Correlação e análise do coeficiente de trilha dos componentes do rendimento de sementes de grama-forquilha

Abstract

RESUMO -Objetivou-se com este trabalho, por meio de uma análise de trilha para rendimento de sementes de gramaforquilha (Paspalum notatum Flügge var. notatum), obter informações básicas para utilização em estratégias de manejo para maior produção de sementes e, consequentemente, maior ressemeadura natural, proporcionando, assim, condições para maior persistência da espécie na pastagem. Foram analisadas as seguintes variáveis: número de perfilhos vegetativos, número de perfilhos reprodutivos, número de racemos/inflorescência, número de sementes/inflorescência, peso de mil sementes e rendimento de sementes. A variável que mais se correlacionou com o rendimento de sementes foi o número de perfilhos reprodutivos (r = 0,94), e essa correlação se deu praticamente apenas pelo efeito direto dessa variável. Entre as demais variáveis, destacou-se o número de perfilhos vegetativos, com coeficiente de correlação de -0,83 e efeitos indiretos sobre os demais componentes do rendimento de sementes. O número de perfilhos reprodutivos parece ser a principal característica a ser considerada na busca de maior produção de sementes de Paspalum notatum.Palavras-chave: componentes do rendimento de sementes, perfilho reprodutivo, perfilho vegetativo, peso de sementes Correlation and path coefficient analyses of seed yield components in the bahia grass (Paspalum notatum Flügge var. notatum)ABSTRACT -The objective of this work was, through a path analysis of seed yield in Paspalum notatum, to obtain basic information for using in management strategies to improve seed production and consequently, high natural reseeding and a better persistence of the species in the pasture. The following variables were analyzed: number of vegetative tiller, number of reproductive tiller, number of raceme/inflorescence, number of seeds/inflorescence, weight of 1000 seeds and seed yield.The most correlated variable with seed yield was the number of reproductive tiller (r = 0.94), and this occurred because its direct effect. Among the other variables, number of vegetative tiller also had a high correlation coefficient (r = -0.83) and indirect effects on the other components. The number of reproductive tiller seems to be the main characteristic to be considered when searching for a higher seed production in Paspalum notatum. IntroduçãoInúmeros acessos de Paspalum notatum têm sido incorporados a experimentos agronômicos, devido ao bom valor forrageiro, à rapidez de estabelecimento e a uma densa cobertura do solo. Steiner (2005), testando genótipos de P. notatum nativos do Rio Grande do Sul, obteve expressivos valores de produção de matéria seca total (MST), próximas a 14.000 kg de MST/ha, provando o potencial produtivo desta espécie nativa, chegando a níveis de produção próximos de cultivares de espécies tropicais introduzidas (Cecato et al., 2000).A utilização da semente, como veículo de propagação de espécies forrageiras, representa importante marco no desenvolvimento da pecuária nacional, ao promover uma rápida disseminação de novos materiais. A produtivida...

Emergence of Razor Grass on the Basis of Origin and Seed Depth in the Soil Profile

“…Carmona et al (1999) found variation of up to 44% in the TSW of species of the genus Paspalum collected in two separate years; the authors attribute the difference between the lots to the proportion between full and empty seeds. Importantly, the TSW values found in the ecotypes Cacoal and Redenção are similar to the values reported by Lopes and Franke (2011b) for the species P. notatum, ecotypes André da Rocha and Bagual, with mean TSW values of 1,640 g and 2,290 g, respectively.…”

Management of consecutive cuts in the production and quality of wintergreen paspalum seeds

“…These two variables showed the same behavior for germination and the decrease of the vigor of the seeds can be explained in the same way as the as the germination variable. Studies evaluating the production of seeds of a certain kind of species always seek, in a way, to identify, quantify, and correlate the production components with the production itself (Lopes and Franke, 2011a). Through correlation analysis, we note that some variables presented significant correlations, both positive and negative, with PROD in P. guenoarum, demonstrating that they somehow influenced the expression of this variable (Table 5).…”

“…The number of reproductive tillers is one of the most important and crucial components of forage grass seed productivity and, therefore, the management should be focused on favoring this component. The strong association of this component with seed yield was proven in Urochloa (Quadros et al, 2010), Paspalum urvillei (Lopes and Franke, 2011a), Paspalum notatum (Lopes and Franke, 2011b), and Panicum maximum (Canto et al, 2012) and even serves as an indicator for breeding programs that seek to produce seeds of forage species (Biligetu et al, 2012). According to Souza (2001), the increased production of reproductive tiller requires a greater number of inflorescences and, therefore, higher final seed yield.…”

“…Although it demonstrated excellent results regarding the production and quality of the forage, its diffusion is limited by the scarce availability of seeds in the market and their low quality (Pinto, 1982). According to Lopes and Franke (2011a), the production of high-quality seeds is a complex process and is conditioned by management practices, environmental factors, and genetic factors.…”

Genetic gain in apomictic species of the genus Paspalum

“…Therefore, path analysis comes up as a complementary technique indicating the true associations of cause and effect on the main variable of interest. This procedure aims to measure the true relationships such as in the components of grain yield of grain species (Lopez & Franke, 2011;Krüger et al, 2011), as well as forage species (Silva et al, 2008;Borges et al, 2011).…”