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Resumen Con el fin de obtener información teórica de los efectos genéticos que gobiernan los componentes del rendimiento y poder tener mayor información que permitiera elegir los mejores progenitores para la formación de híbridos con interés comercial, se estimaron los efectos y la capacidad combinatoria general (H.C.G) y específica (H.C.E) en cinco líneas endocríadas de maíz tropical de endospermo amarillo pertenecientes al programa de mejoramiento genético de maíz tropical de la empresa Sem Latam S.A. Se encontró que los efectos de habilidad combinatoria específica para los caracteres relacionados con el componente rendimiento presentaron valores positivos, no obstante, estos no fueron significativamente distintos de cero, lo que se traduce en la no existencia de un patrón heterótico en las líneas evaluadas. De igual modo, las líneas evaluadas presentaron una escasa capitalización de los efectos genéticos no aditivos o dominantes en el proceso de selección genealógica, permitiendo interpretar la baja manifestación de la heterosis como expresión del vigor hibrido de los cruzamientos F1 comparados con los genotipos parentales.
Abstract The general (GCA) and specific (SCA) combining ability and effects of five inbred lines of tropical endosperm maize from Sem Latam SA's tropical maize breeding programme were estimated for obtaining theoretical information concerning the genetic effects governing yield components and to have more information available for selecting the best progenitors for developing and producing commercially interesting hybrids. Positive SCA effect values were found regarding specific combinatorial ability for yield-related characters; however, they were not significantly different from zero, resulting in the lack of a heterotic pattern concerning the lines evaluated here. Little capitalisation regarding such lines' non-additive or dominant genetic effects concerning genealogical selection was seen here, thereby leading to interpreting the low manifestation of heterosis as an expression of the F1 crosses' hybrid vigour compared to that of the parental genotypes.
Resumo Com o objetivo de obter informações teóricas sobre os efeitos genéticos que regem os componentes de desempenho para escolher os melhores genitores de híbridos com interesse comercial, foram estimados os efeitos e a capacidade combinatória geral (HCG) e específica (HCE) em cinco linhagens de endosperma amarelo tropical pertencentes ao programa de melhoramento genético de milho tropical da empresa Sem Latam S.A. Encontrou-se que os efeitos da habilidade combinatória específica para os caracteres relacionados ao componente desempenho apresentaram valores positivos, porém, estes não foram significativamente diferentes de zero, o que se traduz na ausência de um padrão heterótico nas linhas avaliadas. Da mesma forma, as linhagens avaliadas apresentaram pouca capitalização dos efeitos genéticos não aditivos ou dominantes no processo de seleção genealógica, permitindo interpretar a baixa manifestação de heterose como expressão do vigor híbrido dos cruzamentos F1 em comparação com os genótipos parentais.
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ABSTRACT: Melon or muskmelon (Cucumis melo L.) is of considerable economic importance in Brazil. Nearly all the cultivars currently grown are hybrids. Heterosis has been used to advantage in the melon plant, and the use of uniform hybrids is one of the reasons for successful cultivation. The aim of the present study was to evaluate the agronomic potential of yellow melon lines and hybrids. An experiment was conducted in randomized blocks with three replications to evaluate 24 hybrids generated by crosses among three elite lines used as female parents (AF-01, AF-02, and AF-03) and eight lines used as male parents (LAM-01, LAM-02, LAM-03, LAM-04, LAM-05, LAM-06, LAM-07, and LAM-08). Yield and fruit quality traits were evaluated. Partial diallel analysis was carried out to estimate general combining ability and specific combining ability. Additive and non-additive effects were observed for the yield, mean fruit weight, and pulp thickness traits. The lines AF-02, LAM-02, and LAM-03 are the most promising as parents as they more frequently have favorable alleles. The most prominent hybrids in diallel analysis were AF-02 x LAM-02, AF-02 x LAM-03, AF-02 x LAM-04, and AF-03 x LAM-06.
RESUMO: O melão amarelo (Cucumis melo L.) é uma hortaliça de grande importância econômica. Atualmente as cultivares plantadas, em quase sua totalidade, são híbridos. A heterose tem sido explorada no meloeiro, sendo o emprego de híbridos uniformes uma das razões do sucesso da cultura. O objetivo do presente trabalho foi avaliar o potencial agronômico de linhagens e híbridos de melão amarelo. Foi conduzido um ensaio em blocos casualizados com três repetições para avaliar 24 híbridos gerados pelos cruzamentos entre três linhagens elites utilizadas como genitores femininos (AF-01, AF-02 e AF-03), e oito linhagens utilizadas como genitores masculinos (LAM-01; LAM-02; LAM-03; LAM-04; LAM-05; LAM-06; LAM-07 e LAM-08). Foram avaliados caracteres a produção e a qualidade do fruto. Realizou-se a análise dialélica parcial para estimação das capacidades geral e específica de combinação. Observou-se efeitos aditivos e não aditivos para os caracteres produtividade, peso médio do fruto e espessura da polpa. As linhagens AF-02, LAM-02 e LAM03 são as mais promissoras por possuir maior frequência de alelos favoráveis. Os híbridos de maior destaque foram AF-02 x LAM-02, AF-02 x LAM-03, AF-02 x LAM-04 e AF-03 x LAM-06.
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ABSTRACT: The purpose of this study was to evaluate the discriminatory capacity of tester lines for tropical corn lines converted to supersweet shrunken (sh2) gene, for the development of hybrids adapted to tropical conditions. Lines were used as female parents in crosses with three testers: open-pollinated mixed variety; supersweet line L4; supersweet commercial hybrid Tropical Plus. Four trials were carried out to evaluate topcrosses in Maringá - PR e Sabáudia - PR, Brazil in the main growing season of 2015/16. The following traits were evaluated: total ear weight (TEW, in kg), commercial ear weight (CEW, in kg) and total soluble solids (TSS, in °Brix). The GCA estimates for TEW and CEW were highest for L4. The lines Balu-114 and UEM-25 were selected based on the effects of g ̂ ifor the traits studied and should be used in the establishment of base populations for the breeding of superior lines. The s ̂ ijvalue for TEW was highest for cross BALU-182 x Tropical, while for CEW was the highest value for cross BALU-94 x Mista.
RESUMO: O presente trabalho teve como objetivo avaliar o desempenho de testadores quanto à capacidade de discriminação de linhagens tropicais convertidas à superdoce, por meio da incorporação do gene shrunken (sh2), visando a produção de híbridos adaptados às condições tropicais. As linhagens utilizadas como parentais femininos foram os testadores: variedade de polinização aberta Mista; linhagem superdoce L4; híbrido comercial superdoce Tropical Plus. Os quatro experimentos foram conduzidos em Maringá - PR e Sabáudia - PR, na safra verão de 2015/16. As características avaliadas foram: Peso de espigas totais (PET, em kg), Peso de espigas comerciais (PEC, em kg) e sólidos solúveis totais (SST, em ºBrix). A linhagem L4 foi o testador que mais proporcionou efeito de heterose. As maiores estimativas de CGC para PET e PEC foram obtidas por L4. As linhagens Balu-114 e UEM-25 foram selecionados com base nos efeitos de g ̂ i para as características estudadas e deverão ser utilizados na formação de populações base para a extração de linhagens superiores. O cruzamento BALU-182 x Tropical apresentou o maior valor de s ̂ ijpara PET, enquanto o cruzamento BALU-94 x Mista obteve o melhor valor para PEC.
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Aim: To examine concurrence between yield based and SSR marker based heterotic grouping of late-maturing maize inbred lines. Methodology: A total of 45 F1 crosses derived from 10x10 diallel mating scheme were evaluated along with their parents and hybrid checks across two locations (New Delhi and Dharawada). To group the inbred lines at molecular level, 35 polymorphic SSR primers were used for PCR amplification of repeat sequences from the genomic DNA of each inbred isolated by CTAB method. Cluster analysis was carried out by using NTSYS-pc- 2.02. Results: Analysis of variance revealed significant (P<0.01) variation among the parents and their hybrids across two locations for all the traits. The yield SCA classified 10 late-maturing maize inbred lines into three heterotic groups. Similarly, molecular genetic diversity analysis also categorized the inbred lines into three major clusters. However, correlations between SCA effects and genetic distance were low (r=0.161) for grain yield. Interpretation: Heterosis prediction with the help of molecular markers alone was not found effective. Further, field-testing can be complimented with molecular markers for the elimination of inferior crosses.
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ABSTRACT: The use of mixed models for evaluating diallel crosses is a highly timely option to the reliable prediction of progeny genetic values. In the sweet pepper crop, hybrids are commercially explored on a large scale, mainly because of their characteristics of economic importance. This study aimed to assess the potential of hybrids obtained from a partial diallel among five sweet pepper lines developed for the hydroponic cultivation system and two simple hybrids, by applying mixed models. It was performed crosses in the partial diallel scheme among the (L1B, L6, L7, L18, and L19) lines and the simple hybrids 'Valdor' and 'Atlantis'. Plants were cultivated in hydroponic system with substrate and irrigated three times a day using nutrient solution. On the basis of mixed models, the following traits were assessed: mean fruit diameter (FD), mean fruit length (FL), mean fruit number per plant (FNP), mean fruit mass (FM), early yield (EYIELD), and mean fruit mass per plant (FMP). The L6 line was the one that showed the highest estimate of general combination capacity for FMP, FM, and EYIELD, proving to be promising for recommendation. The hybrid that provided the best specific combining ability for FD, FM, FMP, and EYIELD was L6 x 'Valdor'. Triple hybrids were efficient to maximize yield for the traits of interest by the use of the mixed model.
RESUMO: A utilização de modelos mistos na avaliação de cruzamentos dialélicos é uma opção altamente oportuna para a fidedigna predição dos valores genéticos das progênies. Na cultura do pimentão, os híbridos são largamente explorados comercialmente, principalmente por suas características de importância econômica. O objetivo deste trabalho foi avaliar o potencial de híbridos resultantes de um dialelo parcial entre cinco linhagens de pimentão desenvolvidas para o sistema de cultivo hidropônico e dois híbridos simples, utilizando modelos mistos. Foram realizados cruzamentos no esquema de dialelo parcial entre as linhagens (L1B, L6, L7, L18 e L19) e os híbridos simples 'Valdor' e 'Atlantis'. As plantas foram cultivadas em sistema hidropônico com substrato e irrigadas três vezes ao dia com solução nutritiva. Com base em modelos mistos, foram avaliadas as características: diâmetro médio de frutos (DF); comprimento médio de frutos (CF); número médio de frutos por planta (NFP); massa média de frutos (MMF); produção precoce (PP) e massa média de frutos por planta (MFP). A linhagem L6 foi a que expressou maior estimativa de capacidade geral de combinação para MFP, MMF e PP, revelando-se promissora para recomendação. O híbrido triplo que apresentou melhor capacidade específica de combinação para DF, MMF, MFP e PP, foi L6 x 'Valdor'. Os híbridos triplos foram eficientes para incrementar a produtividade para as características de interesse com a aplicação da modelagem mista.
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Several metabolites are linked to cassava resistance to whitefly. There is limited information however, on the mode of gene action of the metabolites associated with cassava resistance to whitefly (Bemisia tabaci). The objective of the study was to determine the combining abilities and mode of gene action of salicylic acid, antioxidative capacity, total phenolic content, flavonoid, tannin, peroxidase and protein of selected cassava genotypes. Ten genotypes were crossed in half diallel and the parental and 45 S1 progenies evaluated for nymph count, whitefly count, leaf damage and sooty mold at Namulonge in season two of 2016. In season one and two of 2017, the parental genotypes and their corresponding forty-five S1 progenies were evaluated in randomized complete blocks with two replications for Bemisia tabaci population and leaf damage and leaf metabolite content assayed. The results indicated highly significant (P<.001) differences among genotypes for general combining ability (GCA) to antioxidative capacity; (P<.05) for total phenolic content, peroxidase and protein and (P<.01) for salicylic acid, tannin and flavonoid. The specific combining ability (SCA)showed significant (P<.001) differences for salicylic acid; (P<.01) for antioxidative capacity and total phenolic content. The additive variance was significant (P< .05) for flavonoid, protein; (P<.01) for antioxidative capacity, total phenolic content, tannin and peroxidase. The dominance variance had high significance (P<.001) for salicylic acid; (P<.05) for flavonoid and (P<.01) for antioxidative capacity and total phenolic content. Although additive gene action was higher than non-additive, both were influencing most metabolites indicating complexity of inheritance. A critical evaluation is necessary when exploiting metabolite related traits in breeding for resistance to Bemisia tabaci.
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Combining abilities for nutritional quality content were examined in tomato to understand the inheritance pattern of total soluble solids, titrable acidity, carbohydrates, proteins, carotenoids, ascorbic acid, potassium, lycopene and fruit yield plant-1. This experiment comprising a total of 64 treatments (28 F1+28 F2+ 8 parents) was evaluated in RBD. The results indicated that most of the traits were governed by additive gene action however non additive gene actionwas also important. The parent Pusa Ruby was found to be good general combiners for yield and nutritional traits and hence could be utilized in multiple breeding programs in future. The cross Pusa Ruby x Arka Vikas was desirable for fruit yield as well as nutritional characters since it inherited all nutritional traits except TSS content in F1generation and carotene content in F2 generation in desired direction.
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Objetivou-se com este trabalho avaliar o desempenho de quatro linhagens (L1, L2, L3 e L4) de codornas de corte em cruzamentos dialélicos. O presente estudo foi realizado nas instalações do Programa de Melhoramento de Codornas do Departamento de Zootecnia da UFVJM, no período de 16 de dezembro de 2011 a 26 de janeiro de 2012. Foram avaliados o peso corporal médio ao nascimento, aos 35 e aos 42 dias de idade; o consumo médio de dieta e a conversão alimentar do nascimento aos 35 dias e do nascimento aos 42 dias de idade. As análises dialélicas foram desenvolvidas de forma univariada, considerando-se a metodologia de dialelos completos, a partir das médias das combinações genotípicas resultantes de um experimento inteiramente ao acaso com três repetições. A capacidade geral de combinação foi significativa para todas as características avaliadas, com exceção do consumo médio de dieta e da conversão alimentar do nascimento aos 35 dias de idade. Houve efeito significativo da capacidade específica de combinação sobre o peso corporal ao nascimento (L2xL3; L2xL4; L1xL4); conversão alimentar do nascimento aos 35 dias (L1xL3; L2xL4) e do nascimento aos 42 dias (L1xL3; L2xL3; L2xL4); consumo médio de dieta do nascimento aos 35 dias de idade (L1xL3; L2xL3), o que permitiu a identificação de combinações híbridas mais favoráveis. O efeito recíproco foi significativo apenas sobre o peso ao nascimento. Com base na capacidade geral de combinação, as linhagens mais favoráveis para peso corporal foram a L1 e a L2. Para a conversão alimentar, pela capacidade específica de combinação, os cruzamentos L1xL3 e L2xL4 apresentaram o melhor resultado, enquanto para o consumo de dieta do nascimento aos 35 dias de idade, os cruzamentos L1xL3 e L2xL3 são os mais indicados.
The aim of this study was to evaluate the performance of four strains of meat type quails, designated L1, L2, L3 and L4 in diallel crosses. This study was carried out at the premises of the Genetic Improvement Program for Quails of UFVJM, from December 2011 to May 2012. The average body weight at hatch, at 35 and at 42 days old, the average daily feed intake at 35 and at 42 days old, and feed conversion at 35 and 42 days old were evaluated. Diallel analyzes were developed using univariate analyses, considering the methodology of complete diallel, from the average of the genotype combinations resulting in a complete randomized design with three replications. The combining ability analysis revealed significance for general combining ability for all traits, except for average feed intake and feed conversion at 35 days old. There was significant effect of specific combining ability for hatch weight (L2xL3; L2xL4; L1xL4); feed conversion from hatch to 35 days of age (L1xL3; L2xL4), and from hatch to 42 days (L1xL3; L2xL3; L2xL4); and average feed intake from hatch to 35 days of age (L1xL3; L2xL3), thus allowing the identification of more favorable hybrid combinations. The reciprocal effect showed significance only for hatch weight. Based on general combining ability, the strains which are more favorable for increased body weight were L1 and L2. For feed conversion, for the specific combining ability, the crosses L1xL3 and L2xL4 showed the best results, while for feed intake from hatch to 35 days old, the crosses L1xL3 and L2xL3 would be the most suitable.
Subject(s)
Animals , Coturnix/growth & development , Coturnix/genetics , Behavior, AnimalABSTRACT
Heterosis has been exploited in Capsicum annuum commercial hybrids; however, the use of heterosis in C. baccatum still remains to be explored, and studies related to the genetics and breeding of this species are scarce. The present study aimed to estimate the combining ability of five parents of C. baccatum var. pendulum , representatives of two distinct types of fruits (namely, lady's finger and cambuci), to calculate heterosis and to evaluate the agronomic potential of the hybrids for yield and fruit quality. The hybrids were produced from a complete diallel without reciprocals. The parents and hybrids were evaluated under field conditions in a randomized block design with three replications, and the following traits were assessed: number of fruits per plant, fruit weight, yield per plant, fruit length, fruit diameter and soluble solids. All traits were significant for general and specific combining ability, indicating that additive and non-additive effects are involved in the genetic control of these traits. The hybrid combinations between the types lady's finger and cambuci provided elongated fruits with smaller diameters and greater weight compared with the parents of the cambuci type. However, these factors did not lead to a significant increase in the yield per plant due to the decreased number of fruits except in hybrid UENF 1616 x UENF 1732. Considering only the parents and hybrids within each type of fruit, the genitor UENF 1624 (lady's finger) and the hybrid UENF 1639 x UENF 1732 (cambuci x cambuci) stood out for achieving a high yield per plant.
Embora heterose seja bem explorada na produção de híbridos comerciais de C. annuum, em C. baccatum, o uso da heterose permanece como um potencial e estudos relacionados à genética e ao melhoramento dessa espécie são escassos. Os objetivos deste trabalho foram estimar a capacidade combinatória entre cinco genitores de C. baccatum var. pendulum , representantes de dois grupos distintos de tipos de frutos (dedo-de-moça e cambuci); calcular a heterose e avaliar o potencial agronômico dos híbridos produzidos em termos de produção e qualidade dos frutos. Os híbridos foram produzidos a partir de um dialelo completo, sem recíprocos. Os genitores e os híbridos foram avaliados em condições de campo, no delineamento de blocos ao acaso, com três repetições, sendo avaliadas as seguintes características: número de frutos por planta, massa média do fruto, produção por planta, comprimento do fruto, diâmetro do fruto e teor de sólidos solúveis. Todas as características foram significativas para a capacidade geral e específica de combinação, indicando que efeitos aditivos e não-aditivos estão envolvidos no controle genético dessas características. As combinações híbridas entre os tipos dedo-de-moça e cambuci proporcionaram frutos alongados, com menores diâmetros e maior peso, quando comparado com os genitores do tipo cambuci. Contudo, esses fatores não favoreceram um aumento expressivo na produção por planta em virtude da diminuição do número de frutos, com exceção para o híbrido UENF 1616 x UENF 1732. Considerando somente os genitores e os híbridos dentro de cada tipo de fruto, destaca-se a linhagem UENF 1624 (dedo-de-moça) e o híbrido UENF 1639 x UENF 1732 (cambuci x cambuci) em relação à produção por planta.
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The objective of this work was to use a partial diallel to evaluate the combining ability of 14 soybean genotypes and recommend superior combinations. Seven of the genotypes had high oil yield; other seven exhibited tolerance to sudden death syndrome and they generated 49 hybrids in a diallel cross without reciprocals. F2plants of each cross and the parents were evaluated for the following traits: number of days to maturity (NDM), oil content in the seeds (OC), grain yield (GY) and oil yield (OY). The results indicated the existence of genetic variability in the parents and progeny for all the traits. The rank of the parents based on the means was similar to the rank based on general combining ability (GCA) for all the traits. The specific combining ability (SCA) and the GCA were significant for all the traits, with a predominance of additive effects. The parent with the highest GCA and mean for OC was the cultivar A 7002; on the other hand, the lowest values were found in PI 520733 and IAC 100. The crosses with the highest oil yields were those involving parent A 7002, except when it was crossed with IAC 100.
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Objetivou-se com este trabalho avaliar o peso e rendimento de carcaça e cortes de codornas por meio da metodologia de cruzamentos dialélicos. Foram utilizadas quatro linhagens de codornas de corte, denominadas L1, L2, L3 e L4. O sistema de cruzamento proporcionou 16 grupos de progênies, sendo quatro parentais (puros), seis mestiços F1 e seis mestiços F1 recíprocos, alojadas em bateria experimental em três repetições. Aos 42 dias de idade, cinco machos de cada unidade experimental foram escolhidos ao acaso e destinados ao abate, para avaliação do peso aos 42 dias de idade, peso e rendimento de carcaça, do peito, das pernas e das asas. A análise dialélica foi desenvolvida de forma univariada, considerando-se a metodologia de dialelos completos, incluindo as p² combinações das linhagens, a partir das médias das combinações genotípicas. As análises de capacidade combinatória mostraram significância para capacidade geral de combinação (CGC) para peso corporal, da carcaça, peito, pernas e asas, enquanto a capacidade específica de combinação (CEC) foi significativa apenas para o peso e rendimento de pernas. Os quadrados médios da CGG apresentaram, de forma geral, valores maiores que da CEC, revelando a predominância de efeitos aditivos na expressão dessas características, o que indica que melhorias nestas características podem ser conseguidas por meio de processos de seleção intrapopulacional. As linhas L1, L2 e L4 apresentaram valores positivos para CGC em praticamente todas as características avaliadas, e podem ser consideradas superiores à média das linhagens envolvidas no dialelo, sendo, portanto, favoráveis para proporcionarem aumento nas características avaliadas. Foi observado maior efeito dos genes aditivos, indicando que a seleção das linhas puras pode trazer ganhos satisfatórios, sendo a linha L2 a mais promissora, com base em sua capacidade geral de combinação. Para peso de pernas, o cruzamento L2xL4 seria o mais indicado e, para o rendimento de pernas, o cruzamento L1xL4, com base na capacidade específica de combinação.
This study aimed to evaluate the weight and carcass yield and cuts of meat quails through the methodology of diallel crosses. It was used four strains of meat quails, named L1, L2, L3 and L4. The mating system provided 16 groups of progenies, four parents (pure), six F1 crossbred and six F1 reciprocal crossbred, allocated in experimental batteries in three replicates. On the day 42th day of life, five males from each experimental unit were randomly chosen and destined for slaughter, to evaluate weight, weight and production of carcass, chest and legs; and wings yield. The diallel analyses were developed using univariate analysis, considering the methodology of complete diallel, including p² combinations, from the average of the genotype combinations. The analyses of combining ability showed significance for general combining ability (GCA), body weight, carcass weight, breast meat, legs and wings, while specific combining ability (SCA) was significant only for the weight and leg yield. The mean squares of GCA were, in general, higher values than SCA ones, showing the prevalence of additive effects on expression of these traits, indicating that these improved traits can be achieved through the selection process. The lines L1, L2 and L4 showed positive GCA values in almost all traits evaluated, and can be considered above the average of the lines involved in diallel; therefore, provide the most favorable for increasing the assessed traits. It was observed a greater additive effect of genes, suggesting that the selection of inbred lines can bring satisfactory gains, being the line L2 the most promising, based on their general combining ability. For legs' weight crossing L2xL4 would be more appropriate, and for legs yield, crossing L1xL4, based on specific combining ability.
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A possibilidade de predição dos ganhos obtidos por uma seleção constitui-se em uma das principais contribuições da genética quantitativa e, por conseguinte, no processo de melhoramento. Diante do exposto o objetivo do trabalho foi avaliar 21 tratamentos (06 parentais e 15 combinações dialélicas em F2), sob condições de campo em Gurupi- TO, no ano 2010/11, quanto à capacidade geral (CGC) e específica de combinação (CEC), em um esquema de dialelo completo, sem os recíprocos. A metodologia utilizada foi proposta por Griffing (1956). O delineamento experimental utilizado foi inteiramente casualizado, constituído por 21 tratamentos em 04 repetições. As características estudadas foram: o número de vagens por planta, número de grãos por planta e produção de grãos por planta (gramas/planta). Para todas as características foi detectado efeito significativo para CGC e CEC. O genitor M 9056RR foi o mais promissor e a combinação M 9056RR x P98Y70 a mais indicada para formação de uma população segregante com características superiores.
The ability to predict the gains made by a selection is in one of the main contributions of quantitative genetics and therefore in the process of improvement. In this light the objective of this study was to evaluate 21 treatments (06 parental and 15 diallel combinations in F2), under field conditions in Gurupi-TO in the year 2010/11, regarding the general ability (GCA) and specific combining (SCA ) in a complete diallel scheme without reciprocals. The methodology was proposed by Griffing (1956). The experimental design was randomized, consisting of 21 treatments in 04 replications. The characteristics studied were: number of pods per plant, number of grains per plant and yield per plant (grams / plant). For all features significant effects for GCA and SCA. The parent M 9056RR was the most promising and the combination M 9056RR x P98Y70 optimal for formation of a segregating population with superior features.
Subject(s)
Glycine max , Crop Production , GrasslandABSTRACT
The objective of this study was to determine the relationship between heterosis and genetic divergence for phosphorus use efficiency (PUE) in tropical maize. It was used two groups of genitors, each consisting of seven lines, contrasting with each other in the nitrogen and phosphorus use efficiency. It was obtained 41 hybrid combinations between these groups, which were evaluated in low phosphorus. Randomized complete block design with two replications was used. For obtaining the components of variance and the breeding values were used REML/BLUP method. In the genotyping of the parental lines were used 80 microsatellite markers. Through the correlation between genetic distance obtained by the markers and specific combining ability it was not possible to determine with accuracy by molecular markers, the crosses that produced hybrids with the highest heterosis for PUE. Thus, is possible to conclude that there is no relationship between genetic divergence and heterosis for phosphorus use efficiency and its components in tropical maize.
O objetivo deste estudo foi determinar a relação entre divergência genética e heterose para a eficiência no uso de fósforo (EUP) em milho tropical. Utilizaram-se dois grupos de genitores, compostos de sete linhagens cada, contrastantes entre si para as eficiências no uso de nitrogênio e fósforo. Foram obtidas 41 combinações híbridas entre esses grupos, as quais foram avaliadas em baixo fósforo. Usou-se o delineamento em blocos ao acaso com duas repetições. A obtenção dos componentes de variância e valores genéticos foi realizada via REML/BLUP e, para genotipagem das linhagens genitoras, foram utilizados 80 marcadores microssatélites. Através da correlação entre a distância genética obtida pelos marcadores e a capacidade específica de combinação, observou-se não ser possível a determinação com acurácia, via marcadores moleculares, dos cruzamentos que produziram os híbridos com as maiores heteroses para EUP. Com isso, é possível concluir que não há relação entre divergência genética e heterose para eficiência no uso de fósforo e seus componentes em milho tropical.
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The objective of this study was to evaluate four maize testers for identification of superior inbreed lines in testcross. The four testers evaluated are cultivars with narrow or wide genetic base (single-cross hybrids and open pollinated varieties) and two kernel types (flint or dent). SynD and SynF testers are open pollinated varieties with dent and flint kernels, respectively, and FSH and DSH testers are single-cross hybrids with flint and dent kernels, respectively. SynD tester showed the biggest genetic variance among the maize inbreed lines in crosses. The effects of general combining ability (GCA) for lines and specific combining ability (SCA) for lines x testers were significant, whereas GCA effects for testers were not significant. SynD and SynF testers identified the largest number of lines with higher GCA. The DSH and FSH testers showed suitable to identify lines with high SCA. It was concluded that SynD and SynF testers are adequate to identify inbreed lines with high GCA effects, and it's possible to identify new lines with high heterotic potential in each one of the four testers.
O objetivo deste estudo foi avaliar quatro testadores de milho quanto à capacidade de identificar linhagens superiores em testcross. Os quatro testadores avaliados são cultivares com base genética ampla (variedades de polinização aberta) e estreita (híbridos simples) e dois tipos de grãos (duro e dentado). Os testadores SynD e SynF são populações de milho de polinização aberta com grãos dentados e duros, respectivamente, e FSH e DSH são híbridos simples com grãos duros e dentados, respectivamente. O testador SynD possibilitou a maior expressão de variância genética entre os cruzamentos com as linhagens. A capacidade geral de combinação (CGC) das linhagens e a capacidade específica de combinação (CEC) entre linhagens e testadores foram significativas, enquanto que os efeitos de CGC dos testadores foram não significativos. Concluiu-se que os testadores SynD e SynF mostram-se adequados para identificar linhagens com maiores efeitos de GCA e é possível identificar novas linhagens com alto potencial heterótico com cada um dos quatro testadores utilizados.
ABSTRACT
The combining abilities for physiological traits in peanut were examined to understand the type of gene action governing these traits, and to identify peanut genotypes suitable for use as parents in breeding for improvement in physiological traits. Substantial genetic variability was observed among the hybrids for the traits studied. The genotypes, TPT-4 and ICGV-91114 were found to be good combiners for developing early flowering types, while ICGV-91114, TCGS- 584, TPT-4 and JL-220 were good combiners for developing early maturing. For SPAD chlorophyll meter reading was K-1375 was best general combiner. Among the parents K-1375, TIR-25 and TCGS-647 were found to be superior as evident from its highest significant positive general combining ability effects for specific leaf area. The best good combiner for transpiration rate was ICGV-91114 and for photosynthetic rate was TIR-25. For water use efficiency only the genotype, TPT-4 was the best combiner. Best performing parents for harvest index were JL-220 and TPT-4. The hybrid, TPT-4 x TIR-25 was the specific hybrid for high water use efficiency. For SPAD chlorophyll meter reading only one cross, K-1375 x TCGS647 was considered to be the good performing hybrid. Two hybrids viz., TIR-25 x TCGS- 647 and ICGV-91114 x JL-220 were found to be good specific combiners for harvest index. A perusal of results of combining ability analysis indicated considerable non-additive gene action in the inheritance of majority of the attributes studied. The non-fixable dominance deviation and epistatic effects are likely to hinder improvement through simple pedigree selection, which is commonly followed in groundnut. Alternatively intermating of the F2 segregants followed by recurrent selection and pedigree breeding can harness the different kinds of gene - effects. Repeated selection and inter-mating of segregating materials for two or three cycles, makes it possible to achieve simultaneously improvement in physiological attributes.
ABSTRACT
The objectives of this study were to identify promising popcorn lines and hybrids for genetic resistance to tropical rust (Tr, Physopella zeae) in diallel crosses of nine lines derived from a large part of Brazilian popcorn germplasm and to estimate genetic parameters for Tr resistance. Crosses and checks were tested in a random block design, with artificial inoculations under greenhouse conditions. Plots consisted of a single 14-L pot, with four plants. Tr was measured by severity and area under the disease progress curve. Data was analyzed by Griffing's diallel model, and genetic parameters were estimated. Heritability estimates to Tr resistance was medium. Specific combining ability-SCA had significant effects (P<0.10) for resistance, and was eight to nine times larger than general combining ability-GCA (P>0.10). This indicated the major importance of non additive gene effects. In general, breeding possibilities for resistance was restricted. The line 9 (L7.4) had the most outstanding GCA for resistance to Tr, and hybrids 1×7 and 3×6 had outstanding SCA and were recommended for breeding.
Os objetivos deste estudo foram identificar linhagens e híbridos de milho-pipoca promissores quanto à resistência genética à ferrugem tropical (Ftrop, Physopella zeae) em cruzamentos dialélicos, envolvendo nove linhagens derivadas de uma grande parte do germoplasma brasileiro de milho-pipoca, e estimar parâmetros genéticos envolvendo a resistência à Ftrop. Cruzamentos e testemunhas foram testados em delineamento de blocos ao acaso, sob condições de casa-de-vegetação e inoculação artificial. As parcelas consistiram de um vaso de 14 litros, com quatro plantas. A Ftrop foi avaliada pela severidade e pela área abaixo da curva de progresso da doença. Os dados foram analisados pelo modelo dialélico de Griffing e parâmetros genéticos foram estimados. As estimativas de herdabilidade foram médias. A capacidade específica de combinação-CEC teve efeito significativo (P<0,10) para a resistência e foi oito a nove vezes maior que a capacidade geral de combinação-CGC (P>0,10). Isso indicou que os efeitos gênicos não aditivos foram mais importantes. Em geral, as possibilidades de melhoramento foram restritas. A linhagem 9 (L7.4) teve a mais destacada CGC para a resistência e os híbridos 1×7 e 3×6 tiveram destacada CEC e foram recomendados para melhoramento.
ABSTRACT
Rice (Oryza sativa L.) breeding seeking to combine high productivity and cold tolerance for the temperate Latin America region is an important challenge. We estimated some useful parameters which can be used to investigate the genetic control of agronomic characters in crosses combining cold tolerance and productivity. A partial diallel design was used in crosses between six tropical indica rice cold susceptible genotypes (group 1) and seven japonica or indica/japonica cold tolerant rice genotypes (group 2). Parents and crosses were evaluated for agronomic characters under field conditions in two different experiments in 2005. The results showed significant mid-parent heterosis for all characters (plant height, tiller number, days to 50 percent flowering, panicle length, grains per panicle, sterility, and one-hundred grain weight). The predominant direction of dominance effects was negative for days to 50 percent flowering, and positive for all the other characters. General combining ability (GCA) and specific combining ability (SCA) were significant for all characters, although the GCA effects of the two groups were more important than the SCA effects.
ABSTRACT
Foram avaliados 12 híbridos intervarietais de milho (Zea mays L.), cruzados em esquema dialélico parcial 3 x 4 mais as sete populações parentais e 3 testemunhas. Os ensaios foram implantados nas estações experimentais do Iapar em Londrina, Pato Branco, Ponta grossa e Guarapuava. O objetivo foi avaliar um conjunto de sete populações no sentido de se estimar parãmetros que venham a auxiliar na escolha de materiais para posteriores trabalhos com seleção recorrente, extração de linhagens e síntese de compostos. Para a fonte Heterose as diferenças foram constatadas (P<0,01) para as variáveis produtividade de grãos e florescimento feminino, indicando que os cruzamentos foram superiores aos pais. Em relação aos valores de capacidade geral de combinação para rendimento, os parentais do grupo-1, PC 9407 e BR 106, obtiveram como valores 36,7 e 171, 1 kh.ha-1, respectivamente, e os parentais do grupos-2, PC 9701 e PC 9502, apresentaram valores de 131, 1 e 56,8 kg.ha-1, respectivamente. Para a capacidade específica de combinação, os maiores valores foram para PC 9701 x BR 106 (205,4 kg.ha-1) e PC 9502 x PC 9407 (135,3 kg.ha-1), assim como as maiores médias de produtividade de grãos dos cruzamentos avaliados (9.297 e 9.018 kg.ha-1, respectivamente). As populações PC 9701, BR 106, PC 9502 e PC 9407 são promissoras Fontes para a extração de linhagens visando desenvolvimento de híbridos, síntese de compostos e trabalhos com relação recorrente
In the summer season of 2004/2005, 12 intervarietal maize hybrids, crossed by the partial diallel scheme3 x 4, the seven parental populations and three checks were evaluated at Iapar Experimental Stations inLondrina, Pato Branco, Ponta Grossa e Guarapuava. The objective was to identify crosses for futurework with recurrent selection, inbred lines extraction and composite synthesis. For Heterosis variationcause, the differences were determined (P<0.01) for traits grain yield and female flowering, indicating thatcrosses were superior in relation to parentals. Regarding General Combining Ability values for yield, theparentals from Group-1, PC 9407 and BR 106, showed values of 36.7 kg.ha-1 and 171.1 kg.ha-1, respectively,and the parentals from Group-2 presented values of 131.1 kg.ha-1 and 56.8 kg.ha-1, respectively,. ForSpecific Combining Ability, the largest values were from PC 9701 x BR 106 (205.4 kg.ha-1) e PC 9502 x PC9407 (135.3 kg.ha-1) and, the largest values of grain yield average (9297 e 9018 kg.ha-1, respectively). Thepopulations PC 9701, BR 106, PC 9502 and PC 9407 are promising sources for inbred lines extractionaiming to superior maize hybrids development, composite synthesis and recurrent selection
Subject(s)
Genetic Enhancement , Zea mays/growth & developmentABSTRACT
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