RESUMEN
This integrative literature review study analyzes the findings of the last 5 years of the parasite Angiostrongylus cantonensis. It is known that this nematode is found in the pulmonary arteries of rats, where it remains as a definitive host. From mice, the cycle spreads to animals, such as snails, which in contact with humans can trigger the disease. In humans, the parasite causes several neurological, abdominal manifestations and mainly meningitis. Based on the review of studies, its epidemiology shows worldwide distribution, although there are endemic cases for this parasite, such as asian countries. Laboratory findings generally showed altered CSF with turbidity, increased protein and eosinophilia, which generated meningeal signs in the patient, moreover MRI exams showed multiple alterations. Rare findings of the nematode in the eyeball, lung and signs of peritoneal inflammation were reported, which requires further studies to understand the whole pathophysiology. Finally, conservative treatment based on anthelmintics and anti-inflammatories brought good responses, although there are reports of deaths, which demonstrates the importance in the prevention and therapy of this disease.
Asunto(s)
Angiostrongylus cantonensis , Antihelmínticos , Infecciones por Strongylida , Angiostrongylus cantonensis/fisiología , Animales , Antiinflamatorios , Humanos , Ratones , Ratas , Caracoles/parasitología , Infecciones por Strongylida/epidemiologíaRESUMEN
This integrative literature review study analyzes the findings of the last 5 years of the parasite Angiostrongylus cantonensis. It is known that this nematode is found in the pulmonary arteries of rats, where it remains as a definitive host. From mice, the cycle spreads to animals, such as snails, which in contact with humans can trigger the disease. In humans, the parasite causes several neurological, abdominal manifestations and mainly meningitis. Based on the review of studies, its epidemiology shows worldwide distribution, although there are endemic cases for this parasite, such as asian countries. Laboratory findings generally showed altered CSF with turbidity, increased protein and eosinophilia, which generated meningeal signs in the patient, moreover MRI exams showed multiple alterations. Rare findings of the nematode in the eyeball, lung and signs of peritoneal inflammation were reported, which requires further studies to understand the whole pathophysiology. Finally, conservative treatment based on anthelmintics and anti-inflammatories brought good responses, although there are reports of deaths, which demonstrates the importance in the prevention and therapy of this disease.
Este estudo de revisão integrativa da literatura analisa os achados dos últimos 5 anos do parasita Angiostrongylus cantonensis. Sabe-se que esse nematoide é encontrado nas artérias pulmonares de ratos, onde permanece como hospedeiro definitivo. Dos camundongos, o ciclo se espalha para os animais, como os caracóis, que em contato com humanos podem desencadear a doença. Em humanos, o parasita causa diversas manifestações neurológicas, abdominais e principalmente meningite. Com base na revisão de estudos, sua epidemiologia mostra distribuição mundial, embora existam casos endêmicos para esse parasito, como países asiáticos. Os achados laboratoriais geralmente mostraram LCR alterado com turbidez, aumento de proteínas e eosinofilia, o que gerou sinais meníngeos nos pacientes, além disso, os exames de ressonância magnética mostraram múltiplas alterações. Foram relatados achados raros do nematoide no globo ocular, pulmão e sinais de inflamação peritoneal, o que requer mais estudos para o entendimento de toda a fisiopatologia. Por fim, o tratamento conservador à base de anti-helmínticos e anti-inflamatórios trouxe boas respostas, embora haja relatos de óbitos, o que demonstra a importância na prevenção e terapia dessa doença.
Asunto(s)
Ratas , Epidemiología Analítica , AngiostrongylusRESUMEN
Com o objetivo de promover, por meio de acesso único e com o uso de endoscópio flexível, ampla exploração da cavidade peritoneal de equinos em estação, foi concebida uma cânula laparoscópica para dar sustentação ao endoscópio e possibilitar o acesso sob visualização. O procedimento foi realizado a partir da fossa paralombar. Após pequena incisão cutânea, o endoscópio foi inserido na cânula e os músculos e o peritônio foram divulsionados mediante rotação da cânula. Logo depois da perfuração do peritônio, foi realizada a exploração da cavidade e a identificação das estruturas. Em seguida à exploração do lado ipsilateral ao acesso, realizou-se a transposição do conjunto cânula/endoscópio ventralmente à porção caudal do cólon descendente, seguida de exploração do lado contralateral. Concluída a técnica, foi executado, para fins de comparação, o mesmo procedimento por meio da fossa paralombar contralateral. Foi possível a transposição do conjunto cânula/endoscópio para o lado contralateral ao acesso em todos os procedimentos. Também foi possível a identificação da maioria das estruturas abdominais tanto pelo acesso esquerdo quanto pelo direito. A abordagem por acesso único mostrou-se viável para a exploração ampla da cavidade peritoneal, demonstrando ser uma alternativa à técnica laparoscópica convencional.(AU)
A laparoscopic cannula was designed to support a single access approach with a flexible endoscope for the wide exploration of the peritoneal cavity of standing horses. It provides support to the endoscope and allows access to the peritoneal cavity with a visual aid. This procedure was performed through the paralumbar fossa. After a small cutaneous incision, the endoscope was inserted into the cannula, and the muscles and peritoneum were divulsed through the rotation of the cannula. After the peritoneal perforation, cavity exploration and identification of structures were performed. After the exploration of the ipsilateral side of the access, the cannula/endoscope was transposed ventrally to the caudal portion of the descending colon; this was followed by the exploration of the contralateral side. Once this process was completed, the same procedure was performed through the contralateral paralumbar fossa for comparison. It was possible to transpose the cannula/endoscope set to the contralateral access side in all procedures. Further, it was possible to identify most of the abdominal structures in both the left and right access. This single access approach proved to be feasible for the extensive exploration of the peritoneal cavity, thereby indicating it can be an alternative to the conventional laparoscopic technique.(AU)
Asunto(s)
Animales , Peritoneo/diagnóstico por imagen , Endoscopios/veterinaria , Cirugía Asistida por Video/veterinaria , Cánula , Caballos , Procedimientos Quirúrgicos Mínimamente Invasivos/métodosRESUMEN
Com o objetivo de promover, por meio de acesso único e com o uso de endoscópio flexível, ampla exploração da cavidade peritoneal de equinos em estação, foi concebida uma cânula laparoscópica para dar sustentação ao endoscópio e possibilitar o acesso sob visualização. O procedimento foi realizado a partir da fossa paralombar. Após pequena incisão cutânea, o endoscópio foi inserido na cânula e os músculos e o peritônio foram divulsionados mediante rotação da cânula. Logo depois da perfuração do peritônio, foi realizada a exploração da cavidade e a identificação das estruturas. Em seguida à exploração do lado ipsilateral ao acesso, realizou-se a transposição do conjunto cânula/endoscópio ventralmente à porção caudal do cólon descendente, seguida de exploração do lado contralateral. Concluída a técnica, foi executado, para fins de comparação, o mesmo procedimento por meio da fossa paralombar contralateral. Foi possível a transposição do conjunto cânula/endoscópio para o lado contralateral ao acesso em todos os procedimentos. Também foi possível a identificação da maioria das estruturas abdominais tanto pelo acesso esquerdo quanto pelo direito. A abordagem por acesso único mostrou-se viável para a exploração ampla da cavidade peritoneal, demonstrando ser uma alternativa à técnica laparoscópica convencional.(AU)
A laparoscopic cannula was designed to support a single access approach with a flexible endoscope for the wide exploration of the peritoneal cavity of standing horses. It provides support to the endoscope and allows access to the peritoneal cavity with a visual aid. This procedure was performed through the paralumbar fossa. After a small cutaneous incision, the endoscope was inserted into the cannula, and the muscles and peritoneum were divulsed through the rotation of the cannula. After the peritoneal perforation, cavity exploration and identification of structures were performed. After the exploration of the ipsilateral side of the access, the cannula/endoscope was transposed ventrally to the caudal portion of the descending colon; this was followed by the exploration of the contralateral side. Once this process was completed, the same procedure was performed through the contralateral paralumbar fossa for comparison. It was possible to transpose the cannula/endoscope set to the contralateral access side in all procedures. Further, it was possible to identify most of the abdominal structures in both the left and right access. This single access approach proved to be feasible for the extensive exploration of the peritoneal cavity, thereby indicating it can be an alternative to the conventional laparoscopic technique.(AU)
Asunto(s)
Animales , Peritoneo/diagnóstico por imagen , Endoscopios/veterinaria , Cirugía Asistida por Video/veterinaria , Cánula , Caballos , Procedimientos Quirúrgicos Mínimamente Invasivos/métodosRESUMEN
The aim of this study was to evaluate the phenotypic stability and specific and broad adaptability of common black bean genotypes for the Central and Center-South regions of Brazil by using the Annicchiarico and AMMI (weighted average of absolute scores: WAAS, and weighted average of absolute scores and productivity: WAASP) methodologies. We carried out 69 trials, with 43 and 26 trials in the Central and Center-South regions, respectively. Thirteen genotypes were evaluated in a randomized block design with three replications, during the rainy, dry, and winter seasons in 2 years. To obtain estimates of specific adaptation, we analyzed the parameters for each method obtained in the two geographic regions separately. To estimate broad adaptation, we used the average of the parameters obtained from each region. The lines identified with high specific adaptation in each region were not the same based on the Annicchiarico and AMMI (WAAS) methodologies. It was not possible to identify the same genotypes with specific or broad stability by using these methods. By contrast, the Annicchiarico and AMMI (WAASP) methods presented very similar estimates of broad and specific adaptation. Based on these methods, the lines with more specific adaptation were CNFP 8000 and CNFP 7994, in the Central and Center-South regions, respectively, of which the CNFP 8000 line was more widely adapted.
Asunto(s)
Adaptación Fisiológica/genética , Interacción Gen-Ambiente , Modelos Genéticos , Phaseolus/genética , Brasil , Variación Genética , Genotipo , Phaseolus/crecimiento & desarrollo , Fenotipo , Estaciones del AñoRESUMEN
Bacterial wilt of common bean caused by Curtobacterium flaccumfaciens pv. flaccumfaciens is an important disease in terms of economic importance. It reduces grain yield by colonizing xylem vessels, subsequently impeding the translocation of water and nutrients to the superior plant parts. The existence of physiological races in C. flaccumfaciens pv. flaccumfaciens has not so far been reported. The objective of the present investigation was to identify physiological races, evaluate differential interaction, and select resistant genotypes of common bean. Initially, 30 genotypes of common bean were inoculated with eight isolates exhibiting different levels of aggressiveness, under controlled greenhouse conditions. Disease was assessed 15 days after inoculation. The existence of differential interactions between C. flaccumfaciens pv. flaccumfaciens isolates and common bean genotypes were identified by utilizing partial diallel analysis. The most aggressive isolates were BRM 14939 and BRM 14942 and the least aggressive isolates were BRM 14941 and BRM 14946. The genotypes IPA 9, Ouro Branco, and Michelite were selected as more resistant among the test isolates. The genotypes IAC Carioca Akytã, BRS Notável, Pérola, IAC Carioca Aruã, and Coquinho contributed more to the isolate x genotype interaction according to the ecovalence method of estimation, and were, therefore, indicated as differentials. Based on these results, it was possible to conclude that physiological races of the pathogen exist, to select resistant genotypes, and to propose a set of differentials.
Asunto(s)
Actinomycetales/patogenicidad , Resistencia a la Enfermedad , Phaseolus/genética , Enfermedades de las Plantas/microbiología , Actinomycetales/genética , Genes de Plantas , Genotipo , Interacciones Huésped-Patógeno , Phaseolus/microbiología , Factores de Virulencia/genéticaRESUMEN
Slow seed coat darkening is desirable in common bean cultivars and genetic parameters are important to define breeding strategies. The aims of this study were to estimate genetic parameters for plant architecture, grain yield, grain size, and seed-coat darkening in common bean; identify any genetic association among these traits; and select lines that associate desirable phenotypes for these traits. Three experiments were set up in the winter 2012 growing season, in Santo Antônio de Goiás and Brasília, Brazil, including 220 lines obtained from four segregating populations and five parents. A triple lattice 15 x 15 experimental design was used. The traits evaluated were plant architecture, grain yield, grain size, and seed-coat darkening. Analyses of variance were carried out and genetic parameters such as heritability, gain expected from selection, and correlations, were estimated. For selection of superior lines, a "weight-free and parameter-free" index was used. The estimates of genetic variance, heritability, and gain expected from selection were high, indicating good possibility for success in selection of the four traits. The genotype x environment interaction was proportionally more important for yield than for the other traits. There was no strong genetic correlation observed among the four traits, which indicates the possibility of selection of superior lines with many traits. Considering simultaneous selection, it was not possible to join high genetic gains for the four traits. Forty-four lines that combined high yield, more upright plant architecture, slow darkening grains, and commercial grade size were selected.
Asunto(s)
Phaseolus/genética , Carácter Cuantitativo Heredable , Semillas/genética , Cruzamientos Genéticos , Variación Genética , Genotipo , Sitios de Carácter Cuantitativo , Selección GenéticaRESUMEN
Grain yield is strongly influenced by the environment, has polygenic and complex inheritance, and is a key trait in the selection and recommendation of cultivars. Breeding programs should efficiently explore the genetic variability resulting from crosses by selecting the most appropriate method for breeding in segregating populations. The goal of this study was to evaluate and compare the genetic potential of common bean progenies of carioca grain for grain yield, obtained by different breeding methods and evaluated in different environments. Progenies originating from crosses between lines and CNFC 7812 and CNFC 7829 were replanted up to the F7 generation using three breeding methods in segregating populations: population (bulk), bulk within F2 progenies, and single-seed descent (SSD). Fifteen F8 progenies per method, two controls (BRS Estilo and Perola), and the parents were evaluated in a 7 x 7 simple lattice design, with plots of two 4-m rows. The tests were conducted in 10 environments in four States of Brazil and in three growing seasons in 2009 and 2010. Genetic parameters including genetic variance, heritability, variance of interaction, and expected selection gain were estimated. Genetic variability among progenies and the effect of progeny-environment interactions were determined for the three methods. The breeding methods differed significantly due to the effects of sampling procedures on the progenies and due to natural selection, which mainly affected the bulk method. The SSD and bulk methods provided populations with better estimates of genetic parameters and more stable progenies that were less affected by interaction with the environment.
Asunto(s)
Grano Comestible/genética , Variación Genética , Phaseolus/genética , Fitomejoramiento , Brasil , Cruzamientos Genéticos , Interacción Gen-Ambiente , Genotipo , Phaseolus/clasificación , Fenotipo , Selección GenéticaRESUMEN
One of the current focus of common bean breeding programs in Brazil is to increase iron (FeC) and zinc content (ZnC) in grains. The objectives of this study were to estimate genetic parameters for FeC and ZnC in common bean, verify the need for conducting multi-site evaluation tests, identify elite lines that combine high FeC and ZnC with good adaptability, stability, and agronomic potential, and examine the genetic association between FeC and ZnC. Elite lines (140) were evaluated for important agronomic traits in multiple environments. In one trial, FeC and ZnC were evaluated and genetic parameters were estimated. Based on the high heritability estimates and significant selection gains obtained, the conditions for a successful selection was favorable. Of the 140 evaluated lines, 17 had higher FeC and ZnC, and were included in the validation test (2013, five environments), specifically for the evaluation of FeC and ZnC. The line by environment interaction for FeC and ZnC was detected, but it was predominantly simple. The environmental effect strongly influenced FeC and ZnC . The environment Brasília/rainy season was selected as the best evaluation site for preliminary tests for FeC and ZnC, because it resulted in similar conclusions as the mean of the five environments. The lines CNFP 15701 and CNFC 15865 had higher FeC and ZnC and were highly adaptable and stable, and are recommended for utilization in breeding programs. The lines CNFC 15833, CNFC 15703, and CNFP 15676 showed excellent combined agronomic and nutritional traits, and were selected for the development of biofortified cultivars. Additionally, the genetic association between FeC and ZnC was detected.
Asunto(s)
Hierro/química , Phaseolus/genética , Carácter Cuantitativo Heredable , Zinc/química , Brasil , Cruzamiento , Grano Comestible/química , Grano Comestible/genética , Ambiente , Phaseolus/crecimiento & desarrollo , Phaseolus/metabolismo , Fenotipo , Semillas/química , Semillas/genéticaRESUMEN
Gastrointestinal health is of great importance due to the increasing consumption of functional foods, especially those concern-ing diets rich in fiber content. The common bean has been valorized as a nutritious food due to its appreciable fiber content and the fact that it is consumed in many countries. The current study aimed to evaluate and compare the genetic potential of common bean progenies of the carioca group, developed through different breeding methods, for crude fiber content. The progenies originated through hybridization of two advanced strains, CNFC 7812 and CNFC 7829, up to the F7 generation using three breeding methods: bulk-population, bulk within F2 families, and single seed descent. Fifteen F8 progenies were evaluated in each method, as well as two check cultivars and both parents, us-ing a 7 x 7 simple lattice design, with experimental plots comprised of two 4-m long rows. Field trials were conducted in eleven environments encompassing four Brazilian states and three different sowing times during 2009 and 2010. Estimates of genetic parameters indicate differences among the breeding methods, which seem to be related to the different processes for sampling the advanced progenies inherent to each method, given that the trait in question is not subject to natural selection. Variability amongst progenies occurred within the three breeding methods and there was also a significant effect of environment on the progeny for all methods. Progenies developed by bulk-population attained the highest estimates of genetic parameters, had less interaction with the environment, and greater variability.
Asunto(s)
Fibras de la Dieta/metabolismo , Phaseolus/metabolismo , Semillas/genética , Selección Genética/genética , Brasil , Cruzamiento , Cruzamientos Genéticos , Genotipo , Phaseolus/genética , FenotipoRESUMEN
Accumulation of heavy metals in unconsolidated soils can prove toxic to proximal environments, if measures are not taken to stabilize soils. One way to minimize the toxicity of metals in soils is the use of materials capable of immobilizing these contaminants by sorption. Biochar (BC) can retain large amounts of heavy metals due to, among other characteristics, its large surface area. In the current experiment, sugarcane-straw-derived biochar, produced at 700 °C, was applied to a heavy-metal-contaminated mine soil at 1.5, 3.0, and 5.0% (w/w). Jack bean and Mucuna aterrima were grown in pots containing a mine contaminated soil and soil mixed with BC. Pore water was sampled to assess the effects of biochar on zinc solubility, while soils were analyzed by DTPA extraction to confirm available metal concentrations. The application of BC decreased the available concentrations of Cd, Pb, and Zn in the mine contaminated soil leading to a consistent reduction in the concentration of Zn in the pore water. Amendment with BC reduced plant uptake of Cd, Pb, and Zn with the jack bean uptaking higher amounts of Cd and Pb than M. aterrima. This study indicates that biochar application during mine soil remediation could reduce plant concentrations of heavy metals. Coupled with this, symptoms of heavy metal toxicity were absent only in plants growing in pots amended with biochar. The reduction in metal bioavailability and other modifications to the substrate induced by the application of biochar may be beneficial to the establishment of a green cover on top of mine soil to aid remediation and reduce risks.
Asunto(s)
Cadmio/química , Carbón Orgánico/química , Fabaceae/metabolismo , Plomo/química , Contaminantes del Suelo/química , Zinc/química , Biodegradación Ambiental , Cadmio/metabolismo , Plomo/metabolismo , Saccharum/química , Suelo/química , Contaminantes del Suelo/metabolismo , Solubilidad , Zinc/metabolismoRESUMEN
Heavy metals in soil are naturally occurring but may be enhanced by anthropogenic activities such as mining. Bio-accumulation of heavy metals in the food chain, following their uptake to plants can increase the ecotoxicological risks associated with remediation of contaminated soils using plants. In the current experiment sugar cane straw-derived biochar (BC), produced at 700 °C, was applied to a heavy metal contaminated mine soil at 1.5%, 3.0% and 5.0% (w/w). Jack bean (Canavalia ensiformis) and Mucuna aterrima were grown in pots containing soil and biochar mixtures, and control pots without biochar. Pore water was sampled from each pot to confirm the effects of biochar on metal solubility, whilst soils were analyzed by DTPA extraction to confirm available metal concentrations. Leaves were sampled for SEM analysis to detect possible morphological and anatomical changes. The application of BC decreased the available concentrations of Cd, Pb and Zn in 56, 50 and 54% respectively, in the mine contaminated soil leading to a consistent reduction in the concentration of Zn in the pore water (1st collect: 99 to 39 µg L(-1), 2nd: 97 to 57 µg L(-1) and 3rd: 71 to 12 µg L(-1)). The application of BC reduced the uptake of Cd, Pb and Zn by plants with the jack bean translocating high proportions of metals (especially Cd) to shoots. Metals were also taken up by Mucuna aterrima but translocation to shoot was more limited than for jack bean. There were no differences in the internal structures of leaves observed by scanning electron microscopy. This study indicates that biochar application during mine soil remediation reduce plant concentrations of potential toxic metals.
Asunto(s)
Cadmio/farmacocinética , Carbón Orgánico , Plomo/farmacocinética , Contaminantes del Suelo/farmacocinética , Zinc/farmacocinética , Brasil , Cadmio/análisis , Canavalia/efectos de los fármacos , Canavalia/metabolismo , Carbón Orgánico/farmacología , Plomo/análisis , Microscopía Electrónica de Rastreo , Minería , Mucuna/efectos de los fármacos , Mucuna/metabolismo , Fósforo/farmacocinética , Hojas de la Planta/química , Potasio/farmacocinética , Suelo/química , Contaminantes del Suelo/análisis , Zinc/análisisRESUMEN
The common bean is an important source of iron and zinc in humans. Increases in the contents of these minerals can combat mineral deficiencies, but these contents are influenced by environmental conditions. Thus, the objectives of this study were to investigate the interaction between common bean lines and water availability on iron and zinc contents (CFe and CZn, respectively), identify superior lines with stable CFe and CZn, and test for a genetic relationship between CFe and CZn. Six crop trials were performed using a randomized block design with three replications. The trials were performed during the winter sowing period for three different combinations of year and site in Brazil. For each combination, 53 lines were evaluated across two parallel trials; one trial was irrigated according to the crop requirements, and the other trial operated under a water deficit. Interaction was detected between lines and environments, and between lines and water availability for CFe and CZn. However, some lines exhibited high CFe and CZn in both conditions. Lines G 6492 and G 6490 exhibited high mean values, stability, and adaptability for both minerals. Other lines exhibited high CFe (Xamego) or CZn (Bambuí and Iapar 65). A moderate genetic correlation (0.62) between CFe and CZn was detected. Water availability during the common bean cycle had an effect on CFe and CZn; however, lines with high CFe and CZn in different conditions of water availability and environment were detected.
Asunto(s)
Variación Genética , Hierro/metabolismo , Phaseolus/genética , Phaseolus/metabolismo , Agua/metabolismo , Zinc/metabolismo , Adaptación Fisiológica/genética , Algoritmos , Interacción Gen-Ambiente , Genotipo , Humanos , Modelos GenéticosRESUMEN
The maintenance of the light color of the grains of carioca beans is a requirement for the development of new cultivars of common beans because it enables the storage of grains for long periods so that they may be traded at a proper opportunity. Crosses of cultivar BRSMG Madrepérola, which presents slow grain darkening, were made to 10 elite lines presenting normal darkening to obtain information about the genetic control of the trait and estimates of phenotypic and genotypic parameters. Progenies at the tegument generations F3 and F4 and their parents were evaluated at the locations of Santo Antônio de Goiás and Ponta Grossa at 71, 106, and 155 days of storage for seed-coat darkening using a rank of scores ranging from 1 (very light colored grains) to 5 (very dark colored grains). Genotypic and phenotypic variances and broad-sense heritabilities were estimated for each population. The segregation ratios were subjected to the chi-square test to establish the genetic control. Some populations did not present consistent patterns of genetic control, while others presented monogenic or double-recessive digenic segregation, indicating that the trait is controlled by few genes. Six segregant populations were identified with both low means for darkening and high expected gain under selection. Despite the strong environmental influence on the expression of the traits and the occurrence of the genotype by environment interaction, the estimates of genotypic and phenotypic parameters indicate the possibility of successful selection to develop lines with slow seed-coat darkening.
Asunto(s)
Genes de Plantas , Phaseolus/genética , Carácter Cuantitativo Heredable , Semillas/genética , Color , Cruzamientos Genéticos , Almacenamiento de Alimentos , Interacción Gen-Ambiente , Genotipo , Phaseolus/anatomía & histología , Fenotipo , Semillas/anatomía & histologíaRESUMEN
The identification of germplasm genetic variability in breeding programs of the common bean (Phaseolus vulgaris) is essential for determining the potential of each combination of parent plants to obtain superior genotypes. The present study aimed to estimated the extent of genetic diversity in 172 lineages and cultivars of the common bean by integrating five tests of value for cultivation and use (VCU) that were conducted over the last eight years by the breeding program of Embrapa Arroz e Feijão in Brazil. Nine multilocus genotyping systems composed of 36 fluorescent microsatellite markers distributed across 11 different chromosomes of the common bean were used, of which 24 were polymorphic in all trials. One hundred and eighty-seven alleles were identified, with an average of 7.79 alleles per locus and an average gene diversity of 0.65. The combined probability of identity for all loci was 1.32 x 10(-16). Lineages that are more genetically divergent between the selection cycles were identified, allowing the breeding program to develop a crossbreed between elite genotypes with a low degree of genetic relatedness. HE values ranged from 0.31 to 0.63, with a large reduction in the genetic base over successive selection cycles. The test showed a significant degree of differentiation (FST = 0.159). Private alleles (26%) were identified and can be directly incorporated into the gene pool of cultivated germplasm, thereby contributing effectively to the expansion of genetic diversity in this bean-breeding program.
Asunto(s)
Variación Genética , Endogamia , Phaseolus/genética , Cromosomas de las Plantas/genética , Repeticiones de MicrosatéliteRESUMEN
The objectives of the present study were to monitor the effect of backcrossing through microsatellite markers and to compare different marker assisted selection strategies. Four populations were developed using donor parents resistant to the bean golden mosaic virus and, for all crosses, only individuals resistant to the bean golden mosaic virus were backcrossed. For crosses ARC100-4 x DOR303 and ARC100-4 x PHAS8328, assisted selection was carried out in the F(2) and F(2)BC(1) generations, while in the remaining crosses selection was performed only in the F(2)BC(1) generation. For the microsatellite analysis, in each generation, 20 markers were genotyped. The molecular data were analyzed using the NTSys program and the proportion of the recurrent genome introgressed was estimated, based on genotypical configuration of the segregant populations compared to the recurrent parents. The results indicate a higher efficiency in recovering the genotype of the elite genitor through the strategy of backcross assisted selection in the successive generations, and demonstrate a practical and useful application of molecular marker technology associated with bean breeding, to reduce the number of backcrosses and the time to recover the genome of the recurrent genitors.