamame, indicating that planting location and edamame genotype should be considered when developing better edamame for the U.S. market. Nutritional value and sweetness change with the growth of edamame beans. Therefore, harvest time is crucial for harvesting edamame with better nutrition and taste. This study's second objective is to observe edamame's nutritional factors and sweetness over bean development and develop a method using a handheld colorimeter to help determine the optimal harvest time. The results showed that the edamame harvested at the full seed stage (called R6) is the sweetest compared to the other two stages. In addition, the handheld colorimeter combined with the machine learning technique showed high accuracy in separating 'early' and 'late' harvested edamame and 'early' and 'ready' harvested samples. These results indicated that the combination of colorimeter and machine learning could help determine the optimal harvest time of edamame. Food waste and loss not only lead to economic loss but also significant greenhouse gas emissions. Edamame shells, the low-value byproduct from edamame snack/food processing, will potentially threaten the environment if edamame consumption keeps increasing. Like other food waste, edamame shell is rich in dietary fiber (DF). Therefore, it is vital to find a way to recover the DF in edamame for other applications. Ball milling is a green technology that can efficiently break down big particles. Citric acid is a natural and safe food additive and can help break down insoluble cell walls. Therefore, this study aims to produce soluble dietary fiber (SDF) from edamame shells using ball milling and citric acid. We proved that ball-milling assisted acid processing can be an environmentally friendly method to produce edamame shell SDF which can potentially be used as a suitable food ingredient.
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EFFECTS OF HYBRID, HARVEST TIME AND HAIL DAMAGE ON CHEMICAL, NUTRITIONAL AND BIO-METHANE POTENTIAL PROPERTIES OF WHOLE PLANT CORN

GRECCHI, ISABELLA 17 March 2016 (has links)
Il mais rappresenta una delle colture più diffuse nel Nord Italia. Negli ultimi anni si è assistito ad un notevole incremento della superficie a mais legato soprattutto all'uso dell'insilato di mais come substrato per la produzione di biogas. Per questo motivo è necessario avere il maggior numero di informazioni possibili per migliorare le performance della coltura. In letteratura ci sono molti studi che valutano l’impatto dell’ambiente e del management sulle caratteristiche chimico nutrizionali e sul potenziale metanigeno del foraggio di mais ma non ci sono lavori che considerano entrambi i parametri. L’obiettivo della tesi è stato quello di investigare come il danno da grandine , la genetica e il momento di raccolta possano influenzare la composizione della pianta intera tradotta come potenziale metanigeno e valore nutrizionale del foraggio. / In the Po Valley the maize crop represent one of the most cultivated plant used for cattle feeding but in the last 10 years it is also used as biogas substrate. Considering the importance of this cultivation, there is the continuous need to obtain information about this plant with the aim to improve the crop performance. There are numerous studies investigating the impact of environmental aspects and management practices on chemical and nutritional composition, and methane production in the literature but very few that evaluate those parameters together. The general objective of this thesis is to investigate how hail damage, type of hybrid and the harvesting date affect the whole plant composition. To accomplish this, two specific objectives are posed: i) verify the effects of hail damage levels on yield, chemical and nutritional feature as well as on BMP of maize grown in the Po Valley; and ii) to evaluate the value of different hybrids for animal nutrition and methane production in anaerobic fermenters and as delaying harvesting after the usual stage of maturity affects these features. It was also aimed to verify if chemical composition and in vitro digestibility tests could allow to estimate methane yield potential in maize whole plant.

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