Estratégias de seleção e efeito de armazenamento de sementes em populações segregantes de soja
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2016-06-17
Autores
Pereira, Elise de Matos [UNESP]
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Universidade Estadual Paulista (Unesp)
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O presente estudo foi realizado com os objetivos principais de: verificar as associações existentes entre caracteres agronômicos e caracteres relacionados à qualidade fisiológica de sementes de soja; determinar alterações fisiológicas e no teor de óleo em sementes de soja, ao longo do período de armazenamento, além de selecionar progênies superiores de soja por meio de análises multivariadas. Para isto, as relações existentes entre os caracteres agronômicos de plantas e fisiológicos de sementes foram verificadas por meio da análise de correlações canônicas em sete populações e duas cultivares comerciais, em três gerações: plantas F3 e sementes F4; plantas F4 e sementes F5; e sementes e plantas na geração F4. Os caracteres agronômicos de plantas (grupo I) avaliados foram: número de dias para maturidade, altura da planta na maturidade, altura de inserção da primeira vagem, número de vagens, produção de grãos e teor de óleo. A qualidade fisiológica das sementes (grupo II), foi avaliada por meio do teste de germinação, envelhecimento acelerado, emergência e índice de velocidade de emergência. As mesmas populações e cultivares também foram avaliadas antes do armazenamento e após seis meses, armazenadas em ambiente com temperatura e umidade controladas, através de testes de germinação, vigor, teor de água e teor de óleo, em esquema fatorial 2 x 9. Para as análises multivariadas, 20 populações segregantes de geração F4, foram avaliadas para os seguintes caracteres agronômicos: número de dias para florescimento, número de dias para maturidade, altura da planta na maturidade, altura da inserção da primeira vagem, número de ramos, número de vagens, número de nós, produção de grãos e teor de óleo. Utilizou-se a técnica de componentes principais e análise de agrupamento pelo método não hierárquico de k-médias, além dos índices de seleção Mulamba e Mock e Smith e Hazel. Observou-se que os caracteres agronômicos de plantas e fisiológicos de sementes não são independentes. As associações intergrupos para a geração de plantas F3 e sementes F4 foram estabelecidas por plantas com maior número de vagens, mais produtivas e com alto teor de óleo, as quais estão associadas com sementes de alta germinação e velocidade de emergência. Na geração de plantas F4 e sementes F5, há associação entre ciclo de maturidade reduzido, sementes de alta porcentagem de emergência e alta porcentagem de plântulas normais após o envelhecimento acelerado. Pelo segundo par canônico plantas mais produtivas e de porte alto estão associadas com maior vigor de sementes de soja. Para a geração de sementes e plantas F4 as associações estabelecidas foram sementes de alto vigor estão associadas a plantas mais produtivas, com alto teor de óleo e ciclo de maturidade reduzido. E pelo segundo par canônico há associação entre sementes de alta qualidade fisiológica e plantas de porte alto. O armazenamento das sementes por seis meses em ambiente controlado afetou a qualidade fisiológica e o teor de óleo das sementes, sendo que os genótipos de soja apresentam diferentes níveis de tolerância ao armazenamento e teores de óleo. A análise de componentes principais resultou em 3 componentes principais (CP1, CP2 e CP3), os quais explicam 65,82% da variância total contida nas nove variáveis. Os caracteres de maior contribuição na discriminação dos genótipos em CP1 foram produção de grãos, número de ramos, número de vagens, número de nós e número de dias para maturidade. As progênies selecionadas 36, 37, 38, 39, 40, 41, 65, 75, 80, 89 e 95 apresentam bom potencial produtivo. As análises de k-médias formaram nove grupos, o grupo superior foi formado pelas progênies 36, 38, 39, 40, 65, 75, 79 e 80. Dentre as 18 progênies selecionadas pelos índices de seleção, 10 foram concordantes com os componentes principais. As análises multivariadas permitiram a seleção de progênies superiores para os caracteres relacionados à produção de grãos e teor de óleo.
This study aimed to examine the associations between agronomic traits and traits related to physiological seed quality in soybean seeds, determine physiological and oil content alterations during the storage and select superior progenies using multivariate analysis. For this, the relationships between agronomic traits and physiological of seed traits were evaluated using canonical correlation analysis in seven segregating populations and two commercial cultivars conducted in three generations: plants F3 and seeds F4, plants F4 and seeds F5 and seeds and plants in generation F4. The agronomic traits (group I) evaluated were: number of days to maturity, plant height at maturity, first pod height, number of pod per plant, grain yield and oil content. The seed physiological quality (group II) was evaluated by percentage of germination, percentage of emergence, emergence speed index and accelerated aging. The same populations and cultivars were also evaluated before the storage and after six months stored in cold room by germination test, vigor, seed moisture and oil content, arranged in a 2 x 9 factorial design. For the multivariate analysis, 20 segregating populations in generation F4 were evaluated using the following agronomic traits: number of days to flowering, number of days to maturity, plant height at maturity, first pod height, number of branches per plant, number of pod per plant, number of nodes per plant, grain yield and oil content. It was used the principal components technique and the non-hierarchical clustering method of k-means and also the rank summation index Mulamba and Mock and classical selection index Smith and Hazel. The analysis of canonical correlation showed that the groups are not independent. Inter-group associations, in the generation of plants F3 and seeds F4, were establish by plants with more pods, higher grain yield and oil content are associated with seeds with high germination and emergence speed index. For the generation plants F4 and seeds F5, there are associations between short-season plants, seeds with high emergence and percentage of germination under conditions of accelerated aging. In the second canonical pair, higher-yielding and taller plants are associated with high vigor soybean seeds. For the generation seeds and plants F4 the associations established were, seeds with high vigor are associated with short-season and higher-yielding plants and high oil content. And in the second canonical pair there is association between seeds with high physiological quality and tall plants. The storage for six months in cold room affected the physiological quality and the oil content of the seeds and the soybean genotypes shown different levels of tolerance of storage and different oil content. The principal components analysis resulted on 3 principal components (PC1, PC2 and PC3), which explained 65,82% of the total variance in nine variables. The traits with higher contribution to discriminate the progenies in PC1 were grain yield, number of branches, number of pods, number of nodes and number of days to maturity. The selected progenies 36, 37, 38, 39, 40, 41, 65, 75, 80, 89 and 95 shown good productive potencial. The clustering analysis, k-means allowed the formation of nine groups, the superior group contains the progenies 36, 38, 39, 40, 65, 75, 79 and 80. Among the 18 progenies selected by the selection indexes, 10 were consistent with principal components analysis. The multivariate analysis allowed selecting superior progenies for the evaluated characters, especially for the components related to grain production and oil content.
This study aimed to examine the associations between agronomic traits and traits related to physiological seed quality in soybean seeds, determine physiological and oil content alterations during the storage and select superior progenies using multivariate analysis. For this, the relationships between agronomic traits and physiological of seed traits were evaluated using canonical correlation analysis in seven segregating populations and two commercial cultivars conducted in three generations: plants F3 and seeds F4, plants F4 and seeds F5 and seeds and plants in generation F4. The agronomic traits (group I) evaluated were: number of days to maturity, plant height at maturity, first pod height, number of pod per plant, grain yield and oil content. The seed physiological quality (group II) was evaluated by percentage of germination, percentage of emergence, emergence speed index and accelerated aging. The same populations and cultivars were also evaluated before the storage and after six months stored in cold room by germination test, vigor, seed moisture and oil content, arranged in a 2 x 9 factorial design. For the multivariate analysis, 20 segregating populations in generation F4 were evaluated using the following agronomic traits: number of days to flowering, number of days to maturity, plant height at maturity, first pod height, number of branches per plant, number of pod per plant, number of nodes per plant, grain yield and oil content. It was used the principal components technique and the non-hierarchical clustering method of k-means and also the rank summation index Mulamba and Mock and classical selection index Smith and Hazel. The analysis of canonical correlation showed that the groups are not independent. Inter-group associations, in the generation of plants F3 and seeds F4, were establish by plants with more pods, higher grain yield and oil content are associated with seeds with high germination and emergence speed index. For the generation plants F4 and seeds F5, there are associations between short-season plants, seeds with high emergence and percentage of germination under conditions of accelerated aging. In the second canonical pair, higher-yielding and taller plants are associated with high vigor soybean seeds. For the generation seeds and plants F4 the associations established were, seeds with high vigor are associated with short-season and higher-yielding plants and high oil content. And in the second canonical pair there is association between seeds with high physiological quality and tall plants. The storage for six months in cold room affected the physiological quality and the oil content of the seeds and the soybean genotypes shown different levels of tolerance of storage and different oil content. The principal components analysis resulted on 3 principal components (PC1, PC2 and PC3), which explained 65,82% of the total variance in nine variables. The traits with higher contribution to discriminate the progenies in PC1 were grain yield, number of branches, number of pods, number of nodes and number of days to maturity. The selected progenies 36, 37, 38, 39, 40, 41, 65, 75, 80, 89 and 95 shown good productive potencial. The clustering analysis, k-means allowed the formation of nine groups, the superior group contains the progenies 36, 38, 39, 40, 65, 75, 79 and 80. Among the 18 progenies selected by the selection indexes, 10 were consistent with principal components analysis. The multivariate analysis allowed selecting superior progenies for the evaluated characters, especially for the components related to grain production and oil content.
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Palavras-chave
Análises multivariadas, Caracteres agronômicos, Qualidade de sementes, Teor de óleo, Agronomic traits, Glycine max, Multivariate analysis, Oil content, Seed quality