Estratificação de ambientes visando otimização da rede de ensaios de híbridos de milho para primeira e segunda safras
Nenhuma Miniatura disponível
Data
2019-07-11
Autores
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Federal de Goiás
Resumo
The environmental stratification process consists of subdividing heterogeneous regions
into more uniform sub-regions with similar ecological characteristics, so that the genotype by
environment interactions (GE) it is predominantly of single nature. Environmental stratification
procedures can be used to verify whether information generated at the testing locations used for
breeding is complementary or redundant. This study was carried out with the objective of
stratifying environments used to select corn hybrids in the final stage of breeding in the Central
region of Brazil, to optimize the multi environment yield trials, in the first and second growing
seasons. Yield data were obtained of 99 and 125 corn hybrids, tested across four years, in 55 and
49 locations, in the first (normal season) and in the second (“safrinha”) seasons, respectively. All
yield trials were conducted in a randomized complete block design with two replicates. The yield
data were submitted to individual and joint analyzes of the experiments, within each year. The
components of variance were estimated and were tested through the Likelihood Test Ratio. The
effect of GE interaction it was significant in all evaluated years, except for “safrinha” 2013. For the
stratification process, two univariate approaches were used; intraclass correlation and prediction
model based on reaction norm; and two multivariate approaches, GGE biplot and Factor Analysis.
The most efficient method for eliminating redundant locations it was one chosen for the final
stratification. Genetic correlation between pairs of location it was estimated by the univariate
approaches. These correlations were used in cluster analysis, applying a SAHN algorithm
(Sequential, Agglomerative, Hierarquic, Nonoverlapping clustering), associated with complete
linkage method, which established the environmental stratification for the both planting seasons. In
the multivariate approaches the environmental stratification were established according to the
“who-won-where” approach and the factor loading established within each factor, for GGE Biplot
and Factor Analysis, respectively. The verification of the established environmental stratification
allowed to identify pairs of locations that were grouped in the same environmental strata, indifferent years of tests, which means redundancy. To optimize the target population of
environments, the GGE Biplot method it was chosen which eliminated 12,5% of yield test
locations in the both seasons.
Descrição
Palavras-chave
Citação
LEPRE, André Luiz. Estratificação de ambientes visando otimização da rede de ensaios de híbridos de milho para primeira e segunda safras. 2019. 114 f. Tese (Doutorado em Genética e Melhoramento de Plantas) - Universidade Federal de Goiás, Goiânia, 2019.