DOI: 10.5061/dryad.r2280gbb5
title: Improved control of Septoria tritici blotch in durum wheat using cultivar mixtures

description: Mixtures of cultivars with contrasting levels of resistance can suppress
 infectious diseases in wheat, as demonstrated in numerous field
 experiments. Most studies focused on airborne pathogens in bread wheat,
 while splash-dispersed pathogens have received less attention, and no
 studies have been conducted in durum wheat. We conducted a two-year field
 experiment in Tunisia, to evaluate the performance of cultivar mixtures
 with varying proportions of resistance (0–100%) in controlling the
 polycyclic, splash-dispersed disease Septoria tritici blotch (STB) in
 durum wheat. To measure STB severity, we used a high-throughput method
 based on digital image analysis of 3074 infected leaves collected from 42
 and 40 experimental plots during the first and second years, respectively.
 This allowed us to quantify pathogen reproduction on wheat leaves and to
 acquire a large dataset that exceeds previous studies with respect to
 accuracy and precision. Our analyses show that introducing only 25% of a
 disease-resistant cultivar into a pure stand of a susceptible cultivar
 provides a substantial reduction of almost 50% in disease severity
 compared to the susceptible pure stand. However, comprising the resistant
 component of two cultivars instead of one did not further improve disease
 control, contrary to predictions of epidemiological theory. Susceptible
 cultivars can be agronomically superior to resistant cultivars or be
 better accepted by growers for other reasons. Hence, if mixtures with only
 a moderate proportion of the resistant cultivar provide a similar degree
 of disease control as resistant pure stands, as our analysis indicates,
 such mixtures are more likely to be accepted by growers.
description: The data is collected with automated image analysis of pictures
 of infected leaves. The leaves were collected from experimental plots
 where we tested efficacy of cultivar mixtures in contolling Septoria
 tritici blotch. Subset of the leaf images were visually assessed and
 erroneously analysed leaves were excluded. The source code is provided as
 a python package alongside.
description: Files in the data folder:<br> <br>
 2018_Output_final_flag.xls STB severity data of individual
 leaves in the flag leaf layer, in the experiment in year 2018
 2018_Output_final_flag-1.xls STB severity data of individual
 leaves in the flag-1 leaf layer (penultimate), in the experiment in year
 2018 2018_Tunisia_Cultivar_Mix_Yield_Data.xls
 Yield data in 2018
 2018_Tunisia_cultivar_mixtures_weather.xlsx Weather data in 2018
 2019_Output_final_flag.xls STB severity data of individual
 leaves in the flag leaf layer, in the experiment in year 2019
 2019_Output_final_flag-1.xls STB severity data of individual
 leaves in the flag-1 leaf layer (penultimate), in the experiment in year
 2019 2019_Tunisia_Cultivar_Mix_Yield_Data.xls
 Yield data in 2019
 2019_Tunisia_cultivar_mixtures_weather.xlsx Weather data in 2019
 Cultivar_Mix_severity_means_data_all.xls STB severity, plot means
 Cultivar_Mix_severity_relative_leaf_data_all.xls STB severity data on individual
 leaves, relative to the mean over means of the replicate plots of
 the susceptible treatment (cultivar Karim)
 Cultivar_Mix_severity_relative_means_data_all.xls STB severity data, plot means,
 relative to the mean over means of the replicate plots of the susceptible
 treatment (cultivar Karim)
 Cultivar_Mix_spike_densities.xlsx Spike densities in the plots (per
 square meter)
 Cultivar_Mix_yield_relative_all.xls Yield data, relative to the mean
 over means of the replicate plots of the susceptible treatment (cultivar
 Karim)