Potencial produtivo de Pennisetum spp. sob níveis de nitrogênio na zona da mata de Pernambuco

The productive potential, adaptability and stability were evaluated in 16 Pennisetum spp. genotypes under the influence of four nitrogen levels in six evaluations cycles. The experiment was carried out in 2009, at the Itambe Experimental Station of Pernambuco, Agricultural Research Institute-IPA, Northeast Brazil, in split plots scheme, with four nitrogen (N) levels (control, 30, 60 and 90 kg ha-1 cut-1) and 16 Pennisetum spp. genotypes (G) (10 new interspecific hybrids, one cultivated interspecific hybrid and five elephant grass varieties), in three blocks. The cycles (CI) comprised evaluations in 2010 (04/21, 07/19 and 09/28) and 2011 (01/06, 04/07 and 08/03). The forage mass (MF), the leaf length (CF), the leaf width (LF) and the internode length (CE) were influenced by triple interaction (N x G x CI). The new hybrid, IPA-7 (Pioneiro x IPA Bulk-1), was not influenced by the interaction, presenting high adaptability (b1= 1) and high stability (s2di= 0) for the MF, reaching average of 0.88 kg DM shoot-1 cut-1, 76.24 cm and 78.79 mm for MF, CF and CE, respectively. This hybrid can be selected for the next phase of the Breeding Program of Pennisetum spp.