Methods Useful in Self-Incompatibility
More specific methods useful in overcoming self-incompatibility are mentioned below
1. Bud Pollination: In Petunia axillaris early self-pollination of buds leads to normal fertilization.
2. Modification of Stigmatic Surface: Application of the lectin, concanavalin A, to stigma is also helpful in overcoming incompatibility in Brassica. Likewise, prior treatment of stigma with detergent, and organic solvent (hexane) helps to modify the incompatibility reaction. Pretreatment of stigma with NaCl (15g/l) in Brassica campestris blocks the incompatibility reaction.
3. Heat Treatment of Style: In Lilium longiflorum pre-treatment of the style at 50" C for 6 min. could prevent self incompatibility. In rye, even 30" C is effective in inhibiting the incompatibility reaction.
4. Irradiation: Incompatibility in Lycopersicon peruvianum could be overcome by gamma rays. The higher seed-set per plant achieved by this method is ascribed to prevention of flower abscission at early stage. Irradiation seems to be fruitful only in plants where incompatibility is under the control of gametophyte.
5. Increased CO2 Level: In Brassica species, raising of atmospheric level of CO2 by 100 fold, at 100% relative humidity helps to overcome self incompatibility. This method is an important tool to maintain the inbred parental lines of Brassica for the production of S1 hybrid seeds.
6. Parasexual Hybridization: As it includes the hybridization of somatic cells (protoplast) to conquer sexual incompatibility this is termed as "parasexual hybridization".