Progresso genético de caracteres agronômicos do arroz irrigado em Minas Gerais entre 1998 e 2012

• Ano de defesa: 2013
• Autor(a) principal: Reis, Gabriel Gonçalves dos
• Orientador(a): Fritsche Neto, Roberto
• Banca de defesa: Carneiro, Pedro Crescêncio Souza
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Fitotecnia
• Departamento: Plantas daninhas, Alelopatia, Herbicidas e Resíduos; Fisiologia de culturas; Manejo pós-colheita de
• País: BR
• Palavras-chave em Português: Valor de cultivo e uso; REML/BLUP; Estratégias de melhoramento
• Palavras-chave em Inglês: Value for cultivation and use; REML/BLUP; Strategies for improvement
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA
• Link de acesso: http://locus.ufv.br/handle/123456789/4615

Every year, at trials called as value for cultivation and use (VCU s), new rice lines, which have potential to be recommended for the rice farmers, are inserted and evaluated, joining the remaining ones from the last year. Therefore, it is possible to evaluate the genetic progress of the important characters for the crop. This estimative indicates the effectiveness of the selection and the necessity of using new selection methods and strategy. Thus, the objective was estimating the genetic progress of agronomic characters of the irrigated rice breeding program at the state of Minas Gerais between 1998 and 2012. For this, it were evaluated the characters: productivity of grains (Kg.ha-1), 100-grain weight (g), plant height (cm), days until flowering (days), tillering(notes) andlodging (notes) of 108 rice lines of ACT s conduced at randomized block design, with three to four repetitions, at four different regions of Minas Gerais between the years of 1998 and 2012. Not all the sites were included in all crop years, according to their selective accuracy. To obtain true estimates of the genetic values it was used the technic REML/BLUP. The genotypes were evaluated at the sites in every year and between the years through the deviance analyses. After, it was estimated the environmental and genetic progress. There was a significant effect for genotype effect and of the interaction genotype x site and genotype x year. The genetic progress observed during the period was: 195,91 kg.ha-1; 0,10 g; 1,50 cm; 3,17 day; -0,01 points; and, -0,18 points, for productivity, 100-grain weight, plant height, days until flowering, tillering and lodging, respectively. Even though the results were satisfactory, new strategies should be employed, such as increase the genetic base of the program, increase of the repetition number, latice design, use of selection indexes, increase of the substitution rate and reduction of the maintaining rate of the rice lines of the program.