An evaluation of screening techniques to assess Fusarium head blight resistance in spring wheat (Triticum aestivum L.)

Abstract

The primary objective of this research was to determine which of two inoculation methods (the spray method and the injection method) was the better one to use in a head blight screening programme. Although our data did not reveal any clearcut difference between them in terms of their ability to create a disease situation or to generate a consistent ranking of test genotypes, there were, nevertheless, important differences between the two methods. The spray method was the only method that allowed the acquisition of performance data, such as grain yield per plot. In addition, the number of test genotypes that could be inoculated per unit of time was about five times greater with the the spray method than it was with the injection method. The data from these trials did not provide convincing evidence for, or against, the inclusion of post-inoculation covering in an artificial head blight screening protocol. Measures of agronomic impact, such as relative yield reduction, were more closely correlated with plant-based measures of head blight than with seed-based measures. The correlation between relative yield reduction and head blight severity measured 22 days post-inoculation was +0,95 and this was significantly (P<0.05) higher than any of the correlations involving seed-based measures. The inference from these results is that FHB severity recorded at about 3 weeks after inoculation may be the best method of quantifying the level of head blight resistance in test genotypes.