Avalia??o agron?mica e bromatol?gica de h?bridos de milho submetidos a espa?amentos e densidades populacionais

• Ano de defesa: 2020
• Autor(a) principal: Lima, Lorhaine Bernardes de
• Orientador(a): Almeida, Jo?o Carlos de Carvalho
• Banca de defesa: Almeida, Jo?o Carlos de Carvalho, Abreu, Jo?o Batista Rodrigues de, Camargo Filho, S?rgio Trabali
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal Rural do Rio de Janeiro
• Programa de Pós-Graduação: Programa de P?s-Gradua??o em Zootecnia
• Departamento: Instituto de Zootecnia
• País: Brasil
• Palavras-chave em Português: Arranjo espacial; Composi??o qu?mica; Silagem; Valor nutricional; Zea mays L.; Chemical composition; Nutritional value; Silage; Spatial arrangement
• Área do conhecimento CNPq: Zootecnia
• Link de acesso: https://tede.ufrrj.br/jspui/handle/jspui/6255

The objective of the study was to evaluate agronomic characteristics and chemical composition of two maize hybrids, Santa Helena (2B339) and Biomatrix (BM3061) submitted to two spacing (45 and 90 centimeters) and four population densities (60,000, 70,000, 80,000 and 90,000 plants ha-1). The design was in randomized blocks in a 2x4x2 factorial scheme, with four replications. Production of green mass (MV), dry matter (MS), plant height, stem diameter, ear corn insertion height, ear length and diameter, number of ears corn per plant, proportion of leaf, stem and ear corn components were estimated) and bromatological MS, ash (MM), crude protein (PB), neutral detergent fiber (FDN), acid detergent fiber (FDA), cellulose (CEL), hemicellulose (HEM) and lignin (LIG). From the hybrid BM3061, silages were made with the spacing and population densities as treatment, outlined in randomized blocks and in a factorial scheme two (spacing) x four (densities), with four replications. Levels of MS, MM, PB, FDN, FDA, CEL, HEM and LIG were also determined. The data set was analyzed with SISVAR? and the means compared by the Tukey test at 5% probability and by regression for population density data. The MS productivity was higher at the highest densities 90,000, 80,000 and 70,000 plants ha-1 (4,855.99; 4,275.22; 4,138.08 kg ha-1 MS). The number of ears corn per plant was higher at lower densities due to less competition for nutrients and solar radiation and in the BM3061 hybrid. The proportions of leaf and stem were higher in BM3061 and that of ear corn in 2B339. There was a hybrid ? density ? spacing interaction (p = 0.020) for the leaf proportion where BM3061 was superior to 2B339 when cultivated with 90 cm spacing and at densities of 70,000 and 80,000 plants ha-1. There was density x hybrid interaction for the length of ears corn (p = 0.01). The highest length (27.81 cm) occurred for the hybrid BM3061 planted with a density of 70,000 plants ha-1. The leaf stalk relationship did not differ between treatments. The ear diameter was larger in the 2B339 (5.34 cm), possibly due to the better filling of the grains. In the pre-ensiled material, the MS content was higher in 2B339 (38.04%) and the contents of FDN, FDA, CEL and LIG were higher in BM3061 (55.4; 27.20, 20.64 and 5.06%). In addition, there was density x hybrid interaction for LIG, with greater value for BM3061 at density of 80,000 plants ha-1. For silage evaluations, the pH varied as a function of densities, with a higher value for 70,000 plants ha-1 (3.6562), which may indicate an adequate fermentation process. There was no significant difference between MS (p=0,56), MM (p=0,11) and PB (p=0,70), however the values of FDN, FDA, CEL, HEM were higher in the 45 cm spacing (52.68; 27.21; 21.66; 25.47%), respectively. However, it is concluded that the hybrid 2B339 proved to be superior in the conditions presented when destined for corn silage, the reduction in spacing between lines negatively affects bromatological characteristics of the silage.