add field experimental design study and protocol

studies/FieldExperimentalDesign/protocols/FieldExperimentalDesignProtocol.md

+## Field Experimental Design
+
+Twenty-three spring barley (*Hordeum vulgare*) inbred lines (inbreds) were selected from a worldwide collection of 224 barley landraces and cultivars based on their genetic and phenotypic diversity (Weisweiler et al., 2019). These 23 barley inbreds are the parents of the double round-robin population (Casale et al., 2022). All 23 inbreds were grown at three different locations [Bonn (50°37ʹ31.82″ N 6°59ʹ18.508″ E), Cologne (50°57ʹ34.345″ N 6°51ʹ36.407″ E), and Düsseldorf (51°10ʹ42.599″ N 6°48ʹ8.268″ E)] in Germany in 2021. In Bonn, the experimental design was an α-design with two complete replications, where the plants were sown in 10 m2 plots on 31 March 2021. In Düsseldorf, the experimental design was an α-design with three complete replications. The experimental units were single rows with 33 kernels per row, and six rows together were considered as one plot (replicate). The plants in Düsseldorf were sown on 31 March 2021. In Cologne, two distinct trials were performed, which are named in the following as ‘mini-big plot’ and ‘big plot’ trials. Within each of these two trials, 23 inbreds were grown as replicated checks in an augmented design. In the mini-big plot trial, each plot had a size of 2.25 m2. The entire mini-big plot trial had 320 plots, in which the 23 inbreds were grown as replicated checks twice. The big plot trial, in which each plot had a size of 10 m2, comprised also 320 plots and the 23 inbreds were also grown as checks but only one time. Fertilization and crop protection followed local practices. Air temperature and precipitation were recorded during the field experiments at all three locations (Supplementary Fig. S1). In Bonn, the field site has chernozem-para-brown soil, and the field sites, in Cologne and Düsseldorf, have para-brown soil (Bundesanstalt für Geowissenschaften und Rohstoffe).
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