Caracterização de híbridos e associação entre caracteres para produção de silagem em milho

• Autor(a) principal: Ciappina, Angelina Luzia
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• dARK ID: ark:/38995/001300000dp7q
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/9996
• topic: Zea mays L.; Adensamento populacional; Correlação genética; Análise de trilha; Correlação canônica; Zea mays L.; Population density; Genetic correlation; Path analysis; Canonical correlation; CIENCIAS AGRARIAS

The corn hybrids available on the market do not have all the desired traits for making silages with good nutritional value and high productivity. To carry out an improvement breeding program achieve these objectives, it is necessary to characterize the genotypes that can form the base populations of the programs and to understand the interrelationship between the various characters of interest to draw up the best strategies improvement. The objectives of the present work were: i) to perform the agronomic and bromatological characterization of maize hybrids, aiming at the identification of superior genotypes that may comprise base populations of maize breeding programs for silage; ii) to study the interrelationship between characters agronomic and bromatological conditions in maize. Twenty one commercial maize hybrids were evaluated at the Escola de Agronomia da Universidade Federal de Goiás, Goiânia-GO, in the 2017/18 harvest, in two experiments, using the conventional planting density of 55,500 plants.ha -1 , and with a density of 111,000 plants.ha -1 . The experimental design was a randomized complete block with three replications, of a 4.00 m line with twenty plants spaced at 0.20 m. The line spacing was 0.90 m for the standard density and 0.45 m for the densified experiment. The evaluated characters were: male flowering; female flowering; range of flowering; plant height; ear height; ear placement; kernels per ear; number of grains per row; ear diameter; corncob diameter; grain length; ear length; ear weight; weight of one hundred grains; acidity (pH); dry matter content; mineral content; organic matter content; crude protein; neutral detergent fiber (NDF); acid detergent fiber (ADF); total digestible nutrients (TDN); green matter productivity and yield of matter dry. For the experiment with conventional planting density, genetic and phenotypic correlations between the two-to-two traits were estimated, and the direct and indirect effects of these traits on dry matter yield and TDN content. Subsequently, a canonical correlation analysis was performed between the group of characters related to productivity and the group of characters related to silage quality. The increase in density resulted in increase in plant height and a reduction in the size of the ear and biomass produced per plant, however, resulting in higher production per hectare. The AS1596 and AG1051 hybrids presented the best performance, and can be used in the formation of base populations in maize breeding programs for the production and quality of silage, along with hybrids DKB310, BM3061, SHS7920, DKB390, P4285 and RB 9110. A strong relationship was identified between ear components and biomass productivity, and plants with higher grain yields can be used in the indirect selection for dry matter yield. The fiber contents presented a negative correlation with the digestibility of silage and positive with plant height. Knowledge of the indirect effects of the characters between them is important so that the breeder does not make hasty decisions based solely on the correlation estimate. Finally, it is possible to improve maize to simultaneously increase the productivity and the quality of the silage.