Forage yield and nutritive value of Panicum maximum genotypes in the Brazilian savannah

Abstract

The narrow genetic variability of grasslands and the incidence of new biotic and abiotic stresses have motivated the selection of new Panicum maximum genotypes for use as forage for beef cattle in the Brazilian savannah. This study aimed to evaluate forage yield and nutritive value of P. maximum genotypes including 14 accessions (PM30 to PM43), four intraspecifi c hybrids (PM44 to PM47) and six cultivars (Aruana, Massai, Milênio, Mombaça, Tanzania and Vencedor), examining 24 genotypes over two years (2003 and 2004). Milênio cultivar was the genotype with the highest dry matter yield (DMY) in both years (18.4 t ha -1 and 20.9 t ha -1 , respectively) although it presented a high proportion of stems (~ 30 %). Genotypes that showed higher Leaf DMY in both years were the accession PM34 (14.7 t ha -1 ) and the hybrid PM46 (14.0 t ha -1 ), while Mombaça and Tanzania yielded 12.5 and 11.0 t ha -1 , respectively. Leaf organic matter digestibility and leaf DMY for PM40 and PM46 genotypes exceeded the mean (> 656 g kg -1and > 11.7 t ha -1 , respectively). For this reason, PM40 and PM46 can be considered promising P. maximum genotypes for use as forage for grazing systems in the Brazilian savannah. IntroductionThe neotropical savannah known as Cerrado, located in the center of the Brazilian territory, presents 49 million hectares of cultivated pastures (Sano et al., 2007). Even though they are quite well adapted to general environmental conditions, their narrow genetic variability makes these pastures vulnerable to novel biotic and abiotic stresses. Examples of this are the emergent sap-sucking insect well-known as the sugarcane spittlebug (Mahanarva spp.), and a syndrome called 'sudden death' that have reached large areas of Marandu grass (Brachiaria brizantha Hochst. ex A. Rich. Stapf.) pastures in the Northern Brazilian territory, with a complex diagnosis usually related to temporarily fl ooded areas (Auad et al., 2010;Caetano and Dias-Filho, 2008). To expand the genetic diversity with highly productive species and to decrease the susceptibility of Brazilian pastures to upcoming stresses, new grass genotypes have undergone assessment by Brazilian research institutions (Sousa et al., 2011, Pessim et al., 2010, Resende et al., 2004.As an alternative to Brachiaria spp., Guinea grass (Panicum maximum Jacq.) has been used for more intensive cattle production systems. It is recommended for regions where annual rainfall ranges from 800 to 1800 mm in well-drained soil and it requires medium to high soil fertility (Muir and Jank, 2004). Tanzania and Mombaça are the most planted Guinea grass cultivars in Brazil, both collected in Africa in the 1960s by ORSTOM (Offi ce de la Recherche Scientifi que et Technique d'OutreMer) and selected by EMBRAPA (Brazilian Agricultural Research Corporation) in the early 1990s. Currently, these two high-sized tufted grass cultivars are responsible for 10 % of the forage seed market in Brazil, but the incidence of the leaf fungus Bipolaris maydis (Nisik. Schoemaker) has reduced their deman...

IDENTIFICATION OF IDEOTYPES BY CANONICAL ANALYSIS IN Panicum maximum

“…These results suggest that the P. maximum cultivars available in the market are not the most suitable for use in animal production systems in the Agreste, supporting the desirability of studies aimed at identifying forages adapted to the region. The highest LDM yield for PM34 was also observed by Fernandes et al (2014) evaluating the same genotypes in the Brazilian savannah. According to these authors, P. maximum is well suited to the soil and climate conditions of savannahs.…”

“…is the most productive seed-propagated forage species available, and is an excellent option for diversifying and intensifying the use of Brazilian pastures Valle, 2008). In view of its high productivity, studies investigating the adaptation of this crop species to the Agreste region could indicate accessions and/or cultivars for use in the region.…”

Effects of nitrogen fertilization and cutting intensity on the agronomic performance of warm‐season grasses

“…Megathyrsus maximus cultivars are mainly used in intensive cattle systems in Brazil, and M. maximus is a high‐yielding species (Fernandes et al ., ). The herbage accumulation of M. maximus in the current study was similar to that reported by Fernandes et al .…”

“…The herbage accumulation of M. maximus in the current study was similar to that reported by Fernandes et al . (, ~12 t ha −1 ), who compared the herbage accumulation of 24 genotypes of M. maximus . These authors highlighted that the productivity of M. maximus cv.…”

Morphological characteristics, nutritive quality, and methane production of tropical grasses in Brazil

“…Brachiaria) is the most dominant, representing 50% of pastures of the country because of its remarkable adaptability and productivity in tropical climate conditions (Cabral et al, 2014;Demarchi et al, 2016). However, despite being more challenging and demanding for soil fertility, the use of Megathyrsus maximus is increasing as an option to forage grass due to its high-leaf production and nutritional value, factors that may allow the achievement of a superior animal performance (Fernandes et al, 2014).…”