Oilseed rape with low persistence – a strategy for controlling gene transfer through volunteer rape

(2008 - 2011) University of Hohenheim, Faculty of Agricultural Science, Institute for Crop Production and Grassland Research, Stuttgart

Topic

Seeds from the crop plant oilseed rape can survive for a long time in the soil, and often do not germinate until years later, appearing as volunteer plants in the following crops. This can lead to adventitious mixing and outcrosses in subsequent oilseed rape crops.

The aim of this project is to test whether, and to what extent, the cultivation of oilseed rape lines with little or no persistence (secondary dormancy ) reduces the occurrence of volunteer rape plants in the crop rotation, thereby preventing varieties becoming mixed e.g. with transgenic traits, within an oilseed rape crop.

The project will develop reliable laboratory and field methods which

identify genotypes with low persistence in the rape variety spectrum and
determine the suitability and stability of this trait for reducing volunteer rape under field conditions with conventional rape.

Experiment description

After the harvest, the weight of self-sown rape (seeds) is measured.

An estimation frame is used to assess germinated self-sown oilseed rape after the harvest.

Photos above: Albrecht Weber, University of Hohenheim

In order to test rape varieties for the secondary dormancy trait, seeds are buried for six months.

Photo: Kirstin Frick, University of Hohenheim

The following projects will be carried out on the basis of a multi-stage methodological approach using laboratory, greenhouse and field trials:

Assessing oilseed rape varieties for the secondary dormancy trait and selection of non-dormant genotypes. In addition to conventional genotypes, two transgenic lines and their isogenic check lines will be examined in the laboratory. A quick test for dormancy will also be developed.
Developing an on-farm estimation frame and model for predicting the occurrence of volunteer rape in the crop rotation. Data will be collected on farms growing conventional oilseed rape. The data collected will include the level of shattering losses during threshing and the level of the soil seed bank.
Crop rotation experiments to establish the persistence of rape seeds and the occurrence and fitness of conventional volunteer rape in subsequent oilseed rape crops. Volunteer rape will be deliberately established with conventional varieties in various different agricultural crops. The number of volunteers will then be quantified by crop species and the fitness level in the plant population in question will be assessed.

The project is part of the joint project on "Developing and testing confinement strategies for oilseed rape". The network partners - the University of Hohenheim, the University of Göttingen and the Julius Kühn-Institut (JKI) - are collaborating on laboratory analyses, the use of trial fields and data exchange for modelling.