Agroscope | 2014
Type II resistance against Fusarium head blight in the Toronit x 211.12014 mapping population
Charlotte Martin1, Susanne Vogelgsang2, Brigitte Mauch-Mani3 and Fabio Mascher1
1Institute for Plant Production Sciences, Agroscope
2Institute for Sustainability Sciences, Agroscope
3Institute of Biology, University of Neuchâtel
Wheat disposes of different resistance mechanisms against Fusarium Head Blight (FHB). A resistance against the primary pathogen infection during anthesis is considered as type I mechanism. In contrast, the type II resistance limits the propagation of the infection throughout the spike. Toronit is a spring wheat variety, known for its resistance in the field. The aims of this study is to determine the genetic basis of this resistance. For this, the wheat mapping population Toronit x “211.12014”, the latter being a highly FHB susceptible line, grouping 165 double haploid lines, is investigated. Description of these lines, particularly stem height and precocity, infection and symptoms notations are intended to understand resistance mechanisms, and relating them to other characters. The interest is to understand their heritability. This part of the study focuses on type II resistance.
Materials and methods
To evaluate type II resistance, spikes of 165 lines growing in the greenhouse were infected by applying a Fusarium graminearum soaked cotton dabber into the spikelet (Fig 1a).
By placing the inoculum directly into the spikelet, the type I resistance can be bypassed. Thus, it is possible to observe the spreading of the pathogen throughout the spike.
The disease propagation was noted by counting the number of infected spikelets every 3 days. The “Relative Area Under Disease Progression Curve” AUDPCrel was calculated for each line. Stem height and precocity were also been scored.
Fig 1 a: Infection of a spikelet by placing a piece of cotton soaked with a F. graminearum suspension into the spikelet.
b: First infected spikelet 5 days after infection.
c: Propagation of the infection into further spikelets.
Fig 2. Disease severity in the 165 lines expressed as relative AUDPC obtained in 3 independent trials in the greenhouse. Low AUDPC values indicate a higher resistance level of the plants.
Fig 3 a: Relationship between AUDPCrel and lines stem height.
b: Relationship between AUDPCrel and precocity.
a
The first results show significant differences for type II resistance between lines (P < 0.05). Some of these lines showed even higher resistance than Toronit, the resistant parent. AUDPCrel values were not correlated neither with stem height nor with precocity.
• The significant differences in disease resistance allow the study of the underlying mechanisms and their heritability with the Toronit x 211.12014 mapping population.
• Type II resistance is not linked with stem height or precocity.
• Besides a screening of type I resistances, future studies will focus on the role of the high concentration of luteins in cv. Toronit for FHB resistance in the plant and in the grains.
r = 0.040
Stem height (cm)
AUDPCrel
b
r = 0.152
Precocity
AUDPCrel
Photo : C.Parodi AGROSCOPE
