Forschungs- & Entwicklungsinformationsdienst der Gemeinschaft - CORDIS

Updated phenotyping methodology

Our goal was to compare, evaluate and improve artificial inoculation techniques of the participating partners (if necessary). The partners involved in this project have in part different inoculation techniques to investigate FHB resistance. Most of them use irrigation to apply moisture to improve infection. Inoculum is applied by spraying, or diseased plant residues are distributed on the soil. From the latter crop debris spores can infect the wheat ears. P1 and P5 apply the inoculum at flowering time of each individual genotype, whereas the other partners repeatedly spray all lines simultaneously during the flowering period of the lines.

Also the evaluation system was different. P1 and P5 evaluate each line at well defined time points after flowering, whereas the other partners evaluate all wheat lines at the same time independently from the exact flowering date. Also the assessment system (data scale) was different.

On top of that, it is well known that FHB resistance testing is influenced by environmental conditions. The resistance data of the different seasons assessed by each individual partner were in general highly correlated, indicating that the inoculation techniques result in similar or comparable resistance data over years (good repeatability).

In general the data of each partner were also highly correlated with the “true” resistance of the genotypes, indicating that each partner assesses the “correct” resistance level (good accuracy). Taken all these differences in inoculation methodology, assessment method and also locations and years into account, we were surprised that the resistance data of the different partners related pretty well. Interesting are the high correlation coefficients among the data from the breeders (P2, P3 and P4).

The data from the scientific partner P1 significantly correlate with the data from P2, P3 and P4. The data of P5 showed lower correlation with the resistance data of the breeders and only moderate correlations with P1. It is at present not clear what might be the reason for this. All breeders spray the inoculum several times during the flowering period, and assess the resistance of all lines at the same time point. This might be the reason why the data of the those partners correlate well with each other, but less with the data of Partner 1 and 5.

The latter partners inoculate and evaluate each individual wheat line at precise time points during and after flowering. Late flowering and therefore late inoculated wheat lines might show less symptoms as compared to the early wheat lines, simply because the period of time for disease development is shorter for the late genotypes. Partner 1 uses extensive mist irrigation to improve infection success. The late genotypes are irrigated during a shorter time period after inoculation as compared with the early genotypes.

This might result in a stronger disease level on the early genotypes. P5 uses bags to cover the inoculated ears with after inoculation. If inoculation is done during the morning temperature might rise in the bags on sunny days. This factor might influence infection if temperature in the bags would be to high due to strong insolation. These considerations should illustrate that there exist further possibilities to improve our inoculation methodology. The investigated wheat lines could be grouped according to flowering time in order to reduce mist irrigation to a minimum.

A small set of wheat lines could be incorporated as standards or controls to compare infection success of different inoculation days: especially cold temperatures reduce infection success, and temperature between different inoculation days might vary significantly. Other methods of inoculum application such as the distribution of Fusarium infected plant debris should be considered.

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IFA-Tulln
Konrad-Lorenz-Str. 20
3430 Tulln
Austria
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