For decades commercial silos in South Africa was the only option in which maize could be delivered and sold. After deregulation in the late 1990s commercial silo owners came to face the challenge of alternative storage solutions and loss of market share. The reasons are determined for a shift from commercial storage to on-farm storage. The extent to which on-farm storage will change the current maize storage industry is discussed. The study commences by describing the birth and rapid growth of maize production in South Africa. Soon after maize became a major role-player in the export industry, it was characterised by regulation. The rationale why the market was regulated and how it influenced grain storage is explained. The deregulation process and the objectives of the new Marketing of Agricultural Products Act, No. 47 of 1996, are paraphrased. In the deregulated market, current and future, maize prices are determined by supply and demand. Incentives for storage emerged and cheaper substitutes with various other advantages began to propose alternative storage solutions to farmers. These concurrences of circumstances then lead to fragmentation of grain storage in South Africa. As a relatively young free market, the maize value chain is described to illustrate the position of each role-player in relation to the silo owner. The new price determination factors, price movement rationale and the use of market instruments are subsequently explained. Naturally, a critical assessment of the main different storage solutions available for farmers, are investigated next. Fragmentation is defined and discussed in terms of market equilibrium. A comparison is drawn between the South African and the Australian as well as the US maize storage industry. The empirical research was conducted on two sample groups of farmers in the Free State. The first group is farmers that already make use of an on-farm storage facility. The second group is farmers that annually produce more than 5000 tons of maize and currently do not make use of an on-farm storage facility. Seven important reasons for an on-farm storage facility are determined in the literature study as well as a qualitative study that preceded the quantitative study. Respondents are asked to rank the reasons in order of, in their opinion, importance. A generalized profile of a respondent in each sample group was compiled. Hereafter the outcome of the reasons ranked by both sample groups is discussed. It appeared that Flexible Marketing Option was the most important reason for farmers that already make use of on-farm storage. Farmers did not indicate that Handling and Storage costs are the most important reason why they would invest in an on-farm storage facility. Correlations are drawn between groups and the significance of differences is determined. It is concluded that on-farm storage is sustainable and there will be an increase of the phenomenon over the next three years. Recommendations are given for commercial silo owners to regain market share. Costs analyses and effective cost management along with the promotion that marketing options are just as flexible within commercial silos, as it is outside, are some of the recommendations made. / Thesis (MBA)--North-West University, Potchefstroom Campus, 2013.

Orientador: José Ângelo Cagnon / Banca: Ivo Reis Fontes / Banca: Ricardo Martini Rodrigues / Banca: Amâncio Rodrigues da Silva Junior / Banca: Diógenes Pereira Gonzaga / Resumo: O presente trabalho teve por objetivo determinar o potencial de economia de energia elétrica nos sistemas de aeração de silos verticais a partir da implementação de controle eletrônico de velocidade do motor do aerador utilizando inversor de freqüência. O experimento foi montado no setor de armazenamento de grãos da empresa Indústria de Produtos Dallas Ltda, na cidade de Nova Alvorada do Sul (MS), no período de 25/03/04 a 22/10/04, sendo utilizados dois silos contendo, cada um, 5.000m3 de soja a 13,5% de umidade, aqui denominados "silo 11" e "silo 12". O sistema de aeração, em ambos os silos, era composto por um motor de indução com as especificações de 30cv, 4 polos, 380V, 60Hz, 1.765rpm, e ventilador com rotor de pás retas, inclinadas para trás, com característica de consumo de energia elétrica constante para uma mesma velocidade de rotação. O silo 11 foi definido como silo padrão e o aerador funcionou em 60Hz (1.765rpm) durante todo o período do experimento. O aerador do silo 12, cuja implementação de controle de velocidade foi efetuada por um inversor de freqüência, esteve ajustado para funcionamento em quatro estágios, 48Hz (1.405rpm), 45Hz (1.315rpm), 40Hz (1.165rpm) e 35Hz (1.015rpm). O parâmetro utilizado para a definição da freqüência (rotação) de cada estágio foi a vazão específica básica de ar (0,08m3/min.m3), recomendada pela Kleper Weber Industrial para aeração em silos planos e elevados, para grãos comerciais com umidade de até 14%. Os dados de temperatura no interior dos silos e os de temperatura e umidade do ar externo foram coletados através de sensores que alimentavam software de gerenciamento e controle automático de aeração existente na empresa e que,...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This work had the objective of determining the potential of economy of electric energy in the aeration systems of vertical silos through the implementation of electronic control of speed in the aerator engine, using a frequency inverter. The experiment was carried out in the grain storage sector at Produtos Dallas Ltda in Nova Alvorada do Sul (MS) in the period of 25/03/04 and 22/10/04. Two silos have been used, each one with 5.000 m3 of soy bean with 13.3 of humidity, named "silo 11" and "silo 12". The aeration system in both silos was composed of an induction engine with the specifications of 30cv, 4 poles, 380V, 60Hz, 1765 rpm, and of a ventilator with the following characteristics: a straight-shafted rotor, the shafts inclined backwards and a steady consumption of electric energy for the same rotation speed. Silo 11 was defined as the pattern silo and the aerator worked at 60Hz (1765 rpm) during the whole period of the experiment. The aerator of silo 12, whose implementation of speed control was made by a frequency inverter, was adjusted to work in four stages: 48Hz (1.405rpm), 45Hz (1.315rpm), 40Hz (1.165rpm) and 35Hz (1.015rpm). The parameter used to define frequency (rotation) of each stage was the basic specific air release (0,08m3 of air/min/m3grains), recommended by Kleper Weber Industrial for aeration in plain vertical silos, for commercial grains with humidity up to 14%. The data concerning the temperature inside the silos, the external temperature and the air humidity were collected through the sensors that fed the management software existing in the factory that, in turn, controlled automatically the aeration and, following a pre-arranged programming, determined the time to turn on/turn off the aerators. Considering the rotation of the aerators in each stage of frequency and making use of the software MAEV-2000,...(Complete abstract, click electronic access below) / Doutor

Farmers in Nepal lose about a third of their harvested grain due to postharvest handling and storage. This has led to food insecurity and economic losses. Despite the importance of postharvest, the grain storage system in Nepal relies on traditional storage structures like bamboo granaries. The incidence of storage pests is reported up to 100% in these structures. To minimize the storage loss, farmers use different grain protection methods including toxic chemicals. Multiple cases of pesticides-related poisoning and deaths have been caused by misuse and overuse of pesticides. To push safer, chemical-free alternatives like hermetic storage it is important to understand current pest challenges and management practices in Nepal. Adaptation of chemical-free pest management strategies like hermetic storage largely depends upon basic and applied laboratory research findings. Determining the baseline adult mortality under various hypoxia levels and subsequent insect emergence will help determine the effectiveness of a low oxygen environment in controlling <i>Sitophilus oryzae</i> (L.). This would increase our understanding of hermetic storage technology and help improve its application to both farmers and commercial users and serve as a possible substitute to traditional or chemical pest control methods. In chapter one, I report the result of the survey conducted in Nepal to understand i) current post-harvest storage practices and (ii) assessment of the best delivery approach for storage innovations. In chapter 2, I report the result from laboratory experiment conducted to understand the lethality of hypoxia at 5% oxygen level and below against <i>Sitophilus oryzae</i> (L.), which is a major storage pest reported by farmers in Nepal.

This thesis will describe and interpret the development of this Relief Society wheat storage program from its inception in 1876 to 1940 when the program was transferred to the General Church Welfare Committee. Emphasis will be placed on the sisters' attempts to store grain and the problems they encountered. The thesis will also discuss the effects of outside forces on the program and the different ways the sisters used the grain. The final chapter will deal with the relationship between the movement and the history of the Relief Society and its parent organization, the Mormon Church.

Master of Agribusiness / Agricultural Economics / Allen M. Featherstone / The purpose of this thesis is to analyze whether the use of automated aeration systems for reducing moisture in corn during storage provides sufficient net present value for Nebraska corn farmers. The objective is to examine if an automated aeration system provides sufficient energy savings, marketing opportunities and reduced drying costs before corn delivery to an elevator. On-the-farm corn storage has steadily increased and harvesting corn before the moisture has achieved the desired targets cost farmers in drying charges and shrink. Farmers are interested in whether automated aeration systems can remove enough moisture from grain, without over-drying the bin, without spending a large amount of time determining when to run their grain bin aeration fans. Data for this project were obtained from four privately owned 60,000 bushel grain bins outfitted with the IntelliAir™ BinManager™ automated aeration system. Moisture samples were taken from each of the trucks hauling grain to the bin and again after removal of the corn after the automated system had ran for 9 months. Energy usage, drying charges, and shrink were calculated for the initial corn moisture averages and the moisture at the time of removal. Each bin was examined using Net Present Value (NPV) analysis to determine whether the energy savings were enough to offset the initial installation cost and annual expenses of the project. After the NPV was estimated for each of the bins, a sensitivity analysis of how corn price changes and no aeration required would affect the NPV analysis. Finally, an analysis of the total costs savings of a continuously ran aeration system was compared to the automated aeration system. The conclusion of the NPV analysis was that adding an automated aeration system would be profitable under most scenarios. More studies are needed to determine the profitability of automated aeration systems in different regions, moisture inputs, and bin sizes.

Thesis (MBA)--Stellenbosch University, 2006. / ENGLISH ABSTRACT: Grains are generally considered to be low risk products. However food safety laws and consumer demands require companies to implement programs that will ensure food safety. To comply with these demands, South African grain handling companies are required to implement appropriate risk management systems. Companies that do not adopt such systems will not only exclude themselves from international grain markets but also from the whole food industry with related losses in market share. This study involved consultation with various roieplayers in the grain industry and a literature study to determine the current status of food risk management systems in South Africa. The survey investigated the food risk management requirements of local grain handling companies, and how local and international companies manage food risks. Existing food risk management practices currently implemented by Overberg Agri were also analysed. Although Overberg Agri's grain division has been handling grain for many years, attention to quality, safety en food risk factors has been infonnal and fragmented. No formal documented food risk management system has been implemented. This study presents an integrated food risk management system for managing food quality and food safety. The management system aims at identifying all important processes which are to be managed, to formally document the processes and to provide guidelines for implementing the system. Adoption of such an approach would ensure that the system is implemented in a structured way and that processes are regularly reviewed and updated as required in an ever-changing business environment. The management system contains the implementation of a system that includes food quality~ safety and risk, but includes more than just the minimum requirements of the ISO 9001 and Codex standards. The proposed management system focusses on an approach based on logical sequence of the daily business, to involve everyone and keep them involved. This will ensure that processes are executed in a manner that will identify all food risks to limit or exclude them, rather than analysing each element of an existing standard and repeating it as a requirement. The existing management system of Overberg Agri is not effective in managing food risks because several losses still occure. This is because there are insufficient formal systems, documentation and records available to determine wheter losses can be ascribed to structures, work instructions, management or latent grain defects. The proposed system will ensure that the above mentioned will be implemented to supply the company, stakeholders en clients with sound information which is needed for continuous improvement of the company. / AFRIKAANSE OPSOMMING: Oor die algemeen word graan as veilige voedsel beskou. Verbruikers dring al meer daarop aan dat ondememings moet bewys dat hulle stelsels in plek het vir die versekering van veilige voedsel. Om aan die vereistes te voldoen, moet ondememings in Suid-Afrika wat graan hanteer, die gepaste risikobestuurstelsels implementeer. Ondernemings wat dit nie doen, stel hulself bloot aan verliese sowel as uitsluiting, nie net van die intemasionale graanhandel nie, maar ook die hele voedselindustrie. Vir die studie is rolspelers in die graanindustrie genader en literatuur bestudeer om vas te stel wat in Suid-Afrika ten opsigte van voedselrisikobestuur bestaan. Daar is ook vasgestel wat die behoeftes ten opsigte van risikobestuur is vir ondememings wat graan opberg en hanteer en wat plaaslike en internasionale ondememings doen om voedselrisiko's te bestuur. Ook is bepaal wat alreeds in Overberg Agri se graanafdeling rakende voedselrisikobestuur bestaan. Alhoewel die afdeling al jare funksioneer is daar heelwat plekke waar op informele wyse aandag aan kwaliteit, veiligheid en voedselrisiko gegee word, maar nie formeel nie. Die werkstuk poog daarin om 'n geintegreerde bestuurstelsel vir voedselkwaliteit en - veiligheid daar te stel. Die bestuurstelsel het dit ten doel om alle belangrike prosesse wat bestuur word, te identifiseer en op 'n formele wyse te dokumenteer en te implementeer. Sodoende word seker gemaak dat dit reelmatig gebeur en dat sulke prosesse gereeld hersien word om te sien of hulle noodsaaklik vir die bedryf is. Die bestuurstelsel behels die implementering van 'n stelsel wat voedselkwaliteit, -veiligheid en -risiko insluit, maar meer is as net die absolute minimum vereistes van die ISO 9001 en die Codex standaard. Hiervoor kombineer die voorgestelde bestuurstelsel die ISO 9001 en HACCP standaarde. Die bestuurstelsel konsentreer meer op 'n benadering gebaseer op 'n logiese volgorde soos die besigheid daagliks vloei, en om almal betrokke te kry en te hou, en dan te verseker dat prosesse so uitgevoer word dat alle voedselrisiko's geidentifiseer en beperk of uitgesluit word, eerder as om elke element van 'n bestaande standaard te ontIeed en weer te gee as 'n vereiste. Die bestaande bestuurstelsel van Overberg Agri is nie effektief in die bestuur van voedselrisiko's nie, aangesien te veel verliese steeds voorkom. Dit is waarskynlik omdat daar nie genoeg stelsels, dokumentasie en rekords beskikbaar is, sodat oorsake toegeskryf kan word aan strukture, werksinstruksies, bestuur of graan nie. Die voorgestelde stelsel wil verseker dat bogenoemde geimplementeer word om vir die ondememing self, aandeelhouers en kliente konkrete inligting te gee sodat verbetering voortdurend aangebring kan word.

This thesis is composed of two essays that investigate whole farm planning and crop marketing in western Kentucky. In the first essay, contracting decisions between food corn producers and a mill are analyzed to observe factors affecting the bushel amount farmers contract. Unbalanced panel data containing seven years’ worth of pricing and contract information are used with a fixed-effects model to generate parameter estimates and quantify their effect on bushels contracted. It was found that contract attributes, market condition, and relationship-specific assets had a significant effect on producers’ food corn contracting decisions. The second essay utilizes mixed-integer programming to optimize resource allocation and marketing strategy for a hypothetical farm. Post-optimal analysis is performed to determine non-binding capacities for drying and storage equipment. The model is re-run with these non-binding capacities to observe changes in net returns as well as planting, harvesting, and marketing strategies. New equipment and associated costs are identified, and the change in net returns from the base case is used as net cash flow in a net present value investment analysis. Results of the investment analysis indicate increasing drying and storage capacity is a wise investment given the scenario modeled.

Made available in DSpace on 2015-03-26T13:30:16Z (GMT). No. of bitstreams: 1 texto completo.pdf: 183371 bytes, checksum: d1e3f53fdf8243e46cb5663bc7707bdf (MD5) Previous issue date: 2007-02-28 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Acarophenax lacunatus (Cross & Krantz) (Prostigmata: Acarophenacidae) is a parasitoid mite on eggs of some Insecta; this could be a complementary tool for pest management in stored products. This mite has preference for eggs of Rhyzopertha dominica (Fabricius) (Coleoptera: Bostrichidae) attaching to the adult beetles for dispersion, a phenomenon referred to as phoresy. Behavioral studies are critical for the understanding of several aspects of arthropod biology. No investigation on the parasitism behavior of A. lacunatus on and its phoretic relationship with R. dominica has been conducted yet and thus it was the objective of this work. Two sets of studies were conducted: the first investigated the parasitism behavior of A. lacunatus on the egg of R. dominica, and the second investigated whether phoresy of A. lacunatus would affect flight initiation and if phoretic loads would affected the walking behavior of adult beetles. In the study of parasitism behavior of A. lacunatus, the mite was placed in an arena together with in one host egg and observed until the parasitism. Based on observations of several individuals, the parasitism behavior was described with the following behavioral categories: initial exploratory march, exploratory march after finding the host egg and parasitism. In the test of flight initiation, adults of R. dominica with and without phoretic mites were placed in a bioassay chamber, which was evaluated in 10-min intervals for one hour to verify whether or not there were mites attached to the beetles that initiated flight. Results showed that most beetles initiating flight had no mites attached to their bodies. In the second test involving phoresy, beetles with different phoretic loads (0, 2, 4, 6, 8, 11 and 23 mites/insect) were observed in a video-recorded arena so as to determine the distance walked, time spent walking and time without walking. Beetles with phoretic loads of two, four and six mites walked longer distances and stayed less time without walking unlike beetles with phoretic loads of 11 and 23 mites, which tended to show a walking pattern similar to beetles without phoretic mites. In addition to observing a uniform pattern in the parasitism behavior by A. lacunatus on eggs of R. dominica, the presence of phoretic mites was associated with low frequency of flight initiation by the beetle, and depending on the number of mites attached to coleopteran, walking was stimulated or unaffected. / Acarophenax lacunatus (Cross & Krantz) (Prostigmata: Acarophenacidae) é um ácaro parasitóide de ovos de algumas famílias da classe Insecta, podendo ser uma ferramenta complementar no controle de pragas de produtos armazenados. Este ácaro tem preferência por parasitar ovos de Rhyzopertha dominica (Fabricius) (Coleoptera: Bostrichidae), em cujos adultos realiza forésia, forma passiva de deslocamento. Estudos a respeito do comportamento são de fundamental importância para a compreensão de diversos aspectos da biologia de artrópodes; no entanto estudos mais detalhados a respeito do comportamento de parasitismo de A. lacunatus e de sua relação forética com R. dominica ainda são poucos. Desta forma estudou-se o comportamento de parasitismo de A. lacunatus em ovos de R. dominica, bem como sua relação forética com esse coleóptero. Para a realização deste trabalho foram feitos dois ensaios. O primeiro abordou o estudo do comportamento de parasitismo de A. lacunatus em ovos de R. dominica. O segundo ensaio foi realizado em dois testes: um para verificar se a forésia de A. lacunatus afetaria a iniciação de vôo de seu hospedeiro e o outro para averiguar se a carga forética prejudicaria o caminhamento do seu hospedeiro. No estudo do comportamento de parasitismo de A. lacunatus, o ácaro foi colocado em uma arena, juntamente com um ovo hospedeiro, sendo observado até o parasitismo. A partir destas observações, descreveu-se o comportamento de parasitismo com as seguintes categorias comportamentais: marcha exploratória inicial, marcha exploratória após o encontro do ovo e parasitismo propriamente dito. Para o teste da relação entre forésia e iniciação de vôo utilizou-se adultos não-sexados de R. dominica, com e sem ácaros foréticos. Estes coleópteros foram colocados em uma câmara de bioensaio que foi avaliada, em intervalos de 10 minutos, por uma hora, para verificar se os besouros que iniciaram vôo tinham ou não ácaros foréticos. Observou-se que a maior parte dos besouros que iniciaram vôo não tinha ácaros aderidos ao corpo. No teste da relação de cargas foréticas com o caminhamento de R. dominica, besouros contendo diferentes cargas foréticas (0, 2, 4, 6, 8, 11 e 23 ácaros/inseto) foram observados quanto à distância caminhada, ao tempo de caminhamento e o tempo sem caminhar. Besouros com cargas foréticas de dois, quatro e seis ácaros caminharam mais e ficaram menos tempo sem caminhar ao contrário do observado para besouros com cargas foréticas de oito, 11 e 23 ácaros, os quais tenderam a ter um padrão de caminhamento semelhante aos de besouros sem ácaros foréticos. Em conclusão, além de se verificar que há um padrão comportamental uniforme no parasitismo de A. lacunatus sobre ovos de R. dominica, verificou-se que a presença de ácaros foréticos esteve associada à baixa freqüência de iniciação de vôo do besouro, e que, dependendo da densidade de ácaros presos ao coleóptero, o caminhamento parece ser estimulado ou não afetado.

Made available in DSpace on 2014-06-11T19:31:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-12-17Bitstream added on 2014-06-13T19:20:47Z : No. of bitstreams: 1 silvajunior_an_dr_botfca.pdf: 2640495 bytes, checksum: 5a1cf7d0c2044aa88eae209e5eb130e8 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / O presente trabalho teve por objetivo determinar o potencial de economia de energia elétrica nos sistemas de aeração de silos verticais a partir da implementação de controle eletrônico de velocidade do motor do aerador utilizando inversor de freqüência. O experimento foi montado no setor de armazenamento de grãos da empresa Indústria de Produtos Dallas Ltda, na cidade de Nova Alvorada do Sul (MS), no período de 25/03/04 a 22/10/04, sendo utilizados dois silos contendo, cada um, 5.000m3 de soja a 13,5% de umidade, aqui denominados silo 11 e silo 12. O sistema de aeração, em ambos os silos, era composto por um motor de indução com as especificações de 30cv, 4 polos, 380V, 60Hz, 1.765rpm, e ventilador com rotor de pás retas, inclinadas para trás, com característica de consumo de energia elétrica constante para uma mesma velocidade de rotação. O silo 11 foi definido como silo padrão e o aerador funcionou em 60Hz (1.765rpm) durante todo o período do experimento. O aerador do silo 12, cuja implementação de controle de velocidade foi efetuada por um inversor de freqüência, esteve ajustado para funcionamento em quatro estágios, 48Hz (1.405rpm), 45Hz (1.315rpm), 40Hz (1.165rpm) e 35Hz (1.015rpm). O parâmetro utilizado para a definição da freqüência (rotação) de cada estágio foi a vazão específica básica de ar (0,08m3/min.m3), recomendada pela Kleper Weber Industrial para aeração em silos planos e elevados, para grãos comerciais com umidade de até 14%. Os dados de temperatura no interior dos silos e os de temperatura e umidade do ar externo foram coletados através de sensores que alimentavam software de gerenciamento e controle automático de aeração existente na empresa e que,... / This work had the objective of determining the potential of economy of electric energy in the aeration systems of vertical silos through the implementation of electronic control of speed in the aerator engine, using a frequency inverter. The experiment was carried out in the grain storage sector at Produtos Dallas Ltda in Nova Alvorada do Sul (MS) in the period of 25/03/04 and 22/10/04. Two silos have been used, each one with 5.000 m3 of soy bean with 13.3 of humidity, named silo 11 and silo 12. The aeration system in both silos was composed of an induction engine with the specifications of 30cv, 4 poles, 380V, 60Hz, 1765 rpm, and of a ventilator with the following characteristics: a straight-shafted rotor, the shafts inclined backwards and a steady consumption of electric energy for the same rotation speed. Silo 11 was defined as the pattern silo and the aerator worked at 60Hz (1765 rpm) during the whole period of the experiment. The aerator of silo 12, whose implementation of speed control was made by a frequency inverter, was adjusted to work in four stages: 48Hz (1.405rpm), 45Hz (1.315rpm), 40Hz (1.165rpm) and 35Hz (1.015rpm). The parameter used to define frequency (rotation) of each stage was the basic specific air release (0,08m3 of air/min/m3grains), recommended by Kleper Weber Industrial for aeration in plain vertical silos, for commercial grains with humidity up to 14%. The data concerning the temperature inside the silos, the external temperature and the air humidity were collected through the sensors that fed the management software existing in the factory that, in turn, controlled automatically the aeration and, following a pre-arranged programming, determined the time to turn on/turn off the aerators. Considering the rotation of the aerators in each stage of frequency and making use of the software MAEV-2000,...(Complete abstract, click electronic access below)

Submitted by Franciele Moreira (francielemoreyra@gmail.com) on 2018-10-08T13:14:30Z No. of bitstreams: 2 Dissertação - Ludivina Lima Rodrigues - 2018.pdf: 2293271 bytes, checksum: c682aa890844c16d17542816e5049521 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-10-09T10:44:54Z (GMT) No. of bitstreams: 2 Dissertação - Ludivina Lima Rodrigues - 2018.pdf: 2293271 bytes, checksum: c682aa890844c16d17542816e5049521 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-10-09T10:44:54Z (GMT). No. of bitstreams: 2 Dissertação - Ludivina Lima Rodrigues - 2018.pdf: 2293271 bytes, checksum: c682aa890844c16d17542816e5049521 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-02-27 / The darkening of bean grains (Phaseolus vulgaris L.) occurs after harvest and leads to loss of commercial value of the product. This trait is controlled by one gene, in which the dominant allele confers the normal grain darkening of the carioca and pinto type. In the pinto type, this gene was denominated Sd (Slow darkening). However, there are no reports that the gene identified in pinto is the same as in the carioca type. Molecular markers linked to the Sd gene have been identified and validated in carioca type populations: Pvsd-1158 (SSR) and PvbHLHp12804 (SNP). Thus, this study aimed to verify if the gene that controls the darkening of the grains in different genotypes is the same; evaluate the efficiency of the markers Pvsd-1158 and PvbHLHp12804 in a group of genotypes with carioca and mulatinho (cream) grains; and estimate the genetic divergence among these genotypes. For this, 17 bean genotypes were used, which were grown in two experiments in greenhouse. The harvested grains were stored for 135 days and phenotypically evaluated for darkening. In parallel, these genotypes were evaluated genotypically with the markers Pvsd-1158 and PvbHLHp12804 and also with a panel of 24 microsatellite markers for estimation of genetic diversity. Crossings were also performed between genotypes 1533-15, AN512666-0 and BRSMG Madrepérola, which present slow darkening of the grains, to confirm if the gene responsible for the slow darkening is the same. For this, progenies F2:3 were evaluated by segregation tests from the data obtained from the phenotypic evaluation of the darkening. Considering the 17 lines,, 13 lines showed slow darkening, three presented normal darkening and one presented no darkening. The Pvsd-1158 and PvbHLHp12804 markers presented the expected alleles according to the phenotypic evaluation in 14 of the 16 genotypes that presented some darkening, representing 87.5% coincidence with the phenotypic data, indicating that the Sd gene is responsible for the darkening the grains in these genotypes. The line CNFM11940, with grains mulatinho (cream) and the cultivar TAA Dama, with carioca grains presented slow darkening and alleles linked to normal darkening for the two markers. This indicates that there were recombination in this genomic region, taunting the separation between the markers and the Sd gene, or that there is another gene conferring the slow darkening in these genotypes. Estimation of genetic divergence among the genotypes provided additional information for comparison of the genotypes. Additionally, all the progenies F2:3 originating from the three populations showed slow darkening and, therefore, there was no segregation. Thus, the gene that controls the darkening of the grains in beans pinto and carioca is the Sd gene. / O escurecimento dos grãos de feijão (Phaseolus vulgaris L.) ocorre após a colheita e gera perda no valor comercial do produto. Esse caráter é controlado por um gene com dominância do alelo que confere o escurecimento normal em feijões do tipo carioca e pinto. Em feijões do tipo pinto esse gene foi denominado Sd (Slow darkening). Entretanto, não existem relatos de que o gene identificado no tipo pinto é o mesmo do tipo carioca. Existem marcadores moleculares identificados como ligados ao gene Sd e validados em populações de feijão carioca: Pvsd-1158 (SSR) e PvbHLHp12804 (SNP). Assim, esse estudo objetivou verificar se o gene que controla o escurecimento dos grãos em diferentes genótipos de feijão com diferentes origens é o mesmo; avaliar a eficiência dos marcadores Pvsd-1158 e PvbHLHp12804 em um grupo de genótipos com grãos carioca e mulatinho; e estimar a divergência genética entre esses genótipos. Para isso, foram utilizados 17 genótipos de feijão, cultivados em dois experimentos em telado. Os grãos colhidos foram armazenados por 135 dias e avaliados fenotipicamente quanto ao escurecimento. Paralelamente, esses genótipos foram avaliados genotipicamente com os marcadores Pvsd-1158 e PvbHLHp12804 e também com um painel de 24 marcadores microssatélites para estimação da diversidade genética. Também foram realizados cruzamentos entre os genótipos 1533-15, AN512666-0 e BRSMG Madrepérola, que apresentam escurecimento lento dos grãos, para confirmar se o gene responsável pelo escurecimento nesses genótipos é o mesmo. Para isso, foram avaliadas progênies F2:3 por meio de testes de segregação a partir dos dados obtidos da avaliação fenotípica do escurecimento. Considerando as 17 linhagens, 13 apresentaram escurecimento lento, três apresentaram escurecimento normal e uma não apresentou escurecimento. Os marcadores Pvsd-1158 e PvbHLHp12804 apresentaram os alelos esperados de acordo com a avaliação fenotípica em 14 dos 16 genótipos que apresentaram algum escurecimento, representando 87,5% de coincidência com os dados fenotípicos e indicando que o gene Sd é o responsável pelo escurecimento dos grãos nesses genótipos. A linhagem CNFM11940, com grãos mulatinho e a cultivar TAA Dama, com grãos carioca apresentaram escurecimento lento e alelos relativos ao escurecimento normal para os dois marcadores. Isso indica que houve recombinação nessa região genômica, provocando a separação entre os marcadores e o gene Sd, ou que existe outro gene conferindo o escurecimento lento nesses genótipos. As estimativas de divergência genética entre os genótipos forneceram informações adicionais para comparação dos genótipos. Adicionalmente, todas as progênies F2:3 oriundas das três populações, apresentaram escurecimento lento e, portanto, não houve segregação. Assim, o gene que controla o escurecimento dos grãos em feijão pinto e carioca é o gene Sd.