Cleistogamous plants bear flowers that fertilise themselves and set seed without ever opening. This project seeks to find out how well cleistogamous rapeseed prevents gene flow.
It is of critical importance to find out how reliably cleistogamous rapeseed reduces unwanted pollen movement. The project aim is to verify the impact of cleistogamy both on autogamy and pollen dispersal limitation under several climatic and agricultural conditions and cultivation techniques. To do this, two cleistogamous genotypes were tested in the field at five locations (two in the UK, two in Germany and one in France in WP1 of Co-Extra) and under two treatments (with and without application of a growth regulator when the growth is restarting at the end of winter). At the sites, researchers looked at the extent to which flowers stayed shut throughout the entire flowering period, and looked at the extent to which the cleistogamous rapeseed self-pollinated. Since specific cultivars and various environmental conditions could potentially have an effect on the stability and reliability of the cleistogamy trait, it is important to use different cultivars and diverse locations for such trials.
Conventional oilseed rape is a hermaphrodite plant with a highly variable autogamy rate. The autogamy rate seems mainly to depend on the plant genotype, but also depends on environmental conditions. Intraspecific and interspecific cross-pollination can occur and, according to the situation, pollen transfer partly is due to wind or to pollinating insects .
The a priori advantage of cleistogamy (closed flowers) is twofold: firstly, self-pollination is favoured by limiting allopollen deposition on the stigma; secondly, gene flow is reduced by limiting pollen dispersal. The cleistogamous trait was selected from induced mutagenesis in oilseed rape and patented (Renard and Tanguy, 1997). This trait is controlled, for the most part, by one gene (Clg1). Since 1998, several field experiments have been conducted on cleistogamous lines of rapeseed to study the effect of the trait on self- and cross-pollination. Information from these studies has been compiled, and their relevant conclusions are useful in directing new research projects.
The first experiment showed that flowers of cleistogamous lines are mostly totally closed, but a variable proportion of flowers were observed as partially open.
The second multi-site experiment showed that the environment (site x year) had an effect on the pollination, as differences among sites and years were observed.
Pollen containment by cleistogamy in oilseed rape
Public Deliverables of the Co-Extra project
|NAME / ORGANISATION||CONTACT INFORMATION|
Centre Technique Interprofessionnel des Oléagineux Métropolitains (CETIOM), France
|Jacqueline Pierre & Michel Renard|
Institute National de la Recherche Agronomique (INRA), France
|Joachim Schiemann and Alexandra Huesken|
BBA - Federal Biological Research Centre for Agriculture and Forestry, Germany
National Institute of Agricultural Botany (NIAB), United Kingdom