Correlações e análise de trilha em capim-elefante para fins energéticos

Abstract

RESUMOPor sua elevada produção de matéria seca, o capim-elefante tem sido utilizado como fonte de energia renovável. A seleção para a melhoria de características pode influenciar na produção de matéria seca, razão por que se torna necessário o estudo da correlação entre essas características. Assim, os objetivos deste trabalho foram avaliar os coeficientes de correlação e os desdobramentos das correlações genotípicas em efeitos diretos e indiretos das variáveis, como altura das plantas, diâmetro do colmo, número de perfilhos e largura da lâmina foliar na produção de matéria seca em clones de capim-elefante. O experimento foi conduzido em Campos dos Goytacazes-RJ, utilizando-se quarenta genótipos de capim-elefante. O delineamento utilizado foi em blocos ao acaso, com duas repetições. Nos dois cortes avaliados as características de altura da planta, diâmetro do colmo e largura da lâmina foliar apresentaram correlação genotípica positiva e significativa, com a produção de matéria seca. A altura da planta foi a que mais influenciou, direta e positivamente, a produção de matéria seca durante o segundo corte. Já no terceiro corte isto ocorreu para as características diâmetro do colmo e número de perfilhos. Palavras-chave: biomassa, melhoramento de plantas, Pennisetum purpureum Correlations and path analysis in elephant grass for energy ABSTRACTThe elephant grass for its high dry matter production has been used as a source of renewable energy. The selection for the improvement of traits could influence the production of dry matter and therefore it is necessary to study the correlation between these traits. The objectives of this study were to evaluate the correlation coefficients and display genotype correlations into direct and indirect effects of variables such as plant height, stem diameter, number of tillers and leaf blade width in dry matter production in clones of elephant grass. The experiment was conducted in Campos dos Goytacazes-RJ, using forty genotypes of elephant grass. The design was a randomized block with two replications. Evaluated in two cuts, plant height, stem diameter and width of the leaf blade showed positive and significant genotypic correlation with dry matter production. Plant height was the most directly and positively influenced the dry matter production during the second cut. In the third section, it occurred to the characteristics stem diameter and number of tillers.

Effect of nitrogen and potassium fertilizations on elephant grass genotypes used for energy purposes in Northern Rio de Janeiro State, Brazil

“…The highest height (3.50 m) was found in the G5 genotype (Cameroon) at dose K1N3 in the first cut. The H trait was important because it was directly correlated with dry matter production (Xia et al, 2010;Menezes et al 2014). These values are different from those found by Oliveira et al (2015a), who found mean H 3.54 m when they assessed six genotypes of elephant grass grown under increasing N doses and cut at 9 months of age in Campos dos Goytacazes -RJ.…”

“…Oliveira et al (2013) Daher et al (2004), the NT trait has direct effect on DMP, and it is highly desirable in genotypes used in bioenergy production. Menezes et al (2014) found direct positive correlation between NT and DMP, and indirect positive correlation between H and DMP. Thus, when the aim is to increase the DMP, as in the case of the elephant grass used to increase biomass energy, it is possible to select high-tillering plants, because they may have increased H and, consequently, high DMP.…”

Comparison of stability methods in elephant-grass genotypes for energy purposes

“…In the study conducted by Oliveira et al (2014), Pennisetum purpureum genotypes at 12 months of age showed significant differences at 1% probability for dry matter yield. Menezes et al (2014) also found significant differences in dry matter yield in 40 genotypes of P. purpureum. The experimental coefficients of variation ranged from 24.98 to 36.53%, because dry matter yield is a quantitative trait largely influenced by the environment.…”

Genetic diversity of elephant grass (Cenchrus purpureus [Schumach.] Morrone) for energetic production based on quantitative and multi-category traits

“…The stem diameter is also negatively correlated with the ash content; i.e., as the diameter is reduced the percentage or ash increases, which is desirable in elephant grass for energy biomass production (Rossi et al, 2014). In a study conducted by Menezes et al (2014), who evaluated elephant-grass genotypes, the authors observed that plant height was the variable that most influenced the trait DM yield in one of the harvests for evaluation, followed by stem diameter and number of tillers.…”