Erinaldo Viana de Freitas

Produtividade e composição química de gramíneas tropicais na Zona da Mata de Pernambuco

This work was carried out to evaluate the productive potencial and chemical composition of five grasses (Pennisetum purpureum Schum. cv. Pioneiro, P. purpureum Schum cv. Mott; Panicum maximum Jacq. cv. Mombaca, P. maximum Jacq cv. Tanzânia, e Brachiaria brizantha (Hochst) Stapf. cv. Marandu). The cuts were performed at 35 days of intervals and 40 cm above ground. Pioneiro showed higher DM yield (7.35 t DM/ha/35 days) when compared to the Dwarf Elephantgrass (5.28 t DM/ha/35 days) and Tanzânia grass (5.23 t DM/ha/35 days), being similar to the others. Brachiaria brizantha presented the highest total tillering (538.72/m²) however the aerial tiller weight was the lowest for this species. The cultivars of P. purpureum showed higher aerial tillering and lower basal tillering, when compared to the cultivars of P. maximum. The CP concentration ranged from 6.96 to 10.20% and the cultivar Pioneiro presented the highest value. No difference was found among the forages for NDF and ADF, and the mean values were 73.83 and 39.20%, respectively. At the evaluated cut interval, the forages presented a high proportion of leaves (> 80%), showing potential to be used on livestock pasture-based operations in the Forest Zone of Pernambuco.

Caracterização e Seleção de Clones de Capim-Elefante (Pennisetum purpureum Schum.) na Zona da Mata de Pernambuco

This work aimed to characterize an elephantgrass collection (Pennisetum purpureum Schum.) comprising 71 clones and selecting the best ones to be tested later under grazing conditions. It was carried out at Cedro Experimental Station - IPA, located in Vitoria de Santo Antao, forest zone of Pernambuco State. The period of evaluation included both the raining and the dry season. Each clone was represented by a non-replicated plot of 10 m2. According to linear correlation analysis, the more productive clones also showed highest plant height and highest growing point height, greatest stem diameter, highest stem/leaf ratio, highest basal and total tiller numbers and greatest leaf lenght. The same characteristics above were also positively correlated with the leaf blade yield, except stem/leaf ratio. There was a high correlation coefficient (r = 0.9517) between dry matter yield and leaf blade yield. The selection of clones to be tested under grazing conditions was based on the materials that showed the highest leaf blade yield. These materials were: Mineirao/IPEACO, Hexaploide, Mole de Volta Grande, King Grass, 591-76 or Cameroon, CE 5 AD, Gigante de Pinda, CE 4 AD, Elefante da Colombia and Vrukwona

Variability and heritability of morphologic characters in elephant grass clones in the Forest Zone in Pernambuco

Esta pesquisa foi realizada para avaliar a variabilidade e herdabilidade de caracteres morfologicos de 54 clones de capim-elefante na Zona da Mata de Pernambuco (tres testemunhas locais e os demais provenientes da RENACE/CNPGL). Utilizou-se delineamento em blocos casualizados com testemunhas adicionais. Foram realizados tres cortes de avaliacao aos 60 dias de crescimento. Houve diferencas significativas para diâmetro de colmo, densidade de perfilhos basais e aereos, largura da folha 3, comprimento da folha 5, porcentagem de lâminas foliares, porcentagem de colmo e relacao lâmina foliar/colmo. Os clones da RENACE sao semelhantes aos tradicionalmente cultivados nas condicoes da Zona da Mata de Pernambuco quanto a maioria dos caracteres morfologicos. A cultivar Pioneiro floresceu precocemente nas condicoes ambientais deste estudo. As caracteristicas numero de perfilhos basais e aereos/metro apresentaram alta herdabilidade, o que evidenciando pouca influencia do ambiente na variabilidade entre clones. Considerando a variabilidade entre os clones da RENACE para numero de perfilhos basais e aereos/metro e relacao folha/colmo e a alta herdabilidade desses caracteres, e possivel obter ganhos geneticos para essas caracteristicas no melhoramento do capim-elefante na regiao da Zona da Mata de Pernambuco.

Use of morphologic descriptors and trait heritability in dwarf elephant grass clones

The experiment was carried out with the objectives to evaluate the use of morphologic descriptor in the characterization and selection of dwarf elephant grass genotypes, and to evaluate the heritability of the evaluated traits. Nine dwarf elephant grass clones were used (Taiwan A.146 - 2.14, Taiwan A.146 - 2.27, Taiwan A.146 - 2.37, Taiwan A.146 - 2.114, Merker Mexico - 6.2, Merker Mexico - 6.5, Merker Mexico - 6.31, cv. Mott, and CNPGL92F198.7) was allotted to a randomized complete block design was used with three replications. The morphologic descriptors were applied every 60 days after the staging cut. A total of five cuts were performed at 60-day intervals using a height of 10 cm from ground level. Among the evaluated dwarf elephant grass clones the tallest ones were more desirable, and this trait should be considered at the moment of selection. Heritability estimate was high for all evaluated traits of dwarf elephant grass, varying from 66% for sheath wax to 100% for mid-rib color. The Taiwan A.146 - 2.37 clone was similar to the Mott cultivar. Heritability values showed genetic variability among clones, detected at 60 days regrowth. Some of the used morphologic descriptors allowed characterization of the evaluated genotypes. The clones Taiwan A. 146-2.27, Taiwan A. 146-2.37, Taiwan A. 146-2.114, and Merker Mexico 6.31 were the tallest and showed greater total tillering intensity, and were more desirable, presenting greater potential for use under cutting.

Association between the morphological and productive characteristics in the selection of elephant grass clones

The objectives in this work were to study the association between the morphological and productive characteristics in Pennisetum sp. clones, and to identify the morphological characteristics responsible for the productivity in Pennisetum cp. clones. The canonical correlations were evaluated and the path analysis was made from the simple genotypic correlation matrix between the morphological and productive characteristics of eight Pennisetum sp. clones (Taiwan A-146 2.37, Taiwan A-146 2.27, Taiwan-146 2.114, Merker Mexico MX 6.31, Mott, HV-241, Elefante B and IRI-381). The canonical correlations were significant at 1% probability by the Chi-square test. The first pair of canonic factors, with correlation of 0.9999, related the plants with the highest dry matter content to plants with lower leaf area indexes, light perception and leaf angle. The second pair of canonic factors, with correlation of 0.9999, related the plants with the highest dry matter production to the plants with higher basal tiller density, height, and low green leaf number per tiller. The results of the path analysis indicated that the light interception is determinant in dry matter content expression of Pennisetum sp. clones, while the basal tiller density and plant height are responsible for dry matter production in these clones.

Análise de trilha em caracteres produtivos de Pennisetum sob corte em Itambé, Pernambuco

This work aimed to estimate the correlation coefficients, determining the direct and indirect effects (path analysis) of explanatory independent variables on total dry matter production (main dependent variables) of five elephant grass clones in five cuts accomplished at the forest zone of Pernambuco. Each experimental plot measured 24 m2 with 2 m2 of utile area. There was high correlation between almost all the independent variables and the main variable. The characteristic leaf blade number per tiller, however, explained better the potential of dry matter production and leaf blade dry matter production, acting, respectively, in a direct and indirect way on the explanatory variables.

Deposição e composição química de serrapilheira em um bosque de sabiá

This research aimed to evaluate the deposition and chemical composition of the components of the existing and deposited litter in a sabia (Mimosa caesalpiniifolia Benth) canopy. The experiment was carried out from August 2006 to July 2007. The evaluation of the existing and deposited litter was performed every 28 days using 20 squares with 1m2 randomly allocated and new areas were chosen for each evaluation. The canopy showed plants with an average diameter of 26.8 cm at breast height. Monthly deposition of organic matter of leaves and branches during the experimental period was 15,167 kg and 3,373 kg/ha, respectively, and it increased during the highest precipitation period, in a 0.30 relationship with the accumulation, indicating higher accumulation than deposition. Leaf proportion was 87% of the total litter, with means of 2.9% of nitrogen and 0.17% of phosphorus. The carbon/nitrogen ratio of leaves was below 30, while carbon/nitrogen ratio of the branches ranged from 30 to 40, proving a better quality for leaves. During the experimental period, deposition of nitrogen through litter was approximately 462 kg/ha and 30 kg/ha for phosphorus. Litter deposition is essential for maintenance of soil fertility in a sabia canopy and it contributes for conservation and sustainability of the canopy.

Decomposição de serrapilheira em bosque de sabiá na Zona da Mata de Pernambuco

The research aimed to evaluate the decomposition of sabia (Mimosa caesalpiniifolia Benth) litter fractions by using the nylon bag technique. The following litter fractions were incubated: senescent leaves, leaves at the beginning of mineralization, and branches with diameter up to 20 mm. Incubation was performed during periods of 0, 4, 8, 16, 64, 100, and 256 days in 2006 and 2007. The fractions were distributed in a random block design with five replications. It was evaluated the disappearance of biomass, nitrogen (N), and phosphorus (P), concentrations of nitrogen and phosphorus and the carbon/ nitrogen ratio of litter during the periods of incubation. In general, the negative exponential model explained the disappearance of biomass, nitrogen, and phosphorus, however, there was a variation among years and, in some cases, despite of being significant, the models showed a low correlation between predicted and observed data. Biomass disappearance rate was slow because only 30% of leaf biomass was mineralized after 256 days of incubation. Net nitrogen mineralization showed large variation among years, and it differed among the studied fractions. Nitrogen content of the litter increased, on average, until 32 days (leaves) and until 64 days (branches) of incubation followed by stabilization. The linear plateau model was used to explain that process. In the course of the incubation periods, the carbon/nitrogen ration decreased. Despite of the high content of nitrogen, the decomposition of sabia litter is slow, what might reduce the loss of nutrients in the forest, increasing its sustainability and reducing the possible deleterious effects to the environment.

Ensaios preliminares sobre autofecundação e cruzamentos no melhoramento do capim-elefante

The objectives of this work were to evaluate the self-pollination as a tool in the elephantgrass (Pennisetum purpureum) breeding and to compare progenies of Pennisetum purpureum origined from different breeding strategies: self-pollination, intraspecific crossbreeds, and interspecific crossbreeds with Pennisetum glaucum. The experimental treatments were represented by the three fecundation forms: intraspecific crossbreed, interspecific crossbreed and self-pollination. A total of ten families originated from intraspecific crossbreed resulting in 160 progenies; two families originated from interspecific crossbreed resulting in 38 progenies, and two families originated from self-pollination resulting in 40 progenies, was evaluated. The evaluated traits were dry matter production (kg/tussock), dry matter concentration (%), plant height (m), number of basal tillers (n./tussock) and survival index (%), in two evaluations and non-replicated plots. The intraspecific crossbreed, interspecific crossbreed and self-pollination presented average dry matter production of 0.47, 0.78, and 0.46 kg of DM/tussock, at first evaluation and 0.14, 0.23, and 0.22 kg of DM/ tussock, at second evaluation, respectively. This indicates the necessity of plot replication to separate the environmental effect from the genetic effect. The interspecific crossbreed showed potential to generate progenies with satisfactory dry matter concentration which is more appropriated for ensiling. The treatments showed potential to release variability of traits evaluated through vegetative propagation, however, the low survival index of self-pollinated progenies reduces the probability of obtaining pure lines of elephantgrass.

Genótipos de capim-elefante sob pastejo no período de seca na Zona da Mata de Pernambuco: fatores relacionados à eficiência de pastejo

The experiment was carried out to evaluate factors related to the grazing efficiency of five Pennisetum sp. genotypes (CE 08 A.D., Venezuela, HV-241, Elephant B and Hexaploide) during the dry period in the Forest Zone of Pernambuco. Genotypes were managed under rotational stocking (44 days of resting and four days of grazing period). It was used a split-plot arrangement in a complete randomized block design (genotypes represented the plots; grazing cycles, the subplots). Six replications were used to determine pre-grazing total leaf blade mass and green and senescent leaf blade mass. Four replications were used for leaf blade accumulation and grazing efficiency and, for these variables, it was used a complete randomized blocks design. The CE 08 A.D. and Elephant B presented greater pre-graze total leaf blade mass, green leaf blade, green leaf blade accumulation, and grazing efficiency, with averages of 1,374 kg DM/ha, 737 kg DM/ha, 654 kg DM/ha/44 days and 80% of the green leaf blade accumulation, respectively. The highest grazing efficiency (100% of the green leaf blade accumulation) occurred at the HV-241 pastures. This high grazing efficiency was associated to the low green leaf blade accumulation (155 kg of MS/ha/44 days). The lowest grazing efficiency was observed for the Hexaploide (59% of the green leaf blade accumulation), possibly due to high losses under grazing (30% of the pre-grazing total leaf blade mass). The green leaf blade mass decreased mostly until the second grazing day, while the losses of total leaf blade were higher in the second and third grazing days. The genotypes CE 08 A.D. and Elephant B presented potential to be used under rotational stocking, in the Pernambuco Forest Zone.