ABSTRACT. This study investigated whether genotype influences the establishment of Pennisetum purpureum Schumach. The experimental design was a randomized complete blocks with four treatments and eight replications (n=8). The treatments were four genotypes of P. purpureum, two classified as tall sizes: P. purpureum cv. Elephant B and cv. IRI 381; and two as dwarf types: P. purpureum cv. Mott and Taiwan A-146 2.37. They were planted in a tropical wet and dry region of Brazil. Tall genotypes showed superior field sprouting rates (p < 0.05), ranging between 95-99%, while dwarfs varied between 88-90%, however, Elephant B and IRI 381 produced a much lower average number of tillers (31 and 32 linear m-1, respectively), than Taiwan A-146 2.37 and Mott (56 and 41 linear m-1, respectively) (p < 0.05). Dwarf genotypes produced lower biomass yields (p < 0.05), but this was genotype-dependent and did not impact on their establishment. The levels of non-structural carbohydrates (NSC) (>10%) in the planted stems were associated with satisfactory field sprouting of the elephantgrass genotypes. Despite some variations between the genotypes in terms of sprouting, tillering, and growth rates, the kind of genotype had no major significance on the establishment of the elephantgrass.

RESUMO As concentrações de tanino condensado (TC) nas plantas são influenciadas por espécies, parte da planta, estação do ano, fase de crescimento, condições ambientais, doenças e desfolhação. O objetivo deste estudo foi determinar o efeito dos fatores edafoclimáticos na concentração de TC armazenados em folhas e casca de Mimosa tenuiflora (Wild.) Poiret e Anadenanthera macrocarpa (Benth.) Brenan., coletados em três locais distintos no Nordeste do Brasil. Em cada local de estudo, a amostragem foi realizada selecionando-se aleatoriamente cinco árvores, cada árvore representou uma repetição e amostras de folhas e casca de cada espécie de planta foram coletadas. Amostras de solo foram coletadas próximo da base de cada planta para análises físicas, químicas e de umidade. Os dados meteorológicos de cada mês e local foram obtidos em estação automática do INMET. Realizou-se uma análise de componentes principais usando uma técnica multivariada para observar a influência do solo e do clima na concentração de tanino condensado. No geral, Anadenanthera macrocarpa apresentou a menor concentração total de TC em todas as frações e locais de coleta. Estes resultados sugerem que as características químicas do solo, a umidade do solo e as variáveis meteorológicas explicam 76.27% and 75.92% da variação do TC produzido por Mimosa tenuiflora e Anadenanthera macrocarpa, respectivamente. A concentração de tanino condensado nestas duas espécies está negativamente associada à umidade do solo e à precipitação, e positivamente associada à temperatura e aos elementos químicos do solo.

ABSTRACT Condensed tannin (CT) concentrations in plants are influenced by species, plant part, season, growth phase, environmental conditions, disease and defoliation. The objectives of this study were to determine the effects of edaphoclimatic factors on the concentration of CT stored in leaves and bark from Mimosa tenuiflora (Wild.) Poiret and Anadenanthera macrocarpa (Benth.) Brenan., collected at three distinct locations in northeastern Brazil. At each study site, sampling was carried out by randomly selecting five trees, each tree represented one replication and samples of leaves and bark of each plant species was collected. Soil samples were collected near the base of each plant for moisture, physical and chemical analysis. Meteorological data from each month and site were obtained of the INMET automatic station. We conducted a principal components analysis using a multivariate technique to observe the influence of soil and weather on condensed tannin concentration. Overall, Anadenanthera macrocarpa has the least total CT concentration in both plant fraction and site. Our results suggest that soil chemical characteristics, soil moisture and weather explain 76.27% and 75.92% of the variation in CT produced by Mimosa tenuiflora and Anadenanthera macrocarpa, respectively. Condensed tannin concentration in these two species is negatively associated with soil moisture and rainfall, and positively associated with temperature and soil chemical elements.