Anatomical and nutritional characteristics of <i>Megathyrsus maximus</i> genotypes under a silvopastoral system

Abstract

Our objective was to measure chemical composition and anatomy of 5 Megathyrsus maximus (syn. Panicum maximum) genotypes, when grown in combination with eucalypts in a silvopastoral system. Cultivars Massai, Mombaça, BRS Tamani, Tanzânia and intraspecific hybrid accession PM44 were evaluated in full sun and a silvopastoral system at 5 different distances from eucalyptus tree rows. The experimental design was a randomized block in split plot with 2 replications. Plots corresponded with genotypes and subplots with sampling points within the system. Total forage and leaf biomass as well as nutritive value und tissue proportions were evaluated. Our results showed a decrease in biomass as radiation incidence decreased. Forage biomass was greatest in BRS Tamani and Mombaça and lowest in PM44. There was a significant interaction between sampling points and genotype for nutritive value variables, such as crude protein, in vitro digestibility of organic matter, cellulose, hemicellulose and lignin-S, while tissue proportions were not affected by the interaction between sampling points and genotypes. Genotype had more pronounced effects on chemical composition and anatomical characteristics than did sampling points. The leaves of Mombaça were the longest and had greatest total cross-sectional area, and this genotype showed greater proportions of sclerenchyma and vascular tissues than other cultivars and the lowest proportion of mesophyll. The greatest proportion of parenchyma bundle sheaths was also found in Mombaça leaves. Genotypes PM44 and Tanzânia had the lowest proportions of sclerenchyma, and PM44 and BRS Tamani had the lowest proportions of vascular tissues. On the other hand, PM44 and Tanzânia had the greatest proportions of mesophyll. BRS Tamani was comparable with the most used cultivars, Mombaça and Tanzânia, and had forage quality slightly superior to that of Mombaça. Tropical grasses growing under shade can potentially produce less forage but with better nutritive value, in terms of chemical composition and tissue proportions, than grasses grown under full sun. However, as the degree of shading in silvopastoral systems does not occur uniformly across the whole area, the improved nutritive value would not be uniform and may not be very prominent overall.

Multivariate and multiharvesting trial for agronomic traits in the genetic resources of guineagrass

“…Likewise, Pereira et al. (2021) and Habermann et al. (2022) reported that the proportions of different tissues within the leaf are correlated with nutritional value and therefore plant height (which in our research showed a heritability of .88) together with leaf width can be considered as base parameters for projecting measurements of leaf tissue and at the same time estimating nutritional content.…”

“…At the same time, it is highlighted that the leaf width of the genus Megathyrsus is reported to be of high heritability (de Wouw et al, 2008). Likewise, Pereira et al (2021) andHabermann et al (2022) reported that the proportions of different tissues within the leaf are correlated with nutritional value and therefore plant height (which in our research showed a heritability of .88) together with leaf width can be considered as base parameters for projecting measurements of leaf tissue and at the same time estimating nutritional content. The relationship between plant height and tolerance of shade showcases that taller accessions tend to have greater adaptation in silvopastoral arrangements (Malaviya et al, 2020) and other environmental consequences that this implies in livestock systems.…”

Production Potential and Quality of Panicum maximum Cultivars Established in a Semi-Arid Environment

“…Similar concentrations of CP and lower concentrations of NDF and ADF (95.7, 570 and 371 g/kg of DM, respectively) were found in studies by Omotoso et al (2020) in the Savanna Zone Nigeria. It was possible to observe that, in general, Panicum maximum cultivars cultivated in environments with less restrictive climatic conditions present a higher forage quality (Tontini et al, 2021;Pereira et al, 2021). Over the studied periods, cvs.…”