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Trial heterogeneity and variance models in the genetic evaluation of potato tuber yield
Author(s) -
Paget Mark F.,
Alspach Peter A.,
Anderson John A.D.,
Genet Russell A.,
Apiolaza Luis A.
Publication year - 2015
Publication title -
plant breeding
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.583
H-Index - 71
eISSN - 1439-0523
pISSN - 0179-9541
DOI - 10.1111/pbr.12251
Subject(s) - biology , yield (engineering) , selection (genetic algorithm) , variance (accounting) , analysis of variance , genetic variability , statistics , microbiology and biotechnology , agronomy , genotype , mathematics , genetics , materials science , business , accounting , artificial intelligence , computer science , metallurgy , gene
Genetic evaluation aims to identify genotypes with high empirical breeding values ( EBV s) for selection as parents. In this study, 2157 potato genotypes were evaluated for tuber yield using 8 years of early‐stage trial data collected from a potato breeding programme. Using linear mixed models, spatial parameters to target greater control of localised spatial heterogeneity within trials were estimated and variance models to account for across‐trial genetic heterogeneity were tested. When spatial components improved model fit, correlations of errors were mostly small and negative for marketable tuber yield ( MTY ) and total tuber yield ( TTY ), suggesting the presence of interplot competition in some years. For the analysis of multi‐environment trials, a variance model with a simple correlation structure (with heterogeneous variances) was the most favourable variance structure fitted for TTY and PTY (per cent marketable yield). There was very little difference in model fit when comparing a factor analytic structure of order 2 ( FA 2) with either FA 1 or simple correlation structures for MTY , indicating that simple variance models may be preferable for early‐stage genetic evaluation of potato yield.