Integrated management of clubroot-crucial for sustainable oilseed rape production
Ann-Charlotte Wallenhammar: Rural Economy and Agricultural Sociery (REAS)
<div>Clubroot, caused by the soil borne pathogen <em>Plasmodiophora brassicae</em>, is a serious threat to oil seed rape (OSR) production and the proportion of clubroot infected fields in Sweden is steadily increasing. Control of clubroot is particularly difficult due to the long persistence of the pathogen in soil. The aim is to develop a concept for integrated control of clubroot in winter OSR crops, supported by DNA-technology, by examining and comparing infestation levels and yield of resistant and susceptible varieties. The objective is to provide an improved decision support and guidelines for growing winter OSR in fields where <em>P. brassicae </em>DNA occurs. Resistant varieties are partially resistant<em>,</em> as they are infected at low levels of pathogen inoculum. Three resistant varieties and a seed mixture of susceptible varieties were established in four field trials in August 2017. <em>P. brassicae</em> was identified in these fields at levels ranging from 5000 to 2.5 million target copies g<sup>-1</sup> soil. Soil samples were collected plotwise immediately prior to seeding the trials. Quantification of <em>P. brassicae</em> by qPCR analysis was performed and bioassays were carried out in a greenhouse for a six week period to ensure optimal infection. Plants were sampled plot-wise in late autumn and roots assessed for disease symptoms. Preliminary results show a severe infection in susceptible varieties already at 15 000 target copies g<sup>-1</sup> soil while a low infection occurred at 5000 target copies g<sup>-1</sup> soil.</p> <p></div>
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