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More, Larger, Simpler: How Comparable Are On‐Farm and On‐Station Trials for Cultivar Evaluation?
Author(s) -
Schmidt P.,
Möhring J.,
Koch R. J.,
Piepho H.-P.
Publication year - 2018
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci2017.09.0555
Subject(s) - cultivar , biology , yield (engineering) , brassica , microbiology and biotechnology , gene–environment interaction , agronomy , field trial , variance (accounting) , statistics , genotype , mathematics , genetics , gene , materials science , business , accounting , metallurgy
Traditionally, cultivar evaluation trials have been conducted as replicated small‐plot, on‐station trials at multiple locations and years. To this day, this is the method of choice for cultivar registration trials conducted by official federal institutes. Given a different purpose (e.g., marketing), cultivar evaluation may also be done as on‐farm trials with single replicates and fewer plots laid out as large strips. Such trials are often conducted at a larger number of locations. It is not clear how comparable these two trial systems are. Our objective therefore was to compare the precision and accuracy of these two systems using yield data from both on‐farm trials and from official on‐station trials for winter oilseed rape ( Brassica napus L.) across 8 yr. We set up multivariate mixed models to analyze the combined dataset of both trial systems and estimate heterogeneous variance components. Furthermore, based on 23 hybrid genotypes common to both datasets, we investigated the genetic correlation between systems and tested for genotype × system interaction effects. The results suggest that on‐farm trials are comparable with on‐station trials in terms of precision of a single plot, but that there are genotype × system interaction effects prohibiting the comparison of yield estimates for genotypes between systems. One potential explanation for this difference was identified as the system‐specific group effect of semidwarf vs. long‐strawed genotypes.