Parâmetros genéticos e mapeamento associativo de características tecnológicas de cana de açúcar em três épocas de colheita
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Data
2017-01-23
Autores
Coutinho, Alisson Esdras [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O conhecimento dos teores de Pol e fibra tem por finalidade avaliar a qualidade da matéria-prima, seja para a produção de açúcar ou co-geração de energia na própria usina ou produção de etanol de segunda geração. As cultivares de cana-de-açúcar possuem diferentes períodos de maior acúmulo de sacarose, podendo ser no início, meio ou fim de safra. Como o período de safra se estende de abril até novembro, há influência das estações de ano (outono, inverno e primavera) provocando mudanças de temperatura e regime de chuvas. Portanto, a avaliação de experimentos em diferentes épocas de colheita é importante para identificar em qual período da safra os genótipos possuem maior acúmulo de sacarose. Diante deste contexto, o ranqueamento dos genótipos por época de colheita baseado nos valores genéticos preditos de Pol e fibra é de grande utilidade para fins de seleção. Além disto, a identificação de genes associados a características sob diferentes condições é de grande contribuição para a obtenção de novas cultivares pelos programas de melhoramento. Com isto, por meio do mapeamento associativo é possível detectar genes associados aos fenótipos utilizando métodos estatísticos. Sendo assim, o presente trabalho teve os seguintes objetivos: predizer os valores genéticos de 100 genótipos e estimar os parâmetros genéticos de Pol e fibra em três épocas de colheita e identificar marcadores AFLP associados a Pol e fibra usando o método Bayes Cπ. Foram conduzidos três experimentos, cada um correspondente a uma época de colheita nos agrícolas de 2014/2015 e 2015/2016. O ordenamento dos genótipos por cada época de colheita foi realizado mediante os valores genéticos preditos. Para a variável fibra do grupo 1, o IN8458 foi o que obteve o maior teor de fibra para as três épocas de colheita. Enquanto que o US571415 apresentou o maior teor de Pol. No grupo 2, a IACSP972084 apresentou o maior teor de fibra e a IACSP043150, o maior valor de Pol para a análise conjunta. Para a identificação das associações entre marcador e fenótipo, foi avaliada a estrutura genética aplicando marcadores AFLP ao painel composto pelos 100 genótipos de cana-de-açúcar pertencentes ao banco de germoplasma do Centro de Cana do Instituto Agronômico de Campinas. A análise de associação foi conduzida pelo método Bayes Cπ a partir das 640 marcas polimórficas obtidas pela genotipagem. Do total de marcas significativamente associadas com Pol, 39 marcas tiveram efeito ao menos em duas épocas de colheita. Já para fibra, observou-se 12 marcas com efeito ao menos em duas épocas. As marcas AFLP 418, AFLP 435 e AFLP 700 tiveram associações em mais de uma época para a variável Pol. Enquanto que para fibra, houve apenas a marca AFLP 520 com associação para três épocas. Quanto a variação fenotípica explicada pelos marcadores, foram 99,51%, 99,75%, 97,56% e 94,49 para as épocas 1, 2 e 3 (ano agrícola 2014/2015) e época 3 (2015/2016), respetivamente. As marcas significativamente associadas às épocas 1, 2, 3 e 3 (2016) explicaram 97,83%, 94,82%, 68,44% e 74,66%, respectivamente da variação fenotípica.
The knowledge of Pol and fiber contents aims to assess the quality of the raw material either for production of sugar or co-generation of energy in the industry itself or production of second generation ethanol. The cultivars of sugarcane have different periods of higher accumulation of sucrose and may be at the beginning, middle or end of harvest. As the harvest period extends from April to November, there is influence of the seasons (autumn, winter and spring) caused by changes in temperature and rainfall. Therefore the evaluation of experiments in different harvesting times is important to identify in which period of the crop the genotypes have greater accumulation of sucrose. In this context the ranking of genotypes per harvest season based on predicted genetic values of Pol and fiber is a great utility for selection purposes. In addition, the identification of genes associated with characteristics under different conditions is a great contribution, in terms of to obtain new cultivars by breeding programs. Thus, through association mapping it is possible to detect genes associated with phenotypes using statistical methods. The present study aimed to predict the genetic values of 100 genotypes and to estimate the genetic parameters of Pol and fiber at three harvest seasons and to identify AFLP markers associated to Pol and fiber using the Bayes Cπ methodology. Three different experiments, each one correspond a different harvesting season, were carried out in two crops season, 2014/2015 and 2015/2016. The ordering of the genotypes for each harvesting season was performed using predicted genetic values. For the group 1 fiber variable IN8458 was the one that obtained the highest fiber content for the three harvest periods. While US571415 presented the highest Pol content. In group 2 IACSP972084 had the highest fiber content and IACSP043150 the highest Pol value for the joint analysis. For the identification of the associations between marker and phenotype the genetic structure was evaluated by applying AFLP markers to the panel composed of 100 sugarcane genotypes belonging to the germplasm bank of the Cane Center of the Agronomic Institute of Campinas. The association analysis was conducted by the Bayes Cπ method from the 640 polymorphic tags obtained by genotyping. Of the total of markers significantly associated with Pol 39 brands had effect in at least two harvesting seasons. For fiber we observed 12 marks with effect in at least two periods. The AFLP 418 AFLP 435 and AFLP 700 brands had associations in more than one season for the Pol variable. Whereas for fiber there was only the AFLP 520 brand with association for three seasons. The phenotypic variation explained by the markers was 99.51% 99.75% 97.56% and 94.49 for seasons 1 2 and 3 (agricultural year 2014/2015) and season 3 (2015/2016), respectively. Significantly associated with seasons 1 2 3 and 3 (2016) explained 97.83% 94.82% 68.44% and 74.66% respectively of the phenotypic variation.
The knowledge of Pol and fiber contents aims to assess the quality of the raw material either for production of sugar or co-generation of energy in the industry itself or production of second generation ethanol. The cultivars of sugarcane have different periods of higher accumulation of sucrose and may be at the beginning, middle or end of harvest. As the harvest period extends from April to November, there is influence of the seasons (autumn, winter and spring) caused by changes in temperature and rainfall. Therefore the evaluation of experiments in different harvesting times is important to identify in which period of the crop the genotypes have greater accumulation of sucrose. In this context the ranking of genotypes per harvest season based on predicted genetic values of Pol and fiber is a great utility for selection purposes. In addition, the identification of genes associated with characteristics under different conditions is a great contribution, in terms of to obtain new cultivars by breeding programs. Thus, through association mapping it is possible to detect genes associated with phenotypes using statistical methods. The present study aimed to predict the genetic values of 100 genotypes and to estimate the genetic parameters of Pol and fiber at three harvest seasons and to identify AFLP markers associated to Pol and fiber using the Bayes Cπ methodology. Three different experiments, each one correspond a different harvesting season, were carried out in two crops season, 2014/2015 and 2015/2016. The ordering of the genotypes for each harvesting season was performed using predicted genetic values. For the group 1 fiber variable IN8458 was the one that obtained the highest fiber content for the three harvest periods. While US571415 presented the highest Pol content. In group 2 IACSP972084 had the highest fiber content and IACSP043150 the highest Pol value for the joint analysis. For the identification of the associations between marker and phenotype the genetic structure was evaluated by applying AFLP markers to the panel composed of 100 sugarcane genotypes belonging to the germplasm bank of the Cane Center of the Agronomic Institute of Campinas. The association analysis was conducted by the Bayes Cπ method from the 640 polymorphic tags obtained by genotyping. Of the total of markers significantly associated with Pol 39 brands had effect in at least two harvesting seasons. For fiber we observed 12 marks with effect in at least two periods. The AFLP 418 AFLP 435 and AFLP 700 brands had associations in more than one season for the Pol variable. Whereas for fiber there was only the AFLP 520 brand with association for three seasons. The phenotypic variation explained by the markers was 99.51% 99.75% 97.56% and 94.49 for seasons 1 2 and 3 (agricultural year 2014/2015) and season 3 (2015/2016), respectively. Significantly associated with seasons 1 2 3 and 3 (2016) explained 97.83% 94.82% 68.44% and 74.66% respectively of the phenotypic variation.
Descrição
Palavras-chave
Estrutura populacional, Análise bayesiana, Pol, Fibra, Maturação, Population structure, Bayesian analysis, Fiber, Maturation