Allan Kardec Braga Ramos

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

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 intraspe- cifi c hybrids (PM44 to PM47) and six cultivars (Aruana, Massai, Milenio, Mombaca, Tanzania and Vencedor), examining 24 genotypes over two years (2003 and 2004). Milenio 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 Mombaca and Tanzania yielded 12.5 and 11.0 t ha -1 , respectively. Leaf organic mat- ter digestibility and leaf DMY for PM40 and PM46 genotypes exceeded the mean (> 656 g kg -1

Forage yield and nutritive value of Arachis spp. genotypes in the Brazilian savanna.

Forage yield, nutritive value, ground cover and mineral concentration of 10 genotypes of Arachis spp. were evaluated over 3 years in Planaltina, Federal District, Brazil. Experimental plots were arranged in a randomized complete block design with 4 replications. Treatments were 5 genotypes of A. pintoi (accessions 2, 4, 5, 6 and 8), 2 genotypes of A. repens (accessions 1 and 7), 1 hybrid A. pintoi × A. repens (accession 3) and 2 A. pintoi cultivars, BRS Mandobi and Belmonte. All genotypes established well and achieved good ground cover in the first year. Cultivar Belmonte and accessions 2 and 4 produced the highest DM yields (means of 8.8, 8.5 and 8.8 t DM/ha/yr, respectively) throughout, while cv. BRS Mandobi and accession 6 were the worst (5.7 and 5.6 t DM/ha/yr). Most genotypes maintained ground cover above 80% throughout the study but cv. BRS Mandobi plus accessions 6 and 8 had declined to 60% or less by the third year. Mean crude protein concentration overall was 166 g/kg with a range of 154‒182 g/kg among genotypes. There was no major genotypic variation in mineral concentrations, which in all cases were considered marginal to adequate for tropical forage legumes. In conclusion, genotypes 2 and 4 (accessions BRA-039799 and BRA-039187, respectively) of A. pintoi are considered the most promising forage peanut options under the edaphoclimatic conditions of the experimental site. More effort is needed to improve seed set in these accessions to increase adoption by farmers. Their persistence under grazing and impact on production should also be demonstrated. Keywords : Arachis pintoi , Arachis repens , crude protein, digestibility, minerals.