Abstract Pennisetum purpureum Schum. has been a key alternative as an energy source in Brazil because of its higher dry matter accumulation and fiber content. This research aimed to select superior individuals of P. purpureum for energy purposes using among-and-within family selection. The study was carried out in Campos dos Goytacazes- RJ (Brazil), using eight full-sib families. Plants were individually assessed during two pasture cuttings, one in 2014, and another in 2015. The dry matter production (DMP) was correlated with the number of tillers, stem diameter, plant height, and neutral detergent fiber content. Plant selection criteria in both cuts were through direct and indirect selections, and Smith and Hazel index. A joint analysis of variance showed significant differences for all five traits assessed in both cuts. The results achieved with Smith and Hazel index were promising for simultaneous selection of the evaluated traits, favoring selection of superior families and individuals them.

RESUMO A bacia do rio Natuba é um importante polo de produção de hortaliças para o abastecimento, sobretudo, da zona metropolitana do Recife. O planejamento racional do uso das terras nesta bacia se faz necessário para assegurar a conservação deste recurso. Este trabalho objetivou realizar o zoneamento da aptidão agrícola das terras do médio curso da bacia do rio Natuba - PE, considerando o emprego da média (manejo B) e alta (manejo C) tecnologias. A análise baseou-se nos critérios: deficiência de fertilidade, deficiência de água, excesso de água, suscetibilidade à erosão e impedimentos à mecanização. Os resultados indicaram que as formas de uso conservacionistas, mais recomendados são a pastagem plantada e lavouras, de forma restrita, no manejo B. A possibilidade de utilização do solo no manejo C se restringe à unidade dos Latossolos, posicionada em áreas de topo, e dos Gleissolos no ambiente de várzea. O uso atual praticado na área de estudo, somente, em parte está em conformidade com a aptidão agrícola das terras. Nas encostas íngremes, o uso intensivo com agricultura irrigada, está em desacordo com o potencial de uso agrícola. Técnicas de manejo que visam à utilização do solo de modo conservacionista devem ser implantadas em toda área.

ABSTRACT The basin of the river Natuba is an important vegetable production polo for supplies, especially to the metropolitan area of Recife. Rational planning of the land use in the basin is needed to ensure the conservation of this resource. This study aimed to carry out the zoning of the agricultural potential of the land in the middle course of the river Natuba basin - PE, considering the average (management B) and high (management C) technologies application. The analysis was based on the criteria: fertility deficiency, water deficiency, excessive water, susceptibility to erosion and impediments to mechanization. The results indicated that the most recommended conservationist ways of land use are planted crops and pasture, narrowly, in the management B. The possibility of land use in management C is limited to the unit of Latosols located in top areas, and Gleysols in the environment of floodplain. The current use practiced in the studied area complies only partly with the agricultural potential of the land. On the steep slopes, the intensive irrigated agriculture doesn't combine to the agricultural potential use. Management techniques related to conservationist ways of soil use should be deployed throughout the area.