Analysis of field trials

These training matetrials for the analysis of field trials were developed by Jose Crossa of the Biometrics & Statistics Unit, Crop Informatics Laboratory, CIMMYT and Fred van Eeuwijk and Marcos Malosetti of Biometris, Wageningen University and Research Centre.

The materials cover three areas:

Field experimental design in agriculture

The study of strategies for efficient plans for the collection of data, which lead to proper estimates of parameters relevant to the researcher’s objective, is known as experimental design. A properly designed experiment, for a particular research objective, is the basis of success. This document reviews the fundamentals of experimental design and planning, with illustrative diagrams and tables.

Design and analysis of single trials with mixed models

This is a comprehensive presentation that analyses various experimental designs and the analysis of the same.

Practical single trial and GxE analysis

The objective of this practical is to learn how to analyse single trials taking into account their design and how to compile results from single trial analyses in such a way that a multiple trial analysis becomes possible. The practical follows a two stage approach with in the first stage analysis of individual trials to produce predictions (means) per genotype, which are used in the second stage of the analysis for studying GxE. The practical guides you on how to perform stage 1 using the Preliminary Single Environment Analysis menu in the QTL library of GenStat 14, how to perform different analyses and how to use diagnostics to arrive at a model and interpretation of GxE. A data set produced for wheat stressed trials in Mexico is used as an example.

All these resources, together with the example data set, are available for download below.

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