INVESTIGADORES
BALZARINI Monica Graciela
artículos
Título:
Error variation in multi-environment peanut trials: within-trial spatial correlation and between-trial heterogeneity
Autor/es:
CASANOVES F; MACCHIAVELLI R; BALZARINI M
Revista:
CROP SCIENCE
Editorial:
HighWire Press Stanford University
Referencias:
Lugar: California; Año: 2005 vol. 45 p. 1927 - 1933
ISSN:
0011-183X
Resumen:
Multienvironment Trials (MET) are used to make cultivar recom-
mendations about genotypes in plant breeding programs. Because of
the presence of genotype-environment interaction, METs are usu-
ally conducted in multiple environments using designs that involve several
replications per environment. Blocking of plots within each
trial enables one to account for between plot variation. To improve
the comparison of genotype means, taking into account within-trial
spatial correlation as well as between-trial residual variance hetero-
geneity, alternative mixed models can be used. The objective of this study was to compare several spatial models, including or excluding variheterogeneity
of residual variances for cultivar evaluation in a set of
independent peanut (Arachis hypogaea L.) METs. The modeling im-
pact was evaluated by comparing genotype means from each trial. A
series of 18 METs from a peanut breeding program, as according to a
randomized complete block design (RCBD) at each location, were
simultaneously fitted by (i) a classic analysis of variance model for an
RCBD with blocks random and (ii) mixed models incorporating spa-
tial correlation through isotropic and anisotropic covariance structures for
the error terms (power correlation function) and including homog-
enous and heterogeneous residual variances to take into account the different environments having different precision. Results suggest that
the model with stationary anisotropic error structure AR1xAR1 within
each environment and heterogeneous residual variances constitutes
a good alternative analysis for METs, but it was not always better
than the RCBD models for peanut. Differences were found between
long- and short-cycle peanut cultivars with respect to the best model.