Definition of morphofunctional groups in Panicum maximum accessions by canonical variables analysis

Todos os textos, informa??es e resultados apresentados s?o de inteira responsabilidade dos autores.A avalia??o das caracter?sticas morfog?nicas em acesso de Panicum maximum apesenta grande potencial para permitir a identifica??o precoce de grupos de plantas com caracter?sticas morfofuncionais afins. O objetivo com o trabalho foi avaliar as caracter?sticas morfog?nicas de acessos de Panicum maximum e definir grupos morfog?nicos a fins por meio da an?lise de vari?veis can?nicas. Foram avaliados 17 acessos em delineamento em blocos ao acaso com tr?s repeti??es. Ap?s avalia??o da dispers?o dos escores relativos ?s vari?veis can?nicas, verificou-se a forma??o de sete grupos morfofuncionais. Maior destaque foi dado ?s plantas dos grupos 5, 6 e 7. O grupo 7 apresentou maior taxa de alongamento foliar, longa dura??o de vida da folha e o maior comprimento final da l?mina. No grupo 5, registrou-se alta taxa de alongamento e de aparecimento foliar associadas a baixa senesc?ncia. O grupo 6 reuniu maior alongamento de folhas a menor longevidade, indicando necessidade de manejo mais intensivo. Foi poss?vel formar grupos morfofuncionais com base nas caracter?sticas morfog?nicas de acessos de Panicum maximum. Destaca-se a identifica??o das plantas dos grupos 5 e 7 como plantas com grande potencial para produ??o de folhas e longa janela de corte, e das plantas do grupo 6 como plantas que demandar?o manejo mais frequente.ABSTRACT The evaluation of morphogenetic characteristics in Panicum maximum accessions has potential in the previous identification of groups of plants with related morphofunctional characteristics. The study was carried out to evaluate the morphogenetic characteristics of Panicum maximum accessions and to define related morphogenetic groups by analysis of canonical variables. Were evaluated 17 accessions in a complete randomized block design with three replicate. After the evaluation of the scores related to canonical variables, it verified the formation of seven morphofunctional groups. We emphasize the groups 5, 6 and 7. The group 7 had higher leaf elongation rate, leaf life spam and leaf length. In the group 5, was observed high leaf elongation and appearance rate associated with low senescence. The group six had high elongation and low leaf life spam, indicating these plants to a more intensive management. With the canonical variable analysis was possible the identification of morphofunctional groups based on the morphogenetic characteristics of Panicum maximum accessions. The identification of the groups 5 and 7 as high production plants and with a longer harvest period and the groups 6 with plants that needs more frequent defoliation

Genetic parameters of morphogenetic traits in Panicum maximum acessions

Todos os textos, informa??es e resultados apresentados s?o de inteira responsabilidade dos autores.Objetivou-se com este trabalho estimar par?metros gen?ticos de caracter?sticas morfog?nicas em acessos de Panicum maximum. Foram avaliados 17 acessos (previamente selecionados pela Embrapa Gado de Corte) em delineamento em blocos ao acaso com tr?s repeti??es. Os acessos foram avaliados por meio de cortes a 25 cm do n?vel do solo em parcelas de 4,0 m2, com espa?amento de 1 m entre linhas. A partir das an?lises dos resultados, foi poss?vel notar que apenas as caracter?sticas taxa de alongamento de colmo, taxa de alongamento de folha e comprimento final da lamina foram estatisticamente diferentes entre os acessos avaliados. Para taxa de alongamento de colmo o coeficiente de varia??o do ambiente apresentou valor elevado. O coeficiente de varia??o genot?pico da taxa de alongamento de colmo foi o maior entre as vari?veis avaliadas, indicando o potencial de ganho na sele??o para o mesmo. Para o comprimento final da l?mina, foram observados coeficiente da varia??o do ambiente e coeficiente da varia??o genot?pica inferiores ? taxa de alongamento do colmo, contudo, foram obtidos herdabilidade e raz?o CVg/CVe semelhantes. Os coeficientes de varia??o residual e genot?pico da taxa de alongamento foliar foram intermedi?rios em rela??o ?s demais caracter?sticas e assumiram valores pr?ximos, que permitiram a estimativa de uma raz?o CVg/CVe pr?xima da unidade. O alongamento de folhas apresenta maior potencial para ser inserido no processo de avalia??o e sele??o de forrageiras devido a sua alta herdabilidade e raz?o entre os coeficientes de varia??o genot?pico e residual.The experiment was carried out to estimate the genetic parameters of morphogenetic characteristics in Panicum maximum accessions. Were evaluated 17 accessions in a complete block design with three replicate. The accessions were evaluated by cutting at 25 cm from de level soil in plots of 4 m?, with 1 m intercrop. It was possible to note only the stems elongation rate, leaf elongation rate and leaf length were statistically different between the accessions. To stems elongation rate we had high environmental coefficient of variation. In spite of this the genotypic coefficient of variation was also the higher between the characteristics evaluated, indicating potential to reduce this by selection. To leaf length, were observed genotypic and environmental coefficient of variation lower than the stems elongation rate, however were observed similar heritability and genotypic/environmental coefficient of variation rate. The genotypic and environmental coefficient of variation of leaf elongation rate were intermediated between the other characteristics and had next values, so the genotypic/environmental coefficient of variation rate was the higher in the experiment and next from one (0,93). The leaf elongation rate has potential to be included in the process of evaluation and selection of forage plants duly its high heritability and favorable environmental/genotypic coefficient of variation rate