Genetic variability and genetic progress in seed traits in breeding the physic nut

Determining the chemical composition of seeds of the physic nut (Jatropha curcas L.) is of great importance for the species due to the oil content of the seeds (the principal trait of interest). Identifying promising genotypes with selectable seed traits is one of the strategies adopted in breeding the physic nut in order to increase the yield and quality of the oil. Therefore, the aim of this study was to determine the chemical composition of seed traits in ten half-sibling progeny of the physic nut, and to identify which progeny have good genetic performance for transmission to the offspring. The experimental design was completely randomised, with ten treatments and four replications. The treatments were represented by seeds from half-sibling progeny in which the carbohydrate, protein and lipid content, and the composition of the fatty acids were evaluated. The genetic parameters and the gains from their selection were predicted for the principal seed traits using mixed-model analysis, including REML (restricted maximum likelihood) and BLUP (best linear unbiased prediction). The physic-nut seeds showed an average dry matter (DM) concentration of 60 mg g-1 carbohydrates, 42 mg g-1 protein and 142 mg g-1 total lipids. Unsaturated fatty acids represented more than 85% of the total fatty acid composition, with the oil classified as oleic-linoleic. Considering the predictions of the genetic parameters, the lipid traits can be selected for the purpose of breeding, resulting in genetic progress in the yield and quality of physic-nut oil

COEFICIENTES DE SIMILARIDADE PARA AVALIAÇÃO DA DIVERSIDADE GENÉTICA EM PINHÃO-MANSO POR MARCADORES ISSR

Objetivou-se com este trabalho, avaliar a eficiência da utilização de diferentes coeficientes de similaridade na estimação da diversidade genética de Jatropha curcas L. utilizando marcadores moleculares ISSR. O DNA genômico foi extraído a partir de folhas jovens de 43 acessos de pinhão-manso. Matrizes de dissimilaridade genética foram obtidas a partir dos coeficientes Baroni, Coincidência Simples, Hamann, Índice II, Índice III, Jaccard, Nei e Li, Ochiai I, Ochiai II, Rogers e Tanimoto e Sokal e Sneath. Os dendrogramas foram construídos utilizando o método UPGMA e comparados mediante os parâmetros de coeficiente de correlação cofenético, estresse e distorção. Foram estimadas as correlações entre os pares de matrizes pelo teste de Mantel. Houve concordância entre as matrizes originais e as matrizes resultantes do processo de agrupamento para todos os coeficientes estudados. Os índices de Jaccard e Nei e Li não diferiram quanto ao ordenamento dos acessos avaliados e permitiram maior discriminação destes, sendo os mais adequados para avaliar a diversidade genética em pinhão-manso baseada em marcadores moleculares ISSR.Palavras-chave: dissimilaridade genética; análise de agrupamento; Jatropha curcas L. SIMILARITY COEFFICIENTS FOR EVALUATION OF GENETIC DIVERSITY IN JATROPHA BY ISSR MARKERS ABSTRACT:The aim of this work was to evaluate the efficiency of using different similarity coefficients in the estimation of Jatropha curcas L. genetic diversity using ISSR molecular markers. Genomic DNA was extracted from young leaves of the 43 jatropha accessions. Genetic dissimilarity matrices were obtained from the Baroni, Simple Matching, Hamann, Index II, Index III, Jaccard, Nei and Li, Ochiai I, Ochiai II, Rogers and Tanimoto and Sokal and Sneath coefficients. The dendrograms were constructed using the UPGMA method and compared using the co-phenetic correlation coefficient, stress and distortion parameters. Correlations between pairs of matrices were estimated by the Mantel test. There was agreement between the original matrices and the matrices resulting from the grouping process for all the studied coefficients. The Jaccard and Nei and Li indices did not differ in terms of the order of the evaluated accessions and allowed for greater discrimination of these, being the most suitable for assessing genetic diversity in physic nut based on ISSR molecular markers.Keywords: genetic dissimilarity; cluster analysis; Jatropha curcas L

Genetic variability and genetic progress in seed traits in breeding the physic nut

Determining the chemical composition of seeds of the physic nut (Jatropha curcas L.) is of great importance for the species due to the oil content of the seeds (the principal trait of interest). Identifying promising genotypes with selectable seed traits is one of the strategies adopted in breeding the physic nut in order to increase the yield and quality of the oil. Therefore, the aim of this study was to determine the chemical composition of seed traits in ten half-sibling progeny of the physic nut, and to identify which progeny have good genetic performance for transmission to the offspring. The experimental design was completely randomised, with ten treatments and four replications. The treatments were represented by seeds from half-sibling progeny in which the carbohydrate, protein and lipid content, and the composition of the fatty acids were evaluated. The genetic parameters and the gains from their selection were predicted for the principal seed traits using mixed-model analysis, including REML (restricted maximum likelihood) and BLUP (best linear unbiased prediction). The physic-nut seeds showed an average dry matter (DM) concentration of 60 mg g-1 carbohydrates, 42 mg g-1 protein and 142 mg g-1 total lipids. Unsaturated fatty acids represented more than 85% of the total fatty acid composition, with the oil classified as oleic-linoleic. Considering the predictions of the genetic parameters, the lipid traits can be selected for the purpose of breeding, resulting in genetic progress in the yield and quality of physic-nut oil

DIVERSIDADE GENÉTICA EM PINHÃO MANSO COM BASE EM MARCADORES ISSR

A utilização de espécies oleaginosas constitui uma alternativa à busca crescente por biocombustíveis, fazendo com que o pinhão manso venha ganhando destaque pela qualidade do seu óleo e rusticidade. Surge assim uma demanda pelo desenvolvimento de cultivares desta espécie e para isso o conhecimento de sua variabilidade genética é fundamental. Objetivou-se com o presente estudo avaliar a diversidade genética de 23 acessos de pinhão manso coletados em diferentes regiões do Brasil. Os DNAs dos acessos foram extraídos e analisados por meio de 12 iniciadores ISSR. A partir dos perfis eletroforéticos das bandas foi gerada a matriz de dissimilaridade genética, utilizada na elaboração do dendrograma e no agrupamento dos indivíduos, que também foi realizado segundo o método de Tocher.  O Índice de Coincidência foi calculado para verificar a existência de relação entre o agrupamento dos acessos e seu local de coleta. Um total de 44 bandas foram amplificadas, sendo 26 polimórficas (49,08%). As distâncias genéticas entre os genótipos variaram de 0,034 a 0,314. Os métodos de agrupamento permitiram a formação de grupos distintos, com um total de três grupos formados pelo Método de Tocher e sete pelo método UPGMA. Os acessos estudados apresentaram base genética estreita, o que poderá trazer dificuldades ao processo de melhoramento da cultura e levar a uma maior vulnerabilidade genética das novas cultivares lançadas.Palavras-chave: Jatropha curcas; marcadores moleculares; diversidade genética. GENETIC DIVERSITY IN THE PHYSIC NUT BASED ON ISSR MARKERS ABSTRACT: The use of oleaginous species is an alternative in the growing search for biofuels, where the physic nut (Jatropha curcas) stands out due to its robustness and the quality of its oil. The result is a demand to develop cultivars of this species, and for this, a knowledge of its genetic variability is fundamental. The aim of this study was to evaluate the genetic diversity of 23 accessions of jatropha collected in different regions of Brazil. The DNA of the accessions was extracted and analysed by means of 12 ISSR primers. A genetic dissimilarity matrix was generated from the electrophoretic profiles of the bands and used in elaborating the dendrogram and in grouping the individuals, which was also carried out as per the Tocher method. A Coincidence Index was calculated to check the existence of a relationship between the groups of accessions and their places of collection. A total of 44 bands were amplified, of which 26 were polymorphic (49.08%). The genetic distance between the genotypes ranged from 0.034 to 0.314. The clustering methods resulted in the formation of distinct groups, where three groups were formed by the Tocher Method and seven by the UPGMA. The accessions under study had a narrow genetic base, which could cause difficulties for the process of crop breeding, and lead to greater genetic vulnerability in the new cultivars.Keywords: Jatropha curcas; molecular markers; genetic diversity

DIVERSIDADE GENÉTICA EM PINHÃO MANSO COM BASE EM MARCADORES ISSR

A utilização de espécies oleaginosas constitui uma alternativa à busca crescente por biocombustíveis, fazendo com que o pinhão manso venha ganhando destaque pela qualidade do seu óleo e rusticidade. Surge assim uma demanda pelo desenvolvimento de cultivares desta espécie e para isso o conhecimento de sua variabilidade genética é fundamental. Objetivou-se com o presente estudo avaliar a diversidade genética de 23 acessos de pinhão manso coletados em diferentes regiões do Brasil. Os DNAs dos acessos foram extraídos e analisados por meio de 12 iniciadores ISSR. A partir dos perfis eletroforéticos das bandas foi gerada a matriz de dissimilaridade genética, utilizada na elaboração do dendrograma e no agrupamento dos indivíduos, que também foi realizado segundo o método de Tocher.  O Índice de Coincidência foi calculado para verificar a existência de relação entre o agrupamento dos acessos e seu local de coleta. Um total de 44 bandas foram amplificadas, sendo 26 polimórficas (49,08%). As distâncias genéticas entre os genótipos variaram de 0,034 a 0,314. Os métodos de agrupamento permitiram a formação de grupos distintos, com um total de três grupos formados pelo Método de Tocher e sete pelo método UPGMA. Os acessos estudados apresentaram base genética estreita, o que poderá trazer dificuldades ao processo de melhoramento da cultura e levar a uma maior vulnerabilidade genética das novas cultivares lançadas.Palavras-chave: Jatropha curcas; marcadores moleculares; diversidade genética. GENETIC DIVERSITY IN THE PHYSIC NUT BASED ON ISSR MARKERS ABSTRACT: The use of oleaginous species is an alternative in the growing search for biofuels, where the physic nut (Jatropha curcas) stands out due to its robustness and the quality of its oil. The result is a demand to develop cultivars of this species, and for this, a knowledge of its genetic variability is fundamental. The aim of this study was to evaluate the genetic diversity of 23 accessions of jatropha collected in different regions of Brazil. The DNA of the accessions was extracted and analysed by means of 12 ISSR primers. A genetic dissimilarity matrix was generated from the electrophoretic profiles of the bands and used in elaborating the dendrogram and in grouping the individuals, which was also carried out as per the Tocher method. A Coincidence Index was calculated to check the existence of a relationship between the groups of accessions and their places of collection. A total of 44 bands were amplified, of which 26 were polymorphic (49.08%). The genetic distance between the genotypes ranged from 0.034 to 0.314. The clustering methods resulted in the formation of distinct groups, where three groups were formed by the Tocher Method and seven by the UPGMA. The accessions under study had a narrow genetic base, which could cause difficulties for the process of crop breeding, and lead to greater genetic vulnerability in the new cultivars.Keywords: Jatropha curcas; molecular markers; genetic diversity

PROGRESSO GENÉTICO E SELEÇÃO PRECOCE EM GENÓTIPOS DE PINHÃO-MANSO EM FASE JUVENIL

Physic nut (Jatropha curcas L.) is a euphorbia used in the production of biodiesel. The species has a narrow genetic base which the process of launching cultivars is difficult. Early characterization of the genotypes is an important step in crop breending. The aims of this study were to perform an early selection in morpho-agronomic traits, to predict the genetic progress of such traits and to indicate potential parents for progeny development. The experimental design used for the randomized blocks with 26 treatments and three replications. The morpho-agronomic traits were analyzed via mix models and the genetic progress added by direct, indirect selection and selection indexes. The genetic dissimilarity was provided by the Mahalanobis distance, with UPGMA hierarchical grouping and co-phenetic correlation coefficient acquired from 1,000 permutations. The indicators demonstrated genetic variability, with the identification of promising juvenile genotypes. The genotypes JCCE034, JCCE014 and JCCE103 show better genetic progress and the genotypes JCCE036 and JCCE86 show greater genetic divergences, forming individual clusters. J. curcas genotypes are promising in early selection and have satisfactory genetics gains for the traits. The genotypes have a good ability to compose groups of parents in targeted crosses, constituting base populations in the improvement of J. curcas.O pinhão manso (Jatropha curcas L.) é uma euforbiácea utilizada na produção de biodiesel. A espécie possui base genética estreita o que dificulta o processo de lançamento de cultivares. Caracterizar precocemente os genótipos constitui etapa importante no melhoramento da cultura. Objetivou-se com este estudo realizar uma seleção precoce em caracteres morfoagronômicos, predizer o progresso genético de tais caracteres e indicar genitores potenciais para obtenção de progênies. O delineamento experimental utilizado foi o de blocos casualizados com 26 tratamentos e três repetições. As variáveis morfoagronômicas foram analisadas via modelos mistos e o progresso genético obtido pela seleção direta, indireta e índices de seleção. A dissimilaridade genética foi determinada pela distância de Mahalanobis, com agrupamento hierárquico UPGMA e coeficiente de correlação cofenética adquirido de 1.000 permutações. As estimativas demonstraram variabilidade genética, com identificação de genótipos juvenis promissores. Os genótipos JCCE034, JCCE014 e JCCE103 apresentam melhores progressos genéticos e os genótipos JCCE036 e JCCE86 apresentam maiores divergências genéticas, formando clusters individuais. Os genótipos de pinhão-manso são promissores na seleção precoce e possuem satisfatórios ganhos com a seleção para os caracteres avaliados. Os genótipos apresentam boa capacidade para compor grupos de genitores em cruzamentos direcionados, constituindo populações-base no melhoramento de J. curcas. Palavras-chave: Jatropha curcas; diversidade genética; ganhos com a seleção; índices de seleção.   Genetic progress and early selection of juvenile physic nut genotypes   ABSTRACT: Physic nut (Jatropha curcas L.) is a euphorbia used in the production of biodiesel. The species has a narrow genetic base which the process of launching cultivars is difficult. Early characterization of the genotypes is an important step in crop breending. The aims of this study were to perform an early selection in morpho-agronomic traits, to predict the genetic progress of such traits and to indicate potential parents for progeny development. The experimental design used for the randomized blocks with 26 treatments and three replications. The morpho-agronomic traits were analyzed via mix models and the genetic progress added by direct, indirect selection and selection indexes. The genetic dissimilarity was provided by the Mahalanobis distance, with UPGMA hierarchical grouping and co-phenetic correlation coefficient acquired from 1,000 permutations. The indicators demonstrated genetic variability, with the identification of promising juvenile genotypes. The genotypes JCCE034, JCCE014 and JCCE103 show better genetic progress and the genotypes JCCE036 and JCCE86 show greater genetic divergences, forming individual clusters. J. curcas genotypes are promising in early selection and have satisfactory genetics gains for the traits. The genotypes have a good ability to compose groups of parents in targeted crosses, constituting base populations in the improvement of J. curcas. Keywords: Jatropha curcas; genetic diversity; selection gains; selection indexes

COEFICIENTES DE SIMILARIDADE PARA AVALIAÇÃO DA DIVERSIDADE GENÉTICA EM PINHÃO-MANSO POR MARCADORES ISSR

Objetivou-se com este trabalho, avaliar a eficiência da utilização de diferentes coeficientes de similaridade na estimação da diversidade genética de Jatropha curcas L. utilizando marcadores moleculares ISSR. O DNA genômico foi extraído a partir de folhas jovens de 43 acessos de pinhão-manso. Matrizes de dissimilaridade genética foram obtidas a partir dos coeficientes Baroni, Coincidência Simples, Hamann, Índice II, Índice III, Jaccard, Nei e Li, Ochiai I, Ochiai II, Rogers e Tanimoto e Sokal e Sneath. Os dendrogramas foram construídos utilizando o método UPGMA e comparados mediante os parâmetros de coeficiente de correlação cofenético, estresse e distorção. Foram estimadas as correlações entre os pares de matrizes pelo teste de Mantel. Houve concordância entre as matrizes originais e as matrizes resultantes do processo de agrupamento para todos os coeficientes estudados. Os índices de Jaccard e Nei e Li não diferiram quanto ao ordenamento dos acessos avaliados e permitiram maior discriminação destes, sendo os mais adequados para avaliar a diversidade genética em pinhão-manso baseada em marcadores moleculares ISSR.Palavras-chave: dissimilaridade genética; análise de agrupamento; Jatropha curcas L. SIMILARITY COEFFICIENTS FOR EVALUATION OF GENETIC DIVERSITY IN JATROPHA BY ISSR MARKERS ABSTRACT:The aim of this work was to evaluate the efficiency of using different similarity coefficients in the estimation of Jatropha curcas L. genetic diversity using ISSR molecular markers. Genomic DNA was extracted from young leaves of the 43 jatropha accessions. Genetic dissimilarity matrices were obtained from the Baroni, Simple Matching, Hamann, Index II, Index III, Jaccard, Nei and Li, Ochiai I, Ochiai II, Rogers and Tanimoto and Sokal and Sneath coefficients. The dendrograms were constructed using the UPGMA method and compared using the co-phenetic correlation coefficient, stress and distortion parameters. Correlations between pairs of matrices were estimated by the Mantel test. There was agreement between the original matrices and the matrices resulting from the grouping process for all the studied coefficients. The Jaccard and Nei and Li indices did not differ in terms of the order of the evaluated accessions and allowed for greater discrimination of these, being the most suitable for assessing genetic diversity in physic nut based on ISSR molecular markers.Keywords: genetic dissimilarity; cluster analysis; Jatropha curcas L